From: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: dmaengine@vger.kernel.org
Subject: Re: [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
Date: Tue, 27 Jul 2021 13:05:52 +0900 [thread overview]
Message-ID: <3e36256e-d7ac-f727-c714-b79f3d1d1da7@socionext.com> (raw)
In-Reply-To: <20210726073436.GA9691@kili>
Hi Dan,
Thank you for reporting.
On 2021/07/26 16:34, Dan Carpenter wrote:
> Hello Kunihiko Hayashi,
>
> The patch 667b9251440b: "dmaengine: uniphier-xdmac: Add UniPhier
> external DMA controller driver" from Feb 21, 2020, leads to the
> following static checker warning:
>
> drivers/dma/uniphier-xdmac.c:212 uniphier_xdmac_chan_stop()
> warn: sleeping in atomic context
>
> drivers/dma/uniphier-xdmac.c
> 197 static int uniphier_xdmac_chan_stop(struct uniphier_xdmac_chan *xc)
> 198 {
> 199 u32 val;
> 200
> 201 /* disable interrupt */
> 202 val = readl(xc->reg_ch_base + XDMAC_IEN);
> 203 val &= ~(XDMAC_IEN_ENDIEN | XDMAC_IEN_ERRIEN);
> 204 writel(val, xc->reg_ch_base + XDMAC_IEN);
> 205
> 206 /* stop XDMAC */
> 207 val = readl(xc->reg_ch_base + XDMAC_TSS);
> 208 val &= ~XDMAC_TSS_REQ;
> 209 writel(0, xc->reg_ch_base + XDMAC_TSS);
> 210
> 211 /* wait until transfer is stopped */
> --> 212 return readl_poll_timeout(xc->reg_ch_base + XDMAC_STAT, val,
> 213 !(val & XDMAC_STAT_TENF), 100, 1000);
> ^^^
> This is doing a 100 us sleep but both callers hold a spin lock.
Yes, this waiting code is in spin lock context.
I think that the function needs to be rewritten in tasklet.
Thank you,
---
Best Regards
Kunihiko Hayashi
next prev parent reply other threads:[~2021-07-27 4:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-26 7:34 [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver Dan Carpenter
2021-07-27 4:05 ` Kunihiko Hayashi [this message]
2021-07-27 4:47 ` Kunihiko Hayashi
2021-07-27 8:33 Dan Carpenter
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