linux-kernel - Re: [RESEND PATCH v3 5/8] mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting DMA channel

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Date:   Thu, 27 Aug 2020 12:34:26 +0530
From:   Vignesh Raghavendra <vigneshr@...com>
To:     Jan Kiszka <jan.kiszka@...mens.com>,
        Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Mark Brown <broonie@...nel.org>,
        "Jin, Le (RC-CN DF FA R&D)" <le.jin@...mens.com>
CC:     Boris Brezillon <bbrezillon@...nel.org>,
        Ramuthevar Vadivel Murugan 
        <vadivel.muruganx.ramuthevar@...ux.intel.com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-spi@...r.kernel.org>, <simon.k.r.goldschmidt@...il.com>,
        <dinguyen@...nel.org>, <marex@...x.de>
Subject: Re: [RESEND PATCH v3 5/8] mtd: spi-nor: cadence-quadspi: Handle probe
 deferral while requesting DMA channel



On 8/26/20 7:01 PM, Jan Kiszka wrote:
> On 26.08.20 14:18, Vignesh Raghavendra wrote:
>> On 8/26/20 3:42 PM, Jan Kiszka wrote:
>>> On 24.08.20 19:20, Jan Kiszka wrote:
>>>> On 24.08.20 14:49, Jan Kiszka wrote:
>>>>> On 24.08.20 13:45, Vignesh Raghavendra wrote:
>>>>>>
[...]
>> Also, there seems to be DMA mapping related issue, that was always present in 
>> older driver as well. Could you see if diff [2] fixes the issue?
>>
>> [2] Use DMA device for mapping:
>>
>> ---><8---
>>
>>
>> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
>> index b9739ae919340..a546aa4598758 100644
>> --- a/drivers/spi/spi-cadence-quadspi.c
>> +++ b/drivers/spi/spi-cadence-quadspi.c
>> @@ -901,6 +901,7 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
>>  {
>>         struct cqspi_st *cqspi = f_pdata->cqspi;
>>         struct device *dev = &cqspi->pdev->dev;
>> +       struct device *ddev = cqspi->rx_chan->device->dev;
>>         enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
>>         dma_addr_t dma_src = (dma_addr_t)cqspi->mmap_phys_base + from;
>>         int ret = 0;
>> @@ -917,8 +918,8 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
>>                 return 0;
>>         }
>>  
>> -       dma_dst = dma_map_single(dev, buf, len, DMA_FROM_DEVICE);
>> -       if (dma_mapping_error(dev, dma_dst)) {
>> +       dma_dst = dma_map_single(ddev, buf, len, DMA_FROM_DEVICE);
>> +       if (dma_mapping_error(ddev, dma_dst)) {
>>                 dev_err(dev, "dma mapping failed\n");
>>                 return -ENOMEM;
>>         }
>> @@ -952,7 +953,7 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
>>         }
>>  
>>  err_unmap:
>> -       dma_unmap_single(dev, dma_dst, len, DMA_FROM_DEVICE);
>> +       dma_unmap_single(ddev, dma_dst, len, DMA_FROM_DEVICE);
>>  
>>         return ret;
>>  }
>>
> 
> That seems to help! Wasn't able to reproduce the issue with this applied
> so far.
> 

OK, great... I will post this patch soon once I finish a bit more
testing... Thanks!


Regards
Vignesh