dmaengine: ioatdma: disable relaxed ordering for ioatdma
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>
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index d4c63d4..d406056 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -1073,6 +1073,7 @@
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 @@
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;
}