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PCI: rockchip: Don't advertise MSI-X in PCIe capabilities

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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@gmail.com
Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Rick Wertenbroek 2023-04-18 09:46:57 +02:00 committed by Lorenzo Pieralisi
parent 8962b2cb39
commit a52587e0be
2 changed files with 29 additions and 0 deletions
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24
drivers/pci/controller/pcie-rockchip-ep.c
View File

@ -507,6 +507,7 @@ 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)
@ -582,6 +583,29 @@ 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);

5
drivers/pci/controller/pcie-rockchip.h
View File

@ -227,6 +227,8 @@
#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)
@ -234,6 +236,9 @@
#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) \