[PATCH 4.14 012/125] ata: sata_rcar: Fix DMA boundary mask

Greg Kroah-Hartman
2020-11-03T21:09:02Z

From: Geert Uytterhoeven <geert+renesas@glider.be>

commit df9c590986fdb6db9d5636d6cd93bc919c01b451 upstream.

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@glider.be>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/ata/sata_rcar.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -122,7 +122,7 @@
/* 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