From eeda47499f01878d60b3db8883fbbafc3c6a2a54 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Tue, 1 Jul 2014 23:00:32 +0900 Subject: [PATCH] ufs: adjust queue settings to PRDT limitations The data byte count field of PRDT indicates the length of data block which is a segment of data transfer for SCSI commands. The value of this field shall have Dword granularity and the the maximum of length is 256KB. This adjusts dma pad mask and max segment size to the above-mentioned PRDT limitations. Signed-off-by: Akinobu Mita Reviewed-by: Subhash Jadavani Tested-by: Dolev Raviv Acked-by: Vinayak Holikatti Signed-off-by: Christoph Hellwig --- drivers/scsi/ufs/ufshcd.c | 15 +++++++++++++++ drivers/scsi/ufs/ufshci.h | 5 +++++ 2 files changed, 20 insertions(+) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index f189e8a..af1bffc 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -2043,6 +2043,20 @@ int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth, int reason) } /** + * ufshcd_slave_configure - adjust SCSI device configurations + * @sdev: pointer to SCSI device + */ +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); + blk_queue_max_segment_size(q, PRDT_DATA_BYTE_COUNT_MAX); + + return 0; +} + +/** * ufshcd_slave_destroy - remove SCSI device configurations * @sdev: pointer to SCSI device */ @@ -3145,6 +3159,7 @@ static struct scsi_host_template ufshcd_driver_template = { .proc_name = UFSHCD, .queuecommand = ufshcd_queuecommand, .slave_alloc = ufshcd_slave_alloc, + .slave_configure = ufshcd_slave_configure, .slave_destroy = ufshcd_slave_destroy, .change_queue_depth = ufshcd_change_queue_depth, .eh_abort_handler = ufshcd_abort, diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h index 9abc7e3..e1b844b 100644 --- a/drivers/scsi/ufs/ufshci.h +++ b/drivers/scsi/ufs/ufshci.h @@ -296,6 +296,11 @@ enum { MASK_OCS = 0x0F, }; +/* The maximum length of the data byte count field in the PRDT is 256KB */ +#define PRDT_DATA_BYTE_COUNT_MAX (256 * 1024) +/* The granularity of the data byte count field in the PRDT is 32-bit */ +#define PRDT_DATA_BYTE_COUNT_PAD 4 + /** * struct ufshcd_sg_entry - UFSHCI PRD Entry * @base_addr: Lower 32bit physical address DW-0 -- 2.7.4