From 3ea8197e1371abd68aef289cad97feb764281642 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Fri, 10 Jan 2014 14:00:57 -0700 Subject: [PATCH] PCI: Remove unused Latency Tolerance Reporting support My philosophy is unused code is dead code. And dead code is subject to bit rot and is a likely source of bugs. Use it or lose it. This reverts 51c2e0a7e5bc ("PCI: add latency tolerance reporting enable/disable support"), removing these interfaces: pci_enable_ltr() pci_disable_ltr() pci_set_ltr() [bhelgaas: split to separate patch, also remove prototypes from pci.h] Signed-off-by: Stephen Hemminger Signed-off-by: Bjorn Helgaas CC: Jesse Barnes --- drivers/pci/pci.c | 123 -------------------------------------------- include/linux/pci.h | 4 -- 2 files changed, 127 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 33120d156668..020f672deabb 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2223,129 +2223,6 @@ void pci_disable_obff(struct pci_dev *dev) } EXPORT_SYMBOL(pci_disable_obff); -/** - * pci_ltr_supported - check whether a device supports LTR - * @dev: PCI device - * - * RETURNS: - * True if @dev supports latency tolerance reporting, false otherwise. - */ -static bool pci_ltr_supported(struct pci_dev *dev) -{ - u32 cap; - - pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap); - - return cap & PCI_EXP_DEVCAP2_LTR; -} - -/** - * pci_enable_ltr - enable latency tolerance reporting - * @dev: PCI device - * - * Enable LTR on @dev if possible, which means enabling it first on - * upstream ports. - * - * RETURNS: - * Zero on success, errno on failure. - */ -int pci_enable_ltr(struct pci_dev *dev) -{ - int ret; - - /* Only primary function can enable/disable LTR */ - if (PCI_FUNC(dev->devfn) != 0) - return -EINVAL; - - if (!pci_ltr_supported(dev)) - return -ENOTSUPP; - - /* Enable upstream ports first */ - if (dev->bus->self) { - ret = pci_enable_ltr(dev->bus->self); - if (ret) - return ret; - } - - return pcie_capability_set_word(dev, PCI_EXP_DEVCTL2, - PCI_EXP_DEVCTL2_LTR_EN); -} -EXPORT_SYMBOL(pci_enable_ltr); - -/** - * pci_disable_ltr - disable latency tolerance reporting - * @dev: PCI device - */ -void pci_disable_ltr(struct pci_dev *dev) -{ - /* Only primary function can enable/disable LTR */ - if (PCI_FUNC(dev->devfn) != 0) - return; - - if (!pci_ltr_supported(dev)) - return; - - pcie_capability_clear_word(dev, PCI_EXP_DEVCTL2, - PCI_EXP_DEVCTL2_LTR_EN); -} -EXPORT_SYMBOL(pci_disable_ltr); - -static int __pci_ltr_scale(int *val) -{ - int scale = 0; - - while (*val > 1023) { - *val = (*val + 31) / 32; - scale++; - } - return scale; -} - -/** - * pci_set_ltr - set LTR latency values - * @dev: PCI device - * @snoop_lat_ns: snoop latency in nanoseconds - * @nosnoop_lat_ns: nosnoop latency in nanoseconds - * - * Figure out the scale and set the LTR values accordingly. - */ -int pci_set_ltr(struct pci_dev *dev, int snoop_lat_ns, int nosnoop_lat_ns) -{ - int pos, ret, snoop_scale, nosnoop_scale; - u16 val; - - if (!pci_ltr_supported(dev)) - return -ENOTSUPP; - - snoop_scale = __pci_ltr_scale(&snoop_lat_ns); - nosnoop_scale = __pci_ltr_scale(&nosnoop_lat_ns); - - if (snoop_lat_ns > PCI_LTR_VALUE_MASK || - nosnoop_lat_ns > PCI_LTR_VALUE_MASK) - return -EINVAL; - - if ((snoop_scale > (PCI_LTR_SCALE_MASK >> PCI_LTR_SCALE_SHIFT)) || - (nosnoop_scale > (PCI_LTR_SCALE_MASK >> PCI_LTR_SCALE_SHIFT))) - return -EINVAL; - - pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR); - if (!pos) - return -ENOTSUPP; - - val = (snoop_scale << PCI_LTR_SCALE_SHIFT) | snoop_lat_ns; - ret = pci_write_config_word(dev, pos + PCI_LTR_MAX_SNOOP_LAT, val); - if (ret != 4) - return -EIO; - - val = (nosnoop_scale << PCI_LTR_SCALE_SHIFT) | nosnoop_lat_ns; - ret = pci_write_config_word(dev, pos + PCI_LTR_MAX_NOSNOOP_LAT, val); - if (ret != 4) - return -EIO; - - return 0; -} -EXPORT_SYMBOL(pci_set_ltr); - static int pci_acs_enable; /** diff --git a/include/linux/pci.h b/include/linux/pci.h index 1084a15175e0..ee26454746ba 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1009,10 +1009,6 @@ enum pci_obff_signal_type { int pci_enable_obff(struct pci_dev *dev, enum pci_obff_signal_type); void pci_disable_obff(struct pci_dev *dev); -int pci_enable_ltr(struct pci_dev *dev); -void pci_disable_ltr(struct pci_dev *dev); -int pci_set_ltr(struct pci_dev *dev, int snoop_lat_ns, int nosnoop_lat_ns); - /* For use by arch with custom probe code */ void set_pcie_port_type(struct pci_dev *pdev); void set_pcie_hotplug_bridge(struct pci_dev *pdev); -- GitLab