From: Stefan Agner <stefan@agner.ch>
Date: Fri, 8 May 2015 17:07:06 +0000 (+0200)
Subject: mtd: vf610_nfc: remove caching of page in buffer
X-Git-Tag: v2015.07-rc2~99^2~7
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f55bc296a88c0a9d71ad363b89b54975d2aab14f;p=platform%2Fkernel%2Fu-boot.git

mtd: vf610_nfc: remove caching of page in buffer

To improve performance we remember the current page in the buffer
and avoid reading it twice. This implicit page cache increases
complexity while does not increase performance in real world cases.
This patch removes that feature.

Acked-by: Bill Pringlemeir <bpringlemeir@nbsps.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
---

diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
index d98dd28800..fa0bb9dcaf 100644
--- a/drivers/mtd/nand/vf610_nfc.c
+++ b/drivers/mtd/nand/vf610_nfc.c
@@ -147,7 +147,6 @@ struct vf610_nfc {
 	uint               column;
 	int                spareonly;
 	int		   page_sz;
-	int                page;
 	/* Status and ID are in alternate locations. */
 	int                alt_buf;
 #define ALT_BUF_ID   1
@@ -347,7 +346,6 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
 
 	switch (command) {
 	case NAND_CMD_PAGEPROG:
-		nfc->page = -1;
 		vf610_nfc_transfer_size(nfc->regs, nfc->page_sz);
 		vf610_nfc_send_commands(nfc->regs, NAND_CMD_SEQIN,
 					command, PROGRAM_PAGE_CMD_CODE);
@@ -367,10 +365,6 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
 	case NAND_CMD_SEQIN: /* Pre-read for partial writes. */
 	case NAND_CMD_READ0:
 		column = 0;
-		/* Already read? */
-		if (nfc->page == page)
-			return;
-		nfc->page = page;
 		vf610_nfc_transfer_size(nfc->regs, nfc->page_sz);
 		vf610_nfc_send_commands(nfc->regs, NAND_CMD_READ0,
 					NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
@@ -378,7 +372,6 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
 		break;
 
 	case NAND_CMD_ERASE1:
-		nfc->page = -1;
 		vf610_nfc_transfer_size(nfc->regs, 0);
 		vf610_nfc_send_commands(nfc->regs, command,
 					NAND_CMD_ERASE2, ERASE_CMD_CODE);
@@ -532,10 +525,8 @@ static inline int vf610_nfc_correct_data(struct mtd_info *mtd, u_char *dat)
 	flip = count_written_bits(dat, nfc->chip.ecc.size, ecc_count);
 
 	/* ECC failed. */
-	if (flip > ecc_count) {
-		nfc->page = -1;
+	if (flip > ecc_count)
 		return -1;
-	}
 
 	/* Erased page. */
 	memset(dat, 0xff, nfc->chip.ecc.size);