1/* 2 * c 2001 PPC 64 Team, IBM Corp 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * /dev/nvram driver for PPC64 10 * 11 * This perhaps should live in drivers/char 12 */ 13 14 15#include <linux/types.h> 16#include <linux/errno.h> 17#include <linux/init.h> 18#include <linux/spinlock.h> 19#include <asm/uaccess.h> 20#include <asm/nvram.h> 21#include <asm/rtas.h> 22#include <asm/prom.h> 23#include <asm/machdep.h> 24 25static unsigned int nvram_size; 26static int nvram_fetch, nvram_store; 27static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 28static DEFINE_SPINLOCK(nvram_lock); 29 30 31static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 32{ 33 unsigned int i; 34 unsigned long len; 35 int done; 36 unsigned long flags; 37 char *p = buf; 38 39 40 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 41 return -ENODEV; 42 43 if (*index >= nvram_size) 44 return 0; 45 46 i = *index; 47 if (i + count > nvram_size) 48 count = nvram_size - i; 49 50 spin_lock_irqsave(&nvram_lock, flags); 51 52 for (; count != 0; count -= len) { 53 len = count; 54 if (len > NVRW_CNT) 55 len = NVRW_CNT; 56 57 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 58 len) != 0) || len != done) { 59 spin_unlock_irqrestore(&nvram_lock, flags); 60 return -EIO; 61 } 62 63 memcpy(p, nvram_buf, len); 64 65 p += len; 66 i += len; 67 } 68 69 spin_unlock_irqrestore(&nvram_lock, flags); 70 71 *index = i; 72 return p - buf; 73} 74 75static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 76{ 77 unsigned int i; 78 unsigned long len; 79 int done; 80 unsigned long flags; 81 const char *p = buf; 82 83 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 84 return -ENODEV; 85 86 if (*index >= nvram_size) 87 return 0; 88 89 i = *index; 90 if (i + count > nvram_size) 91 count = nvram_size - i; 92 93 spin_lock_irqsave(&nvram_lock, flags); 94 95 for (; count != 0; count -= len) { 96 len = count; 97 if (len > NVRW_CNT) 98 len = NVRW_CNT; 99 100 memcpy(nvram_buf, p, len); 101 102 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 103 len) != 0) || len != done) { 104 spin_unlock_irqrestore(&nvram_lock, flags); 105 return -EIO; 106 } 107 108 p += len; 109 i += len; 110 } 111 spin_unlock_irqrestore(&nvram_lock, flags); 112 113 *index = i; 114 return p - buf; 115} 116 117static ssize_t pSeries_nvram_get_size(void) 118{ 119 return nvram_size ? nvram_size : -ENODEV; 120} 121 122int __init pSeries_nvram_init(void) 123{ 124 struct device_node *nvram; 125 const unsigned int *nbytes_p; 126 unsigned int proplen; 127 128 nvram = of_find_node_by_type(NULL, "nvram"); 129 if (nvram == NULL) 130 return -ENODEV; 131 132 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 133 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { 134 of_node_put(nvram); 135 return -EIO; 136 } 137 138 nvram_size = *nbytes_p; 139 140 nvram_fetch = rtas_token("nvram-fetch"); 141 nvram_store = rtas_token("nvram-store"); 142 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 143 of_node_put(nvram); 144 145 ppc_md.nvram_read = pSeries_nvram_read; 146 ppc_md.nvram_write = pSeries_nvram_write; 147 ppc_md.nvram_size = pSeries_nvram_get_size; 148 149 return 0; 150} 151