OPAL provides an in-memory circular buffer containing a message log
populated with various runtime messages produced by the firmware.
Provide a sysfs interface /sys/firmware/opal/messages for userspace to
view the messages.
Signed-off-by: Joel Stanley <j...@jms.id.au>
---
arch/powerpc/include/asm/opal.h | 4 ++
arch/powerpc/platforms/powernv/Makefile | 1 +
arch/powerpc/platforms/powernv/opal-messages.c | 97 ++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/opal.c | 4 +-
4 files changed, 105 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/platforms/powernv/opal-messages.c
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index ffafab0..6aa757e 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -729,6 +729,9 @@ typedef struct oppanel_line {
/* /sys/firmware/opal */
extern struct kobject *opal_kobj;
+/* /ibm,opal */
+extern struct device_node *opal_node;
+
/* API functions */
int64_t opal_console_write(int64_t term_number, __be64 *length,
const uint8_t *buffer);
@@ -918,6 +921,7 @@ extern void opal_flash_init(void);
extern int opal_elog_init(void);
extern void opal_platform_dump_init(void);
extern void opal_sys_param_init(void);
+extern void opal_messages_init(void);
extern int opal_machine_check(struct pt_regs *regs);
extern bool opal_mce_check_early_recovery(struct pt_regs *regs);
diff --git a/arch/powerpc/platforms/powernv/Makefile
b/arch/powerpc/platforms/powernv/Makefile
index f324ea0..e2ba418 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,6 +1,7 @@
obj-y += setup.o opal-takeover.o opal-wrappers.o opal.o
opal-async.o
obj-y += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o
opal-sensor.o
+obj-y += opal-messages.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_PCI) += pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/opal-messages.c
b/arch/powerpc/platforms/powernv/opal-messages.c
new file mode 100644
index 0000000..3a863e8
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-messages.c
@@ -0,0 +1,97 @@
+/*
+ * PowerNV OPAL in-memory console interface
+ *
+ * Copyright 2014 IBM Corp.
+ *
+ * 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.
+ */
+
+#include <asm/io.h>
+#include <asm/opal.h>
+#include <linux/debugfs.h>
+#include <linux/of.h>
+#include <linux/types.h>
+
+/* OPAL in-memory console. Defined in OPAL source at core/console.c */
+struct memcons {
+ __be64 magic;
+#define MEMCONS_MAGIC 0x6630696567726173L
+ __be64 obuf_phys;
+ __be64 ibuf_phys;
+ __be32 obuf_size;
+ __be32 ibuf_size;
+ __be32 out_pos;
+#define MEMCONS_OUT_POS_WRAP 0x80000000u
+#define MEMCONS_OUT_POS_MASK 0x00ffffffu
+ __be32 in_prod;
+ __be32 in_cons;
+};
+
+static ssize_t opal_messages_read(struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *to, loff_t pos, size_t count)
+{
+ struct memcons *mc = bin_attr->private;
+ const char *conbuf;
+ bool wrapped;
+ size_t num_read;
+ int out_pos;
+
+ if (!mc)
+ return -ENODEV;
+
+ conbuf = phys_to_virt(be64_to_cpu(mc->obuf_phys));
+ wrapped = be32_to_cpu(mc->out_pos) & MEMCONS_OUT_POS_WRAP;
+ out_pos = be32_to_cpu(mc->out_pos) & MEMCONS_OUT_POS_MASK;
+
+ if (!wrapped) {
+ num_read = memory_read_from_buffer(to, count, &pos, conbuf,
+ out_pos);
+ } else {
+ num_read = memory_read_from_buffer(to, count, &pos,
+ conbuf + out_pos,
+ be32_to_cpu(mc->obuf_size) - out_pos);
+
+ if (num_read < 0)
+ goto out;
+
+ num_read += memory_read_from_buffer(to + num_read,
+ count - num_read, &pos, conbuf, out_pos);
+ }
+out:
+ return num_read;
+}
+
+static struct bin_attribute messages_attr = {
+ .attr = {.name = "messages", .mode = 0444},
+ .read = opal_messages_read
+};
+
+void __init opal_messages_init(void)
+{
+ u64 mcaddr;
+ struct memcons *mc;
+
+ if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr)) {
+ pr_warn("OPAL: Property ibm,opal-memcons not found, no message
log\n");
+ return;
+ }
+
+ mc = phys_to_virt(mcaddr);
+ if (!mc) {
+ pr_warn("OPAL: memory console address is invalid\n");
+ return;
+ }
+
+ if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
+ pr_warn("OPAL: memory console version is invalid\n");
+ return;
+ }
+
+ messages_attr.private = mc;
+
+ if (sysfs_create_bin_file(opal_kobj, &messages_attr) != 0)
+ pr_warn("OPAL: sysfs file creation failed\n");
+}
diff --git a/arch/powerpc/platforms/powernv/opal.c
b/arch/powerpc/platforms/powernv/opal.c
index e92f2f6..2bc032a 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -46,7 +46,7 @@ struct mcheck_recoverable_range {
static struct mcheck_recoverable_range *mc_recoverable_range;
static int mc_recoverable_range_len;
-static struct device_node *opal_node;
+struct device_node *opal_node;
static DEFINE_SPINLOCK(opal_write_lock);
extern u64 opal_mc_secondary_handler[];
static unsigned int *opal_irqs;
@@ -574,6 +574,8 @@ static int __init opal_init(void)
opal_platform_dump_init();
/* Setup system parameters interface */
opal_sys_param_init();
+ /* Setup message log interface. */
+ opal_messages_init();
}
return 0;
--
1.9.1
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