* [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
@ 2021-07-26 7:34 Dan Carpenter
2021-07-27 4:05 ` Kunihiko Hayashi
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2021-07-26 7:34 UTC (permalink / raw)
To: hayashi.kunihiko; +Cc: dmaengine
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.
214 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
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
2021-07-27 4:47 ` Kunihiko Hayashi
0 siblings, 1 reply; 4+ messages in thread
From: Kunihiko Hayashi @ 2021-07-27 4:05 UTC (permalink / raw)
To: Dan Carpenter; +Cc: dmaengine
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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
2021-07-27 4:05 ` Kunihiko Hayashi
@ 2021-07-27 4:47 ` Kunihiko Hayashi
0 siblings, 0 replies; 4+ messages in thread
From: Kunihiko Hayashi @ 2021-07-27 4:47 UTC (permalink / raw)
To: Dan Carpenter; +Cc: dmaengine
Hi,
On 2021/07/27 13:05, Kunihiko Hayashi wrote:
> 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.
I found this can be simply replaced with readl_poll_timeout_atomic().
I'll fix it.
Thank you,
---
Best Regards
Kunihiko Hayashi
^ permalink raw reply [flat|nested] 4+ messages in thread
* [bug report] dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver
@ 2021-07-27 8:33 Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2021-07-27 8:33 UTC (permalink / raw)
To: hayashi.kunihiko; +Cc: dmaengine
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 100 means it can sleep. The function is always called with a
spin_lock held.
214 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
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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
2021-07-27 4:47 ` Kunihiko Hayashi
2021-07-27 8:33 Dan Carpenter
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