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
