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