Re: [PATCH] PCI: designware: Fix PORT_LOGIC_LINK_WIDTH_MASK

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On 2015/8/26 10:17, Jingoo Han wrote:
> On 2015. 8. 26., at AM 10:57, Zhou Wang <wangzhou1@xxxxxxxxxxxxx> wrote:
>>
>> Hi Jingoo,
>>
>>> On 2015/8/25 19:14, Jingoo Han wrote:
>>>> On 2015. 8. 25., at PM 7:35, Zhou Wang <wangzhou1@xxxxxxxxxxxxx> wrote:
>>>>
>>>> The value under PORT_LOGIC_LINK_WIDTH_MASK is 0x1, 0x2, 0x4, 0x8. Here change
>>>> this mask to proper value.
>>>>
>>>> In fact, for DesignWare PCIe IP version 4.4, it only uses bit8~12 to indicate
>>>> number of lanes. Original mask will bring a mistake.
>>>
>>> NAK
>>
>> Sorry, maybe above commit message is no very clear. Will explain it below.
>>
>>>
>>> The definitions of bits of registers should be defined based on hardware manual such as datasheet, databook.
>>>
>>> According to the databook, the bits [16:8] are defined for NUM_OF_LANES.
>>
>> Yes, according to databook of v4.2, bits [16:8] are defined for NUM_OF_LANES.
>>
>>>
>>> In the future, if 16 lanes or 32 lanes is supported and 12th bit or 13th bit is used, what will you do?
>>>
>>> Then, in the version 4.4 IP, the bits[16:13] are used for other usage?
>>
>> Yes, according to databook of v4.4, bits [12:8] are defined for NUM_OF_LANES.
>> [16:13] are for other usages(bit16 is AUTO_LANE_FLIP_CTRL_EN, bits [15:13] are
>> PRE_DET_LANE). For details, maybe you can refer to v4.4 databook :)
>>
>> My opinion is that there is no conflict about NUM_OF_LANES between v4.2 and v4.4.
>> We can change this mask to avoid future problem.
> 
> OK, I see.
> I got what you want to say. :-)
> 
> I think that there is no conflict between v4.2 and v4.4.
> So, this patch can be accepted.
> 
> Then, would you send v2 patch with more detailed commit message above mentioned?
>

Thanks. I will prepare v2 patch with more detailed commit message.

Best regards,
Zhou

> Best regards,
> Jingoo Han
>
>> Thanks
>> Zhou
>>
>>> Best regards,
>>> Jingoo Han
>>>
>>>> Signed-off-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
>>>> ---
>>>> drivers/pci/host/pcie-designware.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
>>>> index 69486be..eb549b9 100644
>>>> --- a/drivers/pci/host/pcie-designware.c
>>>> +++ b/drivers/pci/host/pcie-designware.c
>>>> @@ -35,7 +35,7 @@
>>>>
>>>> #define PCIE_LINK_WIDTH_SPEED_CONTROL    0x80C
>>>> #define PORT_LOGIC_SPEED_CHANGE (0x1 << 17)
>>>> -#define PORT_LOGIC_LINK_WIDTH_MASK    (0x1ff << 8)
>>>> +#define PORT_LOGIC_LINK_WIDTH_MASK    (0x1f << 8)
>>>> #define PORT_LOGIC_LINK_WIDTH_1_LANES    (0x1 << 8)
>>>> #define PORT_LOGIC_LINK_WIDTH_2_LANES    (0x2 << 8)
>>>> #define PORT_LOGIC_LINK_WIDTH_4_LANES    (0x4 << 8)
>>>> -- 
>>>> 1.9.1
>>>
>>> .
>>
>>
> 
> .
> 


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