[PATCH v2 2/3] mfd: Intel Platform Monitoring Technology support

[David E. Box]

Intel Platform Monitoring Technology (PMT) is an architecture for
enumerating and accessing hardware monitoring facilities. PMT supports
multiple types of monitoring capabilities. This driver creates platform
devices for each type so that they may be managed by capability specific
drivers (to be introduced). Capabilities are discovered using PCIe DVSEC
ids. Support is included for the 3 current capability types, Telemetry,
Watcher, and Crashlog. The features are available on new Intel platforms
starting from Tiger Lake for which support is added. Tiger Lake however
will not support Watcher and Crashlog even though the capabilities appear
on the device. So add a quirk facility and use it to disable them.

Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
---
 MAINTAINERS                 |   5 ++
 drivers/mfd/Kconfig         |  10 +++
 drivers/mfd/Makefile        |   1 +
 drivers/mfd/intel_pmt.c     | 170 ++++++++++++++++++++++++++++++++++++
 include/linux/intel-dvsec.h |  48 ++++++++++
 5 files changed, 234 insertions(+)
 create mode 100644 drivers/mfd/intel_pmt.c
 create mode 100644 include/linux/intel-dvsec.h

diff --git a/MAINTAINERS b/MAINTAINERS
index e64e5db31497..367e49d27960 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8733,6 +8733,11 @@ F:	drivers/mfd/intel_soc_pmic*
 F:	include/linux/mfd/intel_msic.h
 F:	include/linux/mfd/intel_soc_pmic*
 
+INTEL PMT DRIVER
+M:	"David E. Box" <david.e.box@xxxxxxxxxxxxxxx>
+S:	Maintained
+F:	drivers/mfd/intel_pmt.c
+
 INTEL PRO/WIRELESS 2100, 2200BG, 2915ABG NETWORK CONNECTION SUPPORT
 M:	Stanislav Yakovlev <stas.yakovlev@xxxxxxxxx>
 L:	linux-wireless@xxxxxxxxxxxxxxx
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 0a59249198d3..8777ff99e633 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -632,6 +632,16 @@ config MFD_INTEL_MSIC
 	  Passage) chip. This chip embeds audio, battery, GPIO, etc.
 	  devices used in Intel Medfield platforms.
 
+config MFD_INTEL_PMT
+	tristate "Intel Platform Monitoring Technology support"
+	depends on PCI
+	select MFD_CORE
+	help
+	  The Intel Platform Monitoring Technology (PMT) is an interface that
+	  provides access to hardware monitor registers. This driver supports
+	  Telemetry, Watcher, and Crashlog PMT capabilities/devices for
+	  platforms starting from Tiger Lake.
+
 config MFD_IPAQ_MICRO
 	bool "Atmel Micro ASIC (iPAQ h3100/h3600/h3700) Support"
 	depends on SA1100_H3100 || SA1100_H3600
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f935d10cbf0f..0041f673faa1 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -212,6 +212,7 @@ obj-$(CONFIG_MFD_INTEL_LPSS)	+= intel-lpss.o
 obj-$(CONFIG_MFD_INTEL_LPSS_PCI)	+= intel-lpss-pci.o
 obj-$(CONFIG_MFD_INTEL_LPSS_ACPI)	+= intel-lpss-acpi.o
 obj-$(CONFIG_MFD_INTEL_MSIC)	+= intel_msic.o
+obj-$(CONFIG_MFD_INTEL_PMT)	+= intel_pmt.o
 obj-$(CONFIG_MFD_PALMAS)	+= palmas.o
 obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
 obj-$(CONFIG_MFD_RC5T583)	+= rc5t583.o rc5t583-irq.o
diff --git a/drivers/mfd/intel_pmt.c b/drivers/mfd/intel_pmt.c
new file mode 100644
index 000000000000..951128ec2afa
--- /dev/null
+++ b/drivers/mfd/intel_pmt.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Platform Monitoring Technology MFD driver
+ *
+ * Copyright (c) 2020, Intel Corporation.
+ * All Rights Reserved.
+ *
+ * Authors: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/mfd/core.h>
+#include <linux/intel-dvsec.h>
+
+static const struct pmt_platform_info tgl_info = {
+	.quirks = PMT_QUIRK_NO_WATCHER | PMT_QUIRK_NO_CRASHLOG,
+};
+
+static int
+pmt_add_dev(struct pci_dev *pdev, struct intel_dvsec_header *header,
+	    struct pmt_platform_info *info)
+{
+	struct mfd_cell *cell, *tmp;
+	const char *name;
+	int i;
+
+	switch (header->id) {
+	case DVSEC_INTEL_ID_TELEM:
+		name = TELEM_DEV_NAME;
+		break;
+	case DVSEC_INTEL_ID_WATCHER:
+		if (info->quirks && PMT_QUIRK_NO_WATCHER) {
+			dev_info(&pdev->dev, "Watcher not supported\n");
+			return 0;
+		}
+		name = WATCHER_DEV_NAME;
+		break;
+	case DVSEC_INTEL_ID_CRASHLOG:
+		if (info->quirks && PMT_QUIRK_NO_WATCHER) {
+			dev_info(&pdev->dev, "Crashlog not supported\n");
+			return 0;
+		}
+		name = CRASHLOG_DEV_NAME;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	cell = devm_kcalloc(&pdev->dev, header->num_entries,
+			    sizeof(*cell), GFP_KERNEL);
+	if (!cell)
+		return -ENOMEM;
+
+	/* Create a platform device for each entry. */
+	for (i = 0, tmp = cell; i < header->num_entries; i++, tmp++) {
+		struct resource *res;
+
+		res = devm_kzalloc(&pdev->dev, sizeof(*res), GFP_KERNEL);
+		if (!res)
+			return -ENOMEM;
+
+		tmp->name = name;
+
+		res->start = pdev->resource[header->tbir].start +
+			     header->offset +
+			     (i * (INTEL_DVSEC_ENTRY_SIZE << 2));
+		res->end = res->start + (header->entry_size << 2) - 1;
+		res->flags = IORESOURCE_MEM;
+
+		tmp->resources = res;
+		tmp->num_resources = 1;
+		tmp->platform_data = header;
+		tmp->pdata_size = sizeof(*header);
+
+	}
+
+	return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, cell,
+				    header->num_entries, NULL, 0, NULL);
+}
+
+static int
+pmt_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	u16 vid;
+	u32 table;
+	int ret, pos = 0, last_pos = 0;
+	struct pmt_platform_info *info;
+	struct intel_dvsec_header header;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	while ((pos = pci_find_next_ext_capability(pdev, pos, PCI_EXT_CAP_ID_DVSEC))) {
+		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER1, &vid);
+		if (vid != PCI_VENDOR_ID_INTEL)
+			continue;
+
+		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER2,
+				     &header.id);
+
+		pci_read_config_byte(pdev, pos + INTEL_DVSEC_ENTRIES,
+				     &header.num_entries);
+
+		pci_read_config_byte(pdev, pos + INTEL_DVSEC_SIZE,
+				     &header.entry_size);
+
+		if (!header.num_entries || !header.entry_size)
+			return -EINVAL;
+
+		pci_read_config_dword(pdev, pos + INTEL_DVSEC_TABLE,
+				      &table);
+
+		header.tbir = INTEL_DVSEC_TABLE_BAR(table);
+		header.offset = INTEL_DVSEC_TABLE_OFFSET(table);
+		ret = pmt_add_dev(pdev, &header, info);
+		if (ret)
+			dev_warn(&pdev->dev,
+				 "Failed to add devices for DVSEC id %d\n",
+				 header.id);
+		last_pos = pos;
+	}
+
+	if (!last_pos) {
+		dev_err(&pdev->dev, "No supported PMT capabilities found.\n");
+		return -ENODEV;
+	}
+
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+
+	return 0;
+}
+
+static void pmt_pci_remove(struct pci_dev *pdev)
+{
+	pm_runtime_forbid(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+}
+
+#define PCI_DEVICE_ID_INTEL_PMT_TGL	0x9a0d
+
+static const struct pci_device_id pmt_pci_ids[] = {
+	{ PCI_DEVICE_DATA(INTEL, PMT_TGL, &tgl_info) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, pmt_pci_ids);
+
+static struct pci_driver pmt_pci_driver = {
+	.name = "intel-pmt",
+	.id_table = pmt_pci_ids,
+	.probe = pmt_pci_probe,
+	.remove = pmt_pci_remove,
+};
+
+module_pci_driver(pmt_pci_driver);
+
+MODULE_AUTHOR("David E. Box <david.e.box@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Intel Platform Monitoring Technology MFD driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/intel-dvsec.h b/include/linux/intel-dvsec.h
new file mode 100644
index 000000000000..87bb67fd62f7
--- /dev/null
+++ b/include/linux/intel-dvsec.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef INTEL_DVSEC_H
+#define INTEL_DVSEC_H
+
+#include <linux/types.h>
+
+#define DVSEC_INTEL_ID_TELEM	2
+#define DVSEC_INTEL_ID_WATCHER	3
+#define DVSEC_INTEL_ID_CRASHLOG	4
+
+#define TELEM_DEV_NAME		"pmt_telemetry"
+#define WATCHER_DEV_NAME	"pmt_watcher"
+#define CRASHLOG_DEV_NAME	"pmt_crashlog"
+
+/* Intel DVSEC capability vendor space offsets */
+#define INTEL_DVSEC_ENTRIES		0xA
+#define INTEL_DVSEC_SIZE		0xB
+#define INTEL_DVSEC_TABLE		0xC
+#define INTEL_DVSEC_TABLE_BAR(x)	((x) & GENMASK(2, 0))
+#define INTEL_DVSEC_TABLE_OFFSET(x)	((x) >> 3)
+
+#define INTEL_DVSEC_ENTRY_SIZE		4
+
+/* DVSEC header */
+struct intel_dvsec_header {
+	u16	length;
+	u16	id;
+	u8	num_entries;
+	u8	entry_size;
+	u8	entry_max;
+	u8	tbir;
+	u32	offset;
+};
+
+enum pmt_quirks {
+	/* Watcher capability not supported */
+	PMT_QUIRK_NO_WATCHER	= (1 << 0),
+
+	/* Crashlog capability not supported */
+	PMT_QUIRK_NO_CRASHLOG	= (1 << 1),
+};
+
+struct pmt_platform_info {
+	unsigned long quirks;
+	struct intel_dvsec_header **capabilities;
+};
+
+#endif
-- 
2.20.1