[PATCH v2 4/8] PCI: j721e: Set max_link_speed to enable 100 ms delay after link up

[Manivannan Sadhasivam]

On Thu, May 07, 2026 at 12:11:22AM +0800, Hans Zhang wrote:
> 
> 
> On 5/7/26 00:04, Manivannan Sadhasivam wrote:
> > On Wed, May 06, 2026 at 11:23:42PM +0800, Hans Zhang wrote:
> > > Set cdns_pcie.max_link_speed to the maximum supported link speed
> > > (obtained from the device tree property "max-link-speed") in
> > > j721e_pcie_set_link_speed(). This activates the post-link delay logic
> > > added in cdns_pcie_host_start_link() when the controller supports
> > > speeds greater than 5 GT/s.
> > > 
> > > As required by PCIe r6.0 sec 6.6.1, and following the same approach as
> > > commit 80dc18a0cba8d ("PCI: dwc: Ensure that dw_pcie_wait_for_link()
> > > waits 100 ms after link up"), this ensures a 100 ms delay after link
> > > training completes before any Configuration Request is sent.
> > > 
> > > Signed-off-by: Hans Zhang <18255117159 at 163.com>
> > > ---
> > >   drivers/pci/controller/cadence/pci-j721e.c | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
> > > index bfdfe98d5aba..ee85b8e04f5b 100644
> > > --- a/drivers/pci/controller/cadence/pci-j721e.c
> > > +++ b/drivers/pci/controller/cadence/pci-j721e.c
> > > @@ -206,6 +206,7 @@ static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
> > >   	    (pcie_get_link_speed(link_speed) == PCI_SPEED_UNKNOWN))
> > >   		link_speed = 2;
> > > +	pcie->cdns_pcie.max_link_speed = link_speed;
> > 
> > What about other glue drivers?
> 
> Hi Mani,
> 
> pci-sky1.c:
> There is no time to handle the corresponding DTS yet, and the attribute
> "max-link-speed" has not been parsed either. There will be a plan for the
> subsequent upstream.
> 
> pcie-sg2042.c：
> I'm not familiar with this product.
> 

Since this helper gets called unconditionally for all glue drivers, not setting
'max_link_speed' would cause 100ms delay for all link speeds.

So either set 'max_link_speed' for all drivers, or call the helper directly from
glue drivers.

- Mani

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