Commit 9bb04a0c authored by Jonathan Yong's avatar Jonathan Yong Committed by Bjorn Helgaas

PCI: Add Precision Time Measurement (PTM) support

Add Precision Time Measurement (PTM) support (see PCIe r3.1, sec 6.22).

Enable PTM on PTM Root devices and switch ports.  This does not enable PTM
on endpoints.

There currently are no PTM-capable devices on the market, but it is
expected to be supported by the Intel Apollo Lake platform.

[bhelgaas: complete rework]
Signed-off-by: default avatarJonathan Yong <jonathan.yong@intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 29b4817d
...@@ -332,6 +332,12 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev, ...@@ -332,6 +332,12 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev,
void pci_enable_acs(struct pci_dev *dev); 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 { struct pci_dev_reset_methods {
u16 vendor; u16 vendor;
u16 device; u16 device;
......
...@@ -92,3 +92,14 @@ config PCIE_DPC ...@@ -92,3 +92,14 @@ config PCIE_DPC
will be handled by the DPC driver. If your system doesn't will be handled by the DPC driver. If your system doesn't
have this capability or you do not want to use this feature, have this capability or you do not want to use this feature,
it is safe to answer N. 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.
...@@ -16,3 +16,4 @@ obj-$(CONFIG_PCIEAER) += aer/ ...@@ -16,3 +16,4 @@ obj-$(CONFIG_PCIEAER) += aer/
obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_PME) += pme.o
obj-$(CONFIG_PCIE_DPC) += pcie-dpc.o obj-$(CONFIG_PCIE_DPC) += pcie-dpc.o
obj-$(CONFIG_PCIE_PTM) += ptm.o
/*
* 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);
}
...@@ -1667,6 +1667,9 @@ static void pci_init_capabilities(struct pci_dev *dev) ...@@ -1667,6 +1667,9 @@ static void pci_init_capabilities(struct pci_dev *dev)
pci_enable_acs(dev); pci_enable_acs(dev);
pci_cleanup_aer_error_status_regs(dev); pci_cleanup_aer_error_status_regs(dev);
/* Precision Time Measurement */
pci_ptm_init(dev);
} }
/* /*
......
...@@ -367,6 +367,11 @@ struct pci_dev { ...@@ -367,6 +367,11 @@ struct pci_dev {
int rom_attr_enabled; /* has display of the rom attribute been enabled? */ 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[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of 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 #ifdef CONFIG_PCI_MSI
const struct attribute_group **msi_irq_groups; const struct attribute_group **msi_irq_groups;
#endif #endif
......
...@@ -671,7 +671,8 @@ ...@@ -671,7 +671,8 @@
#define PCI_EXT_CAP_ID_PMUX 0x1A /* Protocol Multiplexing */ #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_PASID 0x1B /* Process Address Space ID */
#define PCI_EXT_CAP_ID_DPC 0x1D /* Downstream Port Containment */ #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_DSN_SIZEOF 12
#define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
...@@ -964,4 +965,11 @@ ...@@ -964,4 +965,11 @@
#define PCI_EXP_DPC_SOURCE_ID 10 /* DPC Source Identifier */ #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 */ #endif /* LINUX_PCI_REGS_H */
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