[PATCH 12/14] hwmon: peci: Add dimmtemp driver

[Iwona Winiarska <iwona.winiarska@intel.com>]

Add peci-dimmtemp driver for Digital Thermal Sensor (DTS) thermal
readings of DIMMs that are accessible via the processor PECI interface.

The main use case for the driver (and PECI interface) is out-of-band
management, where we're able to obtain the DTS readings from an external
entity connected with PECI, e.g. BMC on server platforms.

Co-developed-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/hwmon/peci/Kconfig    |  13 +
 drivers/hwmon/peci/Makefile   |   2 +
 drivers/hwmon/peci/dimmtemp.c | 508 ++++++++++++++++++++++++++++++++++
 3 files changed, 523 insertions(+)
 create mode 100644 drivers/hwmon/peci/dimmtemp.c

diff --git a/drivers/hwmon/peci/Kconfig b/drivers/hwmon/peci/Kconfig
index e10eed68d70a..f2d57efa508b 100644
--- a/drivers/hwmon/peci/Kconfig
+++ b/drivers/hwmon/peci/Kconfig
@@ -14,5 +14,18 @@ config SENSORS_PECI_CPUTEMP
 	  This driver can also be built as a module. If so, the module
 	  will be called peci-cputemp.
 
+config SENSORS_PECI_DIMMTEMP
+	tristate "PECI DIMM temperature monitoring client"
+	depends on PECI
+	select SENSORS_PECI
+	select PECI_CPU
+	help
+	  If you say yes here you get support for the generic Intel PECI hwmon
+	  driver which provides Digital Thermal Sensor (DTS) thermal readings of
+	  DIMM components that are accessible via the processor PECI interface.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called peci-dimmtemp.
+
 config SENSORS_PECI
 	tristate
diff --git a/drivers/hwmon/peci/Makefile b/drivers/hwmon/peci/Makefile
index e8a0ada5ab1f..191cfa0227f3 100644
--- a/drivers/hwmon/peci/Makefile
+++ b/drivers/hwmon/peci/Makefile
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 peci-cputemp-y := cputemp.o
+peci-dimmtemp-y := dimmtemp.o
 
 obj-$(CONFIG_SENSORS_PECI_CPUTEMP)	+= peci-cputemp.o
+obj-$(CONFIG_SENSORS_PECI_DIMMTEMP)	+= peci-dimmtemp.o
diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c
new file mode 100644
index 000000000000..2fcb8607137a
--- /dev/null
+++ b/drivers/hwmon/peci/dimmtemp.c
@@ -0,0 +1,508 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2018-2021 Intel Corporation
+
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/hwmon.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/peci.h>
+#include <linux/peci-cpu.h>
+#include <linux/units.h>
+#include <linux/workqueue.h>
+#include <linux/x86/intel-family.h>
+
+#include "common.h"
+
+#define DIMM_MASK_CHECK_DELAY_JIFFIES	msecs_to_jiffies(5000)
+#define DIMM_MASK_CHECK_RETRY_MAX	60 /* 60 x 5 secs = 5 minutes */
+
+/* Max number of channel ranks and DIMM index per channel */
+#define CHAN_RANK_MAX_ON_HSX	8
+#define DIMM_IDX_MAX_ON_HSX	3
+#define CHAN_RANK_MAX_ON_BDX	4
+#define DIMM_IDX_MAX_ON_BDX	3
+#define CHAN_RANK_MAX_ON_BDXD	2
+#define DIMM_IDX_MAX_ON_BDXD	2
+#define CHAN_RANK_MAX_ON_SKX	6
+#define DIMM_IDX_MAX_ON_SKX	2
+#define CHAN_RANK_MAX_ON_ICX	8
+#define DIMM_IDX_MAX_ON_ICX	2
+#define CHAN_RANK_MAX_ON_ICXD	4
+#define DIMM_IDX_MAX_ON_ICXD	2
+
+#define CHAN_RANK_MAX		CHAN_RANK_MAX_ON_HSX
+#define DIMM_IDX_MAX		DIMM_IDX_MAX_ON_HSX
+#define DIMM_NUMS_MAX		(CHAN_RANK_MAX * DIMM_IDX_MAX)
+
+#define CPU_SEG_MASK		GENMASK(23, 16)
+#define GET_CPU_SEG(x)		(((x) & CPU_SEG_MASK) >> 16)
+#define CPU_BUS_MASK		GENMASK(7, 0)
+#define GET_CPU_BUS(x)		((x) & CPU_BUS_MASK)
+
+#define DIMM_TEMP_MAX		GENMASK(15, 8)
+#define DIMM_TEMP_CRIT		GENMASK(23, 16)
+#define GET_TEMP_MAX(x)		(((x) & DIMM_TEMP_MAX) >> 8)
+#define GET_TEMP_CRIT(x)	(((x) & DIMM_TEMP_CRIT) >> 16)
+
+struct dimm_info {
+	int chan_rank_max;
+	int dimm_idx_max;
+	u8 min_peci_revision;
+};
+
+struct peci_dimmtemp {
+	struct peci_device *peci_dev;
+	struct device *dev;
+	const char *name;
+	const struct dimm_info *gen_info;
+	struct delayed_work detect_work;
+	struct peci_sensor_data temp[DIMM_NUMS_MAX];
+	long temp_max[DIMM_NUMS_MAX];
+	long temp_crit[DIMM_NUMS_MAX];
+	int retry_count;
+	char **dimmtemp_label;
+	DECLARE_BITMAP(dimm_mask, DIMM_NUMS_MAX);
+};
+
+static u8 __dimm_temp(u32 reg, int dimm_order)
+{
+	return (reg >> (dimm_order * 8)) & 0xff;
+}
+
+static int get_dimm_temp(struct peci_dimmtemp *priv, int dimm_no)
+{
+	int dimm_order = dimm_no % priv->gen_info->dimm_idx_max;
+	int chan_rank = dimm_no / priv->gen_info->dimm_idx_max;
+	struct peci_device *peci_dev = priv->peci_dev;
+	u8 cpu_seg, cpu_bus, dev, func;
+	u64 offset;
+	u32 data;
+	u16 reg;
+	int ret;
+
+	if (!peci_sensor_need_update(&priv->temp[dimm_no]))
+		return 0;
+
+	ret = peci_pcs_read(peci_dev, PECI_PCS_DDR_DIMM_TEMP, chan_rank, &data);
+	if (ret)
+		return ret;
+
+	priv->temp[dimm_no].value = __dimm_temp(data, dimm_order) * MILLIDEGREE_PER_DEGREE;
+
+	switch (peci_dev->info.model) {
+	case INTEL_FAM6_ICELAKE_X:
+	case INTEL_FAM6_ICELAKE_D:
+		ret = peci_ep_pci_local_read(peci_dev, 0, 13, 0, 2, 0xd4, &data);
+		if (ret || !(data & BIT(31)))
+			break; /* Use default or previous value */
+
+		ret = peci_ep_pci_local_read(peci_dev, 0, 13, 0, 2, 0xd0, &data);
+		if (ret)
+			break; /* Use default or previous value */
+
+		cpu_seg = GET_CPU_SEG(data);
+		cpu_bus = GET_CPU_BUS(data);
+
+		/*
+		 * Device 26, Offset 224e0: IMC 0 channel 0 -> rank 0
+		 * Device 26, Offset 264e0: IMC 0 channel 1 -> rank 1
+		 * Device 27, Offset 224e0: IMC 1 channel 0 -> rank 2
+		 * Device 27, Offset 264e0: IMC 1 channel 1 -> rank 3
+		 * Device 28, Offset 224e0: IMC 2 channel 0 -> rank 4
+		 * Device 28, Offset 264e0: IMC 2 channel 1 -> rank 5
+		 * Device 29, Offset 224e0: IMC 3 channel 0 -> rank 6
+		 * Device 29, Offset 264e0: IMC 3 channel 1 -> rank 7
+		 */
+		dev = 0x1a + chan_rank / 2;
+		offset = 0x224e0 + dimm_order * 4;
+		if (chan_rank % 2)
+			offset += 0x4000;
+
+		ret = peci_mmio_read(peci_dev, 0, cpu_seg, cpu_bus, dev, 0, offset, &data);
+		if (ret)
+			return ret;
+
+		priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
+		priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
+
+		break;
+	case INTEL_FAM6_SKYLAKE_X:
+		/*
+		 * Device 10, Function 2: IMC 0 channel 0 -> rank 0
+		 * Device 10, Function 6: IMC 0 channel 1 -> rank 1
+		 * Device 11, Function 2: IMC 0 channel 2 -> rank 2
+		 * Device 12, Function 2: IMC 1 channel 0 -> rank 3
+		 * Device 12, Function 6: IMC 1 channel 1 -> rank 4
+		 * Device 13, Function 2: IMC 1 channel 2 -> rank 5
+		 */
+		dev = 10 + chan_rank / 3 * 2 + (chan_rank % 3 == 2 ? 1 : 0);
+		func = chan_rank % 3 == 1 ? 6 : 2;
+		reg = 0x120 + dimm_order * 4;
+
+		ret = peci_pci_local_read(peci_dev, 2, dev, func, reg, &data);
+		if (ret)
+			return ret;
+
+		priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
+		priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
+
+		break;
+	case INTEL_FAM6_BROADWELL_D:
+		/*
+		 * Device 10, Function 2: IMC 0 channel 0 -> rank 0
+		 * Device 10, Function 6: IMC 0 channel 1 -> rank 1
+		 * Device 12, Function 2: IMC 1 channel 0 -> rank 2
+		 * Device 12, Function 6: IMC 1 channel 1 -> rank 3
+		 */
+		dev = 10 + chan_rank / 2 * 2;
+		func = (chan_rank % 2) ? 6 : 2;
+		reg = 0x120 + dimm_order * 4;
+
+		ret = peci_pci_local_read(peci_dev, 2, dev, func, reg, &data);
+		if (ret)
+			return ret;
+
+		priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
+		priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
+
+		break;
+	case INTEL_FAM6_HASWELL_X:
+	case INTEL_FAM6_BROADWELL_X:
+		/*
+		 * Device 20, Function 0: IMC 0 channel 0 -> rank 0
+		 * Device 20, Function 1: IMC 0 channel 1 -> rank 1
+		 * Device 21, Function 0: IMC 0 channel 2 -> rank 2
+		 * Device 21, Function 1: IMC 0 channel 3 -> rank 3
+		 * Device 23, Function 0: IMC 1 channel 0 -> rank 4
+		 * Device 23, Function 1: IMC 1 channel 1 -> rank 5
+		 * Device 24, Function 0: IMC 1 channel 2 -> rank 6
+		 * Device 24, Function 1: IMC 1 channel 3 -> rank 7
+		 */
+		dev = 20 + chan_rank / 2 + chan_rank / 4;
+		func = chan_rank % 2;
+		reg = 0x120 + dimm_order * 4;
+
+		ret = peci_pci_local_read(peci_dev, 1, dev, func, reg, &data);
+		if (ret)
+			return ret;
+
+		priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
+		priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
+
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	peci_sensor_mark_updated(&priv->temp[dimm_no]);
+
+	return 0;
+}
+
+static int dimmtemp_read_string(struct device *dev,
+				enum hwmon_sensor_types type,
+				u32 attr, int channel, const char **str)
+{
+	struct peci_dimmtemp *priv = dev_get_drvdata(dev);
+
+	if (attr != hwmon_temp_label)
+		return -EOPNOTSUPP;
+
+	*str = (const char *)priv->dimmtemp_label[channel];
+
+	return 0;
+}
+
+static int dimmtemp_read(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long *val)
+{
+	struct peci_dimmtemp *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = get_dimm_temp(priv, channel);
+	if (ret)
+		return ret;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		*val = priv->temp[channel].value;
+		break;
+	case hwmon_temp_max:
+		*val = priv->temp_max[channel];
+		break;
+	case hwmon_temp_crit:
+		*val = priv->temp_crit[channel];
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t dimmtemp_is_visible(const void *data, enum hwmon_sensor_types type,
+				   u32 attr, int channel)
+{
+	const struct peci_dimmtemp *priv = data;
+
+	if (test_bit(channel, priv->dimm_mask))
+		return 0444;
+
+	return 0;
+}
+
+static const struct hwmon_ops peci_dimmtemp_ops = {
+	.is_visible = dimmtemp_is_visible,
+	.read_string = dimmtemp_read_string,
+	.read = dimmtemp_read,
+};
+
+static int check_populated_dimms(struct peci_dimmtemp *priv)
+{
+	int chan_rank_max = priv->gen_info->chan_rank_max;
+	int dimm_idx_max = priv->gen_info->dimm_idx_max;
+	int chan_rank, dimm_idx, ret;
+	u64 dimm_mask = 0;
+	u32 pcs;
+
+	for (chan_rank = 0; chan_rank < chan_rank_max; chan_rank++) {
+		ret = peci_pcs_read(priv->peci_dev, PECI_PCS_DDR_DIMM_TEMP, chan_rank, &pcs);
+		if (ret) {
+			/*
+			 * Overall, we expect either success or -EINVAL in
+			 * order to determine whether DIMM is populated or not.
+			 * For anything else - we fall back to defering the
+			 * detection to be performed at a later point in time.
+			 */
+			if (ret == -EINVAL)
+				continue;
+			else
+				return -EAGAIN;
+		}
+
+		for (dimm_idx = 0; dimm_idx < dimm_idx_max; dimm_idx++)
+			if (__dimm_temp(pcs, dimm_idx))
+				dimm_mask |= BIT(chan_rank * dimm_idx_max + dimm_idx);
+	}
+	/*
+	 * It's possible that memory training is not done yet. In this case we
+	 * defer the detection to be performed at a later point in time.
+	 */
+	if (!dimm_mask)
+		return -EAGAIN;
+
+	dev_dbg(priv->dev, "Scanned populated DIMMs: %#llx\n", dimm_mask);
+
+	bitmap_from_u64(priv->dimm_mask, dimm_mask);
+
+	return 0;
+}
+
+static int create_dimm_temp_label(struct peci_dimmtemp *priv, int chan)
+{
+	int rank = chan / priv->gen_info->dimm_idx_max;
+	int idx = chan % priv->gen_info->dimm_idx_max;
+
+	priv->dimmtemp_label[chan] = devm_kasprintf(priv->dev, GFP_KERNEL,
+						    "DIMM %c%d", 'A' + rank,
+						    idx + 1);
+	if (!priv->dimmtemp_label[chan])
+		return -ENOMEM;
+
+	return 0;
+}
+
+static const u32 peci_dimmtemp_temp_channel_config[] = {
+	[0 ... DIMM_NUMS_MAX - 1] = HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT,
+	0
+};
+
+static const struct hwmon_channel_info peci_dimmtemp_temp_channel = {
+	.type = hwmon_temp,
+	.config = peci_dimmtemp_temp_channel_config,
+};
+
+static const struct hwmon_channel_info *peci_dimmtemp_temp_info[] = {
+	&peci_dimmtemp_temp_channel,
+	NULL
+};
+
+static const struct hwmon_chip_info peci_dimmtemp_chip_info = {
+	.ops = &peci_dimmtemp_ops,
+	.info = peci_dimmtemp_temp_info,
+};
+
+static int create_dimm_temp_info(struct peci_dimmtemp *priv)
+{
+	int ret, i, channels;
+	struct device *dev;
+
+	ret = check_populated_dimms(priv);
+	if (ret == -EAGAIN) {
+		if (priv->retry_count < DIMM_MASK_CHECK_RETRY_MAX) {
+			schedule_delayed_work(&priv->detect_work,
+					      DIMM_MASK_CHECK_DELAY_JIFFIES);
+			priv->retry_count++;
+			dev_dbg(priv->dev, "Deferred populating DIMM temp info\n");
+			return ret;
+		}
+
+		dev_info(priv->dev, "Timeout populating DIMM temp info\n");
+		return -ETIMEDOUT;
+	}
+
+	channels = priv->gen_info->chan_rank_max * priv->gen_info->dimm_idx_max;
+
+	priv->dimmtemp_label = devm_kzalloc(priv->dev, channels * sizeof(char *), GFP_KERNEL);
+	if (!priv->dimmtemp_label)
+		return -ENOMEM;
+
+	for_each_set_bit(i, priv->dimm_mask, DIMM_NUMS_MAX) {
+		ret = create_dimm_temp_label(priv, i);
+		if (ret)
+			return ret;
+	}
+
+	dev = devm_hwmon_device_register_with_info(priv->dev, priv->name, priv,
+						   &peci_dimmtemp_chip_info, NULL);
+	if (IS_ERR(dev)) {
+		dev_err(priv->dev, "Failed to register hwmon device\n");
+		return PTR_ERR(dev);
+	}
+
+	dev_dbg(priv->dev, "%s: sensor '%s'\n", dev_name(dev), priv->name);
+
+	return 0;
+}
+
+static void create_dimm_temp_info_delayed(struct work_struct *work)
+{
+	struct peci_dimmtemp *priv = container_of(to_delayed_work(work),
+						  struct peci_dimmtemp,
+						  detect_work);
+	int ret;
+
+	ret = create_dimm_temp_info(priv);
+	if (ret && ret != -EAGAIN)
+		dev_dbg(priv->dev, "Failed to populate DIMM temp info\n");
+}
+
+static int peci_dimmtemp_probe(struct auxiliary_device *adev, const struct auxiliary_device_id *id)
+{
+	struct device *dev = &adev->dev;
+	struct peci_device *peci_dev = to_peci_device(dev->parent);
+	struct peci_dimmtemp *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->name = devm_kasprintf(dev, GFP_KERNEL, "peci_dimmtemp.cpu%d",
+				    peci_dev->info.socket_id);
+	if (!priv->name)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, priv);
+	priv->dev = dev;
+	priv->peci_dev = peci_dev;
+	priv->gen_info = (const struct dimm_info *)id->driver_data;
+
+	INIT_DELAYED_WORK(&priv->detect_work, create_dimm_temp_info_delayed);
+
+	ret = create_dimm_temp_info(priv);
+	if (ret && ret != -EAGAIN) {
+		dev_dbg(dev, "Failed to populate DIMM temp info\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void peci_dimmtemp_remove(struct auxiliary_device *adev)
+{
+	struct peci_dimmtemp *priv = dev_get_drvdata(&adev->dev);
+
+	cancel_delayed_work_sync(&priv->detect_work);
+}
+
+static const struct dimm_info dimm_hsx = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_HSX,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_HSX,
+	.min_peci_revision = 0x30,
+};
+
+static const struct dimm_info dimm_bdx = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_BDX,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_BDX,
+	.min_peci_revision = 0x30,
+};
+
+static const struct dimm_info dimm_bdxd = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_BDXD,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_BDXD,
+	.min_peci_revision = 0x30,
+};
+
+static const struct dimm_info dimm_skx = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_SKX,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_SKX,
+	.min_peci_revision = 0x30,
+};
+
+static const struct dimm_info dimm_icx = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_ICX,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_ICX,
+	.min_peci_revision = 0x40,
+};
+
+static const struct dimm_info dimm_icxd = {
+	.chan_rank_max	= CHAN_RANK_MAX_ON_ICXD,
+	.dimm_idx_max	= DIMM_IDX_MAX_ON_ICXD,
+	.min_peci_revision = 0x40,
+};
+
+static const struct auxiliary_device_id peci_dimmtemp_ids[] = {
+	{
+		.name = "peci_cpu.dimmtemp.hsx",
+		.driver_data = (kernel_ulong_t)&dimm_hsx,
+	},
+	{
+		.name = "peci_cpu.dimmtemp.bdx",
+		.driver_data = (kernel_ulong_t)&dimm_bdx,
+	},
+	{
+		.name = "peci_cpu.dimmtemp.bdxd",
+		.driver_data = (kernel_ulong_t)&dimm_bdxd,
+	},
+	{
+		.name = "peci_cpu.dimmtemp.skx",
+		.driver_data = (kernel_ulong_t)&dimm_skx,
+	},
+	{
+		.name = "peci_cpu.dimmtemp.icx",
+		.driver_data = (kernel_ulong_t)&dimm_icx,
+	},
+	{
+		.name = "peci_cpu.dimmtemp.icxd",
+		.driver_data = (kernel_ulong_t)&dimm_icxd,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(auxiliary, peci_dimmtemp_ids);
+
+static struct auxiliary_driver peci_dimmtemp_driver = {
+	.probe		= peci_dimmtemp_probe,
+	.remove		= peci_dimmtemp_remove,
+	.id_table	= peci_dimmtemp_ids,
+};
+
+module_auxiliary_driver(peci_dimmtemp_driver);
+
+MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
+MODULE_AUTHOR("Iwona Winiarska <iwona.winiarska@intel.com>");
+MODULE_DESCRIPTION("PECI dimmtemp driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PECI_CPU);
-- 
2.31.1