[RFC PATCH] mtd: rawnand: mtk: return errors when reset does not idle

[Pengpeng Hou]

mtk_nfc_hw_reset() waits for the NFI master to become idle after forcing a
reset, but it only logs a warning when the wait times out.  Probe-time
hardware init and later exec_op() calls then continue as if the reset had
completed.

Make the reset helper return the poll error and propagate it through both
initial hardware setup and NAND operation execution.  Keep the final reset
writes so status registers affected by the NFI master are still forced
back to the reset state before the error is returned.

This is marked RFC because the existing code only warns about the idle
timeout and then performs the final reset writes.  Maintainer feedback is
needed on whether this timeout should be treated as fatal or as a
recoverable reset condition on affected hardware.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/mtd/nand/raw/mtk_nand.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c
index 21c7e1102..059b8070f 100644
--- a/drivers/mtd/nand/raw/mtk_nand.c
+++ b/drivers/mtd/nand/raw/mtk_nand.c
@@ -255,7 +255,7 @@ static inline u8 nfi_readb(struct mtk_nfc *nfc, u32 reg)
 	return readb_relaxed(nfc->regs + reg);
 }
 
-static void mtk_nfc_hw_reset(struct mtk_nfc *nfc)
+static int mtk_nfc_hw_reset(struct mtk_nfc *nfc)
 {
 	struct device *dev = nfc->dev;
 	u32 val;
@@ -269,12 +269,14 @@ static void mtk_nfc_hw_reset(struct mtk_nfc *nfc)
 				 !(val & MASTER_STA_MASK), 50,
 				 MTK_RESET_TIMEOUT);
 	if (ret)
-		dev_warn(dev, "master active in reset [0x%x] = 0x%x\n",
-			 NFI_MASTER_STA, val);
+		dev_err(dev, "master active in reset [0x%x] = 0x%x\n",
+			NFI_MASTER_STA, val);
 
 	/* ensure any status register affected by the NFI master is reset */
 	nfi_writel(nfc, CON_FIFO_FLUSH | CON_NFI_RST, NFI_CON);
 	nfi_writew(nfc, STAR_DE, NFI_STRDATA);
+
+	return ret;
 }
 
 static int mtk_nfc_send_command(struct mtk_nfc *nfc, u8 command)
@@ -517,7 +519,10 @@ static int mtk_nfc_exec_op(struct nand_chip *chip,
 	if (check_only)
 		return 0;
 
-	mtk_nfc_hw_reset(nfc);
+	ret = mtk_nfc_hw_reset(nfc);
+	if (ret)
+		return ret;
+
 	nfi_writew(nfc, CNFG_OP_CUST, NFI_CNFG);
 	mtk_nfc_select_target(chip, op->cs);
 
@@ -1084,8 +1089,10 @@ static int mtk_nfc_read_oob_std(struct nand_chip *chip, int page)
 	return mtk_nfc_read_page_raw(chip, NULL, 1, page);
 }
 
-static inline void mtk_nfc_hw_init(struct mtk_nfc *nfc)
+static int mtk_nfc_hw_init(struct mtk_nfc *nfc)
 {
+	int ret;
+
 	/*
 	 * CNRNB: nand ready/busy register
 	 * -------------------------------
@@ -1095,10 +1102,14 @@ static inline void mtk_nfc_hw_init(struct mtk_nfc *nfc)
 	nfi_writew(nfc, 0xf1, NFI_CNRNB);
 	nfi_writel(nfc, PAGEFMT_8K_16K, NFI_PAGEFMT);
 
-	mtk_nfc_hw_reset(nfc);
+	ret = mtk_nfc_hw_reset(nfc);
+	if (ret)
+		return ret;
 
 	nfi_readl(nfc, NFI_INTR_STA);
 	nfi_writel(nfc, 0, NFI_INTR_EN);
+
+	return 0;
 }
 
 static irqreturn_t mtk_nfc_irq(int irq, void *id)
@@ -1411,7 +1422,9 @@ static int mtk_nfc_nand_chip_init(struct device *dev, struct mtk_nfc *nfc,
 	mtd->name = MTK_NAME;
 	mtd_set_ooblayout(mtd, &mtk_nfc_ooblayout_ops);
 
-	mtk_nfc_hw_init(nfc);
+	ret = mtk_nfc_hw_init(nfc);
+	if (ret)
+		return ret;
 
 	ret = nand_scan(nand, nsels);
 	if (ret)
-- 
2.50.1 (Apple Git-155)