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

From: Damien Le Moal
Date: Tue Feb 14 2023 - 20:39:57 EST


On 2/14/23 23:08, Rick Wertenbroek wrote:
> 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;
> + }

Checking this here is late... Given that at most only one physical
function is supported, the check should be in rockchip_pcie_parse_ep_dt().
Something like:

err = of_property_read_u8(dev->of_node, "max-functions",
&ep->epc->max_functions);

if (err < 0 || ep->epc->max_functions > 1)

ep->epc->max_functions = 1;

And all the macros with the (fn) argument could also be simplified
(argument fn removed) since fn will always be 0.

> +
> + if (mmc > 0x5) {
> + dev_err(&epc->dev, "Number of MSI IRQs cannot be more than 32\n");

Long line. Please split it after the comma.

> + return -EINVAL;
> + }
> +
> flags = rockchip_pcie_read(rockchip,
> ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> ROCKCHIP_PCIE_EP_MSI_CTRL_REG);

Another nice cleanup: define ROCKCHIP_PCIE_EP_MSI_CTRL_REG to include the
ROCKCHIP_PCIE_EP_FUNC_BASE(fn) addition so that we do not have to do it
here all the time.

--
Damien Le Moal
Western Digital Research