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

[Hans Zhang]

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@xxxxxxx>
> > ---
> >   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.


Do you mean something like a dwc driver, similar to being placed in the 
file drivers/pci/controller/dwc/pcie-designware.c?
pci->max_link_speed = of_pci_get_max_link_speed(np);

For the Cadence driver, it is located in 
drivers/pci/controller/cadence/pcie-cadence-host-common.c.


Best regards,
Hans

> - Mani