[U-Boot] [PATCH] mvebu: a38x: Force receiver detected on PCIe lanes

[Mario Six]

Hi Stefan,

On Mon, May 28, 2018 at 2:52 PM, Stefan Roese <sr at denx.de> wrote:
> (Added Mario and Chris)
>
>
> On 27.05.2018 17:34, Baruch Siach wrote:
>>
>> From: Rabeeh Khoury <rabeeh at solid-run.com>
>>
>> Some QCA988x based modules presence is not detected by the SERDES lanes,
>> so force this detection which will trigger the LTSSM state machine to
>> negotiate link.
>>
>> An example of such a card is WLE900VX.
>>
>> Signed-off-by: Rabeeh Khoury <rabeeh at solid-run.com>
>> Signed-off-by: Baruch Siach <baruch at tkos.co.il>
>> ---
>>   arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c | 2 ++
>>   arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h         | 1 +
>>   2 files changed, 3 insertions(+)
>>
>> diff --git a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
>> b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
>> index 13553cf96008..33e70569bc48 100644
>> --- a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
>> +++ b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
>> @@ -597,6 +597,8 @@ struct op_params
>> pex_electrical_config_serdes_rev2_params[] = {
>>         {LANE_CFG4_REG, 0x800, 0x8, {0x8}, 0, 0},
>>         /* tximpcal_th and rximpcal_th */
>>         {VTHIMPCAL_CTRL_REG, 0x800, 0xff00, {0x3000}, 0, 0},
>> +       /* Force receiver detected */
>> +       {LANE_CFG0_REG, 0x800, 0x8000, {0x8000}, 0, 0},
>>   };
>>     /* PEX - configuration seq for REF_CLOCK_25MHz */
>> diff --git a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
>> b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
>> index 953445b7d7ae..50b235826659 100644
>> --- a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
>> +++ b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
>> @@ -71,6 +71,7 @@
>>   #define RX_REG3                               0xa0188
>>   #define PCIE_REG1                     0xa0288
>>   #define PCIE_REG3                     0xa0290
>> +#define LANE_CFG0_REG                  0xa0600
>>   #define LANE_CFG1_REG                 0xa0604
>>   #define LANE_CFG4_REG                 0xa0620
>>   #define LANE_CFG5_REG                 0xa0624
>>
>
> I understand that this might fix an issue on a specific board (ClearFog
> in this case, correct?). But are you sure that its safe to force this
> link detection for all A38x boards?
>

I just did a quick test on a controlcenterdc board, and it seems to work. I'll
try to do some more extensive tests this week (unless somebody has another
objection, of course).

> Thanks,
> Stefan

Best regards,
Mario