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Subject[PATCH] PCI: Enable SERR# forwarding for Type-1 PCI devices
Date
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.
Currently PCI_BRIDGE_CTL_SERR is being enabled only in
ACPI flow.
This patch enables PCI_BRIDGE_CTL_SERR for Type-1 PCI device.

Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
---
drivers/pci/probe.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b1c05b5..ed71e8e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1841,8 +1841,6 @@ 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);
@@ -2114,6 +2112,23 @@ static void pci_configure_eetlp_prefix(struct pci_dev *dev)
#endif
}

+static void pci_configure_serr(struct pci_dev *dev)
+{
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ u16 control;
+
+ /*
+ * A Type-1 PCI bridge will not forward ERR_ messages coming
+ * from an endpoint if SERR# forwarding is not 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;
@@ -2124,6 +2139,7 @@ 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);
--
2.7.4
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