Commit 86a44f04 authored by Bart Van Assche's avatar Bart Van Assche Committed by Martin K. Petersen
Browse files

scsi: ufs: core: Increase the maximum data buffer size 

Measurements for one particular UFS controller + UFS device show a 25%
higher read bandwidth if the maximum data buffer size is increased from 512
KiB to 1 MiB. Hence increase the maximum size of the data buffer associated
with a single request from SCSI_DEFAULT_MAX_SECTORS (1024) * 512 bytes =
512 KiB to 1 MiB.

Notes:

 - The maximum data buffer size supported by the UFSHCI specification
   is 65535 * 256 KiB or about 16 GiB.

 - The maximum data buffer size for READ(10) commands is 65535 logical
   blocks. To transfer more than 65535 * 4096 bytes = 255 MiB with a single
   SCSI command, the READ(16) command is required. Support for READ(16) is
   optional in the UFS 3.1 and UFS 4.0 standards.

Link: https://lore.kernel.org/r/20220726225232.1362251-1-bvanassche@acm.org


Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Bean Huo <beanhuo@micron.com>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Tested-by: default avatarAvri Altman <avri.altman@wdc.com>
Acked-by: default avatarAvri Altman <avri.altman@wdc.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent f00e0d77

drivers/ufs/core/ufshcd.c

+1 −0
Original line number Diff line number Diff line
@@ -8304,6 +8304,7 @@ static struct scsi_host_template ufshcd_driver_template = { 
	.cmd_per_lun		= UFSHCD_CMD_PER_LUN,

	.can_queue		= UFSHCD_CAN_QUEUE,

	.max_segment_size	= PRDT_DATA_BYTE_COUNT_MAX,

	.max_sectors		= (1 << 20) / SECTOR_SIZE, /* 1 MiB */

	.max_host_blocked	= 1,

	.track_queue_depth	= 1,

	.sdev_groups		= ufshcd_driver_groups,