aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJesse Barnes <jbarnes@virtuousgeek.org>2010-10-19 16:07:57 -0400
committerJesse Barnes <jbarnes@virtuousgeek.org>2011-05-11 18:18:40 -0400
commitb48d4425b602f5f4978299474743dbea130d940d (patch)
tree7da23c264cab62bce753e60c4e8d5fbbb0aab0e7
parent69643e4829c5cd13bafe44a6b9f3eb2086e0f618 (diff)
PCI: add ID-based ordering enable/disable support
Add support to allow drivers to enable/disable ID-based ordering. Where supported, ID-based ordering can significantly improve the latency of individual requests by preventing them from queueing up behind unrelated traffic. Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
-rw-r--r--drivers/pci/pci.c53
-rw-r--r--include/linux/pci.h13
-rw-r--r--include/linux/pci_regs.h2
3 files changed, 68 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 44d1c7c3876b..d0182bed7acc 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1834,6 +1834,59 @@ void pci_enable_ari(struct pci_dev *dev)
1834 bridge->ari_enabled = 1; 1834 bridge->ari_enabled = 1;
1835} 1835}
1836 1836
1837/**
1838 * pci_enable_ido - enable ID-based ordering on a device
1839 * @dev: the PCI device
1840 * @type: which types of IDO to enable
1841 *
1842 * Enable ID-based ordering on @dev. @type can contain the bits
1843 * %PCI_EXP_IDO_REQUEST and/or %PCI_EXP_IDO_COMPLETION to indicate
1844 * which types of transactions are allowed to be re-ordered.
1845 */
1846void pci_enable_ido(struct pci_dev *dev, unsigned long type)
1847{
1848 int pos;
1849 u16 ctrl;
1850
1851 pos = pci_pcie_cap(dev);
1852 if (!pos)
1853 return;
1854
1855 pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &ctrl);
1856 if (type & PCI_EXP_IDO_REQUEST)
1857 ctrl |= PCI_EXP_IDO_REQ_EN;
1858 if (type & PCI_EXP_IDO_COMPLETION)
1859 ctrl |= PCI_EXP_IDO_CMP_EN;
1860 pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, ctrl);
1861}
1862EXPORT_SYMBOL(pci_enable_ido);
1863
1864/**
1865 * pci_disable_ido - disable ID-based ordering on a device
1866 * @dev: the PCI device
1867 * @type: which types of IDO to disable
1868 */
1869void pci_disable_ido(struct pci_dev *dev, unsigned long type)
1870{
1871 int pos;
1872 u16 ctrl;
1873
1874 if (!pci_is_pcie(dev))
1875 return;
1876
1877 pos = pci_pcie_cap(dev);
1878 if (!pos)
1879 return;
1880
1881 pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &ctrl);
1882 if (type & PCI_EXP_IDO_REQUEST)
1883 ctrl &= ~PCI_EXP_IDO_REQ_EN;
1884 if (type & PCI_EXP_IDO_COMPLETION)
1885 ctrl &= ~PCI_EXP_IDO_CMP_EN;
1886 pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, ctrl);
1887}
1888EXPORT_SYMBOL(pci_disable_ido);
1889
1837static int pci_acs_enable; 1890static int pci_acs_enable;
1838 1891
1839/** 1892/**
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 96f70d7e058d..551ddcb5f940 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -828,6 +828,11 @@ static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state,
828 return __pci_enable_wake(dev, state, false, enable); 828 return __pci_enable_wake(dev, state, false, enable);
829} 829}
830 830
831#define PCI_EXP_IDO_REQUEST (1<<0)
832#define PCI_EXP_IDO_COMPLETION (1<<1)
833void pci_enable_ido(struct pci_dev *dev, unsigned long type);
834void pci_disable_ido(struct pci_dev *dev, unsigned long type);
835
831/* For use by arch with custom probe code */ 836/* For use by arch with custom probe code */
832void set_pcie_port_type(struct pci_dev *pdev); 837void set_pcie_port_type(struct pci_dev *pdev);
833void set_pcie_hotplug_bridge(struct pci_dev *pdev); 838void set_pcie_hotplug_bridge(struct pci_dev *pdev);
@@ -1207,6 +1212,14 @@ static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state,
1207 return 0; 1212 return 0;
1208} 1213}
1209 1214
1215static inline void pci_enable_ido(struct pci_dev *dev, unsigned long type)
1216{
1217}
1218
1219static inline void pci_disable_ido(struct pci_dev *dev, unsigned long type)
1220{
1221}
1222
1210static inline int pci_request_regions(struct pci_dev *dev, const char *res_name) 1223static inline int pci_request_regions(struct pci_dev *dev, const char *res_name)
1211{ 1224{
1212 return -EIO; 1225 return -EIO;
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index be01380f798a..d9acf9b99814 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -510,6 +510,8 @@
510#define PCI_EXP_DEVCAP2_ARI 0x20 /* Alternative Routing-ID */ 510#define PCI_EXP_DEVCAP2_ARI 0x20 /* Alternative Routing-ID */
511#define PCI_EXP_DEVCTL2 40 /* Device Control 2 */ 511#define PCI_EXP_DEVCTL2 40 /* Device Control 2 */
512#define PCI_EXP_DEVCTL2_ARI 0x20 /* Alternative Routing-ID */ 512#define PCI_EXP_DEVCTL2_ARI 0x20 /* Alternative Routing-ID */
513#define PCI_EXP_IDO_REQ_EN 0x100 /* ID-based ordering request enable */
514#define PCI_EXP_IDO_CMP_EN 0x200 /* ID-based ordering completion enable */
513#define PCI_EXP_LNKCTL2 48 /* Link Control 2 */ 515#define PCI_EXP_LNKCTL2 48 /* Link Control 2 */
514#define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */ 516#define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */
515 517