[ PATCH v6 0/2] introduce a quirk to allow only page-aligned sg entries

[ PATCH v6 0/2] introduce a quirk to allow only page-aligned sg entries

[Kiwoong Kim]

v5 -> v6: collect received tags
v4 -> v5: collect received tags
v3 -> v4: fix some typos
v2 -> v3: rename exynos functions
v1 -> v2: rename the vops and fix some typos

Kiwoong Kim (2):
  ufs: introduce a quirk to allow only page-aligned sg entries
  ufs: ufs-exynos: use UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE

 drivers/scsi/ufs/ufs-exynos.c | 3 ++-
 drivers/scsi/ufs/ufshcd.c     | 2 ++
 drivers/scsi/ufs/ufshcd.h     | 4 ++++
 3 files changed, 8 insertions(+), 1 deletion(-)

-- 
2.7.4

[ PATCH v6 1/2] ufs: introduce a quirk to allow only page-aligned sg entries

[Kiwoong Kim]

Some SoCs could require one scatterlist entry for smaller than
page size, i.e. 4KB. For the cases of dispatching commands
with more than one scatterlist entry and under 4KB size,
They could behave as follows:

Given that a command to read something
from device is dispatched with two scatterlist entries that
are named AAA and BBB. After dispatching, host builds two PRDT
entries and during transmission, device sends just one DATA IN
because device doesn't care on host dma. The host then tranfers
the whole data from start address of the area named AAA.
In consequence, the area that follows AAA would be corrupted.

    |<------------->|
    +-------+------------         +-------+
    +  AAA  + (corrupted)   ...   +  BBB  +
    +-------+------------         +-------+

In this case, you need to force an aligment with page size for
sg entries.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/ufshcd.c | 2 ++
 drivers/scsi/ufs/ufshcd.h | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add..847eb02 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4792,6 +4792,8 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 	struct request_queue *q = sdev->request_queue;
 
 	blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1);
+	if (hba->quirks & UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE)
+		blk_queue_update_dma_alignment(q, PAGE_SIZE - 1);
 
 	if (ufshcd_is_rpm_autosuspend_allowed(hba))
 		sdev->rpm_autosuspend = 1;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 9bb5f0e..9e7223f 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -549,6 +549,10 @@ enum ufshcd_quirks {
 	 */
 	UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL		= 1 << 12,
 
+	/*
+	 * This quirk allows only sg entries aligned with page size.
+	 */
+	UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE		= 1 << 13,
 };
 
 enum ufshcd_caps {
-- 
2.7.4

[ PATCH v6 2/2] ufs: ufs-exynos: use UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE

[Kiwoong Kim]

Exynos needs alignment with page size because it isn't capable
to transfer data in one DATA IN to seversal areas.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/scsi/ufs/ufs-exynos.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
index a8770ff..d1f0031 100644
--- a/drivers/scsi/ufs/ufs-exynos.c
+++ b/drivers/scsi/ufs/ufs-exynos.c
@@ -1236,7 +1236,8 @@ struct exynos_ufs_drv_data exynos_ufs_drvs = {
 				  UFSHCI_QUIRK_BROKEN_HCE |
 				  UFSHCI_QUIRK_SKIP_RESET_INTR_AGGR |
 				  UFSHCD_QUIRK_BROKEN_OCS_FATAL_ERROR |
-				  UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL,
+				  UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL |
+				  UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE,
 	.opts			= EXYNOS_UFS_OPT_HAS_APB_CLK_CTRL |
 				  EXYNOS_UFS_OPT_BROKEN_AUTO_CLK_CTRL |
 				  EXYNOS_UFS_OPT_BROKEN_RX_SEL_IDX |
-- 
2.7.4

RE: [ PATCH v6 0/2] introduce a quirk to allow only page-aligned sg entries

[Kiwoong Kim]

> v5 -> v6: collect received tags


There is a mistake on the part of this commit message.
Sorry, I'll post again.


Thanks.
Kiwoong Kim
> v4 -> v5: collect received tags
> v3 -> v4: fix some typos
> v2 -> v3: rename exynos functions
> v1 -> v2: rename the vops and fix some typos
> 
> Kiwoong Kim (2):
>   ufs: introduce a quirk to allow only page-aligned sg entries
>   ufs: ufs-exynos: use UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE
> 
>  drivers/scsi/ufs/ufs-exynos.c | 3 ++-
>  drivers/scsi/ufs/ufshcd.c     | 2 ++
>  drivers/scsi/ufs/ufshcd.h     | 4 ++++
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> --
> 2.7.4