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Subject[PATCH V8 5/5] platform/x86: Intel PMT Crashlog capability driver
Date
From: Alexander Duyck <alexander.h.duyck@linux.intel.com>

Add support for the Intel Platform Monitoring Technology crashlog
interface. This interface provides a few sysfs values to allow for
controlling the crashlog telemetry interface as well as a character
driver to allow for mapping the crashlog memory region so that it can be
accessed after a crashlog has been recorded.

This driver is meant to only support the server version of the crashlog
which is identified as crash_type 1 with a version of zero. Currently no
other types are supported.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
.../ABI/testing/sysfs-class-intel_pmt | 65 ++++
drivers/platform/x86/Kconfig | 11 +
drivers/platform/x86/Makefile | 1 +
drivers/platform/x86/intel_pmt_crashlog.c | 328 ++++++++++++++++++
4 files changed, 405 insertions(+)
create mode 100644 drivers/platform/x86/intel_pmt_crashlog.c

diff --git a/Documentation/ABI/testing/sysfs-class-intel_pmt b/Documentation/ABI/testing/sysfs-class-intel_pmt
index 926b5cf95fd1..ed4c886a21b1 100644
--- a/Documentation/ABI/testing/sysfs-class-intel_pmt
+++ b/Documentation/ABI/testing/sysfs-class-intel_pmt
@@ -52,3 +52,68 @@ Contact: David Box <david.e.box@linux.intel.com>
Description:
(RO) The offset of telemetry region in bytes that corresponds to
the mapping for the telem file.
+
+What: /sys/class/intel_pmt/crashlog<x>
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ The crashlog<x> directory contains files for configuring an
+ instance of a PMT crashlog device that can perform crash data
+ recording. Each crashlog<x> device has an associated crashlog
+ file. This file can be opened and mapped or read to access the
+ resulting crashlog buffer. The register layout for the buffer
+ can be determined from an XML file of specified GUID for the
+ parent device.
+
+What: /sys/class/intel_pmt/crashlog<x>/crashlog
+Date: October 2020
+KernelVersion: 5.10
+Contact: David Box <david.e.box@linux.intel.com>
+Description:
+ (RO) The crashlog buffer for this crashlog device. This file
+ may be mapped or read to obtain the data.
+
+What: /sys/class/intel_pmt/crashlog<x>/guid
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ (RO) The GUID for this crashlog device. The GUID identifies the
+ version of the XML file for the parent device that should be
+ used to determine the register layout.
+
+What: /sys/class/intel_pmt/crashlog<x>/size
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ (RO) The length of the result buffer in bytes that corresponds
+ to the size for the crashlog buffer.
+
+What: /sys/class/intel_pmt/crashlog<x>/offset
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ (RO) The offset of the buffer in bytes that corresponds
+ to the mapping for the crashlog device.
+
+What: /sys/class/intel_pmt/crashlog<x>/enable
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ (RW) Boolean value controlling if the crashlog functionality
+ is enabled for the crashlog device.
+
+What: /sys/class/intel_pmt/crashlog<x>/trigger
+Date: October 2020
+KernelVersion: 5.10
+Contact: Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+ (RW) Boolean value controlling the triggering of the crashlog
+ device node. When read it provides data on if the crashlog has
+ been triggered. When written to it can be used to either clear
+ the current trigger by writing false, or to trigger a new
+ event if the trigger is not currently set.
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 90b4c1bd9532..4ac555a9916b 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1383,6 +1383,17 @@ config INTEL_PMT_TELEMETRY
To compile this driver as a module, choose M here: the module
will be called intel_pmt_telemetry.

+config INTEL_PMT_CRASHLOG
+ tristate "Intel Platform Monitoring Technology (PMT) Crashlog driver"
+ select INTEL_PMT_CLASS
+ help
+ The Intel Platform Monitoring Technology (PMT) crashlog driver provides
+ access to hardware crashlog capabilities on devices that support the
+ feature.
+
+ To compile this driver as a module, choose M here: the module
+ will be called intel_pmt_crashlog.
+
config INTEL_PUNIT_IPC
tristate "Intel P-Unit IPC Driver"
help
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 6a7b61f59ea8..ca82c1344977 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -142,6 +142,7 @@ obj-$(CONFIG_INTEL_MRFLD_PWRBTN) += intel_mrfld_pwrbtn.o
obj-$(CONFIG_INTEL_PMC_CORE) += intel_pmc_core.o intel_pmc_core_pltdrv.o
obj-$(CONFIG_INTEL_PMT_CLASS) += intel_pmt_class.o
obj-$(CONFIG_INTEL_PMT_TELEMETRY) += intel_pmt_telemetry.o
+obj-$(CONFIG_INTEL_PMT_CRASHLOG) += intel_pmt_crashlog.o
obj-$(CONFIG_INTEL_PUNIT_IPC) += intel_punit_ipc.o
obj-$(CONFIG_INTEL_SCU_IPC) += intel_scu_ipc.o
obj-$(CONFIG_INTEL_SCU_PCI) += intel_scu_pcidrv.o
diff --git a/drivers/platform/x86/intel_pmt_crashlog.c b/drivers/platform/x86/intel_pmt_crashlog.c
new file mode 100644
index 000000000000..97dd749c8290
--- /dev/null
+++ b/drivers/platform/x86/intel_pmt_crashlog.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Platform Monitoring Technology Crashlog driver
+ *
+ * Copyright (c) 2020, Intel Corporation.
+ * All Rights Reserved.
+ *
+ * Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/overflow.h>
+
+#include "intel_pmt_class.h"
+
+#define DRV_NAME "pmt_crashlog"
+
+/* Crashlog discovery header types */
+#define CRASH_TYPE_OOBMSM 1
+
+/* Control Flags */
+#define CRASHLOG_FLAG_DISABLE BIT(27)
+
+/*
+ * Bits 28 and 29 control the state of bit 31.
+ *
+ * Bit 28 will clear bit 31, if set, allowing a new crashlog to be captured.
+ * Bit 29 will immediately trigger a crashlog to be generated, setting bit 31.
+ * Bit 30 is read-only and reserved as 0.
+ * Bit 31 is the read-only status with a 1 indicating log is complete.
+ */
+#define CRASHLOG_FLAG_TRIGGER_CLEAR BIT(28)
+#define CRASHLOG_FLAG_TRIGGER_EXECUTE BIT(29)
+#define CRASHLOG_FLAG_TRIGGER_COMPLETE BIT(31)
+#define CRASHLOG_FLAG_TRIGGER_MASK GENMASK(31, 28)
+
+/* Crashlog Discovery Header */
+#define CONTROL_OFFSET 0x0
+#define GUID_OFFSET 0x4
+#define BASE_OFFSET 0x8
+#define SIZE_OFFSET 0xC
+#define GET_ACCESS(v) ((v) & GENMASK(3, 0))
+#define GET_TYPE(v) (((v) & GENMASK(7, 4)) >> 4)
+#define GET_VERSION(v) (((v) & GENMASK(19, 16)) >> 16)
+/* size is in bytes */
+#define GET_SIZE(v) ((v) * sizeof(u32))
+
+struct crashlog_entry {
+ /* entry must be first member of struct */
+ struct intel_pmt_entry entry;
+ struct mutex control_mutex;
+};
+
+struct pmt_crashlog_priv {
+ int num_entries;
+ struct crashlog_entry entry[];
+};
+
+/*
+ * I/O
+ */
+static bool pmt_crashlog_complete(struct intel_pmt_entry *entry)
+{
+ u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+ /* return current value of the crashlog complete flag */
+ return !!(control & CRASHLOG_FLAG_TRIGGER_COMPLETE);
+}
+
+static bool pmt_crashlog_disabled(struct intel_pmt_entry *entry)
+{
+ u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+ /* return current value of the crashlog disabled flag */
+ return !!(control & CRASHLOG_FLAG_DISABLE);
+}
+
+static bool pmt_crashlog_supported(struct intel_pmt_entry *entry)
+{
+ u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);
+ u32 crash_type, version;
+
+ crash_type = GET_TYPE(discovery_header);
+ version = GET_VERSION(discovery_header);
+
+ /*
+ * Currently we only recognize OOBMSM version 0 devices.
+ * We can ignore all other crashlog devices in the system.
+ */
+ return crash_type == CRASH_TYPE_OOBMSM && version == 0;
+}
+
+static void pmt_crashlog_set_disable(struct intel_pmt_entry *entry,
+ bool disable)
+{
+ u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+ /* clear trigger bits so we are only modifying disable flag */
+ control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
+
+ if (disable)
+ control |= CRASHLOG_FLAG_DISABLE;
+ else
+ control &= ~CRASHLOG_FLAG_DISABLE;
+
+ writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+static void pmt_crashlog_set_clear(struct intel_pmt_entry *entry)
+{
+ u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+ control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
+ control |= CRASHLOG_FLAG_TRIGGER_CLEAR;
+
+ writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+static void pmt_crashlog_set_execute(struct intel_pmt_entry *entry)
+{
+ u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+ control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
+ control |= CRASHLOG_FLAG_TRIGGER_EXECUTE;
+
+ writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+/*
+ * sysfs
+ */
+static ssize_t
+enable_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct intel_pmt_entry *entry = dev_get_drvdata(dev);
+ int enabled = !pmt_crashlog_disabled(entry);
+
+ return sprintf(buf, "%d\n", enabled);
+}
+
+static ssize_t
+enable_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct crashlog_entry *entry;
+ bool enabled;
+ int result;
+
+ entry = dev_get_drvdata(dev);
+
+ result = kstrtobool(buf, &enabled);
+ if (result)
+ return result;
+
+ mutex_lock(&entry->control_mutex);
+ pmt_crashlog_set_disable(&entry->entry, !enabled);
+ mutex_unlock(&entry->control_mutex);
+
+ return count;
+}
+static DEVICE_ATTR_RW(enable);
+
+static ssize_t
+trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct intel_pmt_entry *entry;
+ int trigger;
+
+ entry = dev_get_drvdata(dev);
+ trigger = pmt_crashlog_complete(entry);
+
+ return sprintf(buf, "%d\n", trigger);
+}
+
+static ssize_t
+trigger_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct crashlog_entry *entry;
+ bool trigger;
+ int result;
+
+ entry = dev_get_drvdata(dev);
+
+ result = kstrtobool(buf, &trigger);
+ if (result)
+ return result;
+
+ mutex_lock(&entry->control_mutex);
+
+ if (!trigger) {
+ pmt_crashlog_set_clear(&entry->entry);
+ } else if (pmt_crashlog_complete(&entry->entry)) {
+ /* we cannot trigger a new crash if one is still pending */
+ result = -EEXIST;
+ goto err;
+ } else if (pmt_crashlog_disabled(&entry->entry)) {
+ /* if device is currently disabled, return busy */
+ result = -EBUSY;
+ goto err;
+ } else {
+ pmt_crashlog_set_execute(&entry->entry);
+ }
+
+ result = count;
+err:
+ mutex_unlock(&entry->control_mutex);
+ return result;
+}
+static DEVICE_ATTR_RW(trigger);
+
+static struct attribute *pmt_crashlog_attrs[] = {
+ &dev_attr_enable.attr,
+ &dev_attr_trigger.attr,
+ NULL
+};
+
+static struct attribute_group pmt_crashlog_group = {
+ .attrs = pmt_crashlog_attrs,
+};
+
+static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
+ struct intel_pmt_header *header,
+ struct device *dev)
+{
+ void __iomem *disc_table = entry->disc_table;
+ struct crashlog_entry *crashlog;
+
+ if (!pmt_crashlog_supported(entry))
+ return 1;
+
+ /* initialize control mutex */
+ crashlog = container_of(entry, struct crashlog_entry, entry);
+ mutex_init(&crashlog->control_mutex);
+
+ header->access_type = GET_ACCESS(readl(disc_table));
+ header->guid = readl(disc_table + GUID_OFFSET);
+ header->base_offset = readl(disc_table + BASE_OFFSET);
+
+ /* Size is measured in DWORDS, but accessor returns bytes */
+ header->size = GET_SIZE(readl(disc_table + SIZE_OFFSET));
+
+ return 0;
+}
+
+static DEFINE_XARRAY_ALLOC(crashlog_array);
+static struct intel_pmt_namespace pmt_crashlog_ns = {
+ .name = "crashlog",
+ .xa = &crashlog_array,
+ .attr_grp = &pmt_crashlog_group,
+ .pmt_header_decode = pmt_crashlog_header_decode,
+};
+
+/*
+ * initialization
+ */
+static int pmt_crashlog_remove(struct platform_device *pdev)
+{
+ struct pmt_crashlog_priv *priv = platform_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < priv->num_entries; i++)
+ intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
+
+ return 0;
+}
+
+static int pmt_crashlog_probe(struct platform_device *pdev)
+{
+ struct pmt_crashlog_priv *priv;
+ size_t size;
+ int i, ret;
+
+ size = struct_size(priv, entry, pdev->num_resources);
+ priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+
+ for (i = 0; i < pdev->num_resources; i++) {
+ struct intel_pmt_entry *entry = &priv->entry[i].entry;
+
+ ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, pdev, i);
+ if (ret < 0)
+ goto abort_probe;
+ if (ret)
+ continue;
+
+ priv->num_entries++;
+ }
+
+ return 0;
+abort_probe:
+ pmt_crashlog_remove(pdev);
+ return ret;
+}
+
+static struct platform_driver pmt_crashlog_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ },
+ .remove = pmt_crashlog_remove,
+ .probe = pmt_crashlog_probe,
+};
+
+static int __init pmt_crashlog_init(void)
+{
+ return platform_driver_register(&pmt_crashlog_driver);
+}
+
+static void __exit pmt_crashlog_exit(void)
+{
+ platform_driver_unregister(&pmt_crashlog_driver);
+ xa_destroy(&crashlog_array);
+}
+
+module_init(pmt_crashlog_init);
+module_exit(pmt_crashlog_exit);
+
+MODULE_AUTHOR("Alexander Duyck <alexander.h.duyck@linux.intel.com>");
+MODULE_DESCRIPTION("Intel PMT Crashlog driver");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_LICENSE("GPL v2");
--
2.20.1
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