Re: [RFC PATCH v2 1/4] PCI: pcie-rockchip: add Link Control and Status Register 2

Geraldo Nascimento
2025-06-12T02:47:26Z

On Wed, Jun 11, 2025 at 02:42:59PM -0500, Bjorn Helgaas wrote:
> On Tue, Jun 10, 2025 at 06:19:49PM -0300, Geraldo Nascimento wrote:
> > +#define PCIE_RC_CONFIG_DCR (PCIE_RC_CONFIG_CR + PCI_EXP_DEVCAP)
>
> I would really like to see PCI_EXP_DEVCAP referenced in the source
> where we currently use PCIE_RC_CONFIG_DCR. That way, cscope/tags/grep
> will find the actual uses of PCI_EXP_DEVCAP, not just this #define of
> PCIE_RC_CONFIG_DCR.
>
> Something like this:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/pci-mvebu.c?id=v6.15#n265
>

Hi Bjorn,

Yes, thank you for the code snippet, it makes things more clear.

> > #define PCIE_RC_CONFIG_DCR_CSPL_SHIFT 18
> > #define PCIE_RC_CONFIG_DCR_CSPL_LIMIT 0xff
> > #define PCIE_RC_CONFIG_DCR_CPLS_SHIFT 26
>
> Also use PCI_EXP_DEVCAP_PWR_VAL and PCI_EXP_DEVCAP_PWR_SCL here if
> possible. And FIELD_GET()/FIELD_PREP(), which avoid the need to
> define _SHIFT values.
>
> I would do a pure conversion patch of the existing #defines. Then I
> suspect you wouldn't need a patch to add the Link 2 registers at all
> because you could just use the #defines from pci_regs.h.
>

Got it!

Thanks!
Geraldo Nascimento