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/slab.h> 19#include <linux/spinlock.h> 20#include <asm/uaccess.h> 21#include <asm/nvram.h> 22#include <asm/rtas.h> 23#include <asm/prom.h> 24#include <asm/machdep.h> 25 26static unsigned int nvram_size; 27static int nvram_fetch, nvram_store; 28static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 29static DEFINE_SPINLOCK(nvram_lock); 30 31 32static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 33{ 34 unsigned int i; 35 unsigned long len; 36 int done; 37 unsigned long flags; 38 char *p = buf; 39 40 41 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 42 return -ENODEV; 43 44 if (*index >= nvram_size) 45 return 0; 46 47 i = *index; 48 if (i + count > nvram_size) 49 count = nvram_size - i; 50 51 spin_lock_irqsave(&nvram_lock, flags); 52 53 for (; count != 0; count -= len) { 54 len = count; 55 if (len > NVRW_CNT) 56 len = NVRW_CNT; 57 58 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 59 len) != 0) || len != done) { 60 spin_unlock_irqrestore(&nvram_lock, flags); 61 return -EIO; 62 } 63 64 memcpy(p, nvram_buf, len); 65 66 p += len; 67 i += len; 68 } 69 70 spin_unlock_irqrestore(&nvram_lock, flags); 71 72 *index = i; 73 return p - buf; 74} 75 76static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 77{ 78 unsigned int i; 79 unsigned long len; 80 int done; 81 unsigned long flags; 82 const char *p = buf; 83 84 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 85 return -ENODEV; 86 87 if (*index >= nvram_size) 88 return 0; 89 90 i = *index; 91 if (i + count > nvram_size) 92 count = nvram_size - i; 93 94 spin_lock_irqsave(&nvram_lock, flags); 95 96 for (; count != 0; count -= len) { 97 len = count; 98 if (len > NVRW_CNT) 99 len = NVRW_CNT; 100 101 memcpy(nvram_buf, p, len); 102 103 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 104 len) != 0) || len != done) { 105 spin_unlock_irqrestore(&nvram_lock, flags); 106 return -EIO; 107 } 108 109 p += len; 110 i += len; 111 } 112 spin_unlock_irqrestore(&nvram_lock, flags); 113 114 *index = i; 115 return p - buf; 116} 117 118static ssize_t pSeries_nvram_get_size(void) 119{ 120 return nvram_size ? nvram_size : -ENODEV; 121} 122 123int __init pSeries_nvram_init(void) 124{ 125 struct device_node *nvram; 126 const unsigned int *nbytes_p; 127 unsigned int proplen; 128 129 nvram = of_find_node_by_type(NULL, "nvram"); 130 if (nvram == NULL) 131 return -ENODEV; 132 133 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 134 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) 135 return -EIO; 136 137 nvram_size = *nbytes_p; 138 139 nvram_fetch = rtas_token("nvram-fetch"); 140 nvram_store = rtas_token("nvram-store"); 141 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 142 of_node_put(nvram); 143 144 ppc_md.nvram_read = pSeries_nvram_read; 145 ppc_md.nvram_write = pSeries_nvram_write; 146 ppc_md.nvram_size = pSeries_nvram_get_size; 147 148 return 0; 149} 150