This is a note to let you know that I've just added the patch titled
PCI: rockchip: Don't advertise MSI-X in PCIe capabilities
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-rockchip-don-t-advertise-msi-x-in-pcie-capabilit.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 30c4c68808b06e28cf438684c3c0d54ab8a181b4
Author: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>
Date: Tue Apr 18 09:46:57 2023 +0200
PCI: rockchip: Don't advertise MSI-X in PCIe capabilities
[ 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>
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) \
