We have a board it seems cannot shutdown on dw_shutdown(). It hard
to re-produce. It re-produce 2 times those days.
There is the log:
[ 99.283522] system 00:09: shutdown start
[ 99.287942] system 00:09: shutdown stop
[ 99.292279] system 00:08: shutdown start
[ 99.296700] system 00:08: shutdown stop
[ 99.301023] pnp 00:07: shutdown start
[ 99.305144] pnp 00:07: shutdown stop
[ 99.309192] pnp 00:06: shutdown start
[ 99.313323] pnp 00:06: shutdown stop
[ 99.317357] pnp 00:05: shutdown start
[ 99.321503] pnp 00:05: shutdown stop
[ 99.325563] pnp 00:04: shutdown start
[ 99.329761] pnp 00:04: shutdown stop
[ 99.333815] pnp 00:03: shutdown start
[ 99.337947] pnp 00:03: shutdown stop
[ 99.342002] serial 00:02: shutdown start
[ 99.346422] serial 00:02: shutdown stop
[ 99.350742] system 00:01: shutdown start
[ 99.355163] system 00:01: shutdown stop
[ 99.359504] pnp 00:00: shutdown start
[ 99.363632] pnp 00:00: shutdown stop
[ 99.367700] intel_sst_acpi 808622A8:00: shutdown start
[ 99.384530] intel_sst_acpi 808622A8:00: shutdown stop
[ 99.390222] pxa2xx-spi 8086228E:02: shutdown start
[ 99.395983] pxa2xx-spi 8086228E:02: shutdown stop
[ 99.401376] pxa2xx-spi 8086228E:01: shutdown start
[ 99.407197] pxa2xx-spi 8086228E:01: shutdown stop
[ 99.412529] pxa2xx-spi 8086228E:00: shutdown start
[ 99.418343] pxa2xx-spi 8086228E:00: shutdown stop
[ 99.423652] HSU serial 8086228A:01: shutdown start
[ 99.429078] HSU serial 8086228A:01: shutdown stop
[ 99.434383] HSU serial 8086228A:00: shutdown start
[ 99.439796] HSU serial 8086228A:00: shutdown stop
[ 99.445110] dw_dmac 808622C0:00: shutdown start
There is potential risk of a dead loop on dmac shutdown, when the dmac
cannot wait the DW_CFG_DMA_EN bit on CFG register in a fault status.
This dead loop will let the shutdown un-finish, and the battery will drain.
Signed-off-by: Figo <tianfei.zhang@xxxxxxxxx>
---
drivers/dma/dw/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index bedce03..9c5f3f5 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1107,6 +1107,7 @@ static void dwc_issue_pending(struct dma_chan *chan)
static void dw_dma_off(struct dw_dma *dw)
{
int i;
+ int retry = 100;
dma_writel(dw, CFG, 0);
@@ -1115,8 +1116,11 @@ static void dw_dma_off(struct dw_dma *dw)
channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
- while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
- cpu_relax();
+ while ((dma_readl(dw, CFG) & DW_CFG_DMA_EN) && --retry)
+ udelay(100);
+
+ if (retry == 0)
+ dev_err(&dw->dma.dev, "%s error :timeout\n", __func__);
for (i = 0; i < dw->dma.chancnt; i++)
dw->chan[i].initialized = false;
--
1.7.9.5
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