> Exynos requires 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, Exynos behaves 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 consequebnce, the area that follows AAA would be corrupted.
>
> |<------------->|
> +-------+------------ +-------+
> + AAA + (corrupted) ... + BBB +
> +-------+------------ +-------+
>
> Signed-off-by: Kiwoong Kim <kwmad.kim@xxxxxxxxxxx>
> ---
> drivers/scsi/ufs/ufs-exynos.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
> index a8770ff..1fd5265 100644
> --- a/drivers/scsi/ufs/ufs-exynos.c
> +++ b/drivers/scsi/ufs/ufs-exynos.c
> @@ -14,6 +14,7 @@
> #include <linux/of_address.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/blkdev.h>
>
> #include "ufshcd.h"
> #include "ufshcd-pltfrm.h"
> @@ -1193,6 +1194,13 @@ static int exynos_ufs_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> return 0;
> }
>
> +static void exynos_ufs_config_request_queue(struct scsi_device *sdev) {
> + struct request_queue *q = sdev->request_queue;
> +
> + blk_queue_update_dma_alignment(q, PAGE_SIZE - 1); }
> +
> static struct ufs_hba_variant_ops ufs_hba_exynos_ops = {
> .name = "exynos_ufs",
> .init = exynos_ufs_init,
> @@ -1204,6 +1212,7 @@ static struct ufs_hba_variant_ops ufs_hba_exynos_ops
> = {
> .hibern8_notify = exynos_ufs_hibern8_notify,
> .suspend = exynos_ufs_suspend,
> .resume = exynos_ufs_resume,
> + .config_request_queue = exynos_ufs_config_request_queue,
> };
>
> static int exynos_ufs_probe(struct platform_device *pdev)
> --
> 2.7.4
Sorry for bothering all of you posting because of a wrong version of this. Will do again.
Thanks.
Kiwoong Kim
