From 51c0170375e6884b1a5d68953a49e0ccd12e4971 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 25 Apr 2018 13:15:07 +0300 Subject: [PATCH 1/8] x86/PCI: Make pci=earlydump output neat Currently the early dump of PCI configuration space looks quite unhelpful, e.g. [ 0.000000] 60: [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] 00 [ 0.000000] which makes really hard to get anything out of this. Convert the function to use print_hex_dump() to make output neat. In the result we will have [ 0.000000] 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 which is much, much better. Reviewed-by: Mika Westerberg Signed-off-by: Andy Shevchenko Signed-off-by: Bjorn Helgaas Acked-by: Ingo Molnar --- arch/x86/pci/early.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/arch/x86/pci/early.c b/arch/x86/pci/early.c index f0114007e915..e5f753cbb1c3 100644 --- a/arch/x86/pci/early.c +++ b/arch/x86/pci/early.c @@ -59,24 +59,15 @@ int early_pci_allowed(void) void early_dump_pci_device(u8 bus, u8 slot, u8 func) { + u32 value[256 / 4]; int i; - int j; - u32 val; - printk(KERN_INFO "pci 0000:%02x:%02x.%d config space:", - bus, slot, func); + pr_info("pci 0000:%02x:%02x.%d config space:\n", bus, slot, func); - for (i = 0; i < 256; i += 4) { - if (!(i & 0x0f)) - printk("\n %02x:",i); + for (i = 0; i < 256; i += 4) + value[i / 4] = read_pci_config(bus, slot, func, i); - val = read_pci_config(bus, slot, func, i); - for (j = 0; j < 4; j++) { - printk(" %02x", val & 0xff); - val >>= 8; - } - } - printk("\n"); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 1, value, 256, false); } void early_dump_pci_devices(void) From 17e8f0d4cee2bf50c2764bb4318284ce16152c5f Mon Sep 17 00:00:00 2001 From: Gilles Buloz Date: Thu, 3 May 2018 15:21:44 -0500 Subject: [PATCH 2/8] PCI: Check whether bridges allow access to extended config space Even if a device supports extended config space, i.e., it is a PCI-X Mode 2 or a PCI Express device, the extended space may not be accessible if there's a conventional PCI bus in the path to it. We currently figure that out in pci_cfg_space_size() by reading the first dword of extended config space. On most platforms that returns ~0 data if the space is inaccessible, but it may set error bits in PCI status registers, and on some platforms it causes exceptions that we currently don't recover from. For example, a PCIe-to-conventional PCI bridge treats config transactions with a non-zero Extended Register Address as an Unsupported Request on PCIe and a received Master-Abort on the destination bus (see PCI Express to PCI/PCI-X Bridge spec, r1.0, sec 4.1.3). A sample case is a LS1043A CPU (NXP QorIQ Layerscape) platform with the following bus topology: LS1043 PCIe Root Port -> PEX8112 PCIe-to-PCI bridge (doesn't support ext cfg on PCI side) -> PMC slot connector (for legacy PMC modules) With a PMC module topology as follows: PMC connector -> PCI-to-PCIe bridge -> PCIe switch (4 ports) -> 4 PCIe devices (one on each port) The PCIe devices on the PMC module support extended config space, but we can't reach it because the PEX8112 can't generate accesses to the extended space on its secondary bus. Attempts to access it cause Unsupported Request errors, which result in synchronous aborts on this platform. To avoid these errors, check whether bridges are capable of generating extended config space addresses on their secondary interfaces. If they can't, we restrict devices below the bridge to only the 256-byte PCI-compatible config space. Signed-off-by: Gilles Buloz [bhelgaas: changelog, rework patch so bus_flags testing is all in pci_bridge_child_ext_cfg_accessible()] Signed-off-by: Bjorn Helgaas --- drivers/pci/probe.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 53 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index ac91b6fd0bcd..dcc41de1c2c8 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -882,6 +882,45 @@ free: return err; } +static bool pci_bridge_child_ext_cfg_accessible(struct pci_dev *bridge) +{ + int pos; + u32 status; + + /* + * If extended config space isn't accessible on a bridge's primary + * bus, we certainly can't access it on the secondary bus. + */ + if (bridge->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) + return false; + + /* + * PCIe Root Ports and switch ports are PCIe on both sides, so if + * extended config space is accessible on the primary, it's also + * accessible on the secondary. + */ + if (pci_is_pcie(bridge) && + (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(bridge) == PCI_EXP_TYPE_UPSTREAM || + pci_pcie_type(bridge) == PCI_EXP_TYPE_DOWNSTREAM)) + return true; + + /* + * For the other bridge types: + * - PCI-to-PCI bridges + * - PCIe-to-PCI/PCI-X forward bridges + * - PCI/PCI-X-to-PCIe reverse bridges + * extended config space on the secondary side is only accessible + * if the bridge supports PCI-X Mode 2. + */ + pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX); + if (!pos) + return false; + + pci_read_config_dword(bridge, pos + PCI_X_STATUS, &status); + return status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ); +} + static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, struct pci_dev *bridge, int busnr) { @@ -923,6 +962,16 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, pci_set_bus_of_node(child); pci_set_bus_speed(child); + /* + * Check whether extended config space is accessible on the child + * bus. Note that we currently assume it is always accessible on + * the root bus. + */ + if (!pci_bridge_child_ext_cfg_accessible(bridge)) { + child->bus_flags |= PCI_BUS_FLAGS_NO_EXTCFG; + pci_info(child, "extended config space not accessible\n"); + } + /* Set up default resource pointers and names */ for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) { child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i]; @@ -1393,6 +1442,9 @@ int pci_cfg_space_size(struct pci_dev *dev) u32 status; u16 class; + if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) + return PCI_CFG_SPACE_SIZE; + class = dev->class >> 8; if (class == PCI_CLASS_BRIDGE_HOST) return pci_cfg_space_size_ext(dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index 73178a2fcee0..5eb97e198325 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -217,6 +217,7 @@ enum pci_bus_flags { PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1, PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2, PCI_BUS_FLAGS_NO_AERSID = (__force pci_bus_flags_t) 4, + PCI_BUS_FLAGS_NO_EXTCFG = (__force pci_bus_flags_t) 8, }; /* Values from Link Status register, PCIe r3.1, sec 7.8.8 */ From 6f5cdfa802733dcb561bf664cc89d203f2fd958f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 18 May 2018 18:56:24 +0200 Subject: [PATCH 3/8] PCI: Prevent sysfs disable of device while driver is attached Manipulating the enable_cnt behind the back of the driver will wreak complete havoc with the kernel state, so disallow it. Signed-off-by: Christoph Hellwig Signed-off-by: Bjorn Helgaas Reviewed-by: Johannes Thumshirn Acked-by: Keith Busch --- drivers/pci/pci-sysfs.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 366d93af051d..788a200fb2dc 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -288,13 +288,16 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr, if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (!val) { - if (pci_is_enabled(pdev)) - pci_disable_device(pdev); - else - result = -EIO; - } else + device_lock(dev); + if (dev->driver) + result = -EBUSY; + else if (val) result = pci_enable_device(pdev); + else if (pci_is_enabled(pdev)) + pci_disable_device(pdev); + else + result = -EIO; + device_unlock(dev); return result < 0 ? result : count; } From cc04a1dd3f4af21d1a2cd3715e7b337b470a693d Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 30 Mar 2018 13:09:04 -0500 Subject: [PATCH 4/8] bnx2x: Report PCIe link properties with pcie_print_link_status() Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - %s (%c%d) PCI-E x%d %s found at mem %lx, IRQ %d, node addr %pM + %s (%c%d) PCI-E found at mem %lx, IRQ %d, node addr %pM + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) Signed-off-by: Bjorn Helgaas --- .../net/ethernet/broadcom/bnx2x/bnx2x_main.c | 23 +++++-------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c index c766ae23bc74..5b1ed240bf18 100644 --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c @@ -13922,8 +13922,6 @@ static int bnx2x_init_one(struct pci_dev *pdev, { struct net_device *dev = NULL; struct bnx2x *bp; - enum pcie_link_width pcie_width; - enum pci_bus_speed pcie_speed; int rc, max_non_def_sbs; int rx_count, tx_count, rss_count, doorbell_size; int max_cos_est; @@ -14091,21 +14089,12 @@ static int bnx2x_init_one(struct pci_dev *pdev, dev_addr_add(bp->dev, bp->fip_mac, NETDEV_HW_ADDR_T_SAN); rtnl_unlock(); } - if (pcie_get_minimum_link(bp->pdev, &pcie_speed, &pcie_width) || - pcie_speed == PCI_SPEED_UNKNOWN || - pcie_width == PCIE_LNK_WIDTH_UNKNOWN) - BNX2X_DEV_INFO("Failed to determine PCI Express Bandwidth\n"); - else - BNX2X_DEV_INFO( - "%s (%c%d) PCI-E x%d %s found at mem %lx, IRQ %d, node addr %pM\n", - board_info[ent->driver_data].name, - (CHIP_REV(bp) >> 12) + 'A', (CHIP_METAL(bp) >> 4), - pcie_width, - pcie_speed == PCIE_SPEED_2_5GT ? "2.5GHz" : - pcie_speed == PCIE_SPEED_5_0GT ? "5.0GHz" : - pcie_speed == PCIE_SPEED_8_0GT ? "8.0GHz" : - "Unknown", - dev->base_addr, bp->pdev->irq, dev->dev_addr); + BNX2X_DEV_INFO( + "%s (%c%d) PCI-E found at mem %lx, IRQ %d, node addr %pM\n", + board_info[ent->driver_data].name, + (CHIP_REV(bp) >> 12) + 'A', (CHIP_METAL(bp) >> 4), + dev->base_addr, bp->pdev->irq, dev->dev_addr); + pcie_print_link_status(bp->pdev); bnx2x_register_phc(bp); From af125b754e2f09e6061e65db8f4eda0f7730011d Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 30 Mar 2018 14:09:54 -0500 Subject: [PATCH 5/8] bnxt_en: Report PCIe link properties with pcie_print_link_status() Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - PCIe: Speed %s Width x%d + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) Signed-off-by: Bjorn Helgaas --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 19 +------------------ 1 file changed, 1 insertion(+), 18 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index f83769d8047b..34fddb48fecc 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -8621,22 +8621,6 @@ static int bnxt_init_mac_addr(struct bnxt *bp) return rc; } -static void bnxt_parse_log_pcie_link(struct bnxt *bp) -{ - enum pcie_link_width width = PCIE_LNK_WIDTH_UNKNOWN; - enum pci_bus_speed speed = PCI_SPEED_UNKNOWN; - - if (pcie_get_minimum_link(pci_physfn(bp->pdev), &speed, &width) || - speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) - netdev_info(bp->dev, "Failed to determine PCIe Link Info\n"); - else - netdev_info(bp->dev, "PCIe: Speed %s Width x%d\n", - speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : - speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : - speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : - "Unknown", width); -} - static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) { static int version_printed; @@ -8851,8 +8835,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) netdev_info(dev, "%s found at mem %lx, node addr %pM\n", board_info[ent->driver_data].name, (long)pci_resource_start(pdev, 0), dev->dev_addr); - - bnxt_parse_log_pcie_link(bp); + pcie_print_link_status(pdev); return 0; From 57d12fc6f78889677ec49d049fcec35ef8a03c53 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 30 Mar 2018 14:16:06 -0500 Subject: [PATCH 6/8] cxgb4: Report PCIe link properties with pcie_print_link_status() Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - PCIe link speed is %s, device supports %s - PCIe link width is x%d, device supports x%d + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) or, if the device is capable of better performance than is available in the current slot: - A slot with more lanes and/or higher speed is suggested for optimal performance. + %u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link) Signed-off-by: Bjorn Helgaas --- .../net/ethernet/chelsio/cxgb4/cxgb4_main.c | 75 +------------------ 1 file changed, 1 insertion(+), 74 deletions(-) diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c index 24d2865b8806..7328f24ba1dd 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c @@ -5042,79 +5042,6 @@ static int init_rss(struct adapter *adap) return 0; } -static int cxgb4_get_pcie_dev_link_caps(struct adapter *adap, - enum pci_bus_speed *speed, - enum pcie_link_width *width) -{ - u32 lnkcap1, lnkcap2; - int err1, err2; - -#define PCIE_MLW_CAP_SHIFT 4 /* start of MLW mask in link capabilities */ - - *speed = PCI_SPEED_UNKNOWN; - *width = PCIE_LNK_WIDTH_UNKNOWN; - - err1 = pcie_capability_read_dword(adap->pdev, PCI_EXP_LNKCAP, - &lnkcap1); - err2 = pcie_capability_read_dword(adap->pdev, PCI_EXP_LNKCAP2, - &lnkcap2); - if (!err2 && lnkcap2) { /* PCIe r3.0-compliant */ - if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB) - *speed = PCIE_SPEED_8_0GT; - else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB) - *speed = PCIE_SPEED_5_0GT; - else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB) - *speed = PCIE_SPEED_2_5GT; - } - if (!err1) { - *width = (lnkcap1 & PCI_EXP_LNKCAP_MLW) >> PCIE_MLW_CAP_SHIFT; - if (!lnkcap2) { /* pre-r3.0 */ - if (lnkcap1 & PCI_EXP_LNKCAP_SLS_5_0GB) - *speed = PCIE_SPEED_5_0GT; - else if (lnkcap1 & PCI_EXP_LNKCAP_SLS_2_5GB) - *speed = PCIE_SPEED_2_5GT; - } - } - - if (*speed == PCI_SPEED_UNKNOWN || *width == PCIE_LNK_WIDTH_UNKNOWN) - return err1 ? err1 : err2 ? err2 : -EINVAL; - return 0; -} - -static void cxgb4_check_pcie_caps(struct adapter *adap) -{ - enum pcie_link_width width, width_cap; - enum pci_bus_speed speed, speed_cap; - -#define PCIE_SPEED_STR(speed) \ - (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : \ - speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : \ - speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : \ - "Unknown") - - if (cxgb4_get_pcie_dev_link_caps(adap, &speed_cap, &width_cap)) { - dev_warn(adap->pdev_dev, - "Unable to determine PCIe device BW capabilities\n"); - return; - } - - if (pcie_get_minimum_link(adap->pdev, &speed, &width) || - speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) { - dev_warn(adap->pdev_dev, - "Unable to determine PCI Express bandwidth.\n"); - return; - } - - dev_info(adap->pdev_dev, "PCIe link speed is %s, device supports %s\n", - PCIE_SPEED_STR(speed), PCIE_SPEED_STR(speed_cap)); - dev_info(adap->pdev_dev, "PCIe link width is x%d, device supports x%d\n", - width, width_cap); - if (speed < speed_cap || width < width_cap) - dev_info(adap->pdev_dev, - "A slot with more lanes and/or higher speed is " - "suggested for optimal performance.\n"); -} - /* Dump basic information about the adapter */ static void print_adapter_info(struct adapter *adapter) { @@ -5750,7 +5677,7 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent) } /* check for PCI Express bandwidth capabiltites */ - cxgb4_check_pcie_caps(adapter); + pcie_print_link_status(pdev); err = init_rss(adapter); if (err) From 4695ca9d17a2f47e0be3011ef25a4d77b973b547 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 30 Mar 2018 14:26:07 -0500 Subject: [PATCH 7/8] ixgbe: Report PCIe link properties with pcie_print_link_status() Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - PCI Express bandwidth of %dGT/s available - (Speed:%s, Width: x%d, Encoding Loss:%s) + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) or, if the device is capable of better performance than is available in the current slot: - This is not sufficient for optimal performance of this card. - For optimal performance, at least %dGT/s of bandwidth is required. - A slot with more lanes and/or higher speed is suggested. + %u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link) Note that the driver previously used dev_warn() to suggest using a different slot, but pcie_print_link_status() uses dev_info() because if the platform has no faster slot available, the user can't do anything about the warning and may not want to be bothered with it. Signed-off-by: Bjorn Helgaas Acked-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 47 +------------------ 1 file changed, 1 insertion(+), 46 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index afadba99f7b8..8990285f6e12 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -270,9 +270,6 @@ static void ixgbe_check_minimum_link(struct ixgbe_adapter *adapter, int expected_gts) { struct ixgbe_hw *hw = &adapter->hw; - int max_gts = 0; - enum pci_bus_speed speed = PCI_SPEED_UNKNOWN; - enum pcie_link_width width = PCIE_LNK_WIDTH_UNKNOWN; struct pci_dev *pdev; /* Some devices are not connected over PCIe and thus do not negotiate @@ -288,49 +285,7 @@ static void ixgbe_check_minimum_link(struct ixgbe_adapter *adapter, else pdev = adapter->pdev; - if (pcie_get_minimum_link(pdev, &speed, &width) || - speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) { - e_dev_warn("Unable to determine PCI Express bandwidth.\n"); - return; - } - - switch (speed) { - case PCIE_SPEED_2_5GT: - /* 8b/10b encoding reduces max throughput by 20% */ - max_gts = 2 * width; - break; - case PCIE_SPEED_5_0GT: - /* 8b/10b encoding reduces max throughput by 20% */ - max_gts = 4 * width; - break; - case PCIE_SPEED_8_0GT: - /* 128b/130b encoding reduces throughput by less than 2% */ - max_gts = 8 * width; - break; - default: - e_dev_warn("Unable to determine PCI Express bandwidth.\n"); - return; - } - - e_dev_info("PCI Express bandwidth of %dGT/s available\n", - max_gts); - e_dev_info("(Speed:%s, Width: x%d, Encoding Loss:%s)\n", - (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : - speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : - speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : - "Unknown"), - width, - (speed == PCIE_SPEED_2_5GT ? "20%" : - speed == PCIE_SPEED_5_0GT ? "20%" : - speed == PCIE_SPEED_8_0GT ? "<2%" : - "Unknown")); - - if (max_gts < expected_gts) { - e_dev_warn("This is not sufficient for optimal performance of this card.\n"); - e_dev_warn("For optimal performance, at least %dGT/s of bandwidth is required.\n", - expected_gts); - e_dev_warn("A slot with more lanes and/or higher speed is suggested.\n"); - } + pcie_print_link_status(pdev); } static void ixgbe_service_event_schedule(struct ixgbe_adapter *adapter) From e5b1db0186bfb3bede41e412b27c9bcf2b336622 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 30 Mar 2018 14:41:49 -0500 Subject: [PATCH 8/8] PCI: Remove unused pcie_get_minimum_link() In some cases pcie_get_minimum_link() returned misleading information because it found the slowest link and the narrowest link without considering the total bandwidth of the link. For example, consider a path with these two links: - 16.0 GT/s x1 link (16.0 * 10^9 * 128 / 130) * 1 / 8 = 1969 MB/s - 2.5 GT/s x16 link ( 2.5 * 10^9 * 8 / 10) * 16 / 8 = 4000 MB/s The available bandwidth of the path is limited by the 16 GT/s link to about 1969 MB/s, but pcie_get_minimum_link() returned 2.5 GT/s x1, which corresponds to only 250 MB/s. Callers should use pcie_print_link_status() instead, or pcie_bandwidth_available() if they need more detailed information. Remove pcie_get_minimum_link() since there are no callers left. Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 43 ------------------------------------------- include/linux/pci.h | 2 -- 2 files changed, 45 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e597655a5643..4bafa817c40a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5069,49 +5069,6 @@ int pcie_set_mps(struct pci_dev *dev, int mps) } EXPORT_SYMBOL(pcie_set_mps); -/** - * pcie_get_minimum_link - determine minimum link settings of a PCI device - * @dev: PCI device to query - * @speed: storage for minimum speed - * @width: storage for minimum width - * - * This function will walk up the PCI device chain and determine the minimum - * link width and speed of the device. - */ -int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, - enum pcie_link_width *width) -{ - int ret; - - *speed = PCI_SPEED_UNKNOWN; - *width = PCIE_LNK_WIDTH_UNKNOWN; - - while (dev) { - u16 lnksta; - enum pci_bus_speed next_speed; - enum pcie_link_width next_width; - - ret = pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); - if (ret) - return ret; - - next_speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS]; - next_width = (lnksta & PCI_EXP_LNKSTA_NLW) >> - PCI_EXP_LNKSTA_NLW_SHIFT; - - if (next_speed < *speed) - *speed = next_speed; - - if (next_width < *width) - *width = next_width; - - dev = dev->bus->self; - } - - return 0; -} -EXPORT_SYMBOL(pcie_get_minimum_link); - /** * pcie_bandwidth_available - determine minimum link settings of a PCIe * device and its bandwidth limitation diff --git a/include/linux/pci.h b/include/linux/pci.h index 5eb97e198325..f7aa6d9f8999 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1080,8 +1080,6 @@ int pcie_get_readrq(struct pci_dev *dev); int pcie_set_readrq(struct pci_dev *dev, int rq); int pcie_get_mps(struct pci_dev *dev); int pcie_set_mps(struct pci_dev *dev, int mps); -int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, - enum pcie_link_width *width); u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, enum pci_bus_speed *speed, enum pcie_link_width *width);