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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | // 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/of_address.h> #include <linux/spinlock.h> #include <linux/types.h> #include <asm/machdep.h> #include <asm/nvram.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; } |