From: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx> [ Upstream commit a52587e0bee14cbeeadf48a24013828cb04b8df8 ] The RK3399 PCIe endpoint controller cannot generate MSI-X IRQs. This is documented in the RK3399 technical reference manual (TRM) section 17.5.9 "Interrupt Support". MSI-X capability should therefore not be advertised. Remove the MSI-X capability by editing the capability linked-list. The previous entry is the MSI capability, therefore get the next entry from the MSI-X capability entry and set it as next entry for the MSI capability. This in effect removes MSI-X from the list. Linked list before : MSI cap -> MSI-X cap -> PCIe Device cap -> ... Linked list now : MSI cap -> PCIe Device cap -> ... Link: https://lore.kernel.org/r/20230418074700.1083505-11-rick.wertenbroek@xxxxxxxxx Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller") Tested-by: Damien Le Moal <dlemoal@xxxxxxxxxx> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx> Signed-off-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx> Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/pci/controller/pcie-rockchip-ep.c | 24 +++++++++++++++++++++++ drivers/pci/controller/pcie-rockchip.h | 5 +++++ 2 files changed, 29 insertions(+) diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c index 3d6f828d29fc2..0af0e965fb57e 100644 --- a/drivers/pci/controller/pcie-rockchip-ep.c +++ b/drivers/pci/controller/pcie-rockchip-ep.c @@ -508,6 +508,7 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev) size_t max_regions; struct pci_epc_mem_window *windows = NULL; int err, i; + u32 cfg_msi, cfg_msix_cp; ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL); if (!ep) @@ -583,6 +584,29 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev) ep->irq_pci_addr = ROCKCHIP_PCIE_EP_DUMMY_IRQ_ADDR; + /* + * MSI-X is not supported but the controller still advertises the MSI-X + * capability by default, which can lead to the Root Complex side + * allocating MSI-X vectors which cannot be used. Avoid this by skipping + * the MSI-X capability entry in the PCIe capabilities linked-list: get + * the next pointer from the MSI-X entry and set that in the MSI + * capability entry (which is the previous entry). This way the MSI-X + * entry is skipped (left out of the linked-list) and not advertised. + */ + cfg_msi = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE + + ROCKCHIP_PCIE_EP_MSI_CTRL_REG); + + cfg_msi &= ~ROCKCHIP_PCIE_EP_MSI_CP1_MASK; + + cfg_msix_cp = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE + + ROCKCHIP_PCIE_EP_MSIX_CAP_REG) & + ROCKCHIP_PCIE_EP_MSIX_CAP_CP_MASK; + + cfg_msi |= cfg_msix_cp; + + rockchip_pcie_write(rockchip, cfg_msi, + PCIE_EP_CONFIG_BASE + ROCKCHIP_PCIE_EP_MSI_CTRL_REG); + rockchip_pcie_write(rockchip, PCIE_CLIENT_CONF_ENABLE, PCIE_CLIENT_CONFIG); diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h index 498a40251d0be..88e2bf65e433a 100644 --- a/drivers/pci/controller/pcie-rockchip.h +++ b/drivers/pci/controller/pcie-rockchip.h @@ -228,6 +228,8 @@ #define ROCKCHIP_PCIE_EP_CMD_STATUS 0x4 #define ROCKCHIP_PCIE_EP_CMD_STATUS_IS BIT(19) #define ROCKCHIP_PCIE_EP_MSI_CTRL_REG 0x90 +#define ROCKCHIP_PCIE_EP_MSI_CP1_OFFSET 8 +#define ROCKCHIP_PCIE_EP_MSI_CP1_MASK GENMASK(15, 8) #define ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET 16 #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET 17 #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK GENMASK(19, 17) @@ -235,6 +237,9 @@ #define ROCKCHIP_PCIE_EP_MSI_CTRL_MME_MASK GENMASK(22, 20) #define ROCKCHIP_PCIE_EP_MSI_CTRL_ME BIT(16) #define ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP BIT(24) +#define ROCKCHIP_PCIE_EP_MSIX_CAP_REG 0xb0 +#define ROCKCHIP_PCIE_EP_MSIX_CAP_CP_OFFSET 8 +#define ROCKCHIP_PCIE_EP_MSIX_CAP_CP_MASK GENMASK(15, 8) #define ROCKCHIP_PCIE_EP_DUMMY_IRQ_ADDR 0x1 #define ROCKCHIP_PCIE_EP_PCI_LEGACY_IRQ_ADDR 0x3 #define ROCKCHIP_PCIE_EP_FUNC_BASE(fn) \ -- 2.39.2
