[PATCH v4 1/5] mtd: rawnand: meson: fix command sequence for read/write

[Arseniy Krasnov]

This fixes read/write functionality by:
1) Changing NFC_CMD_RB_INT bit value.
2) Adding extra NAND_CMD_STATUS command on each r/w request.
3) Adding extra idle commands during r/w request.
4) Adding extra NAND_CMD_READ0 on each read request.

Without this patch driver works unstable, for example there are a lot
of ECC errors.

Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Suggested-by: Liang Yang <liang.yang@xxxxxxxxxxx>
Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
---
 drivers/mtd/nand/raw/meson_nand.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 074e14225c06..2f4d8c84186b 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -37,7 +37,7 @@
 #define NFC_CMD_SCRAMBLER_ENABLE	BIT(19)
 #define NFC_CMD_SCRAMBLER_DISABLE	0
 #define NFC_CMD_SHORTMODE_DISABLE	0
-#define NFC_CMD_RB_INT		BIT(14)
+#define NFC_CMD_RB_INT ((0xb << 10) | BIT(18) | BIT(16))
 
 #define NFC_CMD_GET_SIZE(x)	(((x) >> 22) & GENMASK(4, 0))
 
@@ -392,7 +392,7 @@ static void meson_nfc_set_data_oob(struct nand_chip *nand,
 	}
 }
 
-static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
+static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms, int cmd_read0)
 {
 	u32 cmd, cfg;
 	int ret = 0;
@@ -407,17 +407,29 @@ static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
 
 	reinit_completion(&nfc->completion);
 
+	cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_STATUS;
+	writel(cmd, nfc->reg_base + NFC_REG_CMD);
+	meson_nfc_cmd_idle(nfc, 5);
+
 	/* use the max erase time as the maximum clock for waiting R/B */
-	cmd = NFC_CMD_RB | NFC_CMD_RB_INT
-		| nfc->param.chip_select | nfc->timing.tbers_max;
+	cmd = NFC_CMD_RB | NFC_CMD_RB_INT | nfc->timing.tbers_max;
 	writel(cmd, nfc->reg_base + NFC_REG_CMD);
+	meson_nfc_cmd_idle(nfc, 2);
 
 	ret = wait_for_completion_timeout(&nfc->completion,
 					  msecs_to_jiffies(timeout_ms));
 	if (ret == 0)
-		ret = -1;
+		return -1;
 
-	return ret;
+	if (!cmd_read0)
+		return 0;
+
+	cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_READ0;
+	writel(cmd, nfc->reg_base + NFC_REG_CMD);
+	meson_nfc_drain_cmd(nfc);
+	meson_nfc_wait_cmd_finish(nfc, CMD_FIFO_EMPTY_TIMEOUT);
+
+	return 0;
 }
 
 static void meson_nfc_set_user_byte(struct nand_chip *nand, u8 *oob_buf)
@@ -623,7 +635,7 @@ static int meson_nfc_rw_cmd_prepare_and_execute(struct nand_chip *nand,
 	if (in) {
 		nfc->cmdfifo.rw.cmd1 = cs | NFC_CMD_CLE | NAND_CMD_READSTART;
 		writel(nfc->cmdfifo.rw.cmd1, nfc->reg_base + NFC_REG_CMD);
-		meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tR_max));
+		meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tR_max), 1);
 	} else {
 		meson_nfc_cmd_idle(nfc, nfc->timing.tadl);
 	}
@@ -669,7 +681,7 @@ static int meson_nfc_write_page_sub(struct nand_chip *nand,
 
 	cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_PAGEPROG;
 	writel(cmd, nfc->reg_base + NFC_REG_CMD);
-	meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tPROG_max));
+	meson_nfc_queue_rb(nfc, PSEC_TO_MSEC(sdr->tPROG_max), 0);
 
 	meson_nfc_dma_buffer_release(nand, data_len, info_len, DMA_TO_DEVICE);
 
@@ -952,7 +964,7 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
 			break;
 
 		case NAND_OP_WAITRDY_INSTR:
-			meson_nfc_queue_rb(nfc, instr->ctx.waitrdy.timeout_ms);
+			meson_nfc_queue_rb(nfc, instr->ctx.waitrdy.timeout_ms, 1);
 			if (instr->delay_ns)
 				meson_nfc_cmd_idle(nfc, delay_idle);
 			break;
-- 
2.35.0