[PATCH v2 1/5] mtd: rawnand: meson: fix NAND access for read/write

[Arseniy Krasnov]

This fixes read/write functionality. New command sequences were ported
from old vendor's driver. Without this patch driver works unstable. This
change is tested with 'nanddump'/'nandwrite' utilities and mounting
JFFS2 filesystem on AXG family (A113X SoC).

Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Signed-off-by: Arseniy Krasnov <AVKrasnov at sberdevices.ru>
---
 drivers/mtd/nand/raw/meson_nand.c | 116 ++++++++++++++++++++++++++----
 1 file changed, 101 insertions(+), 15 deletions(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 074e14225c06..e828ce3809a9 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -26,6 +26,7 @@
 #define NFC_CMD_IDLE		(0xc << 14)
 #define NFC_CMD_CLE		(0x5 << 14)
 #define NFC_CMD_ALE		(0x6 << 14)
+#define NFC_CMD_DRD		(0x8 << 14)
 #define NFC_CMD_ADL		((0 << 16) | (3 << 20))
 #define NFC_CMD_ADH		((1 << 16) | (3 << 20))
 #define NFC_CMD_AIL		((2 << 16) | (3 << 20))
@@ -84,6 +85,7 @@
 
 #define DMA_BUSY_TIMEOUT	0x100000
 #define CMD_FIFO_EMPTY_TIMEOUT	1000
+#define DEVICE_READY_TIMEOUT	1000
 
 #define MAX_CE_NUM		2
 
@@ -255,8 +257,26 @@ static void meson_nfc_select_chip(struct nand_chip *nand, int chip)
 	}
 }
 
+static int meson_nfc_wait_cmd_finish(struct meson_nfc *nfc,
+				     unsigned int timeout_ms)
+{
+	u32 cmd_size = 0;
+	int ret;
+
+	/* wait cmd fifo is empty */
+	ret = readl_relaxed_poll_timeout(nfc->reg_base + NFC_REG_CMD, cmd_size,
+					 !NFC_CMD_GET_SIZE(cmd_size),
+					 10, timeout_ms * USEC_PER_MSEC);
+	if (ret)
+		dev_err(nfc->dev, "wait for empty CMD FIFO timed out\n");
+
+	return ret;
+}
+
 static void meson_nfc_cmd_idle(struct meson_nfc *nfc, u32 time)
 {
+	meson_nfc_wait_cmd_finish(nfc, 0);
+
 	writel(nfc->param.chip_select | NFC_CMD_IDLE | (time & 0x3ff),
 	       nfc->reg_base + NFC_REG_CMD);
 }
@@ -308,23 +328,9 @@ static void meson_nfc_drain_cmd(struct meson_nfc *nfc)
 	 */
 	meson_nfc_cmd_idle(nfc, 0);
 	meson_nfc_cmd_idle(nfc, 0);
+	meson_nfc_wait_cmd_finish(nfc, 1 * MSEC_PER_SEC);
 }
 
-static int meson_nfc_wait_cmd_finish(struct meson_nfc *nfc,
-				     unsigned int timeout_ms)
-{
-	u32 cmd_size = 0;
-	int ret;
-
-	/* wait cmd fifo is empty */
-	ret = readl_relaxed_poll_timeout(nfc->reg_base + NFC_REG_CMD, cmd_size,
-					 !NFC_CMD_GET_SIZE(cmd_size),
-					 10, timeout_ms * 1000);
-	if (ret)
-		dev_err(nfc->dev, "wait for empty CMD FIFO time out\n");
-
-	return ret;
-}
 
 static int meson_nfc_wait_dma_finish(struct meson_nfc *nfc)
 {
@@ -631,6 +637,48 @@ static int meson_nfc_rw_cmd_prepare_and_execute(struct nand_chip *nand,
 	return 0;
 }
 
+static uint8_t meson_nfc_read_byte(struct nand_chip *nand)
+{
+	struct meson_nfc *nfc = nand_get_controller_data(nand);
+
+	writel(NFC_CMD_DRD, nfc->reg_base + NFC_REG_CMD);
+	meson_nfc_cmd_idle(nfc, nfc->timing.twb);
+	meson_nfc_drain_cmd(nfc);
+
+	return readl(nfc->reg_base + NFC_REG_BUF);
+}
+
+static int meson_nfc_wait_dev_ready(struct nand_chip *nand)
+{
+	struct meson_nfc *nfc = nand_get_controller_data(nand);
+	u32 cs = nfc->param.chip_select;
+	unsigned long cnt = 0;
+
+	meson_nfc_drain_cmd(nfc);
+
+	writel(cs | NFC_CMD_CLE | NAND_CMD_STATUS, nfc->reg_base + NFC_REG_CMD);
+
+	/* 10 ms. */
+	while (cnt < DEVICE_READY_TIMEOUT) {
+		uint8_t status;
+
+		status = meson_nfc_read_byte(nand);
+
+		if (status & NAND_STATUS_READY)
+			break;
+
+		usleep_range(10, 11);
+		cnt++;
+	}
+
+	if (cnt == DEVICE_READY_TIMEOUT) {
+		dev_err(nfc->dev, "device ready timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
 static int meson_nfc_write_page_sub(struct nand_chip *nand,
 				    int page, int raw)
 {
@@ -643,6 +691,10 @@ static int meson_nfc_write_page_sub(struct nand_chip *nand,
 	u32 cmd;
 	int ret;
 
+	ret = meson_nfc_wait_dev_ready(nand);
+	if (ret)
+		return ret;
+
 	meson_nfc_select_chip(nand, nand->cur_cs);
 
 	data_len =  mtd->writesize + mtd->oobsize;
@@ -667,12 +719,20 @@ static int meson_nfc_write_page_sub(struct nand_chip *nand,
 				     NFC_CMD_SCRAMBLER_DISABLE);
 	}
 
+	ret = meson_nfc_wait_dma_finish(nfc);
+	if (ret)
+		return ret;
+
 	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_dma_buffer_release(nand, data_len, info_len, DMA_TO_DEVICE);
 
+	ret = meson_nfc_wait_dev_ready(nand);
+	if (ret)
+		return ret;
+
 	return ret;
 }
 
@@ -720,6 +780,21 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
 	} while (!ret);
 }
 
+static inline int meson_nfc_send_read(struct nand_chip *nand)
+{
+	struct meson_nfc *nfc = nand_get_controller_data(nand);
+	u32 cs = nfc->param.chip_select;
+	int ret;
+
+	ret = meson_nfc_wait_dev_ready(nand);
+	if (ret)
+		return ret;
+
+	writel(cs | NFC_CMD_CLE | NAND_CMD_READ0, nfc->reg_base + NFC_REG_CMD);
+
+	return 0;
+}
+
 static int meson_nfc_read_page_sub(struct nand_chip *nand,
 				   int page, int raw)
 {
@@ -734,10 +809,18 @@ static int meson_nfc_read_page_sub(struct nand_chip *nand,
 	data_len =  mtd->writesize + mtd->oobsize;
 	info_len = nand->ecc.steps * PER_INFO_BYTE;
 
+	ret = meson_nfc_wait_dev_ready(nand);
+	if (ret)
+		return ret;
+
 	ret = meson_nfc_rw_cmd_prepare_and_execute(nand, page, DIRREAD);
 	if (ret)
 		return ret;
 
+	ret = meson_nfc_send_read(nand);
+	if (ret)
+		return ret;
+
 	ret = meson_nfc_dma_buffer_setup(nand, meson_chip->data_buf,
 					 data_len, meson_chip->info_buf,
 					 info_len, DMA_FROM_DEVICE);
@@ -754,6 +837,9 @@ static int meson_nfc_read_page_sub(struct nand_chip *nand,
 	}
 
 	ret = meson_nfc_wait_dma_finish(nfc);
+	if (ret)
+		return ret;
+
 	meson_nfc_check_ecc_pages_valid(nfc, nand, raw);
 
 	meson_nfc_dma_buffer_release(nand, data_len, info_len, DMA_FROM_DEVICE);
-- 
2.35.0