linux-kernel - [PATCH v3] ata: sata_rcar: Fix DMA boundary mask

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Message-Id: <20200917130920.6689-1-geert+renesas@glider.be>
Date:   Thu, 17 Sep 2020 15:09:20 +0200
From:   Geert Uytterhoeven <geert+renesas@...der.be>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christoph Hellwig <hch@....de>, Ming Lei <ming.lei@...hat.com>,
        Sergei Shtylyov <sergei.shtylyov@...il.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        linux-ide@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable <stable@...r.kernel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH v3] ata: sata_rcar: Fix DMA boundary mask

Before commit 9495b7e92f716ab2 ("driver core: platform: Initialize
dma_parms for platform devices"), the R-Car SATA device didn't have DMA
parameters.  Hence the DMA boundary mask supplied by its driver was
silently ignored, as __scsi_init_queue() doesn't check the return value
of dma_set_seg_boundary(), and the default value of 0xffffffff was used.

Now the device has gained DMA parameters, the driver-supplied value is
used, and the following warning is printed on Salvator-XS:

    DMA-API: sata_rcar ee300000.sata: mapping sg segment across boundary [start=0x00000000ffffe000] [end=0x00000000ffffefff] [boundary=0x000000001ffffffe]
    WARNING: CPU: 5 PID: 38 at kernel/dma/debug.c:1233 debug_dma_map_sg+0x298/0x300

(the range of start/end values depend on whether IOMMU support is
 enabled or not)

The issue here is that SATA_RCAR_DMA_BOUNDARY doesn't have bit 0 set, so
any typical end value, which is odd, will trigger the check.

Fix this by increasing the DMA boundary value by 1.

This also fixes the following WRITE DMA EXT timeout issue:

    # dd if=/dev/urandom of=/mnt/de1/file1-1024M bs=1M count=1024
    ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
    ata1.00: failed command: WRITE DMA EXT
    ata1.00: cmd 35/00:00:00:e6:0c/00:0a:00:00:00/e0 tag 0 dma 1310720 out
    res 40/00:01:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
    ata1.00: status: { DRDY }

as seen by Shimoda-san since commit 429120f3df2dba2b ("block: fix
splitting segments on boundary masks").

Fixes: 8bfbeed58665dbbf ("sata_rcar: correct 'sata_rcar_sht'")
Fixes: 9495b7e92f716ab2 ("driver core: platform: Initialize dma_parms for platform devices")
Fixes: 429120f3df2dba2b ("block: fix splitting segments on boundary masks")
Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Christoph Hellwig <hch@....de>
Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc: stable <stable@...r.kernel.org>
---
v3:
  - Add Reviewed-by, Tested-by,
  - Augment description and Fixes: with Shimoda-san's problem report
    https://lore.kernel.org/r/1600255098-21411-1-git-send-email-yoshihiro.shimoda.uh@renesas.com,

v2:
  - Add Reviewed-by, Tested-by, Cc.
---
 drivers/ata/sata_rcar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/sata_rcar.c b/drivers/ata/sata_rcar.c
index 141ac600b64c87ef..44b0ed8f6bb8a120 100644
--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -120,7 +120,7 @@
 /* Descriptor table word 0 bit (when DTA32M = 1) */
 #define SATA_RCAR_DTEND			BIT(0)
 
-#define SATA_RCAR_DMA_BOUNDARY		0x1FFFFFFEUL
+#define SATA_RCAR_DMA_BOUNDARY		0x1FFFFFFFUL
 
 /* Gen2 Physical Layer Control Registers */
 #define RCAR_GEN2_PHY_CTL1_REG		0x1704
-- 
2.17.1