Re: [PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
From: Damien Le Moal
Date: Tue Feb 14 2023 - 20:34:41 EST
On 2/14/23 23:08, Rick Wertenbroek wrote:
> Previously u16 variables were used to access 32-bit registers, this
> resulted in not all of the data being read from the registers. Also
> the left shift of more than 16-bits would result in moving data out
> of the variable. Use u32 variables to access 32-bit registers
>
> Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>
> ---
> drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
> drivers/pci/controller/pcie-rockchip.h | 1 +
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> index ca5b363ba..b7865a94e 100644
> --- a/drivers/pci/controller/pcie-rockchip-ep.c
> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
> {
> struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> struct rockchip_pcie *rockchip = &ep->rockchip;
> - u16 flags;
> + u32 flags;
>
> flags = rockchip_pcie_read(rockchip,
> ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
> flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
> flags |=
> - ((multi_msg_cap << 1) << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
> - PCI_MSI_FLAGS_64BIT;
> + (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET is 17 and multi_msg_cap is a u8...
Not nice.
Locally, I added the local variable:
u32 mmc = multi_msg_cap;
And use mmc instead of multi_msg_cap to avoid issues. Also,
> + (PCI_MSI_FLAGS_64BIT << ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET);
> flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP;
> rockchip_pcie_write(rockchip, flags,
> ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> @@ -312,7 +312,7 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
> {
> struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> struct rockchip_pcie *rockchip = &ep->rockchip;
> - u16 flags;
> + u32 flags;
>
> flags = rockchip_pcie_read(rockchip,
> ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> @@ -374,7 +374,7 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
> u8 interrupt_num)
> {
> struct rockchip_pcie *rockchip = &ep->rockchip;
> - u16 flags, mme, data, data_mask;
> + u32 flags, mme, data, data_mask;
> u8 msi_count;
> u64 pci_addr, pci_addr_mask = 0xff;
> u32 r;
> diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
> index e90c2a2b8..11dbf53cd 100644
> --- a/drivers/pci/controller/pcie-rockchip.h
> +++ b/drivers/pci/controller/pcie-rockchip.h
> @@ -227,6 +227,7 @@
> #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_FLAGS_OFFSET 16
You are not using this macro anywhere. The name is also not very
descriptive. Better have it as:
#define ROCKCHIP_PCIE_EP_MSI_CTRL_ME BIT(16)
to match the TRM name and be clear that the bit indicates if MSI is
enabled or not.
> #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET 17
> #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK GENMASK(19, 17)
> #define ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET 20
--
Damien Le Moal
Western Digital Research