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dmaengine: ioatdma: disable relaxed ordering for ioatdma

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ioatdma by default is in snoop mode. Relaxed ordering according to spec
does not do anything in snoop mode. However, it causes hang or significant
performance degrade when tested with NTB. Disabling in the driver due to
some BIOS do not configure it correctly.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Dave Jiang 2016-05-11 14:32:49 -07:00 committed by Vinod Koul
parent 3b2bc8a732
commit 511deae026
2 changed files with 19 additions and 0 deletions
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12
drivers/dma/ioat/init.c
View file

@ -1073,6 +1073,7 @@ static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
struct ioatdma_chan *ioat_chan;
bool is_raid_device = false;
int err;
u16 val16;
dma = &ioat_dma->dma_dev;
dma->device_prep_dma_memcpy = ioat_dma_prep_memcpy_lock;
@ -1172,6 +1173,17 @@ static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
if (dca)
ioat_dma->dca = ioat_dca_init(pdev, ioat_dma->reg_base);
/* disable relaxed ordering */
err = pcie_capability_read_word(pdev, IOAT_DEVCTRL_OFFSET, &val16);
if (err)
return err;
/* clear relaxed ordering enable */
val16 &= ~IOAT_DEVCTRL_ROE;
err = pcie_capability_write_word(pdev, IOAT_DEVCTRL_OFFSET, val16);
if (err)
return err;
return 0;
}

7
drivers/dma/ioat/registers.h
View file

@ -26,6 +26,13 @@
#define IOAT_PCI_CHANERR_INT_OFFSET 0x180
#define IOAT_PCI_CHANERRMASK_INT_OFFSET 0x184
/* PCIe config registers */
/* EXPCAPID + N */
#define IOAT_DEVCTRL_OFFSET 0x8
/* relaxed ordering enable */
#define IOAT_DEVCTRL_ROE 0x10
/* MMIO Device Registers */
#define IOAT_CHANCNT_OFFSET 0x00 /* 8-bit */