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authorBharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>2018-11-14 20:17:01 +0530
committerBjorn Helgaas <bhelgaas@google.com>2019-02-01 18:12:55 -0600
commitb4f6dcb9d35688392d668c46e834f72c55900b49 (patch)
treed113138b2c518059a07e79d1af7ac8674895056e /drivers/pci/probe.c
parent807ffb1e1eabbcdcd46494ee415317aa80ed415c (diff)
PCI: Enable SERR# forwarding for all bridges
As per Figure 6-3 in PCIe r4.0, sec 6.2.6, ERR_ messages will be forwarded from the secondary interface to the primary interface, if the SERR# Enable bit in the Bridge Control register is set. It seems clear that an ACPI hotplug parameter method (_HPP or _HPX) that tells us to "enable SERR in the command register" (ACPI v6.2, sec 6.2.8, 6.2.9.1) refers to PCI_COMMAND_SERR, which enables reporting of errors by the function itself. For bridges, we also interpreted that to mean we should enable PCI_BRIDGE_CTL_SERR, which enables *forwarding* of errors by the bridge. But we didn't enable PCI_BRIDGE_CTL_SERR anywhere else, which means we never enabled it for non-ACPI systems or ACPI systems that didn't supply hotplug parameters. That means errors reported below bridges were often never forwarded up to a Root Port where they could be signaled via AER. Enable PCI_BRIDGE_CTL_SERR for all bridges so we can get better error reporting for downstream devices. Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com> [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/probe.c')
-rw-r--r--drivers/pci/probe.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 257b9f6f2ebb..43e6583417ce 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1856,8 +1856,6 @@ static void program_hpp_type0(struct pci_dev *dev, struct hpp_type0 *hpp)
pci_write_config_byte(dev, PCI_SEC_LATENCY_TIMER,
hpp->latency_timer);
pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &pci_bctl);
- if (hpp->enable_serr)
- pci_bctl |= PCI_BRIDGE_CTL_SERR;
if (hpp->enable_perr)
pci_bctl |= PCI_BRIDGE_CTL_PARITY;
pci_write_config_word(dev, PCI_BRIDGE_CONTROL, pci_bctl);
@@ -2129,6 +2127,24 @@ static void pci_configure_eetlp_prefix(struct pci_dev *dev)
#endif
}
+static void pci_configure_serr(struct pci_dev *dev)
+{
+ u16 control;
+
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+
+ /*
+ * A bridge will not forward ERR_ messages coming from an
+ * endpoint unless SERR# forwarding is enabled.
+ */
+ pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &control);
+ if (!(control & PCI_BRIDGE_CTL_SERR)) {
+ control |= PCI_BRIDGE_CTL_SERR;
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
+ }
+ }
+}
+
static void pci_configure_device(struct pci_dev *dev)
{
struct hotplug_params hpp;
@@ -2139,6 +2155,7 @@ static void pci_configure_device(struct pci_dev *dev)
pci_configure_relaxed_ordering(dev);
pci_configure_ltr(dev);
pci_configure_eetlp_prefix(dev);
+ pci_configure_serr(dev);
memset(&hpp, 0, sizeof(hpp));
ret = pci_get_hp_params(dev, &hpp);