linux-kernel - Re: [PATCH v3 1/2] dmaengine: dw-edma: Fix unmasking STOP and ABORT interrupts for HDMA

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Message-ID: <k4kies4zeeda3nqse7ok5nxlg6nymznkktpalf2bx6wvegvhjo@s7breuqvbnq6>
Date: Fri, 16 Aug 2024 22:04:55 +0300
From: Serge Semin <fancer.lancer@...il.com>
To: Mrinmay Sarkar <quic_msarkar@...cinc.com>
Cc: manivannan.sadhasivam@...aro.org, vkoul@...nel.org, 
	quic_shazhuss@...cinc.com, quic_nitegupt@...cinc.com, quic_ramkri@...cinc.com, 
	quic_nayiluri@...cinc.com, quic_krichai@...cinc.com, quic_vbadigan@...cinc.com, 
	stable@...r.kernel.org, Cai Huoqing <cai.huoqing@...ux.dev>, dmaengine@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] dmaengine: dw-edma: Fix unmasking STOP and ABORT
 interrupts for HDMA

Hi Mrinmay

On Tue, Aug 13, 2024 at 06:45:37PM +0530, Mrinmay Sarkar wrote:
> The current logic is enabling both STOP_INT_MASK and ABORT_INT_MASK
> bit. This is apparently masking those particular interrupts rather than
> unmasking the same. If the interrupts are masked, they would never get
> triggered.
> 
> So fix the issue by unmasking the STOP and ABORT interrupts properly.
> 
> Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
> cc: stable@...r.kernel.org
> Signed-off-by: Mrinmay Sarkar <quic_msarkar@...cinc.com>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> ---
>  drivers/dma/dw-edma/dw-hdma-v0-core.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> index 10e8f07..a0aabdd 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> @@ -247,10 +247,11 @@ static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
>  	if (first) {
>  		/* Enable engine */
>  		SET_CH_32(dw, chan->dir, chan->id, ch_en, BIT(0));
> -		/* Interrupt enable&unmask - done, abort */
> -		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup) |
> -		      HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK |
> -		      HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_ABORT_INT_EN;
> +		/* Interrupt unmask - stop, abort */

> +		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup) &
> +		      ~HDMA_V0_STOP_INT_MASK & ~HDMA_V0_ABORT_INT_MASK;

The gist of my v2 comment was to convert the chunk above to:
		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup);
		tmp &= ~(HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK);

This is a clearer representation of the IRQs _unmasking_. Moreover the
code will turn to looking a bit more like what is implemented in the
similar part of the dw-edma-v0-core.c driver.

-Serge(y)


> +		/* Interrupt enable - stop, abort */
> +		tmp |= HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_ABORT_INT_EN;
>  		if (!(dw->chip->flags & DW_EDMA_CHIP_LOCAL))
>  			tmp |= HDMA_V0_REMOTE_STOP_INT_EN | HDMA_V0_REMOTE_ABORT_INT_EN;
>  		SET_CH_32(dw, chan->dir, chan->id, int_setup, tmp);
> -- 
> 2.7.4
>