[PATCH] arm: a37xx: pci: Program the data strobe for config read requests

[Stefan Roese]

On 01.11.21 10:12, Pali Rohár wrote:
> According to the Armada 3720 Functional Specification Data Strobe applies
> for both read and write config requests.
> 
> Data strobe bits configure which bytes from the start address should be
> returned for read request. Set value 0xf (all 4 bits) into Data Strobe
> register to read all four bytes from specified 32-bit config space
> register. Same value for Data Strobe register is programmed by Linux
> pci-aardvark.c driver for config read requests.
> 
> Without this patch pci-aardvark driver sets data strobe register only
> during config write operations. So any followup config read operations
> could result with just partial datai returned (if previous write operation
> was not 32-bit wide). This patch fixes it and ensures that config read
> operations always read all bytes from requested register.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
>   drivers/pci/pci-aardvark.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c
> index 9e623b6e617b..4e94b776c5b9 100644
> --- a/drivers/pci/pci-aardvark.c
> +++ b/drivers/pci/pci-aardvark.c
> @@ -472,6 +472,9 @@ static int pcie_advk_read_config(const struct udevice *bus, pci_dev_t bdf,
>   	advk_writel(pcie, reg, PIO_ADDR_LS);
>   	advk_writel(pcie, 0, PIO_ADDR_MS);
>   
> +	/* Program the data strobe */
> +	advk_writel(pcie, 0xf, PIO_WR_DATA_STRB);
> +
>   	retry_count = 0;
>   
>   retry:
> 


Viele Grüße,
Stefan

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