[PATCH v2 9/9] PCI: rockchip: Add parameter check for RK3399 PCIe endpoint core set_msi()

[Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>]

The RK3399 PCIe endpoint core supports only a single PCIe physcial
function (function number 0), therefore return -EINVAL if set_msi() is
called with a function number greater than 0.
The PCIe standard only allows the multi message capability (MMC) value
to be up to 0x5 (32 messages), therefore return -EINVAL if set_msi() is
called with a MMC value of over 0x5.

Signed-off-by: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index b7865a94e..80634b690 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -294,6 +294,16 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
 	struct rockchip_pcie *rockchip = &ep->rockchip;
 	u32 flags;
 
+	if (fn) {
+		dev_err(&epc->dev, "This endpoint controller only supports a single physical function\n");
+		return -EINVAL;
+	}
+
+	if (mmc > 0x5) {
+		dev_err(&epc->dev, "Number of MSI IRQs cannot be more than 32\n");
+		return -EINVAL;
+	}
+
 	flags = rockchip_pcie_read(rockchip,
 				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
 				   ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
-- 
2.25.1