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Subject[PATCH 17/29] ioat: preserve chanctrl bits when re-arming interrupts
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Date
The register write in ioat_dma_cleanup_tasklet is unfortunate in two
ways:
1/ It clears the extra 'enable' bits that we set at alloc_chan_resources time
2/ It gives the impression that it disables interrupts when it is in
fact re-arming interrupts

[ Impact: fix, persist the value of the chanctrl register when re-arming ]

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dma/ioat/dma.c | 10 +++-------
drivers/dma/ioat/dma_v2.c | 8 ++------
drivers/dma/ioat/registers.h | 6 +++++-
3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 5173ba9..6dd0af1 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -452,7 +452,6 @@ static int ioat1_dma_alloc_chan_resources(struct dma_chan *c)
struct ioat_dma_chan *ioat = to_ioat_chan(c);
struct ioat_chan_common *chan = &ioat->base;
struct ioat_desc_sw *desc;
- u16 chanctrl;
u32 chanerr;
int i;
LIST_HEAD(tmp_list);
@@ -462,10 +461,7 @@ static int ioat1_dma_alloc_chan_resources(struct dma_chan *c)
return ioat->desccount;

/* Setup register to interrupt and write completion status on error */
- chanctrl = IOAT_CHANCTRL_ERR_INT_EN |
- IOAT_CHANCTRL_ANY_ERR_ABORT_EN |
- IOAT_CHANCTRL_ERR_COMPLETION_EN;
- writew(chanctrl, chan->reg_base + IOAT_CHANCTRL_OFFSET);
+ writew(IOAT_CHANCTRL_RUN, chan->reg_base + IOAT_CHANCTRL_OFFSET);

chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
if (chanerr) {
@@ -672,9 +668,9 @@ ioat1_dma_prep_memcpy(struct dma_chan *c, dma_addr_t dma_dest,
static void ioat1_cleanup_tasklet(unsigned long data)
{
struct ioat_dma_chan *chan = (void *)data;
+
ioat1_cleanup(chan);
- writew(IOAT_CHANCTRL_INT_DISABLE,
- chan->base.reg_base + IOAT_CHANCTRL_OFFSET);
+ writew(IOAT_CHANCTRL_RUN, chan->base.reg_base + IOAT_CHANCTRL_OFFSET);
}

static void ioat_unmap(struct pci_dev *pdev, dma_addr_t addr, size_t len,
diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index 589bbc3..be617db 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -342,8 +342,7 @@ static void ioat2_cleanup_tasklet(unsigned long data)
struct ioat2_dma_chan *ioat = (void *) data;

ioat2_cleanup(ioat);
- writew(IOAT_CHANCTRL_INT_DISABLE,
- ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
+ writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
}

/**
@@ -455,7 +454,6 @@ static int ioat2_alloc_chan_resources(struct dma_chan *c)
struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
struct ioat_chan_common *chan = &ioat->base;
struct ioat_ring_ent **ring;
- u16 chanctrl;
u32 chanerr;
int descs;
int i;
@@ -465,9 +463,7 @@ static int ioat2_alloc_chan_resources(struct dma_chan *c)
return 1 << ioat->alloc_order;

/* Setup register to interrupt and write completion status on error */
- chanctrl = IOAT_CHANCTRL_ERR_INT_EN | IOAT_CHANCTRL_ANY_ERR_ABORT_EN |
- IOAT_CHANCTRL_ERR_COMPLETION_EN;
- writew(chanctrl, chan->reg_base + IOAT_CHANCTRL_OFFSET);
+ writew(IOAT_CHANCTRL_RUN, chan->reg_base + IOAT_CHANCTRL_OFFSET);

chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
if (chanerr) {
diff --git a/drivers/dma/ioat/registers.h b/drivers/dma/ioat/registers.h
index a83c733..4380f6f 100644
--- a/drivers/dma/ioat/registers.h
+++ b/drivers/dma/ioat/registers.h
@@ -75,7 +75,11 @@
#define IOAT_CHANCTRL_ERR_INT_EN 0x0010
#define IOAT_CHANCTRL_ANY_ERR_ABORT_EN 0x0008
#define IOAT_CHANCTRL_ERR_COMPLETION_EN 0x0004
-#define IOAT_CHANCTRL_INT_DISABLE 0x0001
+#define IOAT_CHANCTRL_INT_REARM 0x0001
+#define IOAT_CHANCTRL_RUN (IOAT_CHANCTRL_INT_REARM |\
+ IOAT_CHANCTRL_ERR_COMPLETION_EN |\
+ IOAT_CHANCTRL_ANY_ERR_ABORT_EN |\
+ IOAT_CHANCTRL_ERR_INT_EN)

#define IOAT_DMA_COMP_OFFSET 0x02 /* 16-bit DMA channel compatibility */
#define IOAT_DMA_COMP_V1 0x0001 /* Compatibility with DMA version 1 */


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