Re: [PATCH] PCI: rcar-gen4: Isolate 256B MRRS limit only to R-Car Gen4 SoC PCIe controller

[Marek Vasut <marek.vasut@mailbox.org>]

On 10/30/26 7:06 AM, Manivannan Sadhasivam wrote:

Hello Manivannan,

>> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>> index 9a64a9f4ab0d1..1e4405181eef3 100644
>> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>> @@ -99,6 +99,7 @@ struct rcar_gen4_pcie_drvdata {
>>   	int (*ltssm_control)(struct rcar_gen4_pcie *rcar, bool enable);
>>   	int (*speed_control)(struct rcar_gen4_pcie *rcar);
>>   	enum dw_pcie_device_mode mode;
>> +	bool mrrs_256b_limit;
>>   };
>>   
>>   struct rcar_gen4_pcie {
>> @@ -663,7 +664,7 @@ static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
>>   	if (ret)
>>   		return ret;
>>   
>> -	if (pp->bridge)
>> +	if (rcar->drvdata->mrrs_256b_limit && pp->bridge)
>>   		pp->bridge->enable_device = rcar_gen4_pcie_enable_device;
> 
> I'd suggest moving this check inside enable_device() callback to make it clear
> where exactly the skipping happens.

If we do that, we would end up with assigning a callback which always 
does nothing on R-Car Gen5 (SoC with rcar->drvdata->mrrs_256b_limit = 
false), that is not good. I think it is better to simply not assign the 
callback on R-Car Gen5 at all. Hence this here.

-- 
Best regards,
Marek Vasut