Re: [PATCH 08/12] PCI: tegra: Wait for DLLP to finish before entering L1 or L2

Manikanta Maddireddy
2017-10-30T03:56:21Z

On 29-Oct-17 3:12 PM, Vidya Sagar wrote:
>
>
> On Saturday 28 October 2017 12:59 AM, Manikanta Maddireddy wrote:
>> Set required bit to have LTSSM wait for DLLP to finish before entering L1
>> or L2. This avoids truncation of PM messages which results in receiver
>> errors.
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>> ---
>>   drivers/pci/host/pci-tegra.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
>> index b8cac871712b..6028d5f3d5bb 100644
>> --- a/drivers/pci/host/pci-tegra.c
>> +++ b/drivers/pci/host/pci-tegra.c
>> @@ -217,6 +217,9 @@
>>   #define RP_VEND_CTL1    0xf48
>>   #define  RP_VEND_CTL1_ERPT    (1 << 13)
>>   +#define RP_VEND_XP_BIST    0xf4c
>> +#define  RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE    (1 << 28)
>> +
> BIT macro is preferred here.
Left shift is used everywhere, so to be inline with that I used same format
>>   #define RP_VEND_CTL2 0x00000fa8
>>   #define  RP_VEND_CTL2_PCA_ENABLE (1 << 7)
>>   @@ -2160,6 +2163,13 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port)
>>       value |= RP_VEND_XP_OPPORTUNISTIC_ACK;
>>       value |= RP_VEND_XP_OPPORTUNISTIC_UPDATEFC;
>>       writel(value, port->base + RP_VEND_XP);
>> +
>> +    /* LTSSM will wait for DLLP to finish before entering L1 or L2,
>> +     * to avoid truncation of PM messages which results in receiver errors
>> +     */
>> +    value = readl(port->base + RP_VEND_XP_BIST);
>> +    value |= RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE;
>> +    writel(value, port->base + RP_VEND_XP_BIST);
>>   }
>>   /*
>>    * FIXME: If there are no PCIe cards attached, then calling this function
>