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.
--- /dev/null
+/*
+ * 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)
+{
+ dev_info(&dev->dev, "PTM enabled%s\n", dev->ptm_root ? " (root)" : "");
+}
+
+void pci_ptm_init(struct pci_dev *dev)
+{
+ int pos;
+ u32 cap, ctrl;
+ 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);
+
+ /*
+ * 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;
+ } else {
+ if (cap & PCI_PTM_CAP_ROOT) {
+ ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT;
+ dev->ptm_root = 1;
+ } else
+ return;
+ }
+
+ pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
+ dev->ptm_enabled = 1;
+
+ pci_ptm_info(dev);
+}
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;
+#endif
#ifdef CONFIG_PCI_MSI
const struct attribute_group **msi_irq_groups;
#endif
#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
#define PCI_EXP_DPC_SOURCE_ID 10 /* DPC Source Identifier */
+/* Precision Time Measurement */
+#define PCI_PTM_CAP 0x04 /* PTM Capability */
+#define PCI_PTM_CAP_ROOT 0x00000004 /* Root capable */
+#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 */
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