mtd: sh_flctl: Group sector accesses into a single transfer

When we use hardware ecc, the flctl is run in so-called "sector access
mode". We can bundle 4 sector accesses when using 2KiB page sizes to read
a whole page at once and speed up things.
Signed-off-by: NBastian Hecht <hechtb@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/sh_flctl.c

@@ -368,25 +368,21 @@ static void execmd_read_page_sector(struct mtd_info *mtd, int page_addr)
 	struct sh_flctl *flctl = mtd_to_flctl(mtd);
 	int sector, page_sectors;
 
-	if (flctl->page_size)
-		page_sectors = 4;
-	else
-		page_sectors = 1;
-
-	writel(readl(FLCMNCR(flctl)) | ACM_SACCES_MODE | _4ECCCORRECT,
-		 FLCMNCR(flctl));
+	page_sectors = flctl->page_size ? 4 : 1;
 
 	set_cmd_regs(mtd, NAND_CMD_READ0,
 		(NAND_CMD_READSTART << 8) | NAND_CMD_READ0);
 
-	for (sector = 0; sector < page_sectors; sector++) {
-		int ret;
+	writel(readl(FLCMNCR(flctl)) | ACM_SACCES_MODE | _4ECCCORRECT,
+		 FLCMNCR(flctl));
+	writel(readl(FLCMDCR(flctl)) | page_sectors, FLCMDCR(flctl));
+	writel(page_addr << 2, FLADR(flctl));
 
 	empty_fifo(flctl);
-		writel(readl(FLCMDCR(flctl)) | 1, FLCMDCR(flctl));
-		writel(page_addr << 2 | sector, FLADR(flctl));
-
 	start_translation(flctl);
+
+	for (sector = 0; sector < page_sectors; sector++) {
+		int ret;
 		read_fiforeg(flctl, 512, 512 * sector);
 
 		ret = read_ecfiforeg(flctl,
@@ -397,8 +393,10 @@ static void execmd_read_page_sector(struct mtd_info *mtd, int page_addr)
 			flctl->hwecc_cant_correct[sector] = 1;
 
 		writel(0x0, FL4ECCCR(flctl));
-		wait_completion(flctl);
 	}
+
+	wait_completion(flctl);
+
 	writel(readl(FLCMNCR(flctl)) & ~(ACM_SACCES_MODE | _4ECCCORRECT),
 			FLCMNCR(flctl));
 }
@@ -430,31 +428,27 @@ static void execmd_write_page_sector(struct mtd_info *mtd)
 	int i, page_addr = flctl->seqin_page_addr;
 	int sector, page_sectors;
 
-	if (flctl->page_size)
-		page_sectors = 4;
-	else
-		page_sectors = 1;
-
-	writel(readl(FLCMNCR(flctl)) | ACM_SACCES_MODE, FLCMNCR(flctl));
+	page_sectors = flctl->page_size ? 4 : 1;
 
 	set_cmd_regs(mtd, NAND_CMD_PAGEPROG,
 			(NAND_CMD_PAGEPROG << 8) | NAND_CMD_SEQIN);
 
-	for (sector = 0; sector < page_sectors; sector++) {
 	empty_fifo(flctl);
-		writel(readl(FLCMDCR(flctl)) | 1, FLCMDCR(flctl));
-		writel(page_addr << 2 | sector, FLADR(flctl));
-
+	writel(readl(FLCMNCR(flctl)) | ACM_SACCES_MODE, FLCMNCR(flctl));
+	writel(readl(FLCMDCR(flctl)) | page_sectors, FLCMDCR(flctl));
+	writel(page_addr << 2, FLADR(flctl));
 	start_translation(flctl);
+
+	for (sector = 0; sector < page_sectors; sector++) {
 		write_fiforeg(flctl, 512, 512 * sector);
 
 		for (i = 0; i < 4; i++) {
 			wait_wecfifo_ready(flctl); /* wait for write ready */
 			writel(0xFFFFFFFF, FLECFIFO(flctl));
 		}
-		wait_completion(flctl);
 	}
 
+	wait_completion(flctl);
 	writel(readl(FLCMNCR(flctl)) & ~ACM_SACCES_MODE, FLCMNCR(flctl));
 }