From: Kishon Vijay Abraham I <kishon@xxxxxx> [ Upstream commit 86f271f22bbb6391410a07e08d6ca3757fda01fa ] Errata #i2037 in AM65x/DRA80xM Processors Silicon Revision 1.0 (SPRZ452D_July 2018_Revised December 2019 [1]) mentions when an inbound PCIe TLP spans more than two internal AXI 128-byte bursts, the bus may corrupt the packet payload and the corrupt data may cause associated applications or the processor to hang. The workaround for Errata #i2037 is to limit the maximum read request size and maximum payload size to 128 bytes. Add workaround for Errata #i2037 here. The errata and workaround is applicable only to AM65x SR 1.0 and later versions of the silicon will have this fixed. [1] -> https://www.ti.com/lit/er/sprz452i/sprz452i.pdf Link: https://lore.kernel.org/linux-pci/16e1fcae-1ea7-46be-b157-096e05661b15@xxxxxxxxxxx Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> Signed-off-by: Achal Verma <a-verma1@xxxxxx> Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx> Reviewed-by: Siddharth Vadapalli <s-vadapalli@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/pci/controller/dwc/pci-keystone.c | 44 ++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index 7ecad72cff7e7..daf838caef33d 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -35,6 +35,11 @@ #define PCIE_DEVICEID_SHIFT 16 /* Application registers */ +#define PID 0x000 +#define RTL GENMASK(15, 11) +#define RTL_SHIFT 11 +#define AM6_PCI_PG1_RTL_VER 0x15 + #define CMD_STATUS 0x004 #define LTSSM_EN_VAL BIT(0) #define OB_XLAT_EN_VAL BIT(1) @@ -105,6 +110,8 @@ #define to_keystone_pcie(x) dev_get_drvdata((x)->dev) +#define PCI_DEVICE_ID_TI_AM654X 0xb00c + struct ks_pcie_of_data { enum dw_pcie_device_mode mode; const struct dw_pcie_host_ops *host_ops; @@ -528,7 +535,11 @@ static int ks_pcie_start_link(struct dw_pcie *pci) static void ks_pcie_quirk(struct pci_dev *dev) { struct pci_bus *bus = dev->bus; + struct keystone_pcie *ks_pcie; + struct device *bridge_dev; struct pci_dev *bridge; + u32 val; + static const struct pci_device_id rc_pci_devids[] = { { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2HK), .class = PCI_CLASS_BRIDGE_PCI_NORMAL, .class_mask = ~0, }, @@ -540,6 +551,11 @@ static void ks_pcie_quirk(struct pci_dev *dev) .class = PCI_CLASS_BRIDGE_PCI_NORMAL, .class_mask = ~0, }, { 0, }, }; + static const struct pci_device_id am6_pci_devids[] = { + { PCI_DEVICE(PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_AM654X), + .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, }, + { 0, }, + }; if (pci_is_root_bus(bus)) bridge = dev; @@ -561,10 +577,36 @@ static void ks_pcie_quirk(struct pci_dev *dev) */ if (pci_match_id(rc_pci_devids, bridge)) { if (pcie_get_readrq(dev) > 256) { - dev_info(&dev->dev, "limiting MRRS to 256\n"); + dev_info(&dev->dev, "limiting MRRS to 256 bytes\n"); pcie_set_readrq(dev, 256); } } + + /* + * Memory transactions fail with PCI controller in AM654 PG1.0 + * when MRRS is set to more than 128 bytes. Force the MRRS to + * 128 bytes in all downstream devices. + */ + if (pci_match_id(am6_pci_devids, bridge)) { + bridge_dev = pci_get_host_bridge_device(dev); + if (!bridge_dev && !bridge_dev->parent) + return; + + ks_pcie = dev_get_drvdata(bridge_dev->parent); + if (!ks_pcie) + return; + + val = ks_pcie_app_readl(ks_pcie, PID); + val &= RTL; + val >>= RTL_SHIFT; + if (val != AM6_PCI_PG1_RTL_VER) + return; + + if (pcie_get_readrq(dev) > 128) { + dev_info(&dev->dev, "limiting MRRS to 128 bytes\n"); + pcie_set_readrq(dev, 128); + } + } } DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, ks_pcie_quirk); -- 2.43.0
