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 <linux/slab.h> 20 #include <linux/ctype.h> 21 #include <linux/uaccess.h> 22 #include <asm/nvram.h> 23 #include <asm/rtas.h> 24 #include <asm/prom.h> 25 #include <asm/machdep.h> 26 27 /* Max bytes to read/write in one go */ 28 #define NVRW_CNT 0x20 29 30 static unsigned int nvram_size; 31 static int nvram_fetch, nvram_store; 32 static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 33 static DEFINE_SPINLOCK(nvram_lock); 34 35 /* See clobbering_unread_rtas_event() */ 36 #define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */ 37 static time64_t last_unread_rtas_event; /* timestamp */ 38 39 #ifdef CONFIG_PSTORE 40 time64_t last_rtas_event; 41 #endif 42 43 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 44 { 45 unsigned int i; 46 unsigned long len; 47 int done; 48 unsigned long flags; 49 char *p = buf; 50 51 52 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 53 return -ENODEV; 54 55 if (*index >= nvram_size) 56 return 0; 57 58 i = *index; 59 if (i + count > nvram_size) 60 count = nvram_size - i; 61 62 spin_lock_irqsave(&nvram_lock, flags); 63 64 for (; count != 0; count -= len) { 65 len = count; 66 if (len > NVRW_CNT) 67 len = NVRW_CNT; 68 69 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 70 len) != 0) || len != done) { 71 spin_unlock_irqrestore(&nvram_lock, flags); 72 return -EIO; 73 } 74 75 memcpy(p, nvram_buf, len); 76 77 p += len; 78 i += len; 79 } 80 81 spin_unlock_irqrestore(&nvram_lock, flags); 82 83 *index = i; 84 return p - buf; 85 } 86 87 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 88 { 89 unsigned int i; 90 unsigned long len; 91 int done; 92 unsigned long flags; 93 const char *p = buf; 94 95 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 96 return -ENODEV; 97 98 if (*index >= nvram_size) 99 return 0; 100 101 i = *index; 102 if (i + count > nvram_size) 103 count = nvram_size - i; 104 105 spin_lock_irqsave(&nvram_lock, flags); 106 107 for (; count != 0; count -= len) { 108 len = count; 109 if (len > NVRW_CNT) 110 len = NVRW_CNT; 111 112 memcpy(nvram_buf, p, len); 113 114 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 115 len) != 0) || len != done) { 116 spin_unlock_irqrestore(&nvram_lock, flags); 117 return -EIO; 118 } 119 120 p += len; 121 i += len; 122 } 123 spin_unlock_irqrestore(&nvram_lock, flags); 124 125 *index = i; 126 return p - buf; 127 } 128 129 static ssize_t pSeries_nvram_get_size(void) 130 { 131 return nvram_size ? nvram_size : -ENODEV; 132 } 133 134 /* nvram_write_error_log 135 * 136 * We need to buffer the error logs into nvram to ensure that we have 137 * the failure information to decode. 138 */ 139 int nvram_write_error_log(char * buff, int length, 140 unsigned int err_type, unsigned int error_log_cnt) 141 { 142 int rc = nvram_write_os_partition(&rtas_log_partition, buff, length, 143 err_type, error_log_cnt); 144 if (!rc) { 145 last_unread_rtas_event = ktime_get_real_seconds(); 146 #ifdef CONFIG_PSTORE 147 last_rtas_event = ktime_get_real_seconds(); 148 #endif 149 } 150 151 return rc; 152 } 153 154 /* nvram_read_error_log 155 * 156 * Reads nvram for error log for at most 'length' 157 */ 158 int nvram_read_error_log(char *buff, int length, 159 unsigned int *err_type, unsigned int *error_log_cnt) 160 { 161 return nvram_read_partition(&rtas_log_partition, buff, length, 162 err_type, error_log_cnt); 163 } 164 165 /* This doesn't actually zero anything, but it sets the event_logged 166 * word to tell that this event is safely in syslog. 167 */ 168 int nvram_clear_error_log(void) 169 { 170 loff_t tmp_index; 171 int clear_word = ERR_FLAG_ALREADY_LOGGED; 172 int rc; 173 174 if (rtas_log_partition.index == -1) 175 return -1; 176 177 tmp_index = rtas_log_partition.index; 178 179 rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index); 180 if (rc <= 0) { 181 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc); 182 return rc; 183 } 184 last_unread_rtas_event = 0; 185 186 return 0; 187 } 188 189 /* 190 * Are we using the ibm,rtas-log for oops/panic reports? And if so, 191 * would logging this oops/panic overwrite an RTAS event that rtas_errd 192 * hasn't had a chance to read and process? Return 1 if so, else 0. 193 * 194 * We assume that if rtas_errd hasn't read the RTAS event in 195 * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to. 196 */ 197 int clobbering_unread_rtas_event(void) 198 { 199 return (oops_log_partition.index == rtas_log_partition.index 200 && last_unread_rtas_event 201 && ktime_get_real_seconds() - last_unread_rtas_event <= 202 NVRAM_RTAS_READ_TIMEOUT); 203 } 204 205 static int __init pseries_nvram_init_log_partitions(void) 206 { 207 int rc; 208 209 /* Scan nvram for partitions */ 210 nvram_scan_partitions(); 211 212 rc = nvram_init_os_partition(&rtas_log_partition); 213 nvram_init_oops_partition(rc == 0); 214 return 0; 215 } 216 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions); 217 218 int __init pSeries_nvram_init(void) 219 { 220 struct device_node *nvram; 221 const __be32 *nbytes_p; 222 unsigned int proplen; 223 224 nvram = of_find_node_by_type(NULL, "nvram"); 225 if (nvram == NULL) 226 return -ENODEV; 227 228 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 229 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { 230 of_node_put(nvram); 231 return -EIO; 232 } 233 234 nvram_size = be32_to_cpup(nbytes_p); 235 236 nvram_fetch = rtas_token("nvram-fetch"); 237 nvram_store = rtas_token("nvram-store"); 238 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 239 of_node_put(nvram); 240 241 ppc_md.nvram_read = pSeries_nvram_read; 242 ppc_md.nvram_write = pSeries_nvram_write; 243 ppc_md.nvram_size = pSeries_nvram_get_size; 244 245 return 0; 246 } 247 248