diff mbox

dmaengine: ioatdma: disable relaxed ordering for ioatdma

Message ID 146300236968.195052.10311160849399474647.stgit@djiang5-desk3.ch.intel.com (mailing list archive)
State Accepted
Headers show

Commit Message

Dave Jiang May 11, 2016, 9:32 p.m. UTC 
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>
---
 drivers/dma/ioat/init.c      |   12 ++++++++++++
 drivers/dma/ioat/registers.h |    7 +++++++
 2 files changed, 19 insertions(+)


--
To unsubscribe from this list: send the line "unsubscribe dmaengine" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Vinod Koul May 14, 2016, 8:07 a.m. UTC | #1 
On Wed, May 11, 2016 at 02:32:49PM -0700, Dave Jiang wrote:
> 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.

Applied, thanks
diff mbox

Patch

diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index efdee1a..7177199 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -1074,6 +1074,7 @@  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;
@@ -1173,6 +1174,17 @@  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;
 }
 
diff --git a/drivers/dma/ioat/registers.h b/drivers/dma/ioat/registers.h
index 4994a36..7053498 100644
--- a/drivers/dma/ioat/registers.h
+++ b/drivers/dma/ioat/registers.h
@@ -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 */