[PATCH v8 3/9] misc: smpro-errmon: Add Ampere's SMpro error monitor driver

[Quan Nguyen <quan@os.amperecomputing.com>]

This commit adds Ampere's SMpro error monitor driver for monitoring
and reporting RAS-related errors as reported by SMpro co-processor
found on Ampere's Altra processor family.

Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
Changes in v8:
  + Update wording for SMPRO_ERRMON on Kconfig file             [Quan]
  + Avoid uninitialized variable use               [kernel test robot]
  + Switch to use sysfs_emit()                                  [Greg]
  + Make sysfs to return single value                           [Greg]
  + Change errors_* sysfs to error_*                            [Quan]
  + Add overflow_[core|mem|pcie|other]_[ce|ue] sysfs to report
  overflow status of each type of HW errors                     [Quan]
  + Add some minor refactor                                     [Quan]

Changes in v7:
  + Remove regmap_acquire/release_lock(), read_i2c_block_data() [Quan]
  + Use regmap_noinc_read() instead of errmon_read_block()      [Quan]
  + Validate number of errors before read                       [Quan]
  + Fix wrong return type of *_show() function     [kernel test robot]
  + Adjust patch order to avoid dependence with smpro-mfd  [Lee Jones]
  + Use pointer instead of stack memory                         [Quan]

Changes in v6:
  + First introduced in v6 [Quan]

 drivers/misc/Kconfig        |  12 +
 drivers/misc/Makefile       |   1 +
 drivers/misc/smpro-errmon.c | 477 ++++++++++++++++++++++++++++++++++++
 3 files changed, 490 insertions(+)
 create mode 100644 drivers/misc/smpro-errmon.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 41d2bb0ae23a..9fbe6797c440 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -176,6 +176,18 @@ config SGI_XP
 	  this feature will allow for direct communication between SSIs
 	  based on a network adapter and DMA messaging.
 
+config SMPRO_ERRMON
+	tristate "Ampere Computing SMPro error monitor driver"
+	depends on MFD_SMPRO || COMPILE_TEST
+	help
+	  Say Y here to get support for the SMpro error monitor function
+	  provided by Ampere Computing's Altra and Altra Max SoCs. Upon
+	  loading, the driver creates sysfs files which can be use to gather
+	  multiple HW error data reported via read and write system calls.
+
+	  To compile this driver as a module, say M here. The driver will be
+	  called smpro-errmon.
+
 config CS5535_MFGPT
 	tristate "CS5535/CS5536 Geode Multi-Function General Purpose Timer (MFGPT) support"
 	depends on MFD_CS5535
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 70e800e9127f..483308a6e113 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o
 obj-$(CONFIG_KGDB_TESTS)	+= kgdbts.o
 obj-$(CONFIG_SGI_XP)		+= sgi-xp/
 obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
+obj-$(CONFIG_SMPRO_ERRMON)	+= smpro-errmon.o
 obj-$(CONFIG_CS5535_MFGPT)	+= cs5535-mfgpt.o
 obj-$(CONFIG_GEHC_ACHC)		+= gehc-achc.o
 obj-$(CONFIG_HP_ILO)		+= hpilo.o
diff --git a/drivers/misc/smpro-errmon.c b/drivers/misc/smpro-errmon.c
new file mode 100644
index 000000000000..df7d8fc4ff3f
--- /dev/null
+++ b/drivers/misc/smpro-errmon.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Ampere Computing SoC's SMpro Error Monitoring Driver
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ *
+ */
+
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* GPI RAS Error Registers */
+#define GPI_RAS_ERR		0x7E
+
+/* Core and L2C Error Registers */
+#define CORE_CE_ERR_CNT		0x80
+#define CORE_CE_ERR_LEN		0x81
+#define CORE_CE_ERR_DATA	0x82
+#define CORE_UE_ERR_CNT		0x83
+#define CORE_UE_ERR_LEN		0x84
+#define CORE_UE_ERR_DATA	0x85
+
+/* Memory Error Registers */
+#define MEM_CE_ERR_CNT		0x90
+#define MEM_CE_ERR_LEN		0x91
+#define MEM_CE_ERR_DATA		0x92
+#define MEM_UE_ERR_CNT		0x93
+#define MEM_UE_ERR_LEN		0x94
+#define MEM_UE_ERR_DATA		0x95
+
+/* RAS Error/Warning Registers */
+#define ERR_SMPRO_TYPE		0xA0
+#define ERR_PMPRO_TYPE		0xA1
+#define ERR_SMPRO_INFO_LO	0xA2
+#define ERR_SMPRO_INFO_HI	0xA3
+#define ERR_SMPRO_DATA_LO	0xA4
+#define ERR_SMPRO_DATA_HI	0xA5
+#define WARN_SMPRO_INFO_LO	0xAA
+#define WARN_SMPRO_INFO_HI	0xAB
+#define ERR_PMPRO_INFO_LO	0xA6
+#define ERR_PMPRO_INFO_HI	0xA7
+#define ERR_PMPRO_DATA_LO	0xA8
+#define ERR_PMPRO_DATA_HI	0xA9
+#define WARN_PMPRO_INFO_LO	0xAC
+#define WARN_PMPRO_INFO_HI	0xAD
+
+/* PCIE Error Registers */
+#define PCIE_CE_ERR_CNT		0xC0
+#define PCIE_CE_ERR_LEN		0xC1
+#define PCIE_CE_ERR_DATA	0xC2
+#define PCIE_UE_ERR_CNT		0xC3
+#define PCIE_UE_ERR_LEN		0xC4
+#define PCIE_UE_ERR_DATA	0xC5
+
+/* Other Error Registers */
+#define OTHER_CE_ERR_CNT	0xD0
+#define OTHER_CE_ERR_LEN	0xD1
+#define OTHER_CE_ERR_DATA	0xD2
+#define OTHER_UE_ERR_CNT	0xD8
+#define OTHER_UE_ERR_LEN	0xD9
+#define OTHER_UE_ERR_DATA	0xDA
+
+/* Event Data Registers */
+#define VRD_WARN_FAULT_EVENT_DATA	0x78
+#define VRD_HOT_EVENT_DATA		0x79
+#define DIMM_HOT_EVENT_DATA		0x7A
+#define DIMM_2X_REFRESH_EVENT_DATA	0x96
+
+#define MAX_READ_BLOCK_LENGTH	48
+#define NUM_I2C_MESSAGES	2
+#define MAX_MSG_LEN		128
+
+#define RAS_SMPRO_ERRS		0
+#define RAS_PMPRO_ERRS		1
+
+enum RAS_48BYTES_ERR_TYPES {
+	CORE_CE_ERRS,
+	CORE_UE_ERRS,
+	MEM_CE_ERRS,
+	MEM_UE_ERRS,
+	PCIE_CE_ERRS,
+	PCIE_UE_ERRS,
+	OTHER_CE_ERRS,
+	OTHER_UE_ERRS,
+	NUM_48BYTES_ERR_TYPE,
+};
+
+struct smpro_error_hdr {
+	u8 err_count;	/* Number of the RAS errors */
+	u8 err_len;	/* Number of data bytes */
+	u8 err_data;	/* Start of 48-byte data */
+	u8 max_err_cnt;	/* Max num of errors */
+};
+
+/*
+ * Included Address of registers to get Count, Length of data and Data
+ * of the 48 bytes error data
+ */
+static struct smpro_error_hdr smpro_error_table[NUM_48BYTES_ERR_TYPE] = {
+	{CORE_CE_ERR_CNT, CORE_CE_ERR_LEN, CORE_CE_ERR_DATA, 32},
+	{CORE_UE_ERR_CNT, CORE_UE_ERR_LEN, CORE_UE_ERR_DATA, 32},
+	{MEM_CE_ERR_CNT, MEM_CE_ERR_LEN, MEM_CE_ERR_DATA, 16},
+	{MEM_UE_ERR_CNT, MEM_UE_ERR_LEN, MEM_UE_ERR_DATA, 16},
+	{PCIE_CE_ERR_CNT, PCIE_CE_ERR_LEN, PCIE_CE_ERR_DATA, 96},
+	{PCIE_UE_ERR_CNT, PCIE_UE_ERR_LEN, PCIE_UE_ERR_DATA, 96},
+	{OTHER_CE_ERR_CNT, OTHER_CE_ERR_LEN, OTHER_CE_ERR_DATA, 8},
+	{OTHER_UE_ERR_CNT, OTHER_UE_ERR_LEN, OTHER_UE_ERR_DATA, 8},
+};
+
+/*
+ * List of SCP registers which are used to get
+ * one type of RAS Internal errors.
+ */
+struct smpro_int_error_hdr {
+	u8 err_type;
+	u8 err_info_low;
+	u8 err_info_high;
+	u8 err_data_high;
+	u8 err_data_low;
+	u8 warn_info_low;
+	u8 warn_info_high;
+};
+
+static struct smpro_int_error_hdr list_smpro_int_error_hdr[2] = {
+	{
+	 ERR_SMPRO_TYPE,
+	 ERR_SMPRO_INFO_LO, ERR_SMPRO_INFO_HI,
+	 ERR_SMPRO_DATA_LO, ERR_SMPRO_DATA_HI,
+	 WARN_SMPRO_INFO_LO, WARN_SMPRO_INFO_HI
+	},
+	{
+	 ERR_PMPRO_TYPE,
+	 ERR_PMPRO_INFO_LO, ERR_PMPRO_INFO_HI,
+	 ERR_PMPRO_DATA_LO, ERR_PMPRO_DATA_HI,
+	 WARN_PMPRO_INFO_LO, WARN_PMPRO_INFO_HI
+	},
+};
+
+struct smpro_errmon {
+	struct regmap *regmap;
+};
+
+enum EVENT_TYPES {
+	VRD_WARN_FAULT_EVENTS,
+	VRD_HOT_EVENTS,
+	DIMM_HOT_EVENTS,
+	NUM_EVENTS_TYPE,
+};
+
+/* Included Address of event source and data registers */
+static u8 smpro_event_table[NUM_EVENTS_TYPE] = {
+	VRD_WARN_FAULT_EVENT_DATA,
+	VRD_HOT_EVENT_DATA,
+	DIMM_HOT_EVENT_DATA,
+};
+
+static ssize_t smpro_event_data_read(struct device *dev,
+				     struct device_attribute *da, char *buf,
+				     int channel)
+{
+	struct smpro_errmon *errmon = dev_get_drvdata(dev);
+	s32 event_data;
+	int ret;
+
+	ret = regmap_read(errmon->regmap, smpro_event_table[channel], &event_data);
+	if (ret)
+		goto done;
+
+	ret = sysfs_emit(buf, "%02x%04x\n", channel, event_data);
+	/* Clear event after read */
+	if (event_data != 0)
+		regmap_write(errmon->regmap, smpro_event_table[channel], event_data);
+done:
+	return ret;
+}
+
+static ssize_t smpro_overflow_data_read(struct device *dev, struct device_attribute *da,
+					char *buf, int channel)
+{
+	struct smpro_errmon *errmon = dev_get_drvdata(dev);
+	struct smpro_error_hdr *err_info;
+	s32 err_count;
+	int ret;
+
+	err_info = &smpro_error_table[channel];
+
+	ret = regmap_read(errmon->regmap, err_info->err_count, &err_count);
+	if (ret)
+		return ret;
+
+	/* Bit 8 indicates the overflow status */
+	return sysfs_emit(buf, "%d\n", (err_count & BIT(8)) ? 1 : 0);
+}
+
+static ssize_t smpro_error_data_read(struct device *dev, struct device_attribute *da,
+				     char *buf, int channel)
+{
+	struct smpro_errmon *errmon = dev_get_drvdata(dev);
+	unsigned char err_data[MAX_READ_BLOCK_LENGTH];
+	struct smpro_error_hdr *err_info;
+	s32 err_count, err_length;
+	int count = 0;
+	int ret;
+
+	err_info = &smpro_error_table[channel];
+
+	ret = regmap_read(errmon->regmap, err_info->err_count, &err_count);
+	/* Error count is the low byte */
+	err_count &= 0xff;
+	if (ret || !err_count || err_count > err_info->max_err_cnt)
+		goto done;
+
+	ret = regmap_read(errmon->regmap, err_info->err_len, &err_length);
+	if (ret || err_length <= 0)
+		goto done;
+
+	if (err_length > MAX_READ_BLOCK_LENGTH)
+		err_length = MAX_READ_BLOCK_LENGTH;
+
+	memset(err_data, 0x00, MAX_READ_BLOCK_LENGTH);
+	ret = regmap_noinc_read(errmon->regmap, err_info->err_data, err_data, err_length);
+	if (ret < 0)
+		goto done;
+
+	/*
+	 * The output of Core/Memory/PCIe/Others UE/CE errors follows below format:
+	 * <Error Type><Error SubType><Instance><Error Status>\
+	 * <Error Address><Error Misc 0><Error Misc 1><Error Misc2><Error Misc 3>
+	 * Where:
+	 *  + Error Type: The hardwares cause the errors. (1 byte)
+	 *  + SubType: Sub type of error in the specified hardware error. (1 byte)
+	 *  + Instance: Combination of the socket, channel,
+	 *    slot cause the error. (2 bytes)
+	 *  + Error Status: Encode of error status. (4 bytes)
+	 *  + Error Address: The address in device causes the errors. (8 bytes)
+	 *  + Error Misc 0/1/2/3: Addition info about the errors. (8 bytes for each)
+	 * Reference Altra SOC BMC Interface specification.
+	 */
+	count = sysfs_emit(buf, "%02x%02x%04x%08x%016llx%016llx%016llx%016llx%016llx\n",
+			   err_data[0], err_data[1], *(u16 *)&err_data[2],
+			   *(u32 *)&err_data[4], *(u64 *)&err_data[8],
+			   *(u64 *)&err_data[16], *(u64 *)&err_data[24],
+			   *(u64 *)&err_data[32], *(u64 *)&err_data[40]);
+
+	/* go to next error */
+	ret = regmap_write(errmon->regmap, err_info->err_count, 0x100);
+done:
+	return ret ? ret : count;
+}
+
+/*
+ * Output format:
+ * <errType><image><dir><Location><errorCode><data>
+ * Where:
+ *   + errType: SCP Error Type (3 bits)
+ *      1: Warning
+ *      2: Error
+ *      4: Error with data
+ *   + image: SCP Image Code (8 bits)
+ *   + dir: Direction (1 bit)
+ *      0: Enter
+ *      1: Exit
+ *   + location: SCP Module Location Code (8 bits)
+ *   + errorCode: SCP Error Code (16 bits)
+ *   + data : Extensive data (32 bits)
+ *      All bits are 0 when errType is warning or error.
+ */
+static ssize_t smpro_internal_err_read(struct device *dev, struct device_attribute *da,
+				       char *buf, int channel)
+{
+	struct smpro_errmon *errmon = dev_get_drvdata(dev);
+	struct smpro_int_error_hdr *err_info;
+	unsigned int data_lo = 0, data_hi = 0;
+	unsigned int ret_hi, ret_lo;
+	unsigned int err_type;
+	unsigned int value;
+	int count = 0;
+	int ret;
+
+	/* read error status */
+	ret = regmap_read(errmon->regmap, GPI_RAS_ERR, &value);
+	if (ret)
+		goto done;
+
+	if (!((channel == RAS_SMPRO_ERRS && (value & BIT(0))) ||
+	      (channel == RAS_PMPRO_ERRS && (value & BIT(1)))))
+		goto done;
+
+	err_info = &list_smpro_int_error_hdr[channel];
+	ret = regmap_read(errmon->regmap, err_info->err_type, &err_type);
+	if (ret)
+		goto done;
+
+	ret = regmap_read(errmon->regmap, err_info->err_info_low, &ret_lo);
+	if (ret)
+		goto done;
+
+	ret = regmap_read(errmon->regmap, err_info->err_info_high, &ret_hi);
+	if (ret)
+		goto done;
+
+	if (err_type & BIT(2)) {
+		/* Error with data type */
+		ret = regmap_read(errmon->regmap, err_info->err_data_low, &data_lo);
+		if (ret)
+			goto done;
+
+		ret = regmap_read(errmon->regmap, err_info->err_data_high, &data_hi);
+		if (ret)
+			goto done;
+
+		count = sysfs_emit(buf, "%01x%02x%01x%02x%04x%04x%04x\n",
+				   4, (ret_hi & 0xf000) >> 12, (ret_hi & 0x0800) >> 11,
+				   ret_hi & 0xff, ret_lo, data_hi, data_lo);
+		/* clear the read errors */
+		ret = regmap_write(errmon->regmap, err_info->err_type, BIT(2));
+
+	} else if (err_type & BIT(1)) {
+		/* Error type */
+		count = sysfs_emit(buf, "%01x%02x%01x%02x%04x%04x%04x\n",
+				   2, (ret_hi & 0xf000) >> 12, (ret_hi & 0x0800) >> 11,
+				   ret_hi & 0xff, ret_lo, data_hi, data_lo);
+		/* clear the read errors */
+		ret = regmap_write(errmon->regmap, err_info->err_type, BIT(1));
+
+	} else if (err_type & BIT(0)) {
+		/* Warning type */
+		count = sysfs_emit(buf, "%01x%02x%01x%02x%04x%04x%04x\n",
+				   1, (ret_hi & 0xf000) >> 12, (ret_hi & 0x0800) >> 11,
+				   ret_hi & 0xff, ret_lo, data_hi, data_lo);
+		/* clear the read errors */
+		ret = regmap_write(errmon->regmap, err_info->err_type, BIT(0));
+	}
+done:
+	return ret ? ret : count;
+}
+
+#define ERROR_OVERFLOW_RO(_error, _index) \
+	static ssize_t overflow_##_error##_show(struct device *dev,            \
+						struct device_attribute *da,   \
+						char *buf)                     \
+	{                                                                      \
+		return smpro_overflow_data_read(dev, da, buf, _index);         \
+	}                                                                      \
+	static DEVICE_ATTR_RO(overflow_##_error)
+
+ERROR_OVERFLOW_RO(core_ce, CORE_CE_ERRS);
+ERROR_OVERFLOW_RO(core_ue, CORE_UE_ERRS);
+ERROR_OVERFLOW_RO(mem_ce, MEM_CE_ERRS);
+ERROR_OVERFLOW_RO(mem_ue, MEM_UE_ERRS);
+ERROR_OVERFLOW_RO(pcie_ce, PCIE_CE_ERRS);
+ERROR_OVERFLOW_RO(pcie_ue, PCIE_UE_ERRS);
+ERROR_OVERFLOW_RO(other_ce, OTHER_CE_ERRS);
+ERROR_OVERFLOW_RO(other_ue, OTHER_UE_ERRS);
+
+#define ERROR_RO(_error, _index) \
+	static ssize_t error_##_error##_show(struct device *dev,            \
+					     struct device_attribute *da,   \
+					     char *buf)                     \
+	{                                                                   \
+		return smpro_error_data_read(dev, da, buf, _index);         \
+	}                                                                   \
+	static DEVICE_ATTR_RO(error_##_error)
+
+ERROR_RO(core_ce, CORE_CE_ERRS);
+ERROR_RO(core_ue, CORE_UE_ERRS);
+ERROR_RO(mem_ce, MEM_CE_ERRS);
+ERROR_RO(mem_ue, MEM_UE_ERRS);
+ERROR_RO(pcie_ce, PCIE_CE_ERRS);
+ERROR_RO(pcie_ue, PCIE_UE_ERRS);
+ERROR_RO(other_ce, OTHER_CE_ERRS);
+ERROR_RO(other_ue, OTHER_UE_ERRS);
+
+static ssize_t error_smpro_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	return smpro_internal_err_read(dev, da, buf, RAS_SMPRO_ERRS);
+}
+static DEVICE_ATTR_RO(error_smpro);
+
+static ssize_t error_pmpro_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	return smpro_internal_err_read(dev, da, buf, RAS_PMPRO_ERRS);
+}
+static DEVICE_ATTR_RO(error_pmpro);
+
+#define EVENT_RO(_event, _index) \
+	static ssize_t event_##_event##_show(struct device *dev,            \
+					     struct device_attribute *da,   \
+					     char *buf)                     \
+	{                                                                   \
+		return smpro_event_data_read(dev, da, buf, _index);         \
+	}                                                                   \
+	static DEVICE_ATTR_RO(event_##_event)
+
+EVENT_RO(vrd_warn_fault, VRD_WARN_FAULT_EVENTS);
+EVENT_RO(vrd_hot, VRD_HOT_EVENTS);
+EVENT_RO(dimm_hot, DIMM_HOT_EVENTS);
+
+static struct attribute *smpro_errmon_attrs[] = {
+	&dev_attr_overflow_core_ce.attr,
+	&dev_attr_overflow_core_ue.attr,
+	&dev_attr_overflow_mem_ce.attr,
+	&dev_attr_overflow_mem_ue.attr,
+	&dev_attr_overflow_pcie_ce.attr,
+	&dev_attr_overflow_pcie_ue.attr,
+	&dev_attr_overflow_other_ce.attr,
+	&dev_attr_overflow_other_ue.attr,
+	&dev_attr_error_core_ce.attr,
+	&dev_attr_error_core_ue.attr,
+	&dev_attr_error_mem_ce.attr,
+	&dev_attr_error_mem_ue.attr,
+	&dev_attr_error_pcie_ce.attr,
+	&dev_attr_error_pcie_ue.attr,
+	&dev_attr_error_other_ce.attr,
+	&dev_attr_error_other_ue.attr,
+	&dev_attr_error_smpro.attr,
+	&dev_attr_error_pmpro.attr,
+	&dev_attr_event_vrd_warn_fault.attr,
+	&dev_attr_event_vrd_hot.attr,
+	&dev_attr_event_dimm_hot.attr,
+	NULL
+};
+
+static const struct attribute_group smpro_errmon_attr_group = {
+	.attrs = smpro_errmon_attrs
+};
+
+static int smpro_errmon_probe(struct platform_device *pdev)
+{
+	struct smpro_errmon *errmon;
+	int ret;
+
+	errmon = devm_kzalloc(&pdev->dev, sizeof(struct smpro_errmon), GFP_KERNEL);
+	if (!errmon)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, errmon);
+
+	errmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!errmon->regmap)
+		return -ENODEV;
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &smpro_errmon_attr_group);
+	if (ret)
+		dev_err(&pdev->dev, "SMPro errmon sysfs registration failed\n");
+
+	return 0;
+}
+
+static int smpro_errmon_remove(struct platform_device *pdev)
+{
+	sysfs_remove_group(&pdev->dev.kobj, &smpro_errmon_attr_group);
+	pr_info("SMPro errmon sysfs entries removed");
+
+	return 0;
+}
+
+static struct platform_driver smpro_errmon_driver = {
+	.probe          = smpro_errmon_probe,
+	.remove         = smpro_errmon_remove,
+	.driver = {
+		.name   = "smpro-errmon",
+	},
+};
+
+module_platform_driver(smpro_errmon_driver);
+
+MODULE_AUTHOR("Tung Nguyen <tung.nguyen@amperecomputing.com>");
+MODULE_AUTHOR("Thinh Pham <thinh.pham@amperecomputing.com>");
+MODULE_AUTHOR("Hoang Nguyen <hnguyen@amperecomputing.com>");
+MODULE_AUTHOR("Thu Nguyen <thu@os.amperecomputing.com>");
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Ampere Altra SMpro driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1