[RFC][PATCH] mtd: bcm47xxsflash: writing support

[Brian Norris]

Hi Rafal,

On Wed, May 22, 2013 at 02:39:02PM +0200, Rafał Miłecki wrote:
> ---
>  drivers/mtd/devices/bcm47xxsflash.c |  130 +++++++++++++++++++++++++++++++++--
>  1 file changed, 126 insertions(+), 4 deletions(-)

Can I get a 'Signed-off-by'? Otherwise, is this patch good to go?

> 
> diff --git a/drivers/mtd/devices/bcm47xxsflash.c b/drivers/mtd/devices/bcm47xxsflash.c
> index c485d96..effe624 100644
> --- a/drivers/mtd/devices/bcm47xxsflash.c
> +++ b/drivers/mtd/devices/bcm47xxsflash.c
> @@ -116,6 +116,127 @@ static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
>  	return len;
>  }
>  
> +static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
> +				  const u_char *buf)
> +{
> +	struct bcm47xxsflash *b47s = mtd->priv;
> +	int written = 0;
> +
> +	/* Enable writes */
> +	bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
> +
> +	/* Write first byte */
> +	b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
> +	b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
> +
> +	/* Program page */
> +	if (b47s->bcma_cc->core->id.rev < 20) {
> +		bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
> +		return 1; /* 1B written */
> +	}
> +
> +	/* Program page and set CSA (on newer chips we can continue writing) */
> +	bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
> +	offset++;
> +	len--;
> +	written++;
> +
> +	while (len > 0) {
> +		/* Page boundary, another function call is needed */
> +		if ((offset & 0xFF) == 0)
> +			break;
> +
> +		bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
> +		offset++;
> +		len--;
> +		written++;
> +	}
> +
> +	/* All done, drop CSA & poll */
> +	b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
> +	udelay(1);
> +	if (bcm47xxsflash_poll(b47s, HZ / 10))
> +		pr_err("Flash rejected dropping CSA\n");
> +
> +	return written;
> +}
> +
> +static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
> +				  const u_char *buf)
> +{
> +	struct bcm47xxsflash *b47s = mtd->priv;
> +	u32 mask = b47s->blocksize - 1;
> +	u32 page = (offset & ~mask) << 1;
> +	u32 byte = offset & mask;
> +	int written = 0;
> +
> +	/* If we don't overwrite whole page, read it to the buffer first */
> +	if (byte || (len < b47s->blocksize)) {
> +		int err;
> +
> +		b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
> +		bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
> +		/* 250 us for AT45DB321B */
> +		err = bcm47xxsflash_poll(b47s, HZ / 1000);
> +		if (err) {
> +			pr_err("Timeout reading page 0x%X info buffer\n", page);
> +			return err;
> +		}
> +	}
> +
> +	/* Change buffer content with our data */
> +	while (len > 0) {
> +		/* Page boundary, another function call is needed */
> +		if (byte == b47s->blocksize)
> +			break;
> +
> +		b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
> +		b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
> +		bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
> +		len--;
> +		written++;
> +	}
> +
> +	/* Program page with the buffer content */
> +	b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
> +	bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
> +
> +	return written;
> +}
> +
> +static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
> +			       size_t *retlen, const u_char *buf)
> +{
> +	struct bcm47xxsflash *b47s = mtd->priv;
> +	int written;
> +
> +	/* Writing functions can return without writing all passed data, for
> +	 * example when the hardware is too old or when we git page boundary.
> +	 */
> +	while (len > 0) {
> +		switch (b47s->type) {
> +		case BCM47XXSFLASH_TYPE_ST:
> +			written = bcm47xxsflash_write_st(mtd, to, len, buf);
> +			break;
> +		case BCM47XXSFLASH_TYPE_ATMEL:
> +			written = bcm47xxsflash_write_at(mtd, to, len, buf);
> +			break;
> +		default:
> +			BUG_ON(1);
> +		}
> +		if (written < 0) {
> +			pr_err("Error writing at offset 0x%llX\n", to);
> +			return written;
> +		}
> +		to += (loff_t)written;
> +		len -= written;
> +		*retlen += written;
> +		buf += written;
> +	}
> +
> +	return 0;
> +}
> +
>  static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s)
>  {
>  	struct mtd_info *mtd = &b47s->mtd;
> @@ -123,16 +244,17 @@ static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s)
>  	mtd->priv = b47s;
>  	mtd->name = "bcm47xxsflash";
>  	mtd->owner = THIS_MODULE;
> -	mtd->type = MTD_ROM;
>  
> -	/* TODO: implement writing support and verify/change following code */
> -	mtd->flags = MTD_CAP_ROM;
> +	mtd->type = MTD_NORFLASH;
> +	mtd->flags = MTD_CAP_NORFLASH;
>  	mtd->size = b47s->size;
>  	mtd->erasesize = b47s->blocksize;
> -	mtd->writebufsize = mtd->writesize = 1;
> +	mtd->writesize = 1;
> +	mtd->writebufsize = 1;
>  
>  	mtd->_erase = bcm47xxsflash_erase;
>  	mtd->_read = bcm47xxsflash_read;
> +	mtd->_write = bcm47xxsflash_write;
>  }
>  
>  /**************************************************

Brian