From: Bart Van Assche <bvanassche@acm.org>
Date: Wed, 20 Oct 2021 14:40:24 -0700
Subject: [PATCH] scsi: ufs: core: Micro-optimize ufshcd_map_sg()
Git-commit: 1ea7d8026300f72344bb574a12667f9543f73348
Patch-mainline: v5.16-rc1
References: jsc#PED-818
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>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/ufs/ufshcd.c | 19 +++++++++++++------
drivers/scsi/ufs/ufshci.h | 6 ++----
2 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index dde4d3f607f2..04cb67995750 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -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 {
diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h
index f66cf9e477cb..6a295c88d850 100644
--- a/drivers/scsi/ufs/ufshci.h
+++ b/drivers/scsi/ufs/ufshci.h
@@ -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;
};
--
2.35.3