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161 lines
3.5 KiB
161 lines
3.5 KiB
// 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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#include "powernv.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 memcons_copy(struct memcons *mc, 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 (!mc) |
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return -ENODEV; |
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out_pos = be32_to_cpu(READ_ONCE(mc->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(mc->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(mc->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(mc->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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ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count) |
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{ |
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return memcons_copy(opal_memcons, to, pos, count); |
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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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struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name) |
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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(node, mc_prop_name, &mcaddr)) { |
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pr_warn("%s property not found, no message log\n", |
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mc_prop_name); |
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goto out_err; |
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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("memory console address is invalid\n"); |
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goto out_err; |
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} |
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if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) { |
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pr_warn("memory console version is invalid\n"); |
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goto out_err; |
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} |
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return mc; |
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out_err: |
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return NULL; |
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} |
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u32 memcons_get_size(struct memcons *mc) |
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{ |
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return be32_to_cpu(mc->ibuf_size) + be32_to_cpu(mc->obuf_size); |
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} |
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void __init opal_msglog_init(void) |
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{ |
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opal_memcons = memcons_init(opal_node, "ibm,opal-memcons"); |
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if (!opal_memcons) { |
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pr_warn("OPAL: memcons failed to load from ibm,opal-memcons\n"); |
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return; |
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} |
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opal_msglog_attr.size = memcons_get_size(opal_memcons); |
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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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