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scsi: ufs: core: Micro-optimize ufshcd_map_sg()

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Replace two cpu_to_le32() calls by a single cpu_to_le64() call.

Additionally, issue a warning if the length of an scatter gather list
element exceeds what is allowed by the UFSHCI specification.

Link: https://lore.kernel.org/r/20211020214024.2007615-11-bvanassche@acm.org
Acked-by: Avri Altman <Avri.Altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2021-10-20 14:40:24 -07:00 committed by Martin K. Petersen
parent 9a868c8ad3
commit 1ea7d80263
2 changed files with 15 additions and 10 deletions
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19
drivers/scsi/ufs/ufshcd.c
View File

@ -2379,12 +2379,19 @@ static int ufshcd_map_sg(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
prd_table = lrbp->ucd_prdt_ptr;
scsi_for_each_sg(cmd, sg, sg_segments, i) {
prd_table[i].size =
cpu_to_le32(((u32) sg_dma_len(sg))-1);
prd_table[i].base_addr =
cpu_to_le32(lower_32_bits(sg->dma_address));
prd_table[i].upper_addr =
cpu_to_le32(upper_32_bits(sg->dma_address));
const unsigned int len = sg_dma_len(sg);
/*
* From the UFSHCI spec: "Data Byte Count (DBC): A '0'
* based value that indicates the length, in bytes, of
* the data block. A maximum of length of 256KB may
* exist for any entry. Bits 1:0 of this field shall be
* 11b to indicate Dword granularity. A value of '3'
* indicates 4 bytes, '7' indicates 8 bytes, etc."
*/
WARN_ONCE(len > 256 * 1024, "len = %#x\n", len);
prd_table[i].size = cpu_to_le32(len - 1);
prd_table[i].addr = cpu_to_le64(sg->dma_address);
prd_table[i].reserved = 0;
}
} else {

6
drivers/scsi/ufs/ufshci.h
View File

@ -415,14 +415,12 @@ enum {
/**
* struct ufshcd_sg_entry - UFSHCI PRD Entry
* @base_addr: Lower 32bit physical address DW-0
* @upper_addr: Upper 32bit physical address DW-1
* @addr: Physical address; DW-0 and DW-1.
* @reserved: Reserved for future use DW-2
* @size: size of physical segment DW-3
*/
struct ufshcd_sg_entry {
__le32 base_addr;
__le32 upper_addr;
__le64 addr;
__le32 reserved;
__le32 size;
};