Hi,
Am 12.11.20 um 18:27 schrieb Phil Elwell:
> Commit 04356ac30771 ("PCI: brcmstb: Add bcm7278 PERST# support")
> replaced a single reset function with a pointer to one of two
> implementations, but also removed the call asserting the reset
> at the start of brcm_pcie_setup. Doing so breaks Raspberry Pis with
> VL805 XHCI controllers lacking dedicated SPI EEPROMs, which have been
> used for USB booting but then need to be reset so that the kernel
> can reconfigure them. The lack of a reset causes the firmware's loading
> of the EEPROM image to RAM to fail, breaking USB for the kernel.
>
> Fixes: commit 04356ac30771 ("PCI: brcmstb: Add bcm7278 PERST# support")
>
> Signed-off-by: Phil Elwell <phil@xxxxxxxxxxxxxxx>
> Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
> ---
> Changes in v2:
> - Exclude BCM7278 from the initial reset
> - Ack from Nicolas
> ---
> drivers/pci/controller/pcie-brcmstb.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index bea86899bd5d..83aa85bfe8e3 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -869,6 +869,11 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
>
> /* Reset the bridge */
> pcie->bridge_sw_init_set(pcie, 1);
> +
> + /* Assert the fundemental reset, except on BCM7278 */
> + if (pcie->type != BCM7278)
> + pcie->perst_set(pcie, 1);
since only the Raspberry Pi 4 requires the reset i had changed the logic
to pcie->type == BCM2711. But this isn't totally clean, since we need
this quirk only for the Raspberry Pi 4 and not for CM4 (which also has a
BCM2711 SoC). So maybe we should introduce BCM2711_RPI4 to be on the
safe side. Sorry for the bikeshedding.
Stefan
> +
> usleep_range(100, 200);
>
> /* Take the bridge out of reset */
