From: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
Ultravisor provides an in-memory circular buffer containing a message
log populated with various runtime message produced by firmware.
Based on "powernv/opal-msglog.c", this patch provides a sysfs interface
/sys/firmware/opal/uv_msglog for userspace to view the messages.
CC: Joel Stanley <joel@xxxxxxxxx>
CC: Oliver O'Halloran <oohall@xxxxxxxxx>
Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
[ Read ibm,opal-uv-memcons instead of OPAL's ]
Signed-off-by: Ryan Grimm <grimm@xxxxxxxxxxxxx>
[ Fix license, update the commit message ]
Signed-off-by: Claudio Carvalho <cclaudio@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/opal.h | 2 +
arch/powerpc/platforms/powernv/Makefile | 1 +
.../platforms/powernv/opal-uv-msglog.c | 141 ++++++++++++++++++
arch/powerpc/platforms/powernv/opal.c | 2 +
4 files changed, 146 insertions(+)
create mode 100644 arch/powerpc/platforms/powernv/opal-uv-msglog.c
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 4cc37e708bc7..86299c5d866b 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -351,6 +351,8 @@ extern void opal_platform_dump_init(void);
extern void opal_sys_param_init(void);
extern void opal_msglog_init(void);
extern void opal_msglog_sysfs_init(void);
+extern void opal_uv_msglog_init(void);
+extern void opal_uv_msglog_sysfs_init(void);
extern int opal_async_comp_init(void);
extern int opal_sensor_init(void);
extern int opal_hmi_handler_init(void);
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index da2e99efbd04..216629c63e1d 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,6 +4,7 @@ obj-y += idle.o 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-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
obj-y += opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
+obj-y += opal-uv-msglog.o
obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o
obj-$(CONFIG_PCI) += pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
diff --git a/arch/powerpc/platforms/powernv/opal-uv-msglog.c b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
new file mode 100644
index 000000000000..87d665d7e6ad
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PowerNV OPAL in-memory ultravisor console interface
+ *
+ * Copyright 2018 IBM Corp.
+ */
+#include <asm/io.h>
+#include <asm/opal.h>
+#include <linux/debugfs.h>
+#include <linux/of.h>
+#include <linux/types.h>
+#include <asm/barrier.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 struct memcons *opal_uv_memcons;
+
+ssize_t opal_uv_msglog_copy(char *to, loff_t pos, size_t count)
+{
+ const char *conbuf;
+ ssize_t ret;
+ size_t first_read = 0;
+ uint32_t out_pos, avail;
+
+ if (!opal_uv_memcons)
+ return -ENODEV;
+
+ out_pos = be32_to_cpu(READ_ONCE(opal_uv_memcons->out_pos));
+
+ /*
+ * Now we've read out_pos, put a barrier in before reading the new data
+ * it points to in conbuf.
+ */
+ smp_rmb();
+
+ conbuf = phys_to_virt(be64_to_cpu(opal_uv_memcons->obuf_phys));
+
+ /*
+ * When the buffer has wrapped, read from the out_pos marker to the end
+ * of the buffer, and then read the remaining data as in the un-wrapped
+ * case.
+ */
+ if (out_pos & MEMCONS_OUT_POS_WRAP) {
+
+ out_pos &= MEMCONS_OUT_POS_MASK;
+ avail = be32_to_cpu(opal_uv_memcons->obuf_size) - out_pos;
+
+ ret = memory_read_from_buffer(to, count, &pos,
+ conbuf + out_pos, avail);
+
+ if (ret < 0)
+ goto out;
+
+ first_read = ret;
+ to += first_read;
+ count -= first_read;
+ pos -= avail;
+
+ if (count <= 0)
+ goto out;
+ }
+
+ /* Sanity check. The firmware should not do this to us. */
+ if (out_pos > be32_to_cpu(opal_uv_memcons->obuf_size)) {
+ pr_err("OPAL: memory console corruption. Aborting read.\n");
+ return -EINVAL;
+ }
+
+ ret = memory_read_from_buffer(to, count, &pos, conbuf, out_pos);
+
+ if (ret < 0)
+ goto out;
+
+ ret += first_read;
+out:
+ return ret;
+}
+
+static ssize_t opal_uv_msglog_read(struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *to,
+ loff_t pos, size_t count)
+{
+ return opal_uv_msglog_copy(to, pos, count);
+}
+
+static struct bin_attribute opal_uv_msglog_attr = {
+ .attr = {.name = "uv_msglog", .mode = 0444},
+ .read = opal_uv_msglog_read
+};
+
+void __init opal_uv_msglog_init(void)
+{
+ u64 mcaddr;
+ struct memcons *mc;
+
+ if (of_property_read_u64(opal_node, "ibm,opal-uv-memcons", &mcaddr)) {
+ pr_warn("OPAL: Property ibm,opal-uv-memcons not found\n");
+ return;
+ }
+
+ mc = phys_to_virt(mcaddr);
+ if (!mc) {
+ pr_warn("OPAL: uv memory console address is invalid\n");
+ return;
+ }
+
+ if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
+ pr_warn("OPAL: uv memory console version is invalid\n");
+ return;
+ }
+
+ /* Report maximum size */
+ opal_uv_msglog_attr.size = be32_to_cpu(mc->ibuf_size) +
+ be32_to_cpu(mc->obuf_size);
+
+ opal_uv_memcons = mc;
+}
+
+void __init opal_uv_msglog_sysfs_init(void)
+{
+ if (!opal_uv_memcons) {
+ pr_warn("OPAL: message log initialisation failed, not creating sysfs entry\n");
+ return;
+ }
+
+ if (sysfs_create_bin_file(opal_kobj, &opal_uv_msglog_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 89b6ddc3ed38..ed000a788456 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -946,6 +946,7 @@ static int __init opal_init(void)
/* Initialise OPAL message log interface */
opal_msglog_init();
+ opal_uv_msglog_init();
/* Create "opal" kobject under /sys/firmware */
rc = opal_sysfs_init();
@@ -964,6 +965,7 @@ static int __init opal_init(void)
opal_sys_param_init();
/* Setup message log sysfs interface. */
opal_msglog_sysfs_init();
+ opal_uv_msglog_sysfs_init();
}
/* Export all properties */
--
2.20.1
