[PATCH v2 1/8] PCI: Add pcie_wait_after_link_train() helper

[Hans Zhang]

On 5/6/26 23:34, Biju Das wrote:
> 
> 
>> -----Original Message-----
>> From: Hans Zhang <18255117159 at 163.com>
>> Sent: 06 May 2026 16:24
>> Subject: [PATCH v2 1/8] PCI: Add pcie_wait_after_link_train() helper
>>
>> PCIe r6.0, sec 6.6.1 (Conventional Reset) requires that for a Downstream Port supporting Link speeds
>> greater than 5.0 GT/s, software must wait a minimum of 100 ms after Link training completes before
>> sending any Configuration Request.
>>
>> Introduce a static inline helper pcie_wait_after_link_train() that checks the given max_link_speed (2 =
>> 5.0 GT/s, 3 = 8.0 GT/s, etc.) and calls
>> msleep(100) only when the speed is greater than 5.0 GT/s. The helper uses the existing
>> PCIE_RESET_CONFIG_WAIT_MS macro defined in pci.h.
>>
>> This allows multiple host controller drivers to share the same mandatory delay without duplicating the
>> logic.
>>
>> Signed-off-by: Hans Zhang <18255117159 at 163.com>
>> ---
>>   drivers/pci/pci.h | 13 +++++++++++++
>>   1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 4a14f88e543a..a8705a2a2d85 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -60,6 +60,19 @@ struct pcie_tlp_log;
>>    */
>>   #define PCIE_RESET_CONFIG_WAIT_MS	100
>>
>> +/**
>> + * pcie_wait_after_link_train - Wait 100 ms if link speed > 5 GT/s
>> + * @max_link_speed: the maximum link speed (2 = 5.0 GT/s, 3 = 8.0 GT/s,
>> +...)
>> + *
>> + * Must be called after Link training completes and before the first
>> + * Configuration Request is sent.
>> + */
>> +static inline void pcie_wait_after_link_train(int max_link_speed) {
>> +	if (max_link_speed > 2)
>> +		msleep(PCIE_RESET_CONFIG_WAIT_MS);
>> +}
> 
> Maybe move this patch to the user??

Hi Biju,

Just as Mani's reply stated, I am more inclined to place it in the 
common header file.

Best regards,
Hans

> 
> Cheers,
> Biju
> 
>> +
>>   /* Parameters for the waiting for link up routine */
>>   #define PCIE_LINK_WAIT_MAX_RETRIES	10
>>   #define PCIE_LINK_WAIT_SLEEP_MS		90
>> --
>> 2.34.1
>>