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 12 13 #include <linux/types.h> 14 #include <linux/errno.h> 15 #include <linux/init.h> 16 #include <linux/spinlock.h> 17 #include <linux/slab.h> 18 #include <linux/ctype.h> 19 #include <linux/uaccess.h> 20 #include <asm/nvram.h> 21 #include <asm/rtas.h> 22 #include <asm/prom.h> 23 #include <asm/machdep.h> 24 25 /* Max bytes to read/write in one go */ 26 #define NVRW_CNT 0x20 27 28 static unsigned int nvram_size; 29 static int nvram_fetch, nvram_store; 30 static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 31 static DEFINE_SPINLOCK(nvram_lock); 32 33 /* See clobbering_unread_rtas_event() */ 34 #define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */ 35 static time64_t last_unread_rtas_event; /* timestamp */ 36 37 #ifdef CONFIG_PSTORE 38 time64_t last_rtas_event; 39 #endif 40 41 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 42 { 43 unsigned int i; 44 unsigned long len; 45 int done; 46 unsigned long flags; 47 char *p = buf; 48 49 50 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 51 return -ENODEV; 52 53 if (*index >= nvram_size) 54 return 0; 55 56 i = *index; 57 if (i + count > nvram_size) 58 count = nvram_size - i; 59 60 spin_lock_irqsave(&nvram_lock, flags); 61 62 for (; count != 0; count -= len) { 63 len = count; 64 if (len > NVRW_CNT) 65 len = NVRW_CNT; 66 67 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 68 len) != 0) || len != done) { 69 spin_unlock_irqrestore(&nvram_lock, flags); 70 return -EIO; 71 } 72 73 memcpy(p, nvram_buf, len); 74 75 p += len; 76 i += len; 77 } 78 79 spin_unlock_irqrestore(&nvram_lock, flags); 80 81 *index = i; 82 return p - buf; 83 } 84 85 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 86 { 87 unsigned int i; 88 unsigned long len; 89 int done; 90 unsigned long flags; 91 const char *p = buf; 92 93 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 94 return -ENODEV; 95 96 if (*index >= nvram_size) 97 return 0; 98 99 i = *index; 100 if (i + count > nvram_size) 101 count = nvram_size - i; 102 103 spin_lock_irqsave(&nvram_lock, flags); 104 105 for (; count != 0; count -= len) { 106 len = count; 107 if (len > NVRW_CNT) 108 len = NVRW_CNT; 109 110 memcpy(nvram_buf, p, len); 111 112 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 113 len) != 0) || len != done) { 114 spin_unlock_irqrestore(&nvram_lock, flags); 115 return -EIO; 116 } 117 118 p += len; 119 i += len; 120 } 121 spin_unlock_irqrestore(&nvram_lock, flags); 122 123 *index = i; 124 return p - buf; 125 } 126 127 static ssize_t pSeries_nvram_get_size(void) 128 { 129 return nvram_size ? nvram_size : -ENODEV; 130 } 131 132 /* nvram_write_error_log 133 * 134 * We need to buffer the error logs into nvram to ensure that we have 135 * the failure information to decode. 136 */ 137 int nvram_write_error_log(char * buff, int length, 138 unsigned int err_type, unsigned int error_log_cnt) 139 { 140 int rc = nvram_write_os_partition(&rtas_log_partition, buff, length, 141 err_type, error_log_cnt); 142 if (!rc) { 143 last_unread_rtas_event = ktime_get_real_seconds(); 144 #ifdef CONFIG_PSTORE 145 last_rtas_event = ktime_get_real_seconds(); 146 #endif 147 } 148 149 return rc; 150 } 151 152 /* nvram_read_error_log 153 * 154 * Reads nvram for error log for at most 'length' 155 */ 156 int nvram_read_error_log(char *buff, int length, 157 unsigned int *err_type, unsigned int *error_log_cnt) 158 { 159 return nvram_read_partition(&rtas_log_partition, buff, length, 160 err_type, error_log_cnt); 161 } 162 163 /* This doesn't actually zero anything, but it sets the event_logged 164 * word to tell that this event is safely in syslog. 165 */ 166 int nvram_clear_error_log(void) 167 { 168 loff_t tmp_index; 169 int clear_word = ERR_FLAG_ALREADY_LOGGED; 170 int rc; 171 172 if (rtas_log_partition.index == -1) 173 return -1; 174 175 tmp_index = rtas_log_partition.index; 176 177 rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index); 178 if (rc <= 0) { 179 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc); 180 return rc; 181 } 182 last_unread_rtas_event = 0; 183 184 return 0; 185 } 186 187 /* 188 * Are we using the ibm,rtas-log for oops/panic reports? And if so, 189 * would logging this oops/panic overwrite an RTAS event that rtas_errd 190 * hasn't had a chance to read and process? Return 1 if so, else 0. 191 * 192 * We assume that if rtas_errd hasn't read the RTAS event in 193 * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to. 194 */ 195 int clobbering_unread_rtas_event(void) 196 { 197 return (oops_log_partition.index == rtas_log_partition.index 198 && last_unread_rtas_event 199 && ktime_get_real_seconds() - last_unread_rtas_event <= 200 NVRAM_RTAS_READ_TIMEOUT); 201 } 202 203 static int __init pseries_nvram_init_log_partitions(void) 204 { 205 int rc; 206 207 /* Scan nvram for partitions */ 208 nvram_scan_partitions(); 209 210 rc = nvram_init_os_partition(&rtas_log_partition); 211 nvram_init_oops_partition(rc == 0); 212 return 0; 213 } 214 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions); 215 216 int __init pSeries_nvram_init(void) 217 { 218 struct device_node *nvram; 219 const __be32 *nbytes_p; 220 unsigned int proplen; 221 222 nvram = of_find_node_by_type(NULL, "nvram"); 223 if (nvram == NULL) 224 return -ENODEV; 225 226 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 227 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { 228 of_node_put(nvram); 229 return -EIO; 230 } 231 232 nvram_size = be32_to_cpup(nbytes_p); 233 234 nvram_fetch = rtas_token("nvram-fetch"); 235 nvram_store = rtas_token("nvram-store"); 236 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 237 of_node_put(nvram); 238 239 ppc_md.nvram_read = pSeries_nvram_read; 240 ppc_md.nvram_write = pSeries_nvram_write; 241 ppc_md.nvram_size = pSeries_nvram_get_size; 242 243 return 0; 244 } 245 246