From 511deae0261c839461948f2d4d1c13b8c8a59cd8 Mon Sep 17 00:00:00 2001 From: Dave Jiang Date: Wed, 11 May 2016 14:32:49 -0700 Subject: [PATCH] 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 Signed-off-by: Vinod Koul --- drivers/dma/ioat/init.c | 12 ++++++++++++ drivers/dma/ioat/registers.h | 7 +++++++ 2 files changed, 19 insertions(+) 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 @@ 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; } 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 */ -- 2.7.4