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