// SPDX-License-Identifier: GPL-2.0-or-later /* * memory mapped NVRAM * * (C) Copyright IBM Corp. 2005 * * Authors : Utz Bacher <utz.bacher@de.ibm.com> */ #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/spinlock.h> #include <linux/types.h> #include <asm/machdep.h> #include <asm/nvram.h> #include <asm/prom.h> static void __iomem *mmio_nvram_start; static long mmio_nvram_len; static DEFINE_SPINLOCK(mmio_nvram_lock); static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index) { unsigned long flags; if (*index >= mmio_nvram_len) return 0; if (*index + count > mmio_nvram_len) count = mmio_nvram_len - *index; spin_lock_irqsave(&mmio_nvram_lock, flags); memcpy_fromio(buf, mmio_nvram_start + *index, count); spin_unlock_irqrestore(&mmio_nvram_lock, flags); *index += count; return count; } static unsigned char mmio_nvram_read_val(int addr) { unsigned long flags; unsigned char val; if (addr >= mmio_nvram_len) return 0xff; spin_lock_irqsave(&mmio_nvram_lock, flags); val = ioread8(mmio_nvram_start + addr); spin_unlock_irqrestore(&mmio_nvram_lock, flags); return val; } static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index) { unsigned long flags; if (*index >= mmio_nvram_len) return 0; if (*index + count > mmio_nvram_len) count = mmio_nvram_len - *index; spin_lock_irqsave(&mmio_nvram_lock, flags); memcpy_toio(mmio_nvram_start + *index, buf, count); spin_unlock_irqrestore(&mmio_nvram_lock, flags); *index += count; return count; } static void mmio_nvram_write_val(int addr, unsigned char val) { unsigned long flags; if (addr < mmio_nvram_len) { spin_lock_irqsave(&mmio_nvram_lock, flags); iowrite8(val, mmio_nvram_start + addr); spin_unlock_irqrestore(&mmio_nvram_lock, flags); } } static ssize_t mmio_nvram_get_size(void) { return mmio_nvram_len; } int __init mmio_nvram_init(void) { struct device_node *nvram_node; unsigned long nvram_addr; struct resource r; int ret; nvram_node = of_find_node_by_type(NULL, "nvram"); if (!nvram_node) nvram_node = of_find_compatible_node(NULL, NULL, "nvram"); if (!nvram_node) { printk(KERN_WARNING "nvram: no node found in device-tree\n"); return -ENODEV; } ret = of_address_to_resource(nvram_node, 0, &r); if (ret) { printk(KERN_WARNING "nvram: failed to get address (err %d)\n", ret); goto out; } nvram_addr = r.start; mmio_nvram_len = resource_size(&r); if ( (!mmio_nvram_len) || (!nvram_addr) ) { printk(KERN_WARNING "nvram: address or length is 0\n"); ret = -EIO; goto out; } mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len); if (!mmio_nvram_start) { printk(KERN_WARNING "nvram: failed to ioremap\n"); ret = -ENOMEM; goto out; } printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n", mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start); ppc_md.nvram_read_val = mmio_nvram_read_val; ppc_md.nvram_write_val = mmio_nvram_write_val; ppc_md.nvram_read = mmio_nvram_read; ppc_md.nvram_write = mmio_nvram_write; ppc_md.nvram_size = mmio_nvram_get_size; out: of_node_put(nvram_node); return ret; }