openwrtv3/target/linux/sunxi/patches-4.1/129-nand-sunxi-fix-write-to-USER_DATA-a13.patch

From b1488f1a55da6a297ac4e8e9140922f35b7583c5 Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Mon, 15 Jun 2015 11:09:58 +0200
Subject: [PATCH] nand: sunxi: fix write to USER_DATA reg

The USER_DATA register cannot be updated with readb on A13 SoCs, thus
triggering a bug when using memcpy_toio on this register.
Use writel (plus a temporary variable to old the USER_DATA value) to
address that problem.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
 drivers/mtd/nand/sunxi_nand.c | 38 +++++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -908,7 +908,7 @@ static int sunxi_nfc_hw_ecc_write_page(s
 
 	for (i = 0; i < ecc->steps; i++) {
 		bool rndactiv = false;
-		u8 oob_buf[4];
+		u32 user_data;
 
 		if (i)
 			chip->cmdfunc(mtd, NAND_CMD_RNDIN, i * ecc->size, -1);
@@ -919,15 +919,13 @@ static int sunxi_nfc_hw_ecc_write_page(s
 		offset = layout->eccpos[i * ecc->bytes] - 4 + mtd->writesize;
 
 		/* Fill OOB data in */
-		if (!oob_required)
-			memset(oob_buf, 0xff, 4);
-		else
-			memcpy(oob_buf,
-			       chip->oob_poi + layout->oobfree[i].offset,
-			       4);
-
-
-		memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, oob_buf, 4);
+		if (!oob_required) {
+			user_data = 0xffffffff;
+		} else {
+			memcpy(&user_data,
+			       chip->oob_poi + layout->oobfree[i].offset, 4);
+			user_data = le32_to_cpu(user_data);
+		}
 
 		if (i) {
 			cnt = ecc->bytes + 4;
@@ -946,12 +944,16 @@ static int sunxi_nfc_hw_ecc_write_page(s
 		if (rndactiv) {
 			/* pre randomize to generate FF patterns on the NAND */
 			if (!i) {
+				u8 oob_tmp[2];
 				u16 state = rnd->subseeds[rnd->page % rnd->nseeds];
+				oob_tmp[0] = user_data;
+				oob_tmp[1] = user_data >> 8;
 				state = sunxi_nfc_hwrnd_single_step(state, 15);
-				oob_buf[0] ^= state;
+				oob_tmp[0] ^= state;
 				state = sunxi_nfc_hwrnd_step(rnd, state, 1);
-				oob_buf[1] ^= state;
-				memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, oob_buf, 4);
+				oob_tmp[1] ^= state;
+				user_data &= ~0xffff;
+				user_data |= oob_tmp[0] | (oob_tmp[1] << 8);
 			}
 			tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
 			tmp &= ~(NFC_RANDOM_DIRECTION | NFC_ECC_EXCEPTION);
@@ -959,6 +961,8 @@ static int sunxi_nfc_hw_ecc_write_page(s
 			writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
 		}
 
+		writel(user_data, nfc->regs + NFC_REG_USER_DATA_BASE);
+
 		chip->cmdfunc(mtd, NAND_CMD_RNDIN, offset, -1);
 
 		ret = sunxi_nfc_wait_cmd_fifo_empty(nfc);