Re: [PATCH -next 2/2] i2c: designware: Add support for new SoCs in AMDPSP driver

Mario Limonciello
2023-03-20T00:16:58Z

On 3/17/23 14:18, Mark Hasemeyer wrote:
> - /* Status field in command-response buffer is updated by PSP */
> - status = READ_ONCE(req->hdr.status);
> + if (req) {
> + /* Status field in command-response buffer is updated by PSP */
> + status = READ_ONCE(req->hdr.status);
> + } else {
> + status = psp_smn_read(PSP_MBOX_CMD_OFFSET, &status);
> + status &= ~PSP_MBOX_FIELDS_READY;
> + }
>
> The value of the mbox cmd register is getting clobbered by the return value
> from psp_smn_read. This can cause bus arbitration to fail as the driver will
> think it can grab the bus when it's actually in use by the PSP.

Mark - FYI this approach is being superseded by another patch series
that instead uses MMIO from the CCP driver.

It would be better to comment on that series.