diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/nvram.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/nvram.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c new file mode 100644 index 000000000..8130c3796 --- /dev/null +++ b/arch/powerpc/platforms/pseries/nvram.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * c 2001 PPC 64 Team, IBM Corp + * + * /dev/nvram driver for PPC64 + */ + + +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/uaccess.h> +#include <linux/of.h> +#include <asm/nvram.h> +#include <asm/rtas.h> +#include <asm/machdep.h> + +/* Max bytes to read/write in one go */ +#define NVRW_CNT 0x20 + +static unsigned int nvram_size; +static int nvram_fetch, nvram_store; +static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ +static DEFINE_SPINLOCK(nvram_lock); + +/* See clobbering_unread_rtas_event() */ +#define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */ +static time64_t last_unread_rtas_event; /* timestamp */ + +#ifdef CONFIG_PSTORE +time64_t last_rtas_event; +#endif + +static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) +{ + unsigned int i; + unsigned long len; + int done; + unsigned long flags; + char *p = buf; + + + if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) + return -ENODEV; + + if (*index >= nvram_size) + return 0; + + i = *index; + if (i + count > nvram_size) + count = nvram_size - i; + + spin_lock_irqsave(&nvram_lock, flags); + + for (; count != 0; count -= len) { + len = count; + if (len > NVRW_CNT) + len = NVRW_CNT; + + if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), + len) != 0) || len != done) { + spin_unlock_irqrestore(&nvram_lock, flags); + return -EIO; + } + + memcpy(p, nvram_buf, len); + + p += len; + i += len; + } + + spin_unlock_irqrestore(&nvram_lock, flags); + + *index = i; + return p - buf; +} + +static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) +{ + unsigned int i; + unsigned long len; + int done; + unsigned long flags; + const char *p = buf; + + if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) + return -ENODEV; + + if (*index >= nvram_size) + return 0; + + i = *index; + if (i + count > nvram_size) + count = nvram_size - i; + + spin_lock_irqsave(&nvram_lock, flags); + + for (; count != 0; count -= len) { + len = count; + if (len > NVRW_CNT) + len = NVRW_CNT; + + memcpy(nvram_buf, p, len); + + if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), + len) != 0) || len != done) { + spin_unlock_irqrestore(&nvram_lock, flags); + return -EIO; + } + + p += len; + i += len; + } + spin_unlock_irqrestore(&nvram_lock, flags); + + *index = i; + return p - buf; +} + +static ssize_t pSeries_nvram_get_size(void) +{ + return nvram_size ? nvram_size : -ENODEV; +} + +/* nvram_write_error_log + * + * We need to buffer the error logs into nvram to ensure that we have + * the failure information to decode. + */ +int nvram_write_error_log(char * buff, int length, + unsigned int err_type, unsigned int error_log_cnt) +{ + int rc = nvram_write_os_partition(&rtas_log_partition, buff, length, + err_type, error_log_cnt); + if (!rc) { + last_unread_rtas_event = ktime_get_real_seconds(); +#ifdef CONFIG_PSTORE + last_rtas_event = ktime_get_real_seconds(); +#endif + } + + return rc; +} + +/* nvram_read_error_log + * + * Reads nvram for error log for at most 'length' + */ +int nvram_read_error_log(char *buff, int length, + unsigned int *err_type, unsigned int *error_log_cnt) +{ + return nvram_read_partition(&rtas_log_partition, buff, length, + err_type, error_log_cnt); +} + +/* This doesn't actually zero anything, but it sets the event_logged + * word to tell that this event is safely in syslog. + */ +int nvram_clear_error_log(void) +{ + loff_t tmp_index; + int clear_word = ERR_FLAG_ALREADY_LOGGED; + int rc; + + if (rtas_log_partition.index == -1) + return -1; + + tmp_index = rtas_log_partition.index; + + rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index); + if (rc <= 0) { + printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc); + return rc; + } + last_unread_rtas_event = 0; + + return 0; +} + +/* + * Are we using the ibm,rtas-log for oops/panic reports? And if so, + * would logging this oops/panic overwrite an RTAS event that rtas_errd + * hasn't had a chance to read and process? Return 1 if so, else 0. + * + * We assume that if rtas_errd hasn't read the RTAS event in + * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to. + */ +int clobbering_unread_rtas_event(void) +{ + return (oops_log_partition.index == rtas_log_partition.index + && last_unread_rtas_event + && ktime_get_real_seconds() - last_unread_rtas_event <= + NVRAM_RTAS_READ_TIMEOUT); +} + +static int __init pseries_nvram_init_log_partitions(void) +{ + int rc; + + /* Scan nvram for partitions */ + nvram_scan_partitions(); + + rc = nvram_init_os_partition(&rtas_log_partition); + nvram_init_oops_partition(rc == 0); + return 0; +} +machine_arch_initcall(pseries, pseries_nvram_init_log_partitions); + +int __init pSeries_nvram_init(void) +{ + struct device_node *nvram; + const __be32 *nbytes_p; + unsigned int proplen; + + nvram = of_find_node_by_type(NULL, "nvram"); + if (nvram == NULL) + return -ENODEV; + + nbytes_p = of_get_property(nvram, "#bytes", &proplen); + if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { + of_node_put(nvram); + return -EIO; + } + + nvram_size = be32_to_cpup(nbytes_p); + + nvram_fetch = rtas_function_token(RTAS_FN_NVRAM_FETCH); + nvram_store = rtas_function_token(RTAS_FN_NVRAM_STORE); + printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); + of_node_put(nvram); + + ppc_md.nvram_read = pSeries_nvram_read; + ppc_md.nvram_write = pSeries_nvram_write; + ppc_md.nvram_size = pSeries_nvram_get_size; + + return 0; +} + |