Commit eeda4749 authored by Akinobu Mita's avatar Akinobu Mita Committed by Christoph Hellwig
Browse files

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: default avatarAkinobu Mita <mita@fixstars.com>
Reviewed-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
Tested-by: default avatarDolev Raviv <draviv@codeaurora.org>
Acked-by: default avatarVinayak Holikatti <vinholikatti@gmail.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent b2a6c522

drivers/scsi/ufs/ufshcd.c

+15 −0
Original line number Diff line number Diff line
@@ -2042,6 +2042,20 @@ int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth, int reason) 
	return depth;

}



/**

 * 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,

drivers/scsi/ufs/ufshci.h

+5 −0
Original line number Diff line number Diff line
@@ -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

CRA Git | Maintained and supported by SUSTech CRA and CCSE