[PATCH] usb: xhci-pci: Check for errors from dm_pci_map_bar()

[Bin Meng]

On Mon, Jan 18, 2021 at 7:13 PM Pali Rohár <pali at kernel.org> wrote:
>
> Function dm_pci_map_bar() may fail and returns NULL. Check this to prevent
> dereferencing a NULL pointer.
>
> In xhci-pci this may happen when board does not enable CONFIG_PCI_PNP and
> PCI_BASE_ADDRESS_0 contains unconfigured zero address.
>
> Signed-off-by: Pali Rohár <pali at kernel.org>
> ---
>  drivers/usb/host/xhci-pci.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 2b445f21b5..7f5be95f6c 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -13,7 +13,7 @@
>  #include <usb.h>
>  #include <usb/xhci.h>
>
> -static void xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
> +static int xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
>                           struct xhci_hcor **ret_hcor)

nits: please make "struct xhci_hcor" align to "struct udevice" above

>  {
>         struct xhci_hccr *hccr;
> @@ -22,6 +22,11 @@ static void xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
>
>         hccr = (struct xhci_hccr *)dm_pci_map_bar(dev,
>                         PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
> +       if (!hccr) {
> +               printf("XHCI-PCI init cannot map PCI mem bar\n");

nits: use lower case "xhci-pci"

> +               return -EIO;
> +       }
> +
>         hcor = (struct xhci_hcor *)((uintptr_t) hccr +
>                         HC_LENGTH(xhci_readl(&hccr->cr_capbase)));
>
> @@ -35,14 +40,18 @@ static void xhci_pci_init(struct udevice *dev, struct xhci_hccr **ret_hccr,
>         dm_pci_read_config32(dev, PCI_COMMAND, &cmd);
>         cmd |= PCI_COMMAND_MASTER;
>         dm_pci_write_config32(dev, PCI_COMMAND, cmd);
> +       return 0;
>  }
>
>  static int xhci_pci_probe(struct udevice *dev)
>  {
>         struct xhci_hccr *hccr;
>         struct xhci_hcor *hcor;
> +       int ret;
>
> -       xhci_pci_init(dev, &hccr, &hcor);
> +       ret = xhci_pci_init(dev, &hccr, &hcor);
> +       if (ret)
> +               return ret;
>
>         return xhci_register(dev, hccr, hcor);
>  }

Other than above,

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>