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/kmsg_dump.h> 21 #include <linux/pstore.h> 22 #include <linux/ctype.h> 23 #include <asm/uaccess.h> 24 #include <asm/nvram.h> 25 #include <asm/rtas.h> 26 #include <asm/prom.h> 27 #include <asm/machdep.h> 28 29 /* Max bytes to read/write in one go */ 30 #define NVRW_CNT 0x20 31 32 static unsigned int nvram_size; 33 static int nvram_fetch, nvram_store; 34 static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 35 static DEFINE_SPINLOCK(nvram_lock); 36 37 /* See clobbering_unread_rtas_event() */ 38 #define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */ 39 static time64_t last_unread_rtas_event; /* timestamp */ 40 41 #ifdef CONFIG_PSTORE 42 time64_t last_rtas_event; 43 #endif 44 45 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 46 { 47 unsigned int i; 48 unsigned long len; 49 int done; 50 unsigned long flags; 51 char *p = buf; 52 53 54 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 55 return -ENODEV; 56 57 if (*index >= nvram_size) 58 return 0; 59 60 i = *index; 61 if (i + count > nvram_size) 62 count = nvram_size - i; 63 64 spin_lock_irqsave(&nvram_lock, flags); 65 66 for (; count != 0; count -= len) { 67 len = count; 68 if (len > NVRW_CNT) 69 len = NVRW_CNT; 70 71 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 72 len) != 0) || len != done) { 73 spin_unlock_irqrestore(&nvram_lock, flags); 74 return -EIO; 75 } 76 77 memcpy(p, nvram_buf, len); 78 79 p += len; 80 i += len; 81 } 82 83 spin_unlock_irqrestore(&nvram_lock, flags); 84 85 *index = i; 86 return p - buf; 87 } 88 89 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 90 { 91 unsigned int i; 92 unsigned long len; 93 int done; 94 unsigned long flags; 95 const char *p = buf; 96 97 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 98 return -ENODEV; 99 100 if (*index >= nvram_size) 101 return 0; 102 103 i = *index; 104 if (i + count > nvram_size) 105 count = nvram_size - i; 106 107 spin_lock_irqsave(&nvram_lock, flags); 108 109 for (; count != 0; count -= len) { 110 len = count; 111 if (len > NVRW_CNT) 112 len = NVRW_CNT; 113 114 memcpy(nvram_buf, p, len); 115 116 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 117 len) != 0) || len != done) { 118 spin_unlock_irqrestore(&nvram_lock, flags); 119 return -EIO; 120 } 121 122 p += len; 123 i += len; 124 } 125 spin_unlock_irqrestore(&nvram_lock, flags); 126 127 *index = i; 128 return p - buf; 129 } 130 131 static ssize_t pSeries_nvram_get_size(void) 132 { 133 return nvram_size ? nvram_size : -ENODEV; 134 } 135 136 /* nvram_write_error_log 137 * 138 * We need to buffer the error logs into nvram to ensure that we have 139 * the failure information to decode. 140 */ 141 int nvram_write_error_log(char * buff, int length, 142 unsigned int err_type, unsigned int error_log_cnt) 143 { 144 int rc = nvram_write_os_partition(&rtas_log_partition, buff, length, 145 err_type, error_log_cnt); 146 if (!rc) { 147 last_unread_rtas_event = ktime_get_real_seconds(); 148 #ifdef CONFIG_PSTORE 149 last_rtas_event = ktime_get_real_seconds(); 150 #endif 151 } 152 153 return rc; 154 } 155 156 /* nvram_read_error_log 157 * 158 * Reads nvram for error log for at most 'length' 159 */ 160 int nvram_read_error_log(char *buff, int length, 161 unsigned int *err_type, unsigned int *error_log_cnt) 162 { 163 return nvram_read_partition(&rtas_log_partition, buff, length, 164 err_type, error_log_cnt); 165 } 166 167 /* This doesn't actually zero anything, but it sets the event_logged 168 * word to tell that this event is safely in syslog. 169 */ 170 int nvram_clear_error_log(void) 171 { 172 loff_t tmp_index; 173 int clear_word = ERR_FLAG_ALREADY_LOGGED; 174 int rc; 175 176 if (rtas_log_partition.index == -1) 177 return -1; 178 179 tmp_index = rtas_log_partition.index; 180 181 rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index); 182 if (rc <= 0) { 183 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc); 184 return rc; 185 } 186 last_unread_rtas_event = 0; 187 188 return 0; 189 } 190 191 /* 192 * Are we using the ibm,rtas-log for oops/panic reports? And if so, 193 * would logging this oops/panic overwrite an RTAS event that rtas_errd 194 * hasn't had a chance to read and process? Return 1 if so, else 0. 195 * 196 * We assume that if rtas_errd hasn't read the RTAS event in 197 * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to. 198 */ 199 int clobbering_unread_rtas_event(void) 200 { 201 return (oops_log_partition.index == rtas_log_partition.index 202 && last_unread_rtas_event 203 && ktime_get_real_seconds() - last_unread_rtas_event <= 204 NVRAM_RTAS_READ_TIMEOUT); 205 } 206 207 static int __init pseries_nvram_init_log_partitions(void) 208 { 209 int rc; 210 211 /* Scan nvram for partitions */ 212 nvram_scan_partitions(); 213 214 rc = nvram_init_os_partition(&rtas_log_partition); 215 nvram_init_oops_partition(rc == 0); 216 return 0; 217 } 218 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions); 219 220 int __init pSeries_nvram_init(void) 221 { 222 struct device_node *nvram; 223 const __be32 *nbytes_p; 224 unsigned int proplen; 225 226 nvram = of_find_node_by_type(NULL, "nvram"); 227 if (nvram == NULL) 228 return -ENODEV; 229 230 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 231 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { 232 of_node_put(nvram); 233 return -EIO; 234 } 235 236 nvram_size = be32_to_cpup(nbytes_p); 237 238 nvram_fetch = rtas_token("nvram-fetch"); 239 nvram_store = rtas_token("nvram-store"); 240 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 241 of_node_put(nvram); 242 243 ppc_md.nvram_read = pSeries_nvram_read; 244 ppc_md.nvram_write = pSeries_nvram_write; 245 ppc_md.nvram_size = pSeries_nvram_get_size; 246 247 return 0; 248 } 249 250