Re: [PATCH] [RFC] spi: cadence-quadspi: Disable DAC on SoCFPGA

[Dinh Nguyen <dinguyen@kernel.org>]

On 2/23/22 10:43, Marek Vasut wrote:
> On 2/23/22 17:28, Dinh Nguyen wrote:
>>
>>
>> On 2/22/22 18:54, Marek Vasut wrote:
>>> On 2/22/22 22:32, Dinh Nguyen wrote:
>>>>
>>>>
>>>> On 2/22/22 12:30, Marek Vasut wrote:
>>>>> On 2/22/22 16:49, Dinh Nguyen wrote:
>>>>>>
>>>>>>
>>>>>> On 2/21/22 11:05, Marek Vasut wrote:
>>>>>>> On 2/21/22 17:38, Dinh Nguyen wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 2/20/22 22:32, Marek Vasut wrote:
>>>>>>>>> On SoCFPGA Gen5, DAC memcpy_fromio() in 
>>>>>>>>> cqspi_direct_read_execute()
>>>>>>>>> leads to data abort, disable DAC to avoid triggering it:
>>>>>>>>>
>>>>>>>>> Unhandled fault: imprecise external abort (0x1406) at 0x0400d3e9
>>>>>>>>> [0400d3e9] *pgd=00000000
>>>>>>>>>
>>>>>>>>> Signed-off-by: Marek Vasut <marex@denx.de>
>>>>>>>>> Cc: Dinh Nguyen <dinguyen@kernel.org>
>>>>>>>>> Cc: Pratyush Yadav <p.yadav@ti.com>
>>>>>>>>> ---
>>>>>>>>>   drivers/spi/spi-cadence-quadspi.c | 2 +-
>>>>>>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/spi/spi-cadence-quadspi.c 
>>>>>>>>> b/drivers/spi/spi-cadence-quadspi.c
>>>>>>>>> index b808c94641fa6..65f2c2449be09 100644
>>>>>>>>> --- a/drivers/spi/spi-cadence-quadspi.c
>>>>>>>>> +++ b/drivers/spi/spi-cadence-quadspi.c
>>>>>>>>> @@ -1870,7 +1870,7 @@ static const struct cqspi_driver_platdata 
>>>>>>>>> intel_lgm_qspi = {
>>>>>>>>>   };
>>>>>>>>>   static const struct cqspi_driver_platdata socfpga_qspi = {
>>>>>>>>> -    .quirks = CQSPI_NO_SUPPORT_WR_COMPLETION,
>>>>>>>>> +    .quirks = CQSPI_DISABLE_DAC_MODE | 
>>>>>>>>> CQSPI_NO_SUPPORT_WR_COMPLETION,
>>>>>>>>>   };
>>>>>>>>>   static const struct cqspi_driver_platdata versal_ospi = {
>>>>>>>>
>>>>>>>> Acked-by: Dinh Nguyen <dinguyen@kernel.org>
>>>>>>>
>>>>>>> Is this DAC really not working on socfpga gen5 or is there some 
>>>>>>> other issue ?
>>>>>>
>>>>>> I don't know the answer to this question. What is the DAC in the 
>>>>>> QSPI module and how do I go about testing it?
>>>>>
>>>>> DAC = direct access.
>>>>>
>>>>> How do you go about testing this -- compile kernel with/without 
>>>>> this patch, boot on SoCFPGA Gen5 with QSPI NOR attached, the kernel 
>>>>> crashes without this patch on imprecise external abort.
>>>>
>>>> Hmm...I just tested v5.17-rc3 on a C5 board and QSPI looks to be 
>>>> working fine:
>>>>
>>>> [    1.744489] spi-nor spi1.0: found n25q512ax3, expected mt25qu02g
>>>> [    1.750534] dma-pl330 ffe01000.pdma: Reset Channel-0  CS-f FTC-40000
>>>> [    1.756941] spi-nor spi1.0: n25q512ax3 (65536 Kbytes)
>>>> [    1.762369] 2 fixed-partitions partitions found on MTD device 
>>>> ff705000.spi.0
>>>> [    1.769425] Creating 2 MTD partitions on "ff705000.spi.0":
>>>> [    1.774925] 0x000000000000-0x000000800000 : "Flash 0 Raw Data"
>>>> [    1.781942] 0x000000800000-0x000008000000 : "Flash 0 jffs2 
>>>> Filesystem"
>>>> [    1.788468] mtd: partition "Flash 0 jffs2 Filesystem" extends 
>>>> beyond the end of device "ff705000.spi.0" -- size truncated to 
>>>> 0x3800000
>>>
>>> I wonder if we might be missing some clock enable somewhere.
>>>
>>> Can you mail me the whole boot log ? (I'm using u-boot 2022.01 btw.)
>>
>> I tested with U-Boot 2022.01 as well:
>>
>>
>> => run nfsboot_dinh
>> Kernel image @ 0x1000000 [ 0x000000 - 0x54edd0 ]
>> ## Flattened Device Tree blob at 02000000
>>     Booting using the fdt blob at 0x2000000
>>     Loading Device Tree to 09ff8000, end 09fffeb1 ... OK
>>
>> Starting kernel ...
>>
>> Deasserting all peripheral resets
>> [    0.000000] Booting Linux on physical CPU 0x0
>> [    0.000000] Linux version 5.17.0-rc3 (dinguyen@linux-builds1) 
>> (arm-linux-gnue abihf-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0, 
>> GNU ld (GNU Binutils for U buntu) 2.30) #1 SMP Wed Feb 23 08:51:18 CST 
>> 2022
>> [    0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), 
>> cr=10c5387d
>> [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing 
>> instructio n cache
>> [    0.000000] OF: fdt: Machine model: Altera SOCFPGA Cyclone V SoC 
>> Development  Kit
>> [    0.000000] Memory policy: Data cache writealloc
> 
> This is weird.
> 
> One more thing, I have two SPI NORs on this CQSPI, one on each chip 
> select, do you think that can make any difference ?
> 
> Besides that, I used latest next for my tests, not latest linus tree.

Let me test on latest next.

> 
> Maybe I should try and find the CV devkit too and test on that.