[PATCH v3 02/16] PCI: dwc: Use cached PCIe capability offset in core
Hans Zhang
18255117159 at 163.com
Thu Aug 20 08:16:50 PDT 2026
On 8/13/26 14:06, Manivannan Sadhasivam wrote:
> On Mon, Jul 20, 2026 at 11:06:05PM +0800, Hans Zhang wrote:
>> Modify the DWC core functions to use the cached pcie_cap offset instead
>> of calling dw_pcie_find_capability() each time.
>>
>> In the DWC core, dw_pcie_find_capability() is called at several locations:
>> - dw_pcie_ep_init_non_sticky_registers()
>> - dw_pcie_wait_for_link()
>> - dw_pcie_link_set_max_speed()
>> - dw_pcie_link_get_max_link_width()
>> - dw_pcie_link_set_max_link_width()
>>
>> The cached offset is initialized after hardware is ready:
>> - In host mode: dw_pcie_host_init() calls pp->ops->host_init() (enables
>> clocks/resets), then dw_pcie_get_pcie_cap() caches the offset.
>> - In endpoint mode: the core no longer caches automatically. Instead,
>> drivers must call dw_pcie_get_pcie_cap() after hardware is enabled
>> (e.g., after PERST# deassert).
>
> But you didn't modify all DWC EP drivers to call dw_pcie_get_pcie_cap(). This
> can lead to pcie_cap being 0.
>
>> dw_pcie_ep_init_non_sticky_registers()
>> is called after that point, so it can safely use pci->pcie_cap.
>>
>> dw_pcie_ep_init_non_sticky_registers() now assumes pci->pcie_cap is
>> valid. if not, it prints a warning and skips the operation.
>
> Where is this warning printed?
>
> These are already pointed out by Sashiko. You should go really go through all of
> them (not the pre-existing issues) and comment whether the issues are valid or
> false positive. For a series touching many controller drivers, this is necessary
> to avoid introducing regressions.
>
> I'm not going to merge this series until you fix the real issues Sashiko
> reported or mark them as false positive if not valid.
Hello Mani,
I'm truly sorry. Recently, due to work commitments, I haven't had any
spare time. I plan to handle this series after v7.3-rc1 is released.
Thank you very much for your reply. I will carefully consider the
subsequent review comments regarding Sashiko. Thank you again.
Best regards,
Hans
>
> - Mani
>
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