Merge branch 'pci/ptm' into next
* pci/ptm:
PCI: Add PTM clock granularity information
PCI: Add pci_enable_ptm() for drivers to enable PTM on endpoints
PCI: Add Precision Time Measurement (PTM) support
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9730c47..194521b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -332,6 +332,12 @@
void pci_enable_acs(struct pci_dev *dev);
+#ifdef CONFIG_PCIE_PTM
+void pci_ptm_init(struct pci_dev *dev);
+#else
+static inline void pci_ptm_init(struct pci_dev *dev) { }
+#endif
+
struct pci_dev_reset_methods {
u16 vendor;
u16 device;
diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig
index 7fcea75..7ce7763 100644
--- a/drivers/pci/pcie/Kconfig
+++ b/drivers/pci/pcie/Kconfig
@@ -92,3 +92,14 @@
will be handled by the DPC driver. If your system doesn't
have this capability or you do not want to use this feature,
it is safe to answer N.
+
+config PCIE_PTM
+ bool "PCIe Precision Time Measurement support"
+ default n
+ depends on PCIEPORTBUS
+ help
+ This enables PCI Express Precision Time Measurement (PTM)
+ support.
+
+ This is only useful if you have devices that support PTM, but it
+ is safe to enable even if you don't.
diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
index b24525b..36e35ea 100644
--- a/drivers/pci/pcie/Makefile
+++ b/drivers/pci/pcie/Makefile
@@ -16,3 +16,4 @@
obj-$(CONFIG_PCIE_PME) += pme.o
obj-$(CONFIG_PCIE_DPC) += pcie-dpc.o
+obj-$(CONFIG_PCIE_PTM) += ptm.o
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
new file mode 100644
index 0000000..bab8ac6
--- /dev/null
+++ b/drivers/pci/pcie/ptm.c
@@ -0,0 +1,142 @@
+/*
+ * PCI Express Precision Time Measurement
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include "../pci.h"
+
+static void pci_ptm_info(struct pci_dev *dev)
+{
+ char clock_desc[8];
+
+ switch (dev->ptm_granularity) {
+ case 0:
+ snprintf(clock_desc, sizeof(clock_desc), "unknown");
+ break;
+ case 255:
+ snprintf(clock_desc, sizeof(clock_desc), ">254ns");
+ break;
+ default:
+ snprintf(clock_desc, sizeof(clock_desc), "%udns",
+ dev->ptm_granularity);
+ break;
+ }
+ dev_info(&dev->dev, "PTM enabled%s, %s granularity\n",
+ dev->ptm_root ? " (root)" : "", clock_desc);
+}
+
+void pci_ptm_init(struct pci_dev *dev)
+{
+ int pos;
+ u32 cap, ctrl;
+ u8 local_clock;
+ struct pci_dev *ups;
+
+ if (!pci_is_pcie(dev))
+ return;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
+ if (!pos)
+ return;
+
+ /*
+ * Enable PTM only on interior devices (root ports, switch ports,
+ * etc.) on the assumption that it causes no link traffic until an
+ * endpoint enables it.
+ */
+ if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ENDPOINT ||
+ pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END))
+ return;
+
+ pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+ local_clock = (cap & PCI_PTM_GRANULARITY_MASK) >> 8;
+
+ /*
+ * There's no point in enabling PTM unless it's enabled in the
+ * upstream device or this device can be a PTM Root itself. Per
+ * the spec recommendation (PCIe r3.1, sec 7.32.3), select the
+ * furthest upstream Time Source as the PTM Root.
+ */
+ ups = pci_upstream_bridge(dev);
+ if (ups && ups->ptm_enabled) {
+ ctrl = PCI_PTM_CTRL_ENABLE;
+ if (ups->ptm_granularity == 0)
+ dev->ptm_granularity = 0;
+ else if (ups->ptm_granularity > local_clock)
+ dev->ptm_granularity = ups->ptm_granularity;
+ } else {
+ if (cap & PCI_PTM_CAP_ROOT) {
+ ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT;
+ dev->ptm_root = 1;
+ dev->ptm_granularity = local_clock;
+ } else
+ return;
+ }
+
+ ctrl |= dev->ptm_granularity << 8;
+ pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
+ dev->ptm_enabled = 1;
+
+ pci_ptm_info(dev);
+}
+
+int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
+{
+ int pos;
+ u32 cap, ctrl;
+ struct pci_dev *ups;
+
+ if (!pci_is_pcie(dev))
+ return -EINVAL;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM);
+ if (!pos)
+ return -EINVAL;
+
+ pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+ if (!(cap & PCI_PTM_CAP_REQ))
+ return -EINVAL;
+
+ /*
+ * For a PCIe Endpoint, PTM is only useful if the endpoint can
+ * issue PTM requests to upstream devices that have PTM enabled.
+ *
+ * For Root Complex Integrated Endpoints, there is no upstream
+ * device, so there must be some implementation-specific way to
+ * associate the endpoint with a time source.
+ */
+ if (pci_pcie_type(dev) == PCI_EXP_TYPE_ENDPOINT) {
+ ups = pci_upstream_bridge(dev);
+ if (!ups || !ups->ptm_enabled)
+ return -EINVAL;
+
+ dev->ptm_granularity = ups->ptm_granularity;
+ } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) {
+ dev->ptm_granularity = 0;
+ } else
+ return -EINVAL;
+
+ ctrl = PCI_PTM_CTRL_ENABLE;
+ ctrl |= dev->ptm_granularity << 8;
+ pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
+ dev->ptm_enabled = 1;
+
+ pci_ptm_info(dev);
+
+ if (granularity)
+ *granularity = dev->ptm_granularity;
+ return 0;
+}
+EXPORT_SYMBOL(pci_enable_ptm);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 93f280d..e2e4244 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1667,6 +1667,9 @@
pci_enable_acs(dev);
pci_cleanup_aer_error_status_regs(dev);
+
+ /* Precision Time Measurement */
+ pci_ptm_init(dev);
}
/*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2599a98..7256f33 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -367,6 +367,12 @@
int rom_attr_enabled; /* has display of the rom attribute been enabled? */
struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */
+
+#ifdef CONFIG_PCIE_PTM
+ unsigned int ptm_root:1;
+ unsigned int ptm_enabled:1;
+ u8 ptm_granularity;
+#endif
#ifdef CONFIG_PCI_MSI
const struct attribute_group **msi_irq_groups;
#endif
@@ -1402,6 +1408,13 @@
static inline int pci_ats_queue_depth(struct pci_dev *d) { return -ENODEV; }
#endif
+#ifdef CONFIG_PCIE_PTM
+int pci_enable_ptm(struct pci_dev *dev, u8 *granularity);
+#else
+static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
+{ return -EINVAL; }
+#endif
+
void pci_cfg_access_lock(struct pci_dev *dev);
bool pci_cfg_access_trylock(struct pci_dev *dev);
void pci_cfg_access_unlock(struct pci_dev *dev);
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 4040951..d812172 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -671,7 +671,8 @@
#define PCI_EXT_CAP_ID_PMUX 0x1A /* Protocol Multiplexing */
#define PCI_EXT_CAP_ID_PASID 0x1B /* Process Address Space ID */
#define PCI_EXT_CAP_ID_DPC 0x1D /* Downstream Port Containment */
-#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_DPC
+#define PCI_EXT_CAP_ID_PTM 0x1F /* Precision Time Measurement */
+#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PTM
#define PCI_EXT_CAP_DSN_SIZEOF 12
#define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
@@ -964,4 +965,13 @@
#define PCI_EXP_DPC_SOURCE_ID 10 /* DPC Source Identifier */
+/* Precision Time Measurement */
+#define PCI_PTM_CAP 0x04 /* PTM Capability */
+#define PCI_PTM_CAP_REQ 0x00000001 /* Requester capable */
+#define PCI_PTM_CAP_ROOT 0x00000004 /* Root capable */
+#define PCI_PTM_GRANULARITY_MASK 0x0000FF00 /* Clock granularity */
+#define PCI_PTM_CTRL 0x08 /* PTM Control */
+#define PCI_PTM_CTRL_ENABLE 0x00000001 /* PTM enable */
+#define PCI_PTM_CTRL_ROOT 0x00000002 /* Root select */
+
#endif /* LINUX_PCI_REGS_H */