>-----Original Message----- >From: Bart Van Assche [mailto:bvanassche@xxxxxxx] >Sent: Friday, January 13, 2023 5:12 AM >To: Martin K . Petersen <martin.petersen@xxxxxxxxxx> >Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>; linux-scsi@xxxxxxxxxxxxxxx; Adrian >Hunter <adrian.hunter@xxxxxxxxx>; Alim Akhtar ><alim.akhtar@xxxxxxxxxxx>; Bart Van Assche <bvanassche@xxxxxxx>; Avri >Altman <avri.altman@xxxxxxx>; Kiwoong Kim <kwmad.kim@xxxxxxxxxxx>; >James E.J. Bottomley <jejb@xxxxxxxxxxxxx>; Bean Huo ><beanhuo@xxxxxxxxxx>; Stanley Chu <stanley.chu@xxxxxxxxxxxx>; >Jinyoung Choi <j-young.choi@xxxxxxxxxxx> >Subject: [PATCH v2 3/3] scsi: ufs: Enable DMA clustering > >All UFS host controllers support DMA clustering. Hence enable DMA >clustering. > >Notes: >- The max_segment_size parameter implements the 256 KiB limit for the > PRDT. The dma_boundary parameter represents a boundary that must not > be crossed by DMA scatter/gather lists. I'm not aware of any > restrictions on DMA scatter/gather lists in the UFSHCI specification > other than the 256 KiB limit for the PRDT and the 32-bit address > restriction for controllers that only support 32-bits DMA. The latter > restriction is already handled by ufshcd_set_dma_mask(). >- Without patch "Exynos: Fix the maximum segment size", this patch > breaks support for the Exynos controller. > >The history of the dma_boundary parameter in the UFS driver is as >follows: >* The initial UFS driver did not set the dma_boundary parameter. >* Commit 4dd4130a722f ("scsi: make sure all drivers set the > use_clustering flag") set the .use_clustering flag. >* Commit 4af14d113bcf ("scsi: remove the use_clustering flag") removed > the use_clustering flag and set the dma_boundary parameter instead. > >Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> >Cc: Avri Altman <avri.altman@xxxxxxx> >Cc: Alim Akhtar <alim.akhtar@xxxxxxxxxxx> >Cc: Kiwoong Kim <kwmad.kim@xxxxxxxxxxx> >Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> >--- Reviewed-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx> > drivers/ufs/core/ufshcd.c | 1 - > 1 file changed, 1 deletion(-) > >diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index >5fdbc983ce2e..d28b44a1ffcf 100644 >--- a/drivers/ufs/core/ufshcd.c >+++ b/drivers/ufs/core/ufshcd.c >@@ -8460,7 +8460,6 @@ static struct scsi_host_template >ufshcd_driver_template = { > .max_host_blocked = 1, > .track_queue_depth = 1, > .sdev_groups = ufshcd_driver_groups, >- .dma_boundary = PAGE_SIZE - 1, > .rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS, > }; >
