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

[Dinh Nguyen <dinguyen@kernel.org>]

On 2/23/22 11:16, Marek Vasut wrote:
> On 2/23/22 17:46, Dinh Nguyen wrote:
>>
>>
>> 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.
> 
> Thank you
> 
> If you cannot reproduce it there, drop this patch and I'll revisit this 
> on my side.

Hmm...it doesn't look like the same error, but I'm getting this on the 
-next. I disable QSPI and the error still shows up. I'll dig more into it.

[    1.685301] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 
5.17.0-rc5-next-20220222 #3
[    1.692771] Hardware name: Altera SOCFPGA
[    1.696771] Backtrace:
[    1.699217]  dump_backtrace from show_stack+0x20/0x24
[    1.704277]  r7:c0d03cc8 r6:c05fb6dc r5:c0b1d644 r4:60000093
[    1.709919]  show_stack from dump_stack_lvl+0x48/0x54
[    1.714965]  dump_stack_lvl from dump_stack+0x18/0x1c
[    1.720009]  r5:c1020600 r4:c0dc0b98
[    1.723573]  dump_stack from check_flush_dependency+0x1d4/0x1d8
[    1.729483]  check_flush_dependency from __flush_work+0x88/0x268
[    1.735481]  r7:c0d03cc8 r6:c0d82520 r5:c1020800 r4:c0dc0b98
[    1.741122]  __flush_work from flush_work+0x1c/0x20
[    1.745996]  r8:c1178000 r7:00000000 r6:c05fbd2c r5:00000001 r4:c0ddb72c
[    1.752674]  flush_work from deferred_probe_initcall+0x58/0xb8
[    1.758508]  deferred_probe_initcall from do_one_initcall+0x58/0x218
[    1.764860]  r5:c0db1ea0 r4:c0d03cc8
[    1.768426]  do_one_initcall from kernel_init_freeable+0x250/0x298
[    1.774602]  r8:c10e0d00 r7:00000008 r6:c0c47838 r5:c0c741a8 r4:c0bd1920
[    1.781281]  kernel_init_freeable from kernel_init+0x24/0x148
[    1.787023]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 
r6:00000000 r5:c0951e84
[    1.794828]  r4:00003cc0
[    1.797356]  kernel_init from ret_from_fork+0x14/0x2c
[    1.802401] Exception stack(0xf0831fb0 to 0xf0831ff8)
[    1.807441] 1fa0:                                     00000000 
00000000 00000000 00000000
[    1.815595] 1fc0: 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000
[    1.823748] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    1.830342]  r5:c0951e84 r4:00000000
[    1.834751] at24 0-0051: supply vcc not found, using dummy regulator
[    1.842334] at24 0-0051: 4096 byte 24c32 EEPROM, writable, 32 bytes/write
[    1.854814] rtc-ds1307 0-0068: registered as rtc0
[    1.861327] rtc-ds1307 0-0068: setting system clock to 
2018-03-17T07:37:25 UTC (1521272245)
[    1.874183] dma-pl330 ffe01000.pdma: Loaded driver for PL330 DMAC-341330
[    1.880887] dma-pl330 ffe01000.pdma:         DBUFF-512x8bytes 
Num_Chans-8 Num_Peri-32 Num_Events-8