Re: [PATCH v2] PCI: cadence: Fix Gen2 Link Retraining process

Bjorn Helgaas
2023-03-29T17:09:16Z

On Wed, Mar 29, 2023 at 08:11:25PM +0530, Raghavendra, Vignesh wrote:
> Hi Lorenzo, Bjorn,
>
> On 3/15/2023 12:38 PM, Siddharth Vadapalli wrote:
> > The Link Retraining process is initiated to account for the Gen2 defect in
> > the Cadence PCIe controller in J721E SoC. The errata corresponding to this
> > is i2085, documented at:
> > https://www.ti.com/lit/er/sprz455c/sprz455c.pdf
> >
> > The existing workaround implemented for the errata waits for the Data Link
> > initialization to complete and assumes that the link retraining process
> > at the Physical Layer has completed. However, it is possible that the
> > Physical Layer training might be ongoing as indicated by the
> > PCI_EXP_LNKSTA_LT bit in the PCI_EXP_LNKSTA register.
> >
> > Fix the existing workaround, to ensure that the Physical Layer training
> > has also completed, in addition to the Data Link initialization.
> >
> > Fixes: 4740b969aaf5 ("PCI: cadence: Retrain Link to work around Gen2 training defect")
> > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> > Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
> > ---
> > Changes from v1:
> > 1. Collect Reviewed-by tag from Vignesh Raghavendra.
> > 2. Rebase on next-20230315.
> >
> > v1:
> > https://lore.kernel.org/r/20230102075656.260333-1-s-vadapalli@ti.com
> >
> > .../controller/cadence/pcie-cadence-host.c | 27 +++++++++++++++++++
> > 1 file changed, 27 insertions(+)
>
> Wondering do one of you be pulling this patch in? This patch was never
> picked for 6.3-rc1 merge cycle... Just want to make sure
> pcie-cadence*.c and pci-j721e.c patches have a path to reach pci tree.

Yes, Lorenzo or Krzysztof will likely pick this up. I think Lorenzo
is out of the office this week.

Drive-by comment: the current patch doesn't seem to give any
indication to the user when cdns_pcie_host_training_complete() times
out. Is that timeout potentially of interest to a user? Should there
be a log message there?

Bjorn