Re: [PATCH] spi: cadence-quadspi: Fix indirect write timeout when DMA read mode is enabled

[Pandey, Radhey Shyam]

> When use_dma_read is enabled, the IRQ handler unconditionally overwrites
> irq_status with the return value of get_dma_status(). For write operations,
> DMA status returns 0 since no DMA read is in progress, causing irq_status
> to become 0. The subsequent completion signal is never triggered and the
> write operation times out with -ETIMEDOUT:
>
>    cadence-qspi f1010000.spi: Indirect write timeout
>    spi-nor spi0.1: operation failed with -110
>
> Fix this by separating the DMA completion path from the write interrupt
> path. If get_dma_status() indicates DMA read completion, signal completion
> and return immediately. Otherwise, preserve the original irq_status so that
> write completion interrupts are correctly recognized and signalled.
>
> Fixes: aac733a96636 ("spi: cadence-qspi: Fix style and improve readability")
> Signed-off-by: Srikanth Boyapally <srikanth.boyapally@xxxxxxx>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
Thanks!
> ---
>   drivers/spi/spi-cadence-quadspi.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
> index 65aff2e70265..89873f8b3f21 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -382,12 +382,16 @@ static irqreturn_t cqspi_irq_handler(int this_irq, void *dev)
>   	/* Clear interrupt */
>   	writel(irq_status, cqspi->iobase + CQSPI_REG_IRQSTATUS);
>   
> -	if (cqspi->use_dma_read && ddata && ddata->get_dma_status)
> -		irq_status = ddata->get_dma_status(cqspi);
> -	else if (cqspi->slow_sram)
> +	if (cqspi->use_dma_read && ddata && ddata->get_dma_status) {
> +		if (ddata->get_dma_status(cqspi)) {
> +			complete(&cqspi->transfer_complete);
> +			return IRQ_HANDLED;
> +		}
> +	} else if (cqspi->slow_sram) {
>   		irq_status &= CQSPI_IRQ_MASK_RD_SLOW_SRAM | CQSPI_IRQ_MASK_WR;
> -	else
> +	} else {
>   		irq_status &= CQSPI_IRQ_MASK_RD | CQSPI_IRQ_MASK_WR;
> +	}
>   
>   	if (irq_status)
>   		complete(&cqspi->transfer_complete);