Keystone PCI controller has a limitation that memory read request
size must not exceed 256 bytes. This is a hardware limitation and
add a quirk to force this limit on all downstream devices by
updating mrrs.
Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
---
-v3: added check for vendor id and use pci_matc_id() to do matching
-v2: made the quirk happens after tuning
-v1: changed printk to indicate PCI bdf
drivers/pci/host/pci-keystone.c | 47 +++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
index c1cfaef..0a477e5 100644
--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -42,8 +42,55 @@
/* DEV_STAT_CTRL */
#define PCIE_CAP_BASE 0x70
+/* PCIE controller device IDs */
+#define PCIE_RC_K2HK 0xb008
+#define PCIE_RC_K2E 0xb009
+#define PCIE_RC_K2L 0xb00a
+
#define to_keystone_pcie(x) container_of(x, struct keystone_pcie, pp)
+
+
+static void quirk_limit_mrrs(struct pci_dev *dev)
+{
+ struct pci_bus *bus = dev->bus;
+ struct pci_dev *bridge = bus->self;
+ static const struct pci_device_id rc_pci_devids[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2HK),
+ .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
+ { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2E),
+ .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
+ { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2L),
+ .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
+ { 0, },
+ };
+
+ if (pci_is_root_bus(bus))
+ return;
+
+ /* look for the host bridge */
+ while (!pci_is_root_bus(bus)) {
+ bridge = bus->self;
+ bus = bus->parent;
+ }
+
+ if (bridge) {
+ /*
+ * Keystone PCI controller has a h/w limitation of
+ * 256 bytes maximum read request size. It can't handle
+ * anything higher than this. So force this limit on
+ * all downstream devices
+ */
+ if (pci_match_id(rc_pci_devids, bridge)) {
+ if (pcie_get_readrq(dev) > 256) {
+ dev_info(&dev->dev, "limiting mrrs to 256\n");
+ pcie_set_readrq(dev, 256);
+ }
+ }
+ }
+}
+DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, quirk_limit_mrrs);
+
static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
{
struct pcie_port *pp = &ks_pcie->pp;
--
1.7.9.5
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