From: Alexander Duyck <alexander.h.du...@linux.intel.com>

PMT Telemetry is a capability of the Intel Platform Monitoring Technology.
The Telemetry capability provides access to device telemetry metrics that
provide hardware performance data to users from read-only register spaces.

With this driver present the intel_pmt directory can be populated with
telem<x> devices. These devices will contain the standard intel_pmt sysfs
data and a "telem" binary sysfs attribute which can be used to access the
telemetry data.

Also create a PCI device id list for early telemetry hardware that require
workarounds for known issues.

Co-developed-by: David E. Box <david.e....@linux.intel.com>
Signed-off-by: David E. Box <david.e....@linux.intel.com>
Signed-off-by: Alexander Duyck <alexander.h.du...@linux.intel.com>
---
 drivers/platform/x86/Kconfig               |  11 ++
 drivers/platform/x86/Makefile              |   1 +
 drivers/platform/x86/intel_pmt_telemetry.c | 160 +++++++++++++++++++++
 3 files changed, 172 insertions(+)
 create mode 100644 drivers/platform/x86/intel_pmt_telemetry.c

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 12431e0e974d..90b4c1bd9532 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1372,6 +1372,17 @@ config INTEL_PMT_CLASS
          To compile this driver as a module, choose M here: the module
          will be called intel_pmt_class.
 
+config INTEL_PMT_TELEMETRY
+       tristate "Intel Platform Monitoring Technology (PMT) Telemetry driver"
+       select INTEL_PMT_CLASS
+       help
+         The Intel Platform Monitory Technology (PMT) Telemetry driver provides
+         access to hardware telemetry metrics on devices that support the
+         feature.
+
+         To compile this driver as a module, choose M here: the module
+         will be called intel_pmt_telemetry.
+
 config INTEL_PUNIT_IPC
        tristate "Intel P-Unit IPC Driver"
        help
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index f4b1f87f2401..6a7b61f59ea8 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -141,6 +141,7 @@ obj-$(CONFIG_INTEL_MID_POWER_BUTTON)        += 
intel_mid_powerbtn.o
 obj-$(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_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_telemetry.c 
b/drivers/platform/x86/intel_pmt_telemetry.c
new file mode 100644
index 000000000000..f8a87614efa4
--- /dev/null
+++ b/drivers/platform/x86/intel_pmt_telemetry.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Platform Monitory Technology Telemetry driver
+ *
+ * Copyright (c) 2020, Intel Corporation.
+ * All Rights Reserved.
+ *
+ * Author: "David E. Box" <david.e....@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 TELEM_DEV_NAME         "pmt_telemetry"
+
+#define TELEM_SIZE_OFFSET      0x0
+#define TELEM_GUID_OFFSET      0x4
+#define TELEM_BASE_OFFSET      0x8
+#define TELEM_ACCESS(v)                ((v) & GENMASK(3, 0))
+/* size is in bytes */
+#define TELEM_SIZE(v)          (((v) & GENMASK(27, 12)) >> 10)
+
+/* Used by client hardware to identify a fixed telemetry entry*/
+#define TELEM_CLIENT_FIXED_BLOCK_GUID  0x10000000
+
+struct pmt_telem_priv {
+       int                             num_entries;
+       struct intel_pmt_entry          entry[];
+};
+
+/*
+ * Early implementations of PMT on client platforms have some
+ * differences from the server platforms (which use the Out Of Band
+ * Management Services Module OOBMSM). This list tracks those
+ * platforms as needed to handle those differences. Newer client
+ * platforms are expected to be fully compatible with server.
+ */
+static const struct pci_device_id pmt_telem_early_client_pci_ids[] = {
+       { PCI_VDEVICE(INTEL, 0x9a0d) }, /* TGL */
+       { PCI_VDEVICE(INTEL, 0x467d) }, /* ADL */
+       { }
+};
+
+static bool intel_pmt_is_early_client_hw(struct device *dev)
+{
+       struct pci_dev *parent = to_pci_dev(dev->parent);
+
+       return !!pci_match_id(pmt_telem_early_client_pci_ids, parent);
+}
+
+static bool pmt_telem_region_overlaps(struct intel_pmt_entry *entry,
+                                     struct device *dev)
+{
+       u32 guid = readl(entry->disc_table + TELEM_GUID_OFFSET);
+
+       if (guid != TELEM_CLIENT_FIXED_BLOCK_GUID)
+               return false;
+
+       return intel_pmt_is_early_client_hw(dev);
+}
+
+static int pmt_telem_header_decode(struct intel_pmt_entry *entry,
+                                  struct intel_pmt_header *header,
+                                  struct device *dev)
+{
+       void __iomem *disc_table = entry->disc_table;
+
+       if (pmt_telem_region_overlaps(entry, dev))
+               return 1;
+
+       header->access_type = TELEM_ACCESS(readl(disc_table));
+       header->guid = readl(disc_table + TELEM_GUID_OFFSET);
+       header->base_offset = readl(disc_table + TELEM_BASE_OFFSET);
+
+       /* Size is measured in DWORDS, but accessor returns bytes */
+       header->size = TELEM_SIZE(readl(disc_table));
+
+       return 0;
+}
+
+static DEFINE_XARRAY_ALLOC(telem_array);
+static struct intel_pmt_namespace pmt_telem_ns = {
+       .name = "telem",
+       .xa = &telem_array,
+       .pmt_header_decode = pmt_telem_header_decode,
+};
+
+static int pmt_telem_remove(struct platform_device *pdev)
+{
+       struct pmt_telem_priv *priv = platform_get_drvdata(pdev);
+       int i;
+
+       for (i = 0; i < priv->num_entries; i++)
+               intel_pmt_dev_destroy(&priv->entry[i], &pmt_telem_ns);
+
+       return 0;
+}
+
+static int pmt_telem_probe(struct platform_device *pdev)
+{
+       struct pmt_telem_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];
+
+               ret = intel_pmt_dev_create(entry, &pmt_telem_ns, pdev, i);
+               if (ret < 0)
+                       goto abort_probe;
+               if (ret)
+                       continue;
+
+               priv->num_entries++;
+       }
+
+       return 0;
+abort_probe:
+       pmt_telem_remove(pdev);
+       return ret;
+}
+
+static struct platform_driver pmt_telem_driver = {
+       .driver = {
+               .name   = TELEM_DEV_NAME,
+       },
+       .remove = pmt_telem_remove,
+       .probe  = pmt_telem_probe,
+};
+
+static int __init pmt_telem_init(void)
+{
+       return platform_driver_register(&pmt_telem_driver);
+}
+module_init(pmt_telem_init);
+
+static void __exit pmt_telem_exit(void)
+{
+       platform_driver_unregister(&pmt_telem_driver);
+       xa_destroy(&telem_array);
+}
+module_exit(pmt_telem_exit);
+
+MODULE_AUTHOR("David E. Box <david.e....@linux.intel.com>");
+MODULE_DESCRIPTION("Intel PMT Telemetry driver");
+MODULE_ALIAS("platform:" TELEM_DEV_NAME);
+MODULE_LICENSE("GPL v2");
-- 
2.20.1

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