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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2016-03-18 14:26:32 +0200
committerVinod Koul <vinod.koul@intel.com>2016-04-04 09:41:43 -0700
commit4f4bc0abff79dc9d7ccbd3143adbf8ad1f4fe6ab (patch)
treee3a2e86b00b408c281c6d1304228a5c4c9a6111b
parenta197f3c7d48c0c1f45076ea47533a76ba9b1a959 (diff)
dmaengine: hsu: correct use of channel status register
There is a typo in documentation regarding to descriptor empty bit (DESCE) which is set to 1 when descriptor is empty. Thus, status register at the end of a transfer usually returns all DESCE bits set and thus it will never be zero. Moreover, there are 2 bits (CDESC) that encode current descriptor, on which interrupt has been asserted. In case when we have few descriptors programmed we might have non-zero value. Remove DESCE and CDESC bits from DMA channel status register (HSU_CH_SR) when reading it. Fixes: 2b49e0c56741 ("dmaengine: append hsu DMA driver") Cc: stable@vger.kernel.org Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
-rw-r--r--drivers/dma/hsu/hsu.c2
-rw-r--r--drivers/dma/hsu/hsu.h3
2 files changed, 4 insertions, 1 deletions
diff --git a/drivers/dma/hsu/hsu.c b/drivers/dma/hsu/hsu.c
index b3b212146620..ee510515ce18 100644
--- a/drivers/dma/hsu/hsu.c
+++ b/drivers/dma/hsu/hsu.c
@@ -135,7 +135,7 @@ static u32 hsu_dma_chan_get_sr(struct hsu_dma_chan *hsuc)
sr = hsu_chan_readl(hsuc, HSU_CH_SR);
spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
- return sr;
+ return sr & ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY);
}
irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr)
diff --git a/drivers/dma/hsu/hsu.h b/drivers/dma/hsu/hsu.h
index 578a8ee8cd05..6b070c22b1df 100644
--- a/drivers/dma/hsu/hsu.h
+++ b/drivers/dma/hsu/hsu.h
@@ -41,6 +41,9 @@
#define HSU_CH_SR_DESCTO(x) BIT(8 + (x))
#define HSU_CH_SR_DESCTO_ANY (BIT(11) | BIT(10) | BIT(9) | BIT(8))
#define HSU_CH_SR_CHE BIT(15)
+#define HSU_CH_SR_DESCE(x) BIT(16 + (x))
+#define HSU_CH_SR_DESCE_ANY (BIT(19) | BIT(18) | BIT(17) | BIT(16))
+#define HSU_CH_SR_CDESC_ANY (BIT(31) | BIT(30))
/* Bits in HSU_CH_CR */
#define HSU_CH_CR_CHA BIT(0)