mtd: nand: don't use read_buf for 8-bit ONFI transfers

Porting below commit from linux-tree, preserving original authorship & commit log
commit bd9c6e99b58255b9de1982711ac9487c9a2f18be
Author:     Brian Norris <computersforpeace@gmail.com>
mtd: nand: don't use read_buf for 8-bit ONFI transfers

  Use a repeated read_byte() instead of read_buf(), since for x16 buswidth
  devices, we need to avoid the upper I/O[16:9] bits. See the following
  commit for reference:

  commit 05f7835975dad6b3b517f9e23415985e648fb875 (from linux-tree)
  Author: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
  Date:   Thu Dec 5 22:22:04 2013 +0100

      mtd: nand: don't use {read,write}_buf for 8-bit transfers

  Now, I think that all barriers to probing ONFI on x16 devices are
  removed, so remove the check from nand_flash_detect_onfi().

Signed-off-by: Pekon Gupta <pekon@ti.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1ce55fde8b7b9191e31f63c773f00a2d10fe3b0e..5d3232c634c60c16fa81c91c22a3ea4db1634fce 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2582,7 +2582,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
                                        int *busw)
 {
        struct nand_onfi_params *p = &chip->onfi_params;
-       int i;
+       int i, j;
        int val;
 
        /* Try ONFI for unknown chip or LP */
@@ -2593,7 +2593,8 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 
        chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
        for (i = 0; i < 3; i++) {
-               chip->read_buf(mtd, (uint8_t *)p, sizeof(*p));
+               for (j = 0; j < sizeof(*p); j++)
+                       ((uint8_t *)p)[j] = chip->read_byte(mtd);
                if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) ==
                                le16_to_cpu(p->crc)) {
                        pr_info("ONFI param page %d valid\n", i);