[PATCH 0/4] mtd: rawnand: au1550nd: Convert the driver to exec_op()

[PATCH 0/4] mtd: rawnand: au1550nd: Convert the driver to exec_op()

[Boris Brezillon]

Hello,

An attempt at converting the au1550nd to exec_op(). The patchset it only
compile-tested, so that'd be great to have someone with a db1550 to test
it. If there's no one owning such a board, maybe we should consider
removing it, as such ancient drivers make the NAND subsystem maintenance
harder.

Regards,

Boris

Boris Brezillon (4):
  mtd: rawnand: au1550nd: Stop using IO_ADDR_{R,W} in
    au_{read,write}_buf[16]()
  mtd: rawnand: au1550nd: Implement exec_op()
  mtd: rawnand: au1550nd: Get rid of the legacy interface implementation
  mtd: rawnand: au1550nd: Patch the read/write buf helper prototypes

 drivers/mtd/nand/raw/au1550nd.c | 410 +++++++++++---------------------
 1 file changed, 135 insertions(+), 275 deletions(-)

-- 
2.25.2

[PATCH 1/4] mtd: rawnand: au1550nd: Stop using IO_ADDR_{R,W} in au_{read,write}_buf[16]()

[Boris Brezillon]

We are about to re-use those for the exec_op() implementation which
will not rely on au1550_hwcontrol(). Let's patch those helpers to
simply use the iomem address stored in the context.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/mtd/nand/raw/au1550nd.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/raw/au1550nd.c b/drivers/mtd/nand/raw/au1550nd.c
index 75eb3e97fae3..2f8004f20349 100644
--- a/drivers/mtd/nand/raw/au1550nd.c
+++ b/drivers/mtd/nand/raw/au1550nd.c
@@ -23,6 +23,11 @@ struct au1550nd_ctx {
 	void (*write_byte)(struct nand_chip *, u_char);
 };
 
+static struct au1550nd_ctx *chip_to_au_ctx(struct nand_chip *this)
+{
+	return container_of(this, struct au1550nd_ctx, chip);
+}
+
 /**
  * au_read_byte -  read one byte from the chip
  * @this:	NAND chip object
@@ -85,10 +90,11 @@ static void au_write_byte16(struct nand_chip *this, u_char byte)
  */
 static void au_write_buf(struct nand_chip *this, const u_char *buf, int len)
 {
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
 	int i;
 
 	for (i = 0; i < len; i++) {
-		writeb(buf[i], this->legacy.IO_ADDR_W);
+		writeb(buf[i], ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 }
@@ -103,10 +109,11 @@ static void au_write_buf(struct nand_chip *this, const u_char *buf, int len)
  */
 static void au_read_buf(struct nand_chip *this, u_char *buf, int len)
 {
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
 	int i;
 
 	for (i = 0; i < len; i++) {
-		buf[i] = readb(this->legacy.IO_ADDR_R);
+		buf[i] = readb(ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 }
@@ -121,12 +128,13 @@ static void au_read_buf(struct nand_chip *this, u_char *buf, int len)
  */
 static void au_write_buf16(struct nand_chip *this, const u_char *buf, int len)
 {
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
 	int i;
 	u16 *p = (u16 *) buf;
 	len >>= 1;
 
 	for (i = 0; i < len; i++) {
-		writew(p[i], this->legacy.IO_ADDR_W);
+		writew(p[i], ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 
@@ -142,12 +150,13 @@ static void au_write_buf16(struct nand_chip *this, const u_char *buf, int len)
  */
 static void au_read_buf16(struct nand_chip *this, u_char *buf, int len)
 {
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
 	int i;
 	u16 *p = (u16 *) buf;
 	len >>= 1;
 
 	for (i = 0; i < len; i++) {
-		p[i] = readw(this->legacy.IO_ADDR_R);
+		p[i] = readw(ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 }
-- 
2.25.2

Re: [PATCH 1/4] mtd: rawnand: au1550nd: Stop using IO_ADDR_{R,W} in au_{read,write}_buf[16]()

[Miquel Raynal]

Hi Boris,

Boris Brezillon <boris.brezillon@collabora.com> wrote on Sun, 19 Apr
2020 21:30:34 +0200:

> We are about to re-use those for the exec_op() implementation which
> will not rely on au1550_hwcontrol(). Let's patch those helpers to
> simply use the iomem address stored in the context.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miquèl

Re: [PATCH 1/4] mtd: rawnand: au1550nd: Stop using IO_ADDR_{R, W} in au_{read, write}_buf[16]()

[Miquel Raynal]

On Sun, 2020-04-19 at 19:30:34 UTC, Boris Brezillon wrote:
> We are about to re-use those for the exec_op() implementation which
> will not rely on au1550_hwcontrol(). Let's patch those helpers to
> simply use the iomem address stored in the context.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel

[PATCH 2/4] mtd: rawnand: au1550nd: Implement exec_op()

[Boris Brezillon]

So we can later get rid of the legacy interface implementation.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/mtd/nand/raw/au1550nd.c | 110 ++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)

diff --git a/drivers/mtd/nand/raw/au1550nd.c b/drivers/mtd/nand/raw/au1550nd.c
index 2f8004f20349..79bf9fbeeb22 100644
--- a/drivers/mtd/nand/raw/au1550nd.c
+++ b/drivers/mtd/nand/raw/au1550nd.c
@@ -16,6 +16,7 @@
 
 
 struct au1550nd_ctx {
+	struct nand_controller controller;
 	struct nand_chip chip;
 
 	int cs;
@@ -382,6 +383,112 @@ static int find_nand_cs(unsigned long nand_base)
 	return -ENODEV;
 }
 
+static int au1550nd_waitrdy(struct nand_chip *this, unsigned int timeout_ms)
+{
+	unsigned long timeout_jiffies = jiffies;
+
+	timeout_jiffies += msecs_to_jiffies(timeout_ms) + 1;
+	do {
+		if (alchemy_rdsmem(AU1000_MEM_STSTAT) & 0x1)
+			return 0;
+
+		usleep_range(10, 100);
+	} while (time_before(jiffies, timeout_jiffies));
+
+	return -ETIMEDOUT;
+}
+
+static int au1550nd_exec_instr(struct nand_chip *this,
+			       const struct nand_op_instr *instr)
+{
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
+	unsigned int i;
+	int ret = 0;
+
+	switch (instr->type) {
+	case NAND_OP_CMD_INSTR:
+		writeb(instr->ctx.cmd.opcode,
+		       ctx->base + MEM_STNAND_CMD);
+		/* Drain the writebuffer */
+		wmb();
+		break;
+
+	case NAND_OP_ADDR_INSTR:
+		for (i = 0; i < instr->ctx.addr.naddrs; i++) {
+			writeb(instr->ctx.addr.addrs[i],
+			       ctx->base + MEM_STNAND_ADDR);
+			/* Drain the writebuffer */
+			wmb();
+		}
+		break;
+
+	case NAND_OP_DATA_IN_INSTR:
+		if ((this->options & NAND_BUSWIDTH_16) &&
+		    !instr->ctx.data.force_8bit)
+			au_read_buf16(this, instr->ctx.data.buf.in,
+				      instr->ctx.data.len);
+		else
+			au_read_buf(this, instr->ctx.data.buf.in,
+				    instr->ctx.data.len);
+		break;
+
+	case NAND_OP_DATA_OUT_INSTR:
+		if ((this->options & NAND_BUSWIDTH_16) &&
+		    !instr->ctx.data.force_8bit)
+			au_write_buf16(this, instr->ctx.data.buf.out,
+				       instr->ctx.data.len);
+		else
+			au_write_buf(this, instr->ctx.data.buf.out,
+				     instr->ctx.data.len);
+		break;
+
+	case NAND_OP_WAITRDY_INSTR:
+		ret = au1550nd_waitrdy(this, instr->ctx.waitrdy.timeout_ms);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (instr->delay_ns)
+		ndelay(instr->delay_ns);
+
+	return ret;
+}
+
+static int au1550nd_exec_op(struct nand_chip *this,
+			    const struct nand_operation *op,
+			    bool check_only)
+{
+	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
+	unsigned int i;
+	int ret;
+
+	if (check_only)
+		return 0;
+
+	/* assert (force assert) chip enable */
+	alchemy_wrsmem((1 << (4 + ctx->cs)), AU1000_MEM_STNDCTL);
+	/* Drain the writebuffer */
+	wmb();
+
+	for (i = 0; i < op->ninstrs; i++) {
+		ret = au1550nd_exec_instr(this, &op->instrs[i]);
+		if (ret)
+			break;
+	}
+
+	/* deassert chip enable */
+	alchemy_wrsmem(0, AU1000_MEM_STNDCTL);
+	/* Drain the writebuffer */
+	wmb();
+
+	return ret;
+}
+
+static const struct nand_controller_ops au1550nd_ops = {
+	.exec_op = au1550nd_exec_op,
+};
+
 static int au1550nd_probe(struct platform_device *pdev)
 {
 	struct au1550nd_platdata *pd;
@@ -439,6 +546,9 @@ static int au1550nd_probe(struct platform_device *pdev)
 
 	/* 30 us command delay time */
 	this->legacy.chip_delay = 30;
+	nand_controller_init(&ctx->controller);
+	ctx->controller.ops = &au1550nd_ops;
+	this->controller = &ctx->controller;
 	this->ecc.mode = NAND_ECC_SOFT;
 	this->ecc.algo = NAND_ECC_HAMMING;
 
-- 
2.25.2

Re: [PATCH 2/4] mtd: rawnand: au1550nd: Implement exec_op()

[Miquel Raynal]

Hi Boris,

Boris Brezillon <boris.brezillon@collabora.com> wrote on Sun, 19 Apr
2020 21:30:35 +0200:

> So we can later get rid of the legacy interface implementation.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>


Thanks,
Miquèl

Re: [PATCH 2/4] mtd: rawnand: au1550nd: Implement exec_op()

[Miquel Raynal]

On Sun, 2020-04-19 at 19:30:35 UTC, Boris Brezillon wrote:
> So we can later get rid of the legacy interface implementation.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel

[PATCH 3/4] mtd: rawnand: au1550nd: Get rid of the legacy interface implementation

[Boris Brezillon]

Now that exec_op() is implemented we can get rid of all other hooks.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/mtd/nand/raw/au1550nd.c | 263 --------------------------------
 1 file changed, 263 deletions(-)

diff --git a/drivers/mtd/nand/raw/au1550nd.c b/drivers/mtd/nand/raw/au1550nd.c
index 79bf9fbeeb22..dbcbc1c8b6ff 100644
--- a/drivers/mtd/nand/raw/au1550nd.c
+++ b/drivers/mtd/nand/raw/au1550nd.c
@@ -29,58 +29,6 @@ static struct au1550nd_ctx *chip_to_au_ctx(struct nand_chip *this)
 	return container_of(this, struct au1550nd_ctx, chip);
 }
 
-/**
- * au_read_byte -  read one byte from the chip
- * @this:	NAND chip object
- *
- * read function for 8bit buswidth
- */
-static u_char au_read_byte(struct nand_chip *this)
-{
-	u_char ret = readb(this->legacy.IO_ADDR_R);
-	wmb(); /* drain writebuffer */
-	return ret;
-}
-
-/**
- * au_write_byte -  write one byte to the chip
- * @this:	NAND chip object
- * @byte:	pointer to data byte to write
- *
- * write function for 8it buswidth
- */
-static void au_write_byte(struct nand_chip *this, u_char byte)
-{
-	writeb(byte, this->legacy.IO_ADDR_W);
-	wmb(); /* drain writebuffer */
-}
-
-/**
- * au_read_byte16 -  read one byte endianness aware from the chip
- * @this:	NAND chip object
- *
- * read function for 16bit buswidth with endianness conversion
- */
-static u_char au_read_byte16(struct nand_chip *this)
-{
-	u_char ret = (u_char) cpu_to_le16(readw(this->legacy.IO_ADDR_R));
-	wmb(); /* drain writebuffer */
-	return ret;
-}
-
-/**
- * au_write_byte16 -  write one byte endianness aware to the chip
- * @this:	NAND chip object
- * @byte:	pointer to data byte to write
- *
- * write function for 16bit buswidth with endianness conversion
- */
-static void au_write_byte16(struct nand_chip *this, u_char byte)
-{
-	writew(le16_to_cpu((u16) byte), this->legacy.IO_ADDR_W);
-	wmb(); /* drain writebuffer */
-}
-
 /**
  * au_write_buf -  write buffer to chip
  * @this:	NAND chip object
@@ -162,206 +110,6 @@ static void au_read_buf16(struct nand_chip *this, u_char *buf, int len)
 	}
 }
 
-/* Select the chip by setting nCE to low */
-#define NAND_CTL_SETNCE		1
-/* Deselect the chip by setting nCE to high */
-#define NAND_CTL_CLRNCE		2
-/* Select the command latch by setting CLE to high */
-#define NAND_CTL_SETCLE		3
-/* Deselect the command latch by setting CLE to low */
-#define NAND_CTL_CLRCLE		4
-/* Select the address latch by setting ALE to high */
-#define NAND_CTL_SETALE		5
-/* Deselect the address latch by setting ALE to low */
-#define NAND_CTL_CLRALE		6
-
-static void au1550_hwcontrol(struct mtd_info *mtd, int cmd)
-{
-	struct nand_chip *this = mtd_to_nand(mtd);
-	struct au1550nd_ctx *ctx = container_of(this, struct au1550nd_ctx,
-						chip);
-
-	switch (cmd) {
-
-	case NAND_CTL_SETCLE:
-		this->legacy.IO_ADDR_W = ctx->base + MEM_STNAND_CMD;
-		break;
-
-	case NAND_CTL_CLRCLE:
-		this->legacy.IO_ADDR_W = ctx->base + MEM_STNAND_DATA;
-		break;
-
-	case NAND_CTL_SETALE:
-		this->legacy.IO_ADDR_W = ctx->base + MEM_STNAND_ADDR;
-		break;
-
-	case NAND_CTL_CLRALE:
-		this->legacy.IO_ADDR_W = ctx->base + MEM_STNAND_DATA;
-		/* FIXME: Nobody knows why this is necessary,
-		 * but it works only that way */
-		udelay(1);
-		break;
-
-	case NAND_CTL_SETNCE:
-		/* assert (force assert) chip enable */
-		alchemy_wrsmem((1 << (4 + ctx->cs)), AU1000_MEM_STNDCTL);
-		break;
-
-	case NAND_CTL_CLRNCE:
-		/* deassert chip enable */
-		alchemy_wrsmem(0, AU1000_MEM_STNDCTL);
-		break;
-	}
-
-	this->legacy.IO_ADDR_R = this->legacy.IO_ADDR_W;
-
-	wmb(); /* Drain the writebuffer */
-}
-
-int au1550_device_ready(struct nand_chip *this)
-{
-	return (alchemy_rdsmem(AU1000_MEM_STSTAT) & 0x1) ? 1 : 0;
-}
-
-/**
- * au1550_select_chip - control -CE line
- *	Forbid driving -CE manually permitting the NAND controller to do this.
- *	Keeping -CE asserted during the whole sector reads interferes with the
- *	NOR flash and PCMCIA drivers as it causes contention on the static bus.
- *	We only have to hold -CE low for the NAND read commands since the flash
- *	chip needs it to be asserted during chip not ready time but the NAND
- *	controller keeps it released.
- *
- * @this:	NAND chip object
- * @chip:	chipnumber to select, -1 for deselect
- */
-static void au1550_select_chip(struct nand_chip *this, int chip)
-{
-}
-
-/**
- * au1550_command - Send command to NAND device
- * @this:	NAND chip object
- * @command:	the command to be sent
- * @column:	the column address for this command, -1 if none
- * @page_addr:	the page address for this command, -1 if none
- */
-static void au1550_command(struct nand_chip *this, unsigned command,
-			   int column, int page_addr)
-{
-	struct mtd_info *mtd = nand_to_mtd(this);
-	struct au1550nd_ctx *ctx = container_of(this, struct au1550nd_ctx,
-						chip);
-	int ce_override = 0, i;
-	unsigned long flags = 0;
-
-	/* Begin command latch cycle */
-	au1550_hwcontrol(mtd, NAND_CTL_SETCLE);
-	/*
-	 * Write out the command to the device.
-	 */
-	if (command == NAND_CMD_SEQIN) {
-		int readcmd;
-
-		if (column >= mtd->writesize) {
-			/* OOB area */
-			column -= mtd->writesize;
-			readcmd = NAND_CMD_READOOB;
-		} else if (column < 256) {
-			/* First 256 bytes --> READ0 */
-			readcmd = NAND_CMD_READ0;
-		} else {
-			column -= 256;
-			readcmd = NAND_CMD_READ1;
-		}
-		ctx->write_byte(this, readcmd);
-	}
-	ctx->write_byte(this, command);
-
-	/* Set ALE and clear CLE to start address cycle */
-	au1550_hwcontrol(mtd, NAND_CTL_CLRCLE);
-
-	if (column != -1 || page_addr != -1) {
-		au1550_hwcontrol(mtd, NAND_CTL_SETALE);
-
-		/* Serially input address */
-		if (column != -1) {
-			/* Adjust columns for 16 bit buswidth */
-			if (this->options & NAND_BUSWIDTH_16 &&
-					!nand_opcode_8bits(command))
-				column >>= 1;
-			ctx->write_byte(this, column);
-		}
-		if (page_addr != -1) {
-			ctx->write_byte(this, (u8)(page_addr & 0xff));
-
-			if (command == NAND_CMD_READ0 ||
-			    command == NAND_CMD_READ1 ||
-			    command == NAND_CMD_READOOB) {
-				/*
-				 * NAND controller will release -CE after
-				 * the last address byte is written, so we'll
-				 * have to forcibly assert it. No interrupts
-				 * are allowed while we do this as we don't
-				 * want the NOR flash or PCMCIA drivers to
-				 * steal our precious bytes of data...
-				 */
-				ce_override = 1;
-				local_irq_save(flags);
-				au1550_hwcontrol(mtd, NAND_CTL_SETNCE);
-			}
-
-			ctx->write_byte(this, (u8)(page_addr >> 8));
-
-			if (this->options & NAND_ROW_ADDR_3)
-				ctx->write_byte(this,
-						((page_addr >> 16) & 0x0f));
-		}
-		/* Latch in address */
-		au1550_hwcontrol(mtd, NAND_CTL_CLRALE);
-	}
-
-	/*
-	 * Program and erase have their own busy handlers.
-	 * Status and sequential in need no delay.
-	 */
-	switch (command) {
-
-	case NAND_CMD_PAGEPROG:
-	case NAND_CMD_ERASE1:
-	case NAND_CMD_ERASE2:
-	case NAND_CMD_SEQIN:
-	case NAND_CMD_STATUS:
-		return;
-
-	case NAND_CMD_RESET:
-		break;
-
-	case NAND_CMD_READ0:
-	case NAND_CMD_READ1:
-	case NAND_CMD_READOOB:
-		/* Check if we're really driving -CE low (just in case) */
-		if (unlikely(!ce_override))
-			break;
-
-		/* Apply a short delay always to ensure that we do wait tWB. */
-		ndelay(100);
-		/* Wait for a chip to become ready... */
-		for (i = this->legacy.chip_delay;
-		     !this->legacy.dev_ready(this) && i > 0; --i)
-			udelay(1);
-
-		/* Release -CE and re-enable interrupts. */
-		au1550_hwcontrol(mtd, NAND_CTL_CLRNCE);
-		local_irq_restore(flags);
-		return;
-	}
-	/* Apply this short delay always to ensure that we do wait tWB. */
-	ndelay(100);
-
-	while(!this->legacy.dev_ready(this));
-}
-
 static int find_nand_cs(unsigned long nand_base)
 {
 	void __iomem *base =
@@ -540,12 +288,6 @@ static int au1550nd_probe(struct platform_device *pdev)
 	}
 	ctx->cs = cs;
 
-	this->legacy.dev_ready = au1550_device_ready;
-	this->legacy.select_chip = au1550_select_chip;
-	this->legacy.cmdfunc = au1550_command;
-
-	/* 30 us command delay time */
-	this->legacy.chip_delay = 30;
 	nand_controller_init(&ctx->controller);
 	ctx->controller.ops = &au1550nd_ops;
 	this->controller = &ctx->controller;
@@ -555,11 +297,6 @@ static int au1550nd_probe(struct platform_device *pdev)
 	if (pd->devwidth)
 		this->options |= NAND_BUSWIDTH_16;
 
-	this->legacy.read_byte = (pd->devwidth) ? au_read_byte16 : au_read_byte;
-	ctx->write_byte = (pd->devwidth) ? au_write_byte16 : au_write_byte;
-	this->legacy.write_buf = (pd->devwidth) ? au_write_buf16 : au_write_buf;
-	this->legacy.read_buf = (pd->devwidth) ? au_read_buf16 : au_read_buf;
-
 	ret = nand_scan(this, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "NAND scan failed with %d\n", ret);
-- 
2.25.2

Re: [PATCH 3/4] mtd: rawnand: au1550nd: Get rid of the legacy interface implementation

[Miquel Raynal]

Hi Boris,

Boris Brezillon <boris.brezillon@collabora.com> wrote on Sun, 19 Apr
2020 21:30:36 +0200:

> Now that exec_op() is implemented we can get rid of all other hooks.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>


Thanks,
Miquèl

Re: [PATCH 3/4] mtd: rawnand: au1550nd: Get rid of the legacy interface implementation

[Miquel Raynal]

On Sun, 2020-04-19 at 19:30:36 UTC, Boris Brezillon wrote:
> Now that exec_op() is implemented we can get rid of all other hooks.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel

[PATCH 4/4] mtd: rawnand: au1550nd: Patch the read/write buf helper prototypes

[Boris Brezillon]

To match the types passed by au1550nd_exec_instr() function.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/mtd/nand/raw/au1550nd.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/nand/raw/au1550nd.c b/drivers/mtd/nand/raw/au1550nd.c
index dbcbc1c8b6ff..7158298119cf 100644
--- a/drivers/mtd/nand/raw/au1550nd.c
+++ b/drivers/mtd/nand/raw/au1550nd.c
@@ -37,13 +37,15 @@ static struct au1550nd_ctx *chip_to_au_ctx(struct nand_chip *this)
  *
  * write function for 8bit buswidth
  */
-static void au_write_buf(struct nand_chip *this, const u_char *buf, int len)
+static void au_write_buf(struct nand_chip *this, const void *buf,
+			 unsigned int len)
 {
 	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
+	const u8 *p = buf;
 	int i;
 
 	for (i = 0; i < len; i++) {
-		writeb(buf[i], ctx->base + MEM_STNAND_DATA);
+		writeb(p[i], ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 }
@@ -56,13 +58,15 @@ static void au_write_buf(struct nand_chip *this, const u_char *buf, int len)
  *
  * read function for 8bit buswidth
  */
-static void au_read_buf(struct nand_chip *this, u_char *buf, int len)
+static void au_read_buf(struct nand_chip *this, void *buf,
+			unsigned int len)
 {
 	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
+	u8 *p = buf;
 	int i;
 
 	for (i = 0; i < len; i++) {
-		buf[i] = readb(ctx->base + MEM_STNAND_DATA);
+		p[i] = readb(ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
 }
@@ -75,18 +79,18 @@ static void au_read_buf(struct nand_chip *this, u_char *buf, int len)
  *
  * write function for 16bit buswidth
  */
-static void au_write_buf16(struct nand_chip *this, const u_char *buf, int len)
+static void au_write_buf16(struct nand_chip *this, const void *buf,
+			   unsigned int len)
 {
 	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
-	int i;
-	u16 *p = (u16 *) buf;
-	len >>= 1;
+	const u16 *p = buf;
+	unsigned int i;
 
+	len >>= 1;
 	for (i = 0; i < len; i++) {
 		writew(p[i], ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
 	}
-
 }
 
 /**
@@ -97,13 +101,13 @@ static void au_write_buf16(struct nand_chip *this, const u_char *buf, int len)
  *
  * read function for 16bit buswidth
  */
-static void au_read_buf16(struct nand_chip *this, u_char *buf, int len)
+static void au_read_buf16(struct nand_chip *this, void *buf, unsigned int len)
 {
 	struct au1550nd_ctx *ctx = chip_to_au_ctx(this);
-	int i;
-	u16 *p = (u16 *) buf;
-	len >>= 1;
+	unsigned int i;
+	u16 *p = buf;
 
+	len >>= 1;
 	for (i = 0; i < len; i++) {
 		p[i] = readw(ctx->base + MEM_STNAND_DATA);
 		wmb(); /* drain writebuffer */
-- 
2.25.2

Re: [PATCH 4/4] mtd: rawnand: au1550nd: Patch the read/write buf helper prototypes

[Miquel Raynal]

Hi Boris,

Boris Brezillon <boris.brezillon@collabora.com> wrote on Sun, 19 Apr
2020 21:30:37 +0200:

> To match the types passed by au1550nd_exec_instr() function.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>


Thanks,
Miquèl

Re: [PATCH 4/4] mtd: rawnand: au1550nd: Patch the read/write buf helper prototypes

[Miquel Raynal]

On Sun, 2020-04-19 at 19:30:37 UTC, Boris Brezillon wrote:
> To match the types passed by au1550nd_exec_instr() function.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel