xref: /openbmc/linux/arch/sh/kernel/cpu/sh4/sq.c (revision 22246614)
1 /*
2  * arch/sh/kernel/cpu/sh4/sq.c
3  *
4  * General management API for SH-4 integrated Store Queues
5  *
6  * Copyright (C) 2001 - 2006  Paul Mundt
7  * Copyright (C) 2001, 2002  M. R. Brown
8  *
9  * This file is subject to the terms and conditions of the GNU General Public
10  * License.  See the file "COPYING" in the main directory of this archive
11  * for more details.
12  */
13 #include <linux/init.h>
14 #include <linux/cpu.h>
15 #include <linux/bitmap.h>
16 #include <linux/sysdev.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/vmalloc.h>
21 #include <linux/mm.h>
22 #include <linux/io.h>
23 #include <asm/page.h>
24 #include <asm/cacheflush.h>
25 #include <asm/cpu/sq.h>
26 
27 struct sq_mapping;
28 
29 struct sq_mapping {
30 	const char *name;
31 
32 	unsigned long sq_addr;
33 	unsigned long addr;
34 	unsigned int size;
35 
36 	struct sq_mapping *next;
37 };
38 
39 static struct sq_mapping *sq_mapping_list;
40 static DEFINE_SPINLOCK(sq_mapping_lock);
41 static struct kmem_cache *sq_cache;
42 static unsigned long *sq_bitmap;
43 
44 #define store_queue_barrier()			\
45 do {						\
46 	(void)ctrl_inl(P4SEG_STORE_QUE);	\
47 	ctrl_outl(0, P4SEG_STORE_QUE + 0);	\
48 	ctrl_outl(0, P4SEG_STORE_QUE + 8);	\
49 } while (0);
50 
51 /**
52  * sq_flush_range - Flush (prefetch) a specific SQ range
53  * @start: the store queue address to start flushing from
54  * @len: the length to flush
55  *
56  * Flushes the store queue cache from @start to @start + @len in a
57  * linear fashion.
58  */
59 void sq_flush_range(unsigned long start, unsigned int len)
60 {
61 	unsigned long *sq = (unsigned long *)start;
62 
63 	/* Flush the queues */
64 	for (len >>= 5; len--; sq += 8)
65 		prefetchw(sq);
66 
67 	/* Wait for completion */
68 	store_queue_barrier();
69 }
70 EXPORT_SYMBOL(sq_flush_range);
71 
72 static inline void sq_mapping_list_add(struct sq_mapping *map)
73 {
74 	struct sq_mapping **p, *tmp;
75 
76 	spin_lock_irq(&sq_mapping_lock);
77 
78 	p = &sq_mapping_list;
79 	while ((tmp = *p) != NULL)
80 		p = &tmp->next;
81 
82 	map->next = tmp;
83 	*p = map;
84 
85 	spin_unlock_irq(&sq_mapping_lock);
86 }
87 
88 static inline void sq_mapping_list_del(struct sq_mapping *map)
89 {
90 	struct sq_mapping **p, *tmp;
91 
92 	spin_lock_irq(&sq_mapping_lock);
93 
94 	for (p = &sq_mapping_list; (tmp = *p); p = &tmp->next)
95 		if (tmp == map) {
96 			*p = tmp->next;
97 			break;
98 		}
99 
100 	spin_unlock_irq(&sq_mapping_lock);
101 }
102 
103 static int __sq_remap(struct sq_mapping *map, unsigned long flags)
104 {
105 #if defined(CONFIG_MMU)
106 	struct vm_struct *vma;
107 
108 	vma = __get_vm_area(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
109 	if (!vma)
110 		return -ENOMEM;
111 
112 	vma->phys_addr = map->addr;
113 
114 	if (ioremap_page_range((unsigned long)vma->addr,
115 			       (unsigned long)vma->addr + map->size,
116 			       vma->phys_addr, __pgprot(flags))) {
117 		vunmap(vma->addr);
118 		return -EAGAIN;
119 	}
120 #else
121 	/*
122 	 * Without an MMU (or with it turned off), this is much more
123 	 * straightforward, as we can just load up each queue's QACR with
124 	 * the physical address appropriately masked.
125 	 */
126 	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
127 	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
128 #endif
129 
130 	return 0;
131 }
132 
133 /**
134  * sq_remap - Map a physical address through the Store Queues
135  * @phys: Physical address of mapping.
136  * @size: Length of mapping.
137  * @name: User invoking mapping.
138  * @flags: Protection flags.
139  *
140  * Remaps the physical address @phys through the next available store queue
141  * address of @size length. @name is logged at boot time as well as through
142  * the sysfs interface.
143  */
144 unsigned long sq_remap(unsigned long phys, unsigned int size,
145 		       const char *name, unsigned long flags)
146 {
147 	struct sq_mapping *map;
148 	unsigned long end;
149 	unsigned int psz;
150 	int ret, page;
151 
152 	/* Don't allow wraparound or zero size */
153 	end = phys + size - 1;
154 	if (unlikely(!size || end < phys))
155 		return -EINVAL;
156 	/* Don't allow anyone to remap normal memory.. */
157 	if (unlikely(phys < virt_to_phys(high_memory)))
158 		return -EINVAL;
159 
160 	phys &= PAGE_MASK;
161 	size = PAGE_ALIGN(end + 1) - phys;
162 
163 	map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
164 	if (unlikely(!map))
165 		return -ENOMEM;
166 
167 	map->addr = phys;
168 	map->size = size;
169 	map->name = name;
170 
171 	page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
172 				       get_order(map->size));
173 	if (unlikely(page < 0)) {
174 		ret = -ENOSPC;
175 		goto out;
176 	}
177 
178 	map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
179 
180 	ret = __sq_remap(map, pgprot_val(PAGE_KERNEL_NOCACHE) | flags);
181 	if (unlikely(ret != 0))
182 		goto out;
183 
184 	psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
185 	pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
186 		likely(map->name) ? map->name : "???",
187 		psz, psz == 1 ? " " : "s",
188 		map->sq_addr, map->addr);
189 
190 	sq_mapping_list_add(map);
191 
192 	return map->sq_addr;
193 
194 out:
195 	kmem_cache_free(sq_cache, map);
196 	return ret;
197 }
198 EXPORT_SYMBOL(sq_remap);
199 
200 /**
201  * sq_unmap - Unmap a Store Queue allocation
202  * @map: Pre-allocated Store Queue mapping.
203  *
204  * Unmaps the store queue allocation @map that was previously created by
205  * sq_remap(). Also frees up the pte that was previously inserted into
206  * the kernel page table and discards the UTLB translation.
207  */
208 void sq_unmap(unsigned long vaddr)
209 {
210 	struct sq_mapping **p, *map;
211 	int page;
212 
213 	for (p = &sq_mapping_list; (map = *p); p = &map->next)
214 		if (map->sq_addr == vaddr)
215 			break;
216 
217 	if (unlikely(!map)) {
218 		printk("%s: bad store queue address 0x%08lx\n",
219 		       __func__, vaddr);
220 		return;
221 	}
222 
223 	page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
224 	bitmap_release_region(sq_bitmap, page, get_order(map->size));
225 
226 #ifdef CONFIG_MMU
227 	{
228 		/*
229 		 * Tear down the VMA in the MMU case.
230 		 */
231 		struct vm_struct *vma;
232 
233 		vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
234 		if (!vma) {
235 			printk(KERN_ERR "%s: bad address 0x%08lx\n",
236 			       __func__, map->sq_addr);
237 			return;
238 		}
239 	}
240 #endif
241 
242 	sq_mapping_list_del(map);
243 
244 	kmem_cache_free(sq_cache, map);
245 }
246 EXPORT_SYMBOL(sq_unmap);
247 
248 /*
249  * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
250  * there is any other easy way to add things on a per-cpu basis without
251  * putting the directory entries somewhere stupid and having to create
252  * links in sysfs by hand back in to the per-cpu directories.
253  *
254  * Some day we may want to have an additional abstraction per store
255  * queue, but considering the kobject hell we already have to deal with,
256  * it's simply not worth the trouble.
257  */
258 static struct kobject *sq_kobject[NR_CPUS];
259 
260 struct sq_sysfs_attr {
261 	struct attribute attr;
262 	ssize_t (*show)(char *buf);
263 	ssize_t (*store)(const char *buf, size_t count);
264 };
265 
266 #define to_sq_sysfs_attr(a)	container_of(a, struct sq_sysfs_attr, attr)
267 
268 static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
269 			     char *buf)
270 {
271 	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
272 
273 	if (likely(sattr->show))
274 		return sattr->show(buf);
275 
276 	return -EIO;
277 }
278 
279 static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
280 			      const char *buf, size_t count)
281 {
282 	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
283 
284 	if (likely(sattr->store))
285 		return sattr->store(buf, count);
286 
287 	return -EIO;
288 }
289 
290 static ssize_t mapping_show(char *buf)
291 {
292 	struct sq_mapping **list, *entry;
293 	char *p = buf;
294 
295 	for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
296 		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
297 			     entry->sq_addr, entry->sq_addr + entry->size,
298 			     entry->addr, entry->name);
299 
300 	return p - buf;
301 }
302 
303 static ssize_t mapping_store(const char *buf, size_t count)
304 {
305 	unsigned long base = 0, len = 0;
306 
307 	sscanf(buf, "%lx %lx", &base, &len);
308 	if (!base)
309 		return -EIO;
310 
311 	if (likely(len)) {
312 		int ret = sq_remap(base, len, "Userspace",
313 				   pgprot_val(PAGE_SHARED));
314 		if (ret < 0)
315 			return ret;
316 	} else
317 		sq_unmap(base);
318 
319 	return count;
320 }
321 
322 static struct sq_sysfs_attr mapping_attr =
323 	__ATTR(mapping, 0644, mapping_show, mapping_store);
324 
325 static struct attribute *sq_sysfs_attrs[] = {
326 	&mapping_attr.attr,
327 	NULL,
328 };
329 
330 static struct sysfs_ops sq_sysfs_ops = {
331 	.show	= sq_sysfs_show,
332 	.store	= sq_sysfs_store,
333 };
334 
335 static struct kobj_type ktype_percpu_entry = {
336 	.sysfs_ops	= &sq_sysfs_ops,
337 	.default_attrs	= sq_sysfs_attrs,
338 };
339 
340 static int __devinit sq_sysdev_add(struct sys_device *sysdev)
341 {
342 	unsigned int cpu = sysdev->id;
343 	struct kobject *kobj;
344 	int error;
345 
346 	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
347 	if (unlikely(!sq_kobject[cpu]))
348 		return -ENOMEM;
349 
350 	kobj = sq_kobject[cpu];
351 	error = kobject_init_and_add(kobj, &ktype_percpu_entry, &sysdev->kobj,
352 				     "%s", "sq");
353 	if (!error)
354 		kobject_uevent(kobj, KOBJ_ADD);
355 	return error;
356 }
357 
358 static int __devexit sq_sysdev_remove(struct sys_device *sysdev)
359 {
360 	unsigned int cpu = sysdev->id;
361 	struct kobject *kobj = sq_kobject[cpu];
362 
363 	kobject_put(kobj);
364 	return 0;
365 }
366 
367 static struct sysdev_driver sq_sysdev_driver = {
368 	.add		= sq_sysdev_add,
369 	.remove		= __devexit_p(sq_sysdev_remove),
370 };
371 
372 static int __init sq_api_init(void)
373 {
374 	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
375 	unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
376 	int ret = -ENOMEM;
377 
378 	printk(KERN_NOTICE "sq: Registering store queue API.\n");
379 
380 	sq_cache = kmem_cache_create("store_queue_cache",
381 				sizeof(struct sq_mapping), 0, 0, NULL);
382 	if (unlikely(!sq_cache))
383 		return ret;
384 
385 	sq_bitmap = kzalloc(size, GFP_KERNEL);
386 	if (unlikely(!sq_bitmap))
387 		goto out;
388 
389 	ret = sysdev_driver_register(&cpu_sysdev_class, &sq_sysdev_driver);
390 	if (unlikely(ret != 0))
391 		goto out;
392 
393 	return 0;
394 
395 out:
396 	kfree(sq_bitmap);
397 	kmem_cache_destroy(sq_cache);
398 
399 	return ret;
400 }
401 
402 static void __exit sq_api_exit(void)
403 {
404 	sysdev_driver_unregister(&cpu_sysdev_class, &sq_sysdev_driver);
405 	kfree(sq_bitmap);
406 	kmem_cache_destroy(sq_cache);
407 }
408 
409 module_init(sq_api_init);
410 module_exit(sq_api_exit);
411 
412 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
413 MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
414 MODULE_LICENSE("GPL");
415