cell/spufs/file.c

/*
 * SPU file system -- file contents
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>

#include <asm/io.h>
#include <asm/time.h>
#include <asm/spu.h>
#include <asm/spu_info.h>
#include <asm/uaccess.h>

#include "spufs.h"
#include "sputrace.h"

#define SPUFS_MMAP_4K (PAGE_SIZE == 0x1000)

/* Simple attribute files */
struct spufs_attr {
	int (*get)(void *, u64 *);
	int (*set)(void *, u64);
	char get_buf[24];       /* enough to store a u64 and "\n\0" */
	char set_buf[24];
	void *data;
	const char *fmt;        /* format for read operation */
	struct mutex mutex;     /* protects access to these buffers */
};

static int spufs_attr_open(struct inode *inode, struct file *file,
		int (*get)(void *, u64 *), int (*set)(void *, u64),
		const char *fmt)
{
	struct spufs_attr *attr;

	attr = kmalloc(sizeof(*attr), GFP_KERNEL);
	if (!attr)
		return -ENOMEM;

	attr->get = get;
	attr->set = set;
	attr->data = inode->i_private;
	attr->fmt = fmt;
	mutex_init(&attr->mutex);
	file->private_data = attr;

	return nonseekable_open(inode, file);
}

static int spufs_attr_release(struct inode *inode, struct file *file)
{
       kfree(file->private_data);
	return 0;
}

static ssize_t spufs_attr_read(struct file *file, char __user *buf,
		size_t len, loff_t *ppos)
{
	struct spufs_attr *attr;
	size_t size;
	ssize_t ret;

	attr = file->private_data;
	if (!attr->get)
		return -EACCES;

	ret = mutex_lock_interruptible(&attr->mutex);
	if (ret)
		return ret;

	if (*ppos) {		/* continued read */
		size = strlen(attr->get_buf);
	} else {		/* first read */
		u64 val;
		ret = attr->get(attr->data, &val);
		if (ret)
			goto out;

		size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
				 attr->fmt, (unsigned long long)val);
	}

	ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
out:
	mutex_unlock(&attr->mutex);
	return ret;
}

static ssize_t spufs_attr_write(struct file *file, const char __user *buf,
		size_t len, loff_t *ppos)
{
	struct spufs_attr *attr;
	u64 val;
	size_t size;
	ssize_t ret;

	attr = file->private_data;
	if (!attr->set)
		return -EACCES;

	ret = mutex_lock_interruptible(&attr->mutex);
	if (ret)
		return ret;

	ret = -EFAULT;
	size = min(sizeof(attr->set_buf) - 1, len);
	if (copy_from_user(attr->set_buf, buf, size))
		goto out;

	ret = len; /* claim we got the whole input */
	attr->set_buf[size] = '\0';
	val = simple_strtol(attr->set_buf, NULL, 0);
	attr->set(attr->data, val);
out:
	mutex_unlock(&attr->mutex);
	return ret;
}

#define DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)	\
static int __fops ## _open(struct inode *inode, struct file *file)	\
{									\
	__simple_attr_check_format(__fmt, 0ull);			\
	return spufs_attr_open(inode, file, __get, __set, __fmt);	\
}									\
static const struct file_operations __fops = {				\
	.owner	 = THIS_MODULE,						\
	.open	 = __fops ## _open,					\
	.release = spufs_attr_release,					\
	.read	 = spufs_attr_read,					\
	.write	 = spufs_attr_write,					\
};


static int
spufs_mem_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = ctx;
	if (!i->i_openers++)
		ctx->local_store = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static int
spufs_mem_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->local_store = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static ssize_t
__spufs_mem_read(struct spu_context *ctx, char __user *buffer,
			size_t size, loff_t *pos)
{
	char *local_store = ctx->ops->get_ls(ctx);
	return simple_read_from_buffer(buffer, size, pos, local_store,
					LS_SIZE);
}

static ssize_t
spufs_mem_read(struct file *file, char __user *buffer,
				size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	ssize_t ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ret = __spufs_mem_read(ctx, buffer, size, pos);
	spu_release(ctx);

	return ret;
}

static ssize_t
spufs_mem_write(struct file *file, const char __user *buffer,
					size_t size, loff_t *ppos)
{
	struct spu_context *ctx = file->private_data;
	char *local_store;
	loff_t pos = *ppos;
	int ret;

	if (pos < 0)
		return -EINVAL;
	if (pos > LS_SIZE)
		return -EFBIG;
	if (size > LS_SIZE - pos)
		size = LS_SIZE - pos;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;

	local_store = ctx->ops->get_ls(ctx);
	ret = copy_from_user(local_store + pos, buffer, size);
	spu_release(ctx);

	if (ret)
		return -EFAULT;
	*ppos = pos + size;
	return size;
}

static int
spufs_mem_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct spu_context *ctx	= vma->vm_file->private_data;
	unsigned long address = (unsigned long)vmf->virtual_address;
	unsigned long pfn, offset;

#ifdef CONFIG_SPU_FS_64K_LS
	struct spu_state *csa = &ctx->csa;
	int psize;

	/* Check what page size we are using */
	psize = get_slice_psize(vma->vm_mm, address);

	/* Some sanity checking */
	BUG_ON(csa->use_big_pages != (psize == MMU_PAGE_64K));

	/* Wow, 64K, cool, we need to align the address though */
	if (csa->use_big_pages) {
		BUG_ON(vma->vm_start & 0xffff);
		address &= ~0xfffful;
	}
#endif /* CONFIG_SPU_FS_64K_LS */

	offset = vmf->pgoff << PAGE_SHIFT;
	if (offset >= LS_SIZE)
		return VM_FAULT_SIGBUS;

	pr_debug("spufs_mem_mmap_fault address=0x%lx, offset=0x%lx\n",
			address, offset);

	if (spu_acquire(ctx))
		return VM_FAULT_NOPAGE;

	if (ctx->state == SPU_STATE_SAVED) {
		vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
		pfn = vmalloc_to_pfn(ctx->csa.lscsa->ls + offset);
	} else {
		vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
		pfn = (ctx->spu->local_store_phys + offset) >> PAGE_SHIFT;
	}
	vm_insert_pfn(vma, address, pfn);

	spu_release(ctx);

	return VM_FAULT_NOPAGE;
}

static int spufs_mem_mmap_access(struct vm_area_struct *vma,
				unsigned long address,
				void *buf, int len, int write)
{
	struct spu_context *ctx = vma->vm_file->private_data;
	unsigned long offset = address - vma->vm_start;
	char *local_store;

	if (write && !(vma->vm_flags & VM_WRITE))
		return -EACCES;
	if (spu_acquire(ctx))
		return -EINTR;
	if ((offset + len) > vma->vm_end)
		len = vma->vm_end - offset;
	local_store = ctx->ops->get_ls(ctx);
	if (write)
		memcpy_toio(local_store + offset, buf, len);
	else
		memcpy_fromio(buf, local_store + offset, len);
	spu_release(ctx);
	return len;
}

static const struct vm_operations_struct spufs_mem_mmap_vmops = {
	.fault = spufs_mem_mmap_fault,
	.access = spufs_mem_mmap_access,
};

static int spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
{
#ifdef CONFIG_SPU_FS_64K_LS
	struct spu_context	*ctx = file->private_data;
	struct spu_state	*csa = &ctx->csa;

	/* Sanity check VMA alignment */
	if (csa->use_big_pages) {
		pr_debug("spufs_mem_mmap 64K, start=0x%lx, end=0x%lx,"
			 " pgoff=0x%lx\n", vma->vm_start, vma->vm_end,
			 vma->vm_pgoff);
		if (vma->vm_start & 0xffff)
			return -EINVAL;
		if (vma->vm_pgoff & 0xf)
			return -EINVAL;
	}
#endif /* CONFIG_SPU_FS_64K_LS */

	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);

	vma->vm_ops = &spufs_mem_mmap_vmops;
	return 0;
}

#ifdef CONFIG_SPU_FS_64K_LS
static unsigned long spufs_get_unmapped_area(struct file *file,
		unsigned long addr, unsigned long len, unsigned long pgoff,
		unsigned long flags)
{
	struct spu_context	*ctx = file->private_data;
	struct spu_state	*csa = &ctx->csa;

	/* If not using big pages, fallback to normal MM g_u_a */
	if (!csa->use_big_pages)
		return current->mm->get_unmapped_area(file, addr, len,
						      pgoff, flags);

	/* Else, try to obtain a 64K pages slice */
	return slice_get_unmapped_area(addr, len, flags,
				       MMU_PAGE_64K, 1, 0);
}
#endif /* CONFIG_SPU_FS_64K_LS */

static const struct file_operations spufs_mem_fops = {
	.open			= spufs_mem_open,
	.release		= spufs_mem_release,
	.read			= spufs_mem_read,
	.write			= spufs_mem_write,
	.llseek			= generic_file_llseek,
	.mmap			= spufs_mem_mmap,
#ifdef CONFIG_SPU_FS_64K_LS
	.get_unmapped_area	= spufs_get_unmapped_area,
#endif
};

static int spufs_ps_fault(struct vm_area_struct *vma,
				    struct vm_fault *vmf,
				    unsigned long ps_offs,
				    unsigned long ps_size)
{
	struct spu_context *ctx = vma->vm_file->private_data;
	unsigned long area, offset = vmf->pgoff << PAGE_SHIFT;
	int ret = 0;

	spu_context_nospu_trace(spufs_ps_fault__enter, ctx);

	if (offset >= ps_size)
		return VM_FAULT_SIGBUS;

	if (fatal_signal_pending(current))
		return VM_FAULT_SIGBUS;

	/*
	 * Because we release the mmap_sem, the context may be destroyed while
	 * we're in spu_wait. Grab an extra reference so it isn't destroyed
	 * in the meantime.
	 */
	get_spu_context(ctx);

	/*
	 * We have to wait for context to be loaded before we have
	 * pages to hand out to the user, but we don't want to wait
	 * with the mmap_sem held.
	 * It is possible to drop the mmap_sem here, but then we need
	 * to return VM_FAULT_NOPAGE because the mappings may have
	 * hanged.
	 */
	if (spu_acquire(ctx))
		goto refault;

	if (ctx->state == SPU_STATE_SAVED) {
		up_read(&current->mm->mmap_sem);
		spu_context_nospu_trace(spufs_ps_fault__sleep, ctx);
		ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
		spu_context_trace(spufs_ps_fault__wake, ctx, ctx->spu);
		down_read(&current->mm->mmap_sem);
	} else {
		area = ctx->spu->problem_phys + ps_offs;
		vm_insert_pfn(vma, (unsigned long)vmf->virtual_address,
					(area + offset) >> PAGE_SHIFT);
		spu_context_trace(spufs_ps_fault__insert, ctx, ctx->spu);
	}

	if (!ret)
		spu_release(ctx);

refault:
	put_spu_context(ctx);
	return VM_FAULT_NOPAGE;
}

#if SPUFS_MMAP_4K
static int spufs_cntl_mmap_fault(struct vm_area_struct *vma,
					   struct vm_fault *vmf)
{
	return spufs_ps_fault(vma, vmf, 0x4000, SPUFS_CNTL_MAP_SIZE);
}

static const struct vm_operations_struct spufs_cntl_mmap_vmops = {
	.fault = spufs_cntl_mmap_fault,
};

/*
 * mmap support for problem state control area [0x4000 - 0x4fff].
 */
static int spufs_cntl_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_cntl_mmap_vmops;
	return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_cntl_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_cntl_get(void *data, u64 *val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	*val = ctx->ops->status_read(ctx);
	spu_release(ctx);

	return 0;
}

static int spufs_cntl_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->runcntl_write(ctx, val);
	spu_release(ctx);

	return 0;
}

static int spufs_cntl_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = ctx;
	if (!i->i_openers++)
		ctx->cntl = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return simple_attr_open(inode, file, spufs_cntl_get,
					spufs_cntl_set, "0x%08lx");
}

static int
spufs_cntl_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	simple_attr_release(inode, file);

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->cntl = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static const struct file_operations spufs_cntl_fops = {
	.open = spufs_cntl_open,
	.release = spufs_cntl_release,
	.read = simple_attr_read,
	.write = simple_attr_write,
	.mmap = spufs_cntl_mmap,
};

static int
spufs_regs_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	file->private_data = i->i_ctx;
	return 0;
}

static ssize_t
__spufs_regs_read(struct spu_context *ctx, char __user *buffer,
			size_t size, loff_t *pos)
{
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	return simple_read_from_buffer(buffer, size, pos,
				      lscsa->gprs, sizeof lscsa->gprs);
}

static ssize_t
spufs_regs_read(struct file *file, char __user *buffer,
		size_t size, loff_t *pos)
{
	int ret;
	struct spu_context *ctx = file->private_data;

	/* pre-check for file position: if we'd return EOF, there's no point
	 * causing a deschedule */
	if (*pos >= sizeof(ctx->csa.lscsa->gprs))
		return 0;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	ret = __spufs_regs_read(ctx, buffer, size, pos);
	spu_release_saved(ctx);
	return ret;
}

static ssize_t
spufs_regs_write(struct file *file, const char __user *buffer,
		 size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	if (*pos >= sizeof(lscsa->gprs))
		return -EFBIG;

	size = min_t(ssize_t, sizeof(lscsa->gprs) - *pos, size);
	*pos += size;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;

	ret = copy_from_user((char *)lscsa->gprs + *pos - size,
			     buffer, size) ? -EFAULT : size;

	spu_release_saved(ctx);
	return ret;
}

static const struct file_operations spufs_regs_fops = {
	.open	 = spufs_regs_open,
	.read    = spufs_regs_read,
	.write   = spufs_regs_write,
	.llseek  = generic_file_llseek,
};

static ssize_t
__spufs_fpcr_read(struct spu_context *ctx, char __user * buffer,
			size_t size, loff_t * pos)
{
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	return simple_read_from_buffer(buffer, size, pos,
				      &lscsa->fpcr, sizeof(lscsa->fpcr));
}

static ssize_t
spufs_fpcr_read(struct file *file, char __user * buffer,
		size_t size, loff_t * pos)
{
	int ret;
	struct spu_context *ctx = file->private_data;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	ret = __spufs_fpcr_read(ctx, buffer, size, pos);
	spu_release_saved(ctx);
	return ret;
}

static ssize_t
spufs_fpcr_write(struct file *file, const char __user * buffer,
		 size_t size, loff_t * pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	if (*pos >= sizeof(lscsa->fpcr))
		return -EFBIG;

	size = min_t(ssize_t, sizeof(lscsa->fpcr) - *pos, size);

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;

	*pos += size;
	ret = copy_from_user((char *)&lscsa->fpcr + *pos - size,
			     buffer, size) ? -EFAULT : size;

	spu_release_saved(ctx);
	return ret;
}

static const struct file_operations spufs_fpcr_fops = {
	.open = spufs_regs_open,
	.read = spufs_fpcr_read,
	.write = spufs_fpcr_write,
	.llseek = generic_file_llseek,
};

/* generic open function for all pipe-like files */
static int spufs_pipe_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	file->private_data = i->i_ctx;

	return nonseekable_open(inode, file);
}

/*
 * Read as many bytes from the mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 */
static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 mbox_data, __user *udata;
	ssize_t count;

	if (len < 4)
		return -EINVAL;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	udata = (void __user *)buf;

	count = spu_acquire(ctx);
	if (count)
		return count;

	for (count = 0; (count + 4) <= len; count += 4, udata++) {
		int ret;
		ret = ctx->ops->mbox_read(ctx, &mbox_data);
		if (ret == 0)
			break;

		/*
		 * at the end of the mapped area, we can fault
		 * but still need to return the data we have
		 * read successfully so far.
		 */
		ret = __put_user(mbox_data, udata);
		if (ret) {
			if (!count)
				count = -EFAULT;
			break;
		}
	}
	spu_release(ctx);

	if (!count)
		count = -EAGAIN;

	return count;
}

static const struct file_operations spufs_mbox_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_mbox_read,
};

static ssize_t spufs_mbox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	ssize_t ret;
	u32 mbox_stat;

	if (len < 4)
		return -EINVAL;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;

	mbox_stat = ctx->ops->mbox_stat_read(ctx) & 0xff;

	spu_release(ctx);

	if (copy_to_user(buf, &mbox_stat, sizeof mbox_stat))
		return -EFAULT;

	return 4;
}

static const struct file_operations spufs_mbox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_mbox_stat_read,
};

/* low-level ibox access function */
size_t spu_ibox_read(struct spu_context *ctx, u32 *data)
{
	return ctx->ops->ibox_read(ctx, data);
}

static int spufs_ibox_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;

	return fasync_helper(fd, file, on, &ctx->ibox_fasync);
}

/* interrupt-level ibox callback function. */
void spufs_ibox_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	if (!ctx)
		return;

	wake_up_all(&ctx->ibox_wq);
	kill_fasync(&ctx->ibox_fasync, SIGIO, POLLIN);
}

/*
 * Read as many bytes from the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * any data is available, but return when we have been able to
 * read something.
 */
static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 ibox_data, __user *udata;
	ssize_t count;

	if (len < 4)
		return -EINVAL;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	udata = (void __user *)buf;

	count = spu_acquire(ctx);
	if (count)
		goto out;

	/* wait only for the first element */
	count = 0;
	if (file->f_flags & O_NONBLOCK) {
		if (!spu_ibox_read(ctx, &ibox_data)) {
			count = -EAGAIN;
			goto out_unlock;
		}
	} else {
		count = spufs_wait(ctx->ibox_wq, spu_ibox_read(ctx, &ibox_data));
		if (count)
			goto out;
	}

	/* if we can't write at all, return -EFAULT */
	count = __put_user(ibox_data, udata);
	if (count)
		goto out_unlock;

	for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
		int ret;
		ret = ctx->ops->ibox_read(ctx, &ibox_data);
		if (ret == 0)
			break;
		/*
		 * at the end of the mapped area, we can fault
		 * but still need to return the data we have
		 * read successfully so far.
		 */
		ret = __put_user(ibox_data, udata);
		if (ret)
			break;
	}

out_unlock:
	spu_release(ctx);
out:
	return count;
}

static unsigned int spufs_ibox_poll(struct file *file, poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	unsigned int mask;

	poll_wait(file, &ctx->ibox_wq, wait);

	/*
	 * For now keep this uninterruptible and also ignore the rule
	 * that poll should not sleep.  Will be fixed later.
	 */
	mutex_lock(&ctx->state_mutex);
	mask = ctx->ops->mbox_stat_poll(ctx, POLLIN | POLLRDNORM);
	spu_release(ctx);

	return mask;
}

static const struct file_operations spufs_ibox_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_ibox_read,
	.poll	= spufs_ibox_poll,
	.fasync	= spufs_ibox_fasync,
};

static ssize_t spufs_ibox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	ssize_t ret;
	u32 ibox_stat;

	if (len < 4)
		return -EINVAL;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ibox_stat = (ctx->ops->mbox_stat_read(ctx) >> 16) & 0xff;
	spu_release(ctx);

	if (copy_to_user(buf, &ibox_stat, sizeof ibox_stat))
		return -EFAULT;

	return 4;
}

static const struct file_operations spufs_ibox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_ibox_stat_read,
};

/* low-level mailbox write */
size_t spu_wbox_write(struct spu_context *ctx, u32 data)
{
	return ctx->ops->wbox_write(ctx, data);
}

static int spufs_wbox_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	ret = fasync_helper(fd, file, on, &ctx->wbox_fasync);

	return ret;
}

/* interrupt-level wbox callback function. */
void spufs_wbox_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	if (!ctx)
		return;

	wake_up_all(&ctx->wbox_wq);
	kill_fasync(&ctx->wbox_fasync, SIGIO, POLLOUT);
}

/*
 * Write as many bytes to the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - the mailbox is full
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * space is availabyl, but return when we have been able to
 * write something.
 */
static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 wbox_data, __user *udata;
	ssize_t count;

	if (len < 4)
		return -EINVAL;

	udata = (void __user *)buf;
	if (!access_ok(VERIFY_READ, buf, len))
		return -EFAULT;

	if (__get_user(wbox_data, udata))
		return -EFAULT;

	count = spu_acquire(ctx);
	if (count)
		goto out;

	/*
	 * make sure we can at least write one element, by waiting
	 * in case of !O_NONBLOCK
	 */
	count = 0;
	if (file->f_flags & O_NONBLOCK) {
		if (!spu_wbox_write(ctx, wbox_data)) {
			count = -EAGAIN;
			goto out_unlock;
		}
	} else {
		count = spufs_wait(ctx->wbox_wq, spu_wbox_write(ctx, wbox_data));
		if (count)
			goto out;
	}


	/* write as much as possible */
	for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
		int ret;
		ret = __get_user(wbox_data, udata);
		if (ret)
			break;

		ret = spu_wbox_write(ctx, wbox_data);
		if (ret == 0)
			break;
	}

out_unlock:
	spu_release(ctx);
out:
	return count;
}

static unsigned int spufs_wbox_poll(struct file *file, poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	unsigned int mask;

	poll_wait(file, &ctx->wbox_wq, wait);

	/*
	 * For now keep this uninterruptible and also ignore the rule
	 * that poll should not sleep.  Will be fixed later.
	 */
	mutex_lock(&ctx->state_mutex);
	mask = ctx->ops->mbox_stat_poll(ctx, POLLOUT | POLLWRNORM);
	spu_release(ctx);

	return mask;
}

static const struct file_operations spufs_wbox_fops = {
	.open	= spufs_pipe_open,
	.write	= spufs_wbox_write,
	.poll	= spufs_wbox_poll,
	.fasync	= spufs_wbox_fasync,
};

static ssize_t spufs_wbox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	ssize_t ret;
	u32 wbox_stat;

	if (len < 4)
		return -EINVAL;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	wbox_stat = (ctx->ops->mbox_stat_read(ctx) >> 8) & 0xff;
	spu_release(ctx);

	if (copy_to_user(buf, &wbox_stat, sizeof wbox_stat))
		return -EFAULT;

	return 4;
}

static const struct file_operations spufs_wbox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_wbox_stat_read,
};

static int spufs_signal1_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = ctx;
	if (!i->i_openers++)
		ctx->signal1 = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return nonseekable_open(inode, file);
}

static int
spufs_signal1_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->signal1 = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static ssize_t __spufs_signal1_read(struct spu_context *ctx, char __user *buf,
			size_t len, loff_t *pos)
{
	int ret = 0;
	u32 data;

	if (len < 4)
		return -EINVAL;

	if (ctx->csa.spu_chnlcnt_RW[3]) {
		data = ctx->csa.spu_chnldata_RW[3];
		ret = 4;
	}

	if (!ret)
		goto out;

	if (copy_to_user(buf, &data, 4))
		return -EFAULT;

out:
	return ret;
}

static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	int ret;
	struct spu_context *ctx = file->private_data;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	ret = __spufs_signal1_read(ctx, buf, len, pos);
	spu_release_saved(ctx);

	return ret;
}

static ssize_t spufs_signal1_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx;
	ssize_t ret;
	u32 data;

	ctx = file->private_data;

	if (len < 4)
		return -EINVAL;

	if (copy_from_user(&data, buf, 4))
		return -EFAULT;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->signal1_write(ctx, data);
	spu_release(ctx);

	return 4;
}

static int
spufs_signal1_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
	return spufs_ps_fault(vma, vmf, 0x14000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
	/* For 64k pages, both signal1 and signal2 can be used to mmap the whole
	 * signal 1 and 2 area
	 */
	return spufs_ps_fault(vma, vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal1_mmap_vmops = {
	.fault = spufs_signal1_mmap_fault,
};

static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_signal1_mmap_vmops;
	return 0;
}

static const struct file_operations spufs_signal1_fops = {
	.open = spufs_signal1_open,
	.release = spufs_signal1_release,
	.read = spufs_signal1_read,
	.write = spufs_signal1_write,
	.mmap = spufs_signal1_mmap,
};

static const struct file_operations spufs_signal1_nosched_fops = {
	.open = spufs_signal1_open,
	.release = spufs_signal1_release,
	.write = spufs_signal1_write,
	.mmap = spufs_signal1_mmap,
};

static int spufs_signal2_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = ctx;
	if (!i->i_openers++)
		ctx->signal2 = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return nonseekable_open(inode, file);
}

static int
spufs_signal2_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->signal2 = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static ssize_t __spufs_signal2_read(struct spu_context *ctx, char __user *buf,
			size_t len, loff_t *pos)
{
	int ret = 0;
	u32 data;

	if (len < 4)
		return -EINVAL;

	if (ctx->csa.spu_chnlcnt_RW[4]) {
		data =  ctx->csa.spu_chnldata_RW[4];
		ret = 4;
	}

	if (!ret)
		goto out;

	if (copy_to_user(buf, &data, 4))
		return -EFAULT;

out:
	return ret;
}

static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	ret = __spufs_signal2_read(ctx, buf, len, pos);
	spu_release_saved(ctx);

	return ret;
}

static ssize_t spufs_signal2_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx;
	ssize_t ret;
	u32 data;

	ctx = file->private_data;

	if (len < 4)
		return -EINVAL;

	if (copy_from_user(&data, buf, 4))
		return -EFAULT;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->signal2_write(ctx, data);
	spu_release(ctx);

	return 4;
}

#if SPUFS_MMAP_4K
static int
spufs_signal2_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
	return spufs_ps_fault(vma, vmf, 0x1c000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
	/* For 64k pages, both signal1 and signal2 can be used to mmap the whole
	 * signal 1 and 2 area
	 */
	return spufs_ps_fault(vma, vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal2_mmap_vmops = {
	.fault = spufs_signal2_mmap_fault,
};

static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_signal2_mmap_vmops;
	return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_signal2_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static const struct file_operations spufs_signal2_fops = {
	.open = spufs_signal2_open,
	.release = spufs_signal2_release,
	.read = spufs_signal2_read,
	.write = spufs_signal2_write,
	.mmap = spufs_signal2_mmap,
};

static const struct file_operations spufs_signal2_nosched_fops = {
	.open = spufs_signal2_open,
	.release = spufs_signal2_release,
	.write = spufs_signal2_write,
	.mmap = spufs_signal2_mmap,
};

/*
 * This is a wrapper around DEFINE_SIMPLE_ATTRIBUTE which does the
 * work of acquiring (or not) the SPU context before calling through
 * to the actual get routine. The set routine is called directly.
 */
#define SPU_ATTR_NOACQUIRE	0
#define SPU_ATTR_ACQUIRE	1
#define SPU_ATTR_ACQUIRE_SAVED	2

#define DEFINE_SPUFS_ATTRIBUTE(__name, __get, __set, __fmt, __acquire)	\
static int __##__get(void *data, u64 *val)				\
{									\
	struct spu_context *ctx = data;					\
	int ret = 0;							\
									\
	if (__acquire == SPU_ATTR_ACQUIRE) {				\
		ret = spu_acquire(ctx);					\
		if (ret)						\
			return ret;					\
		*val = __get(ctx);					\
		spu_release(ctx);					\
	} else if (__acquire == SPU_ATTR_ACQUIRE_SAVED)	{		\
		ret = spu_acquire_saved(ctx);				\
		if (ret)						\
			return ret;					\
		*val = __get(ctx);					\
		spu_release_saved(ctx);					\
	} else								\
		*val = __get(ctx);					\
									\
	return 0;							\
}									\
DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__name, __##__get, __set, __fmt);

static int spufs_signal1_type_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->signal1_type_set(ctx, val);
	spu_release(ctx);

	return 0;
}

static u64 spufs_signal1_type_get(struct spu_context *ctx)
{
	return ctx->ops->signal1_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal1_type, spufs_signal1_type_get,
		       spufs_signal1_type_set, "%llu\n", SPU_ATTR_ACQUIRE);


static int spufs_signal2_type_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->signal2_type_set(ctx, val);
	spu_release(ctx);

	return 0;
}

static u64 spufs_signal2_type_get(struct spu_context *ctx)
{
	return ctx->ops->signal2_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal2_type, spufs_signal2_type_get,
		       spufs_signal2_type_set, "%llu\n", SPU_ATTR_ACQUIRE);

#if SPUFS_MMAP_4K
static int
spufs_mss_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	return spufs_ps_fault(vma, vmf, 0x0000, SPUFS_MSS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mss_mmap_vmops = {
	.fault = spufs_mss_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mss_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_mss_mmap_vmops;
	return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mss_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mss_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	file->private_data = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!i->i_openers++)
		ctx->mss = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return nonseekable_open(inode, file);
}

static int
spufs_mss_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->mss = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static const struct file_operations spufs_mss_fops = {
	.open	 = spufs_mss_open,
	.release = spufs_mss_release,
	.mmap	 = spufs_mss_mmap,
};

static int
spufs_psmap_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	return spufs_ps_fault(vma, vmf, 0x0000, SPUFS_PS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_psmap_mmap_vmops = {
	.fault = spufs_psmap_mmap_fault,
};

/*
 * mmap support for full problem state area [0x00000 - 0x1ffff].
 */
static int spufs_psmap_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_psmap_mmap_vmops;
	return 0;
}

static int spufs_psmap_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = i->i_ctx;
	if (!i->i_openers++)
		ctx->psmap = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return nonseekable_open(inode, file);
}

static int
spufs_psmap_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->psmap = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

static const struct file_operations spufs_psmap_fops = {
	.open	 = spufs_psmap_open,
	.release = spufs_psmap_release,
	.mmap	 = spufs_psmap_mmap,
};


#if SPUFS_MMAP_4K
static int
spufs_mfc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	return spufs_ps_fault(vma, vmf, 0x3000, SPUFS_MFC_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mfc_mmap_vmops = {
	.fault = spufs_mfc_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mfc_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_ops = &spufs_mfc_mmap_vmops;
	return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mfc_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mfc_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	/* we don't want to deal with DMA into other processes */
	if (ctx->owner != current->mm)
		return -EINVAL;

	if (atomic_read(&inode->i_count) != 1)
		return -EBUSY;

	mutex_lock(&ctx->mapping_lock);
	file->private_data = ctx;
	if (!i->i_openers++)
		ctx->mfc = inode->i_mapping;
	mutex_unlock(&ctx->mapping_lock);
	return nonseekable_open(inode, file);
}

static int
spufs_mfc_release(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	mutex_lock(&ctx->mapping_lock);
	if (!--i->i_openers)
		ctx->mfc = NULL;
	mutex_unlock(&ctx->mapping_lock);
	return 0;
}

/* interrupt-level mfc callback function. */
void spufs_mfc_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	if (!ctx)
		return;

	wake_up_all(&ctx->mfc_wq);

	pr_debug("%s %s\n", __func__, spu->name);
	if (ctx->mfc_fasync) {
		u32 free_elements, tagstatus;
		unsigned int mask;

		/* no need for spu_acquire in interrupt context */
		free_elements = ctx->ops->get_mfc_free_elements(ctx);
		tagstatus = ctx->ops->read_mfc_tagstatus(ctx);

		mask = 0;
		if (free_elements & 0xffff)
			mask |= POLLOUT;
		if (tagstatus & ctx->tagwait)
			mask |= POLLIN;

		kill_fasync(&ctx->mfc_fasync, SIGIO, mask);
	}
}

static int spufs_read_mfc_tagstatus(struct spu_context *ctx, u32 *status)
{
	/* See if there is one tag group is complete */
	/* FIXME we need locking around tagwait */
	*status = ctx->ops->read_mfc_tagstatus(ctx) & ctx->tagwait;
	ctx->tagwait &= ~*status;
	if (*status)
		return 1;

	/* enable interrupt waiting for any tag group,
	   may silently fail if interrupts are already enabled */
	ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
	return 0;
}

static ssize_t spufs_mfc_read(struct file *file, char __user *buffer,
			size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret = -EINVAL;
	u32 status;

	if (size != 4)
		goto out;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;

	ret = -EINVAL;
	if (file->f_flags & O_NONBLOCK) {
		status = ctx->ops->read_mfc_tagstatus(ctx);
		if (!(status & ctx->tagwait))
			ret = -EAGAIN;
		else
			/* XXX(hch): shouldn't we clear ret here? */
			ctx->tagwait &= ~status;
	} else {
		ret = spufs_wait(ctx->mfc_wq,
			   spufs_read_mfc_tagstatus(ctx, &status));
		if (ret)
			goto out;
	}
	spu_release(ctx);

	ret = 4;
	if (copy_to_user(buffer, &status, 4))
		ret = -EFAULT;

out:
	return ret;
}

static int spufs_check_valid_dma(struct mfc_dma_command *cmd)
{
	pr_debug("queueing DMA %x %llx %x %x %x\n", cmd->lsa,
		 cmd->ea, cmd->size, cmd->tag, cmd->cmd);

	switch (cmd->cmd) {
	case MFC_PUT_CMD:
	case MFC_PUTF_CMD:
	case MFC_PUTB_CMD:
	case MFC_GET_CMD:
	case MFC_GETF_CMD:
	case MFC_GETB_CMD:
		break;
	default:
		pr_debug("invalid DMA opcode %x\n", cmd->cmd);
		return -EIO;
	}

	if ((cmd->lsa & 0xf) != (cmd->ea &0xf)) {
		pr_debug("invalid DMA alignment, ea %llx lsa %x\n",
				cmd->ea, cmd->lsa);
		return -EIO;
	}

	switch (cmd->size & 0xf) {
	case 1:
		break;
	case 2:
		if (cmd->lsa & 1)
			goto error;
		break;
	case 4:
		if (cmd->lsa & 3)
			goto error;
		break;
	case 8:
		if (cmd->lsa & 7)
			goto error;
		break;
	case 0:
		if (cmd->lsa & 15)
			goto error;
		break;
	error:
	default:
		pr_debug("invalid DMA alignment %x for size %x\n",
			cmd->lsa & 0xf, cmd->size);
		return -EIO;
	}

	if (cmd->size > 16 * 1024) {
		pr_debug("invalid DMA size %x\n", cmd->size);
		return -EIO;
	}

	if (cmd->tag & 0xfff0) {
		/* we reserve the higher tag numbers for kernel use */
		pr_debug("invalid DMA tag\n");
		return -EIO;
	}

	if (cmd->class) {
		/* not supported in this version */
		pr_debug("invalid DMA class\n");
		return -EIO;
	}

	return 0;
}

static int spu_send_mfc_command(struct spu_context *ctx,
				struct mfc_dma_command cmd,
				int *error)
{
	*error = ctx->ops->send_mfc_command(ctx, &cmd);
	if (*error == -EAGAIN) {
		/* wait for any tag group to complete
		   so we have space for the new command */
		ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
		/* try again, because the queue might be
		   empty again */
		*error = ctx->ops->send_mfc_command(ctx, &cmd);
		if (*error == -EAGAIN)
			return 0;
	}
	return 1;
}

static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
			size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	struct mfc_dma_command cmd;
	int ret = -EINVAL;

	if (size != sizeof cmd)
		goto out;

	ret = -EFAULT;
	if (copy_from_user(&cmd, buffer, sizeof cmd))
		goto out;

	ret = spufs_check_valid_dma(&cmd);
	if (ret)
		goto out;

	ret = spu_acquire(ctx);
	if (ret)
		goto out;

	ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
	if (ret)
		goto out;

	if (file->f_flags & O_NONBLOCK) {
		ret = ctx->ops->send_mfc_command(ctx, &cmd);
	} else {
		int status;
		ret = spufs_wait(ctx->mfc_wq,
				 spu_send_mfc_command(ctx, cmd, &status));
		if (ret)
			goto out;
		if (status)
			ret = status;
	}

	if (ret)
		goto out_unlock;

	ctx->tagwait |= 1 << cmd.tag;
	ret = size;

out_unlock:
	spu_release(ctx);
out:
	return ret;
}

static unsigned int spufs_mfc_poll(struct file *file,poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	u32 free_elements, tagstatus;
	unsigned int mask;

	poll_wait(file, &ctx->mfc_wq, wait);

	/*
	 * For now keep this uninterruptible and also ignore the rule
	 * that poll should not sleep.  Will be fixed later.
	 */
	mutex_lock(&ctx->state_mutex);
	ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2);
	free_elements = ctx->ops->get_mfc_free_elements(ctx);
	tagstatus = ctx->ops->read_mfc_tagstatus(ctx);
	spu_release(ctx);

	mask = 0;
	if (free_elements & 0xffff)
		mask |= POLLOUT | POLLWRNORM;
	if (tagstatus & ctx->tagwait)
		mask |= POLLIN | POLLRDNORM;

	pr_debug("%s: free %d tagstatus %d tagwait %d\n", __func__,
		free_elements, tagstatus, ctx->tagwait);

	return mask;
}

static int spufs_mfc_flush(struct file *file, fl_owner_t id)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		goto out;
#if 0
/* this currently hangs */
	ret = spufs_wait(ctx->mfc_wq,
			 ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2));
	if (ret)
		goto out;
	ret = spufs_wait(ctx->mfc_wq,
			 ctx->ops->read_mfc_tagstatus(ctx) == ctx->tagwait);
	if (ret)
		goto out;
#else
	ret = 0;
#endif
	spu_release(ctx);
out:
	return ret;
}

static int spufs_mfc_fsync(struct file *file, struct dentry *dentry,
			   int datasync)
{
	return spufs_mfc_flush(file, NULL);
}

static int spufs_mfc_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;

	return fasync_helper(fd, file, on, &ctx->mfc_fasync);
}

static const struct file_operations spufs_mfc_fops = {
	.open	 = spufs_mfc_open,
	.release = spufs_mfc_release,
	.read	 = spufs_mfc_read,
	.write	 = spufs_mfc_write,
	.poll	 = spufs_mfc_poll,
	.flush	 = spufs_mfc_flush,
	.fsync	 = spufs_mfc_fsync,
	.fasync	 = spufs_mfc_fasync,
	.mmap	 = spufs_mfc_mmap,
};

static int spufs_npc_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;
	ctx->ops->npc_write(ctx, val);
	spu_release(ctx);

	return 0;
}

static u64 spufs_npc_get(struct spu_context *ctx)
{
	return ctx->ops->npc_read(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_npc_ops, spufs_npc_get, spufs_npc_set,
		       "0x%llx\n", SPU_ATTR_ACQUIRE);

static int spufs_decr_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	lscsa->decr.slot[0] = (u32) val;
	spu_release_saved(ctx);

	return 0;
}

static u64 spufs_decr_get(struct spu_context *ctx)
{
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	return lscsa->decr.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_ops, spufs_decr_get, spufs_decr_set,
		       "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED);

static int spufs_decr_status_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	if (val)
		ctx->csa.priv2.mfc_control_RW |= MFC_CNTL_DECREMENTER_RUNNING;
	else
		ctx->csa.priv2.mfc_control_RW &= ~MFC_CNTL_DECREMENTER_RUNNING;
	spu_release_saved(ctx);

	return 0;
}

static u64 spufs_decr_status_get(struct spu_context *ctx)
{
	if (ctx->csa.priv2.mfc_control_RW & MFC_CNTL_DECREMENTER_RUNNING)
		return SPU_DECR_STATUS_RUNNING;
	else
		return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_status_ops, spufs_decr_status_get,
		       spufs_decr_status_set, "0x%llx\n",
		       SPU_ATTR_ACQUIRE_SAVED);

static int spufs_event_mask_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	lscsa->event_mask.slot[0] = (u32) val;
	spu_release_saved(ctx);

	return 0;
}

static u64 spufs_event_mask_get(struct spu_context *ctx)
{
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	return lscsa->event_mask.slot[0];
}

DEFINE_SPUFS_ATTRIBUTE(spufs_event_mask_ops, spufs_event_mask_get,
		       spufs_event_mask_set, "0x%llx\n",
		       SPU_ATTR_ACQUIRE_SAVED);

static u64 spufs_event_status_get(struct spu_context *ctx)
{
	struct spu_state *state = &ctx->csa;
	u64 stat;
	stat = state->spu_chnlcnt_RW[0];
	if (stat)
		return state->spu_chnldata_RW[0];
	return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_event_status_ops, spufs_event_status_get,
		       NULL, "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static int spufs_srr0_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	lscsa->srr0.slot[0] = (u32) val;
	spu_release_saved(ctx);

	return 0;
}

static u64 spufs_srr0_get(struct spu_context *ctx)
{
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	return lscsa->srr0.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_srr0_ops, spufs_srr0_get, spufs_srr0_set,
		       "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static u64 spufs_id_get(struct spu_context *ctx)
{
	u64 num;

	if (ctx->state == SPU_STATE_RUNNABLE)
		num = ctx->spu->number;
	else
		num = (unsigned int)-1;

	return num;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_id_ops, spufs_id_get, NULL, "0x%llx\n",
		       SPU_ATTR_ACQUIRE)

static u64 spufs_object_id_get(struct spu_context *ctx)
{
	/* FIXME: Should there really be no locking here? */
	return ctx->object_id;
}

static int spufs_object_id_set(void *data, u64 id)
{
	struct spu_context *ctx = data;
	ctx->object_id = id;

	return 0;
}

DEFINE_SPUFS_ATTRIBUTE(spufs_object_id_ops, spufs_object_id_get,
		       spufs_object_id_set, "0x%llx\n", SPU_ATTR_NOACQUIRE);

static u64 spufs_lslr_get(struct spu_context *ctx)
{
	return ctx->csa.priv2.spu_lslr_RW;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_lslr_ops, spufs_lslr_get, NULL, "0x%llx\n",
		       SPU_ATTR_ACQUIRE_SAVED);

static int spufs_info_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;
	file->private_data = ctx;
	return 0;
}

static int spufs_caps_show(struct seq_file *s, void *private)
{
	struct spu_context *ctx = s->private;

	if (!(ctx->flags & SPU_CREATE_NOSCHED))
		seq_puts(s, "sched\n");
	if (!(ctx->flags & SPU_CREATE_ISOLATE))
		seq_puts(s, "step\n");
	return 0;
}

static int spufs_caps_open(struct inode *inode, struct file *file)
{
	return single_open(file, spufs_caps_show, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_caps_fops = {
	.open		= spufs_caps_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
			char __user *buf, size_t len, loff_t *pos)
{
	u32 data;

	/* EOF if there's no entry in the mbox */
	if (!(ctx->csa.prob.mb_stat_R & 0x0000ff))
		return 0;

	data = ctx->csa.prob.pu_mb_R;

	return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
				   size_t len, loff_t *pos)
{
	int ret;
	struct spu_context *ctx = file->private_data;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	spin_lock(&ctx->csa.register_lock);
	ret = __spufs_mbox_info_read(ctx, buf, len, pos);
	spin_unlock(&ctx->csa.register_lock);
	spu_release_saved(ctx);

	return ret;
}

static const struct file_operations spufs_mbox_info_fops = {
	.open = spufs_info_open,
	.read = spufs_mbox_info_read,
	.llseek  = generic_file_llseek,
};

static ssize_t __spufs_ibox_info_read(struct spu_context *ctx,
				char __user *buf, size_t len, loff_t *pos)
{
	u32 data;

	/* EOF if there's no entry in the ibox */
	if (!(ctx->csa.prob.mb_stat_R & 0xff0000))
		return 0;

	data = ctx->csa.priv2.puint_mb_R;

	return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
				   size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	spin_lock(&ctx->csa.register_lock);
	ret = __spufs_ibox_info_read(ctx, buf, len, pos);
	spin_unlock(&ctx->csa.register_lock);
	spu_release_saved(ctx);

	return ret;
}

static const struct file_operations spufs_ibox_info_fops = {
	.open = spufs_info_open,
	.read = spufs_ibox_info_read,
	.llseek  = generic_file_llseek,
};

static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
			char __user *buf, size_t len, loff_t *pos)
{
	int i, cnt;
	u32 data[4];
	u32 wbox_stat;

	wbox_stat = ctx->csa.prob.mb_stat_R;
	cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
	for (i = 0; i < cnt; i++) {
		data[i] = ctx->csa.spu_mailbox_data[i];
	}

	return simple_read_from_buffer(buf, len, pos, &data,
				cnt * sizeof(u32));
}

static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
				   size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	spin_lock(&ctx->csa.register_lock);
	ret = __spufs_wbox_info_read(ctx, buf, len, pos);
	spin_unlock(&ctx->csa.register_lock);
	spu_release_saved(ctx);

	return ret;
}

static const struct file_operations spufs_wbox_info_fops = {
	.open = spufs_info_open,
	.read = spufs_wbox_info_read,
	.llseek  = generic_file_llseek,
};

static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
			char __user *buf, size_t len, loff_t *pos)
{
	struct spu_dma_info info;
	struct mfc_cq_sr *qp, *spuqp;
	int i;

	info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
	info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
	info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
	info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
	info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
	for (i = 0; i < 16; i++) {
		qp = &info.dma_info_command_data[i];
		spuqp = &ctx->csa.priv2.spuq[i];

		qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
		qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
		qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
		qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
	}

	return simple_read_from_buffer(buf, len, pos, &info,
				sizeof info);
}

static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
			      size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	spin_lock(&ctx->csa.register_lock);
	ret = __spufs_dma_info_read(ctx, buf, len, pos);
	spin_unlock(&ctx->csa.register_lock);
	spu_release_saved(ctx);

	return ret;
}

static const struct file_operations spufs_dma_info_fops = {
	.open = spufs_info_open,
	.read = spufs_dma_info_read,
};

static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
			char __user *buf, size_t len, loff_t *pos)
{
	struct spu_proxydma_info info;
	struct mfc_cq_sr *qp, *puqp;
	int ret = sizeof info;
	int i;

	if (len < ret)
		return -EINVAL;

	if (!access_ok(VERIFY_WRITE, buf, len))
		return -EFAULT;

	info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
	info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
	info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
	for (i = 0; i < 8; i++) {
		qp = &info.proxydma_info_command_data[i];
		puqp = &ctx->csa.priv2.puq[i];

		qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
		qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
		qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
		qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
	}

	return simple_read_from_buffer(buf, len, pos, &info,
				sizeof info);
}

static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
				   size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	ret = spu_acquire_saved(ctx);
	if (ret)
		return ret;
	spin_lock(&ctx->csa.register_lock);
	ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
	spin_unlock(&ctx->csa.register_lock);
	spu_release_saved(ctx);

	return ret;
}

static const struct file_operations spufs_proxydma_info_fops = {
	.open = spufs_info_open,
	.read = spufs_proxydma_info_read,
};

static int spufs_show_tid(struct seq_file *s, void *private)
{
	struct spu_context *ctx = s->private;

	seq_printf(s, "%d\n", ctx->tid);
	return 0;
}

static int spufs_tid_open(struct inode *inode, struct file *file)
{
	return single_open(file, spufs_show_tid, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_tid_fops = {
	.open		= spufs_tid_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static const char *ctx_state_names[] = {
	"user", "system", "iowait", "loaded"
};

static unsigned long long spufs_acct_time(struct spu_context *ctx,
		enum spu_utilization_state state)
{
	struct timespec ts;
	unsigned long long time = ctx->stats.times[state];

	/*
	 * In general, utilization statistics are updated by the controlling
	 * thread as the spu context moves through various well defined
	 * state transitions, but if the context is lazily loaded its
	 * utilization statistics are not updated as the controlling thread
	 * is not tightly coupled with the execution of the spu context.  We
	 * calculate and apply the time delta from the last recorded state
	 * of the spu context.
	 */
	if (ctx->spu && ctx->stats.util_state == state) {
		ktime_get_ts(&ts);
		time += timespec_to_ns(&ts) - ctx->stats.tstamp;
	}

	return time / NSEC_PER_MSEC;
}

static unsigned long long spufs_slb_flts(struct spu_context *ctx)
{
	unsigned long long slb_flts = ctx->stats.slb_flt;

	if (ctx->state == SPU_STATE_RUNNABLE) {
		slb_flts += (ctx->spu->stats.slb_flt -
			     ctx->stats.slb_flt_base);
	}

	return slb_flts;
}

static unsigned long long spufs_class2_intrs(struct spu_context *ctx)
{
	unsigned long long class2_intrs = ctx->stats.class2_intr;

	if (ctx->state == SPU_STATE_RUNNABLE) {
		class2_intrs += (ctx->spu->stats.class2_intr -
				 ctx->stats.class2_intr_base);
	}

	return class2_intrs;
}


static int spufs_show_stat(struct seq_file *s, void *private)
{
	struct spu_context *ctx = s->private;
	int ret;

	ret = spu_acquire(ctx);
	if (ret)
		return ret;

	seq_printf(s, "%s %llu %llu %llu %llu "
		      "%llu %llu %llu %llu %llu %llu %llu %llu\n",
		ctx_state_names[ctx->stats.util_state],
		spufs_acct_time(ctx, SPU_UTIL_USER),
		spufs_acct_time(ctx, SPU_UTIL_SYSTEM),
		spufs_acct_time(ctx, SPU_UTIL_IOWAIT),
		spufs_acct_time(ctx, SPU_UTIL_IDLE_LOADED),
		ctx->stats.vol_ctx_switch,
		ctx->stats.invol_ctx_switch,
		spufs_slb_flts(ctx),
		ctx->stats.hash_flt,
		ctx->stats.min_flt,
		ctx->stats.maj_flt,
		spufs_class2_intrs(ctx),
		ctx->stats.libassist);
	spu_release(ctx);
	return 0;
}

static int spufs_stat_open(struct inode *inode, struct file *file)
{
	return single_open(file, spufs_show_stat, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_stat_fops = {
	.open		= spufs_stat_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static inline int spufs_switch_log_used(struct spu_context *ctx)
{
	return (ctx->switch_log->head - ctx->switch_log->tail) %
		SWITCH_LOG_BUFSIZE;
}

static inline int spufs_switch_log_avail(struct spu_context *ctx)
{
	return SWITCH_LOG_BUFSIZE - spufs_switch_log_used(ctx);
}

static int spufs_switch_log_open(struct inode *inode, struct file *file)
{
	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
	int rc;

	rc = spu_acquire(ctx);
	if (rc)
		return rc;

	if (ctx->switch_log) {
		rc = -EBUSY;
		goto out;
	}

	ctx->switch_log = kmalloc(sizeof(struct switch_log) +
		SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
		GFP_KERNEL);

	if (!ctx->switch_log) {
		rc = -ENOMEM;
		goto out;
	}

	ctx->switch_log->head = ctx->switch_log->tail = 0;
	init_waitqueue_head(&ctx->switch_log->wait);
	rc = 0;

out:
	spu_release(ctx);
	return rc;
}

static int spufs_switch_log_release(struct inode *inode, struct file *file)
{
	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
	int rc;

	rc = spu_acquire(ctx);
	if (rc)
		return rc;

	kfree(ctx->switch_log);
	ctx->switch_log = NULL;
	spu_release(ctx);

	return 0;
}

static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
{
	struct switch_log_entry *p;

	p = ctx->switch_log->log + ctx->switch_log->tail % SWITCH_LOG_BUFSIZE;

	return snprintf(tbuf, n, "%u.%09u %d %u %u %llu\n",
			(unsigned int) p->tstamp.tv_sec,
			(unsigned int) p->tstamp.tv_nsec,
			p->spu_id,
			(unsigned int) p->type,
			(unsigned int) p->val,
			(unsigned long long) p->timebase);
}

static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
			     size_t len, loff_t *ppos)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
	int error = 0, cnt = 0;

	if (!buf)
		return -EINVAL;

	error = spu_acquire(ctx);
	if (error)
		return error;

	while (cnt < len) {
		char tbuf[128];
		int width;

		if (spufs_switch_log_used(ctx) == 0) {
			if (cnt > 0) {
				/* If there's data ready to go, we can
				 * just return straight away */
				break;

			} else if (file->f_flags & O_NONBLOCK) {
				error = -EAGAIN;
				break;

			} else {
				/* spufs_wait will drop the mutex and
				 * re-acquire, but since we're in read(), the
				 * file cannot be _released (and so
				 * ctx->switch_log is stable).
				 */
				error = spufs_wait(ctx->switch_log->wait,
						spufs_switch_log_used(ctx) > 0);

				/* On error, spufs_wait returns without the
				 * state mutex held */
				if (error)
					return error;

				/* We may have had entries read from underneath
				 * us while we dropped the mutex in spufs_wait,
				 * so re-check */
				if (spufs_switch_log_used(ctx) == 0)
					continue;
			}
		}

		width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
		if (width < len)
			ctx->switch_log->tail =
				(ctx->switch_log->tail + 1) %
				 SWITCH_LOG_BUFSIZE;
		else
			/* If the record is greater than space available return
			 * partial buffer (so far) */
			break;

		error = copy_to_user(buf + cnt, tbuf, width);
		if (error)
			break;
		cnt += width;
	}

	spu_release(ctx);

	return cnt == 0 ? error : cnt;
}

static unsigned int spufs_switch_log_poll(struct file *file, poll_table *wait)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
	unsigned int mask = 0;
	int rc;

	poll_wait(file, &ctx->switch_log->wait, wait);

	rc = spu_acquire(ctx);
	if (rc)
		return rc;

	if (spufs_switch_log_used(ctx) > 0)
		mask |= POLLIN;

	spu_release(ctx);

	return mask;
}

static const struct file_operations spufs_switch_log_fops = {
	.owner		= THIS_MODULE,
	.open		= spufs_switch_log_open,
	.read		= spufs_switch_log_read,
	.poll		= spufs_switch_log_poll,
	.release	= spufs_switch_log_release,
};

/**
 * Log a context switch event to a switch log reader.
 *
 * Must be called with ctx->state_mutex held.
 */
void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
		u32 type, u32 val)
{
	if (!ctx->switch_log)
		return;

	if (spufs_switch_log_avail(ctx) > 1) {
		struct switch_log_entry *p;

		p = ctx->switch_log->log + ctx->switch_log->head;
		ktime_get_ts(&p->tstamp);
		p->timebase = get_tb();
		p->spu_id = spu ? spu->number : -1;
		p->type = type;
		p->val = val;

		ctx->switch_log->head =
			(ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
	}

	wake_up(&ctx->switch_log->wait);
}

static int spufs_show_ctx(struct seq_file *s, void *private)
{
	struct spu_context *ctx = s->private;
	u64 mfc_control_RW;

	mutex_lock(&ctx->state_mutex);
	if (ctx->spu) {
		struct spu *spu = ctx->spu;
		struct spu_priv2 __iomem *priv2 = spu->priv2;

		spin_lock_irq(&spu->register_lock);
		mfc_control_RW = in_be64(&priv2->mfc_control_RW);
		spin_unlock_irq(&spu->register_lock);
	} else {
		struct spu_state *csa = &ctx->csa;

		mfc_control_RW = csa->priv2.mfc_control_RW;
	}

	seq_printf(s, "%c flgs(%lx) sflgs(%lx) pri(%d) ts(%d) spu(%02d)"
		" %c %llx %llx %llx %llx %x %x\n",
		ctx->state == SPU_STATE_SAVED ? 'S' : 'R',
		ctx->flags,
		ctx->sched_flags,
		ctx->prio,
		ctx->time_slice,
		ctx->spu ? ctx->spu->number : -1,
		!list_empty(&ctx->rq) ? 'q' : ' ',
		ctx->csa.class_0_pending,
		ctx->csa.class_0_dar,
		ctx->csa.class_1_dsisr,
		mfc_control_RW,
		ctx->ops->runcntl_read(ctx),
		ctx->ops->status_read(ctx));

	mutex_unlock(&ctx->state_mutex);

	return 0;
}

static int spufs_ctx_open(struct inode *inode, struct file *file)
{
	return single_open(file, spufs_show_ctx, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_ctx_fops = {
	.open           = spufs_ctx_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release        = single_release,
};

const struct spufs_tree_descr spufs_dir_contents[] = {
	{ "capabilities", &spufs_caps_fops, 0444, },
	{ "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
	{ "regs", &spufs_regs_fops,  0666, sizeof(struct spu_reg128[128]), },
	{ "mbox", &spufs_mbox_fops, 0444, },
	{ "ibox", &spufs_ibox_fops, 0444, },
	{ "wbox", &spufs_wbox_fops, 0222, },
	{ "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
	{ "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
	{ "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
	{ "signal1", &spufs_signal1_fops, 0666, },
	{ "signal2", &spufs_signal2_fops, 0666, },
	{ "signal1_type", &spufs_signal1_type, 0666, },
	{ "signal2_type", &spufs_signal2_type, 0666, },
	{ "cntl", &spufs_cntl_fops,  0666, },
	{ "fpcr", &spufs_fpcr_fops, 0666, sizeof(struct spu_reg128), },
	{ "lslr", &spufs_lslr_ops, 0444, },
	{ "mfc", &spufs_mfc_fops, 0666, },
	{ "mss", &spufs_mss_fops, 0666, },
	{ "npc", &spufs_npc_ops, 0666, },
	{ "srr0", &spufs_srr0_ops, 0666, },
	{ "decr", &spufs_decr_ops, 0666, },
	{ "decr_status", &spufs_decr_status_ops, 0666, },
	{ "event_mask", &spufs_event_mask_ops, 0666, },
	{ "event_status", &spufs_event_status_ops, 0444, },
	{ "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
	{ "phys-id", &spufs_id_ops, 0666, },
	{ "object-id", &spufs_object_id_ops, 0666, },
	{ "mbox_info", &spufs_mbox_info_fops, 0444, sizeof(u32), },
	{ "ibox_info", &spufs_ibox_info_fops, 0444, sizeof(u32), },
	{ "wbox_info", &spufs_wbox_info_fops, 0444, sizeof(u32), },
	{ "dma_info", &spufs_dma_info_fops, 0444,
		sizeof(struct spu_dma_info), },
	{ "proxydma_info", &spufs_proxydma_info_fops, 0444,
		sizeof(struct spu_proxydma_info)},
	{ "tid", &spufs_tid_fops, 0444, },
	{ "stat", &spufs_stat_fops, 0444, },
	{ "switch_log", &spufs_switch_log_fops, 0444 },
	{},
};

const struct spufs_tree_descr spufs_dir_nosched_contents[] = {
	{ "capabilities", &spufs_caps_fops, 0444, },
	{ "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
	{ "mbox", &spufs_mbox_fops, 0444, },
	{ "ibox", &spufs_ibox_fops, 0444, },
	{ "wbox", &spufs_wbox_fops, 0222, },
	{ "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
	{ "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
	{ "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
	{ "signal1", &spufs_signal1_nosched_fops, 0222, },
	{ "signal2", &spufs_signal2_nosched_fops, 0222, },
	{ "signal1_type", &spufs_signal1_type, 0666, },
	{ "signal2_type", &spufs_signal2_type, 0666, },
	{ "mss", &spufs_mss_fops, 0666, },
	{ "mfc", &spufs_mfc_fops, 0666, },
	{ "cntl", &spufs_cntl_fops,  0666, },
	{ "npc", &spufs_npc_ops, 0666, },
	{ "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
	{ "phys-id", &spufs_id_ops, 0666, },
	{ "object-id", &spufs_object_id_ops, 0666, },
	{ "tid", &spufs_tid_fops, 0444, },
	{ "stat", &spufs_stat_fops, 0444, },
	{},
};

const struct spufs_tree_descr spufs_dir_debug_contents[] = {
	{ ".ctx", &spufs_ctx_fops, 0444, },
	{},
};

const struct spufs_coredump_reader spufs_coredump_read[] = {
	{ "regs", __spufs_regs_read, NULL, sizeof(struct spu_reg128[128])},
	{ "fpcr", __spufs_fpcr_read, NULL, sizeof(struct spu_reg128) },
	{ "lslr", NULL, spufs_lslr_get, 19 },
	{ "decr", NULL, spufs_decr_get, 19 },
	{ "decr_status", NULL, spufs_decr_status_get, 19 },
	{ "mem", __spufs_mem_read, NULL, LS_SIZE, },
	{ "signal1", __spufs_signal1_read, NULL, sizeof(u32) },
	{ "signal1_type", NULL, spufs_signal1_type_get, 19 },
	{ "signal2", __spufs_signal2_read, NULL, sizeof(u32) },
	{ "signal2_type", NULL, spufs_signal2_type_get, 19 },
	{ "event_mask", NULL, spufs_event_mask_get, 19 },
	{ "event_status", NULL, spufs_event_status_get, 19 },
	{ "mbox_info", __spufs_mbox_info_read, NULL, sizeof(u32) },
	{ "ibox_info", __spufs_ibox_info_read, NULL, sizeof(u32) },
	{ "wbox_info", __spufs_wbox_info_read, NULL, 4 * sizeof(u32)},
	{ "dma_info", __spufs_dma_info_read, NULL, sizeof(struct spu_dma_info)},
	{ "proxydma_info", __spufs_proxydma_info_read,
			   NULL, sizeof(struct spu_proxydma_info)},
	{ "object-id", NULL, spufs_object_id_get, 19 },
	{ "npc", NULL, spufs_npc_get, 19 },
	{ NULL },
};