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authorBjorn Helgaas <bhelgaas@google.com>2018-08-15 14:58:52 -0500
committerBjorn Helgaas <bhelgaas@google.com>2018-08-15 14:58:52 -0500
commita8bcb5e5966ccbd99a6d06cf69ada7f95416aabc (patch)
treee907b0f723700e6901c278dde6f1bc7fc3044449 /drivers
parent1ca358a8e3ffa123a2e655b1b3569f7868597c59 (diff)
parent9f0e89359775ee21fe1ea732e34edb52aef5addf (diff)
Merge branch 'pci/enumeration'
- Work around IDT switch ACS Source Validation erratum (James Puthukattukaran) - Emit diagnostics for all cases of PCIe Link downtraining (Links operating slower than they're capable of) (Alexandru Gagniuc) - Skip VFs when configuring Max Payload Size (Myron Stowe) - Reduce Root Port Max Payload Size if necessary when hot-adding a device below it (Myron Stowe) * pci/enumeration: PCI: Match Root Port's MPS to endpoint's MPSS as necessary PCI: Skip MPS logic for Virtual Functions (VFs) PCI: Check for PCIe Link downtraining PCI: Workaround IDT switch ACS Source Validation erratum
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci.c27
-rw-r--r--drivers/pci/pci.h5
-rw-r--r--drivers/pci/probe.c59
-rw-r--r--drivers/pci/quirks.c55
4 files changed, 135 insertions, 11 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index cada2954ecb4..709e44e7578b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5301,14 +5301,16 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed,
}
/**
- * pcie_print_link_status - Report the PCI device's link speed and width
+ * __pcie_print_link_status - Report the PCI device's link speed and width
* @dev: PCI device to query
+ * @verbose: Print info even when enough bandwidth is available
*
- * Report the available bandwidth at the device. If this is less than the
- * device is capable of, report the device's maximum possible bandwidth and
- * the upstream link that limits its performance to less than that.
+ * If the available bandwidth at the device is less than the device is
+ * capable of, report the device's maximum possible bandwidth and the
+ * upstream link that limits its performance. If @verbose, always print
+ * the available bandwidth, even if the device isn't constrained.
*/
-void pcie_print_link_status(struct pci_dev *dev)
+void __pcie_print_link_status(struct pci_dev *dev, bool verbose)
{
enum pcie_link_width width, width_cap;
enum pci_bus_speed speed, speed_cap;
@@ -5318,11 +5320,11 @@ void pcie_print_link_status(struct pci_dev *dev)
bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap);
bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width);
- if (bw_avail >= bw_cap)
+ if (bw_avail >= bw_cap && verbose)
pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth (%s x%d link)\n",
bw_cap / 1000, bw_cap % 1000,
PCIE_SPEED2STR(speed_cap), width_cap);
- else
+ else if (bw_avail < bw_cap)
pci_info(dev, "%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)\n",
bw_avail / 1000, bw_avail % 1000,
PCIE_SPEED2STR(speed), width,
@@ -5330,6 +5332,17 @@ void pcie_print_link_status(struct pci_dev *dev)
bw_cap / 1000, bw_cap % 1000,
PCIE_SPEED2STR(speed_cap), width_cap);
}
+
+/**
+ * pcie_print_link_status - Report the PCI device's link speed and width
+ * @dev: PCI device to query
+ *
+ * Report the available bandwidth at the device.
+ */
+void pcie_print_link_status(struct pci_dev *dev)
+{
+ __pcie_print_link_status(dev, true);
+}
EXPORT_SYMBOL(pcie_print_link_status);
/**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 3ac0d99afe67..ccb0537d5d89 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -225,6 +225,10 @@ enum pci_bar_type {
int pci_configure_extended_tags(struct pci_dev *dev, void *ign);
bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,
int crs_timeout);
+bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,
+ int crs_timeout);
+int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *pl, int crs_timeout);
+
int pci_setup_device(struct pci_dev *dev);
int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
struct resource *res, unsigned int reg);
@@ -259,6 +263,7 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev);
enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev);
u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed,
enum pcie_link_width *width);
+void __pcie_print_link_status(struct pci_dev *dev, bool verbose);
/* Single Root I/O Virtualization */
struct pci_sriov {
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 155d4333a291..f3d2fcc05cda 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1724,11 +1724,15 @@ int pci_setup_device(struct pci_dev *dev)
static void pci_configure_mps(struct pci_dev *dev)
{
struct pci_dev *bridge = pci_upstream_bridge(dev);
- int mps, p_mps, rc;
+ int mps, mpss, p_mps, rc;
if (!pci_is_pcie(dev) || !bridge || !pci_is_pcie(bridge))
return;
+ /* MPS and MRRS fields are of type 'RsvdP' for VFs, short-circuit out */
+ if (dev->is_virtfn)
+ return;
+
mps = pcie_get_mps(dev);
p_mps = pcie_get_mps(bridge);
@@ -1748,6 +1752,14 @@ static void pci_configure_mps(struct pci_dev *dev)
if (pcie_bus_config != PCIE_BUS_DEFAULT)
return;
+ mpss = 128 << dev->pcie_mpss;
+ if (mpss < p_mps && pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT) {
+ pcie_set_mps(bridge, mpss);
+ pci_info(dev, "Upstream bridge's Max Payload Size set to %d (was %d, max %d)\n",
+ mpss, p_mps, 128 << bridge->pcie_mpss);
+ p_mps = pcie_get_mps(bridge);
+ }
+
rc = pcie_set_mps(dev, p_mps);
if (rc) {
pci_warn(dev, "can't set Max Payload Size to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n",
@@ -1756,7 +1768,7 @@ static void pci_configure_mps(struct pci_dev *dev)
}
pci_info(dev, "Max Payload Size set to %d (was %d, max %d)\n",
- p_mps, mps, 128 << dev->pcie_mpss);
+ p_mps, mps, mpss);
}
static struct hpp_type0 pci_default_type0 = {
@@ -2156,8 +2168,8 @@ static bool pci_bus_wait_crs(struct pci_bus *bus, int devfn, u32 *l,
return true;
}
-bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
- int timeout)
+bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
+ int timeout)
{
if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
return false;
@@ -2172,6 +2184,24 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
return true;
}
+
+bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
+ int timeout)
+{
+#ifdef CONFIG_PCI_QUIRKS
+ struct pci_dev *bridge = bus->self;
+
+ /*
+ * Certain IDT switches have an issue where they improperly trigger
+ * ACS Source Validation errors on completions for config reads.
+ */
+ if (bridge && bridge->vendor == PCI_VENDOR_ID_IDT &&
+ bridge->device == 0x80b5)
+ return pci_idt_bus_quirk(bus, devfn, l, timeout);
+#endif
+
+ return pci_bus_generic_read_dev_vendor_id(bus, devfn, l, timeout);
+}
EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
/*
@@ -2205,6 +2235,25 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
return dev;
}
+static void pcie_report_downtraining(struct pci_dev *dev)
+{
+ if (!pci_is_pcie(dev))
+ return;
+
+ /* Look from the device up to avoid downstream ports with no devices */
+ if ((pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT) &&
+ (pci_pcie_type(dev) != PCI_EXP_TYPE_LEG_END) &&
+ (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM))
+ return;
+
+ /* Multi-function PCIe devices share the same link/status */
+ if (PCI_FUNC(dev->devfn) != 0 || dev->is_virtfn)
+ return;
+
+ /* Print link status only if the device is constrained by the fabric */
+ __pcie_print_link_status(dev, false);
+}
+
static void pci_init_capabilities(struct pci_dev *dev)
{
/* Enhanced Allocation */
@@ -2240,6 +2289,8 @@ static void pci_init_capabilities(struct pci_dev *dev)
/* Advanced Error Reporting */
pci_aer_init(dev);
+ pcie_report_downtraining(dev);
+
if (pci_probe_reset_function(dev) == 0)
dev->reset_fn = 1;
}
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index f439de848658..cab2d5f922a9 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4753,3 +4753,58 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMD, PCI_ANY_ID,
PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);
+
+/*
+ * Some IDT switches incorrectly flag an ACS Source Validation error on
+ * completions for config read requests even though PCIe r4.0, sec
+ * 6.12.1.1, says that completions are never affected by ACS Source
+ * Validation. Here's the text of IDT 89H32H8G3-YC, erratum #36:
+ *
+ * Item #36 - Downstream port applies ACS Source Validation to Completions
+ * Section 6.12.1.1 of the PCI Express Base Specification 3.1 states that
+ * completions are never affected by ACS Source Validation. However,
+ * completions received by a downstream port of the PCIe switch from a
+ * device that has not yet captured a PCIe bus number are incorrectly
+ * dropped by ACS Source Validation by the switch downstream port.
+ *
+ * The workaround suggested by IDT is to issue a config write to the
+ * downstream device before issuing the first config read. This allows the
+ * downstream device to capture its bus and device numbers (see PCIe r4.0,
+ * sec 2.2.9), thus avoiding the ACS error on the completion.
+ *
+ * However, we don't know when the device is ready to accept the config
+ * write, so we do config reads until we receive a non-Config Request Retry
+ * Status, then do the config write.
+ *
+ * To avoid hitting the erratum when doing the config reads, we disable ACS
+ * SV around this process.
+ */
+int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *l, int timeout)
+{
+ int pos;
+ u16 ctrl = 0;
+ bool found;
+ struct pci_dev *bridge = bus->self;
+
+ pos = pci_find_ext_capability(bridge, PCI_EXT_CAP_ID_ACS);
+
+ /* Disable ACS SV before initial config reads */
+ if (pos) {
+ pci_read_config_word(bridge, pos + PCI_ACS_CTRL, &ctrl);
+ if (ctrl & PCI_ACS_SV)
+ pci_write_config_word(bridge, pos + PCI_ACS_CTRL,
+ ctrl & ~PCI_ACS_SV);
+ }
+
+ found = pci_bus_generic_read_dev_vendor_id(bus, devfn, l, timeout);
+
+ /* Write Vendor ID (read-only) so the endpoint latches its bus/dev */
+ if (found)
+ pci_bus_write_config_word(bus, devfn, PCI_VENDOR_ID, 0);
+
+ /* Re-enable ACS_SV if it was previously enabled */
+ if (ctrl & PCI_ACS_SV)
+ pci_write_config_word(bridge, pos + PCI_ACS_CTRL, ctrl);
+
+ return found;
+}