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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 17:45:09 +07:00
3b8070335f
The OPAL NVRAM driver does not sleep in case it gets OPAL_BUSY or OPAL_BUSY_EVENT from firmware, which causes large scheduling latencies, and various lockup errors to trigger (again, BMC reboot can cause it). Fix this by converting it to the standard form OPAL_BUSY loop that sleeps. Fixes:628daa8d5a("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks") Depends-on:34dd25de9f("powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops") Cc: stable@vger.kernel.org # v3.2+ Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
108 lines
2.1 KiB
C
108 lines
2.1 KiB
C
/*
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* PowerNV nvram code.
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*
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* Copyright 2011 IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define DEBUG
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <asm/opal.h>
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#include <asm/nvram.h>
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#include <asm/machdep.h>
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static unsigned int nvram_size;
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static ssize_t opal_nvram_size(void)
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{
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return nvram_size;
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}
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static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
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{
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s64 rc;
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int off;
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if (*index >= nvram_size)
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return 0;
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off = *index;
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if ((off + count) > nvram_size)
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count = nvram_size - off;
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rc = opal_read_nvram(__pa(buf), count, off);
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if (rc != OPAL_SUCCESS)
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return -EIO;
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*index += count;
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return count;
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}
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static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
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{
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s64 rc = OPAL_BUSY;
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int off;
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if (*index >= nvram_size)
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return 0;
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off = *index;
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if ((off + count) > nvram_size)
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count = nvram_size - off;
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while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
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rc = opal_write_nvram(__pa(buf), count, off);
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if (rc == OPAL_BUSY_EVENT) {
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msleep(OPAL_BUSY_DELAY_MS);
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opal_poll_events(NULL);
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} else if (rc == OPAL_BUSY) {
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msleep(OPAL_BUSY_DELAY_MS);
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}
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}
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if (rc)
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return -EIO;
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*index += count;
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return count;
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}
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static int __init opal_nvram_init_log_partitions(void)
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{
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/* Scan nvram for partitions */
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nvram_scan_partitions();
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nvram_init_oops_partition(0);
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return 0;
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}
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machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
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void __init opal_nvram_init(void)
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{
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struct device_node *np;
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const __be32 *nbytes_p;
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np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
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if (np == NULL)
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return;
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nbytes_p = of_get_property(np, "#bytes", NULL);
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if (!nbytes_p) {
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of_node_put(np);
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return;
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}
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nvram_size = be32_to_cpup(nbytes_p);
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pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
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of_node_put(np);
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ppc_md.nvram_read = opal_nvram_read;
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ppc_md.nvram_write = opal_nvram_write;
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ppc_md.nvram_size = opal_nvram_size;
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}
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