2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
139 lines
3.1 KiB
C
139 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* PowerNV OPAL in-memory console interface
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*
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* Copyright 2014 IBM Corp.
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*/
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#include <asm/io.h>
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#include <asm/opal.h>
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#include <linux/debugfs.h>
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#include <linux/of.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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/* OPAL in-memory console. Defined in OPAL source at core/console.c */
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struct memcons {
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__be64 magic;
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#define MEMCONS_MAGIC 0x6630696567726173L
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__be64 obuf_phys;
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__be64 ibuf_phys;
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__be32 obuf_size;
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__be32 ibuf_size;
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__be32 out_pos;
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#define MEMCONS_OUT_POS_WRAP 0x80000000u
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#define MEMCONS_OUT_POS_MASK 0x00ffffffu
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__be32 in_prod;
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__be32 in_cons;
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};
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static struct memcons *opal_memcons = NULL;
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ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
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{
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const char *conbuf;
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ssize_t ret;
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size_t first_read = 0;
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uint32_t out_pos, avail;
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if (!opal_memcons)
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return -ENODEV;
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out_pos = be32_to_cpu(READ_ONCE(opal_memcons->out_pos));
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/* Now we've read out_pos, put a barrier in before reading the new
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* data it points to in conbuf. */
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smp_rmb();
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conbuf = phys_to_virt(be64_to_cpu(opal_memcons->obuf_phys));
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/* When the buffer has wrapped, read from the out_pos marker to the end
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* of the buffer, and then read the remaining data as in the un-wrapped
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* case. */
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if (out_pos & MEMCONS_OUT_POS_WRAP) {
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out_pos &= MEMCONS_OUT_POS_MASK;
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avail = be32_to_cpu(opal_memcons->obuf_size) - out_pos;
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ret = memory_read_from_buffer(to, count, &pos,
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conbuf + out_pos, avail);
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if (ret < 0)
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goto out;
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first_read = ret;
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to += first_read;
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count -= first_read;
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pos -= avail;
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if (count <= 0)
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goto out;
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}
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/* Sanity check. The firmware should not do this to us. */
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if (out_pos > be32_to_cpu(opal_memcons->obuf_size)) {
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pr_err("OPAL: memory console corruption. Aborting read.\n");
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return -EINVAL;
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}
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ret = memory_read_from_buffer(to, count, &pos, conbuf, out_pos);
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if (ret < 0)
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goto out;
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ret += first_read;
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out:
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return ret;
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}
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static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *to,
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loff_t pos, size_t count)
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{
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return opal_msglog_copy(to, pos, count);
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}
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static struct bin_attribute opal_msglog_attr = {
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.attr = {.name = "msglog", .mode = 0400},
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.read = opal_msglog_read
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};
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void __init opal_msglog_init(void)
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{
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u64 mcaddr;
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struct memcons *mc;
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if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr)) {
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pr_warn("OPAL: Property ibm,opal-memcons not found, no message log\n");
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return;
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}
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mc = phys_to_virt(mcaddr);
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if (!mc) {
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pr_warn("OPAL: memory console address is invalid\n");
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return;
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}
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if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
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pr_warn("OPAL: memory console version is invalid\n");
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return;
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}
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/* Report maximum size */
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opal_msglog_attr.size = be32_to_cpu(mc->ibuf_size) +
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be32_to_cpu(mc->obuf_size);
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opal_memcons = mc;
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}
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void __init opal_msglog_sysfs_init(void)
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{
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if (!opal_memcons) {
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pr_warn("OPAL: message log initialisation failed, not creating sysfs entry\n");
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return;
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}
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if (sysfs_create_bin_file(opal_kobj, &opal_msglog_attr) != 0)
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pr_warn("OPAL: sysfs file creation failed\n");
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}
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