[adding David Woodhouse]
(Btw, you should cc: David Woodhouse and the mtd list on the MTD patches).
On Mon, Aug 2, 2010 at 1:52 AM, Mingkai Hu wrote:
> For Freescale's eSPI controller, the max transaction length one time
> is limitted by the SPCOM[TRANSLEN] field which is 0x. When used
> mkfs.ext2 command to create ext2 filesystem on the flash, the read
> length will exceed the max value of the SPCOM[TRANSLEN] field, so
> change the read function to read page by page.
>
> For other SPI flash driver, also needed to supply the read function
> if used the eSPI controller.
>
> Signed-off-by: Mingkai Hu
This one bothers me, but I can't put my finger on it. The flag feels
like a controller specific hack. David, can you take a look at this
patch?
g.
> ---
>
> v2:
> - Add SPI_MASTER_TRANS_LIMIT flag to indicate the master's trans length
> limitation, so the MTD driver can select the correct transfer behaviour
> at driver probe time
>
> drivers/mtd/devices/m25p80.c | 78
> ++
> drivers/spi/spi_fsl_espi.c | 1 +
> include/linux/spi/spi.h | 1 +
> 3 files changed, 80 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 5f00075..30e4568 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -376,6 +376,81 @@ static int m25p80_read(struct mtd_info *mtd, loff_t
> from, size_t len,
> }
>
> /*
> + * Read an address range from the flash chip page by page.
> + * Some controller has transaction length limitation such as the
> + * Freescale's eSPI controller can only trasmit 0x bytes one
> + * time, so we have to read page by page if the len is more than
> + * the limitation.
> + */
> +static int m25p80_page_read(struct mtd_info *mtd, loff_t from, size_t len,
> + size_t *retlen, u_char *buf)
> +{
> + struct m25p *flash = mtd_to_m25p(mtd);
> + struct spi_transfer t[2];
> + struct spi_message m;
> + u32 i, page_size = 0;
> +
> + DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
> + dev_name(&flash->spi->dev), __func__, "from",
> + (u32)from, len);
> +
> + /* sanity checks */
> + if (!len)
> + return 0;
> +
> + if (from + len > flash->mtd.size)
> + return -EINVAL;
> +
> + spi_message_init(&m);
> + memset(t, 0, (sizeof t));
> +
> + /* NOTE:
> + * OPCODE_FAST_READ (if available) is faster.
> + * Should add 1 byte DUMMY_BYTE.
> + */
> + t[0].tx_buf = flash->command;
> + t[0].len = m25p_cmdsz(flash) + FAST_READ_DUMMY_BYTE;
> + spi_message_add_tail(&t[0], &m);
> +
> + t[1].rx_buf = buf;
> + spi_message_add_tail(&t[1], &m);
> +
> + /* Byte count starts at zero. */
> + if (retlen)
> + *retlen = 0;
> +
> + mutex_lock(&flash->lock);
> +
> + /* Wait till previous write/erase is done. */
> + if (wait_till_ready(flash)) {
> + /* REVISIT status return?? */
> + mutex_unlock(&flash->lock);
> + return 1;
> + }
> +
> + /* Set up the write data buffer. */
> + flash->command[0] = OPCODE_READ;
> +
> + for (i = page_size; i < len; i += page_size) {
> + page_size = len - i;
> + if (page_size > flash->page_size)
> + page_size = flash->page_size;
> + m25p_addr2cmd(flash, from + i, flash->command);
> + t[1].len = page_size;
> + t[1].rx_buf = buf + i;
> +
> + spi_sync(flash->spi, &m);
> +
> + *retlen += m.actual_length - m25p_cmdsz(flash)
> + - FAST_READ_DUMMY_BYTE;
> + }
> +
> + mutex_unlock(&flash->lock);
> +
> + return 0;
> +}
> +
> +/*
> * Write an address range to the flash chip. Data must be written in
> * FLASH_PAGESIZE chunks. The address range may be any size provided
> * it is within the physical boundaries.
> @@ -877,6 +952,9 @@ static int __devinit m25p_probe(struct spi_device *spi)
> flash->mtd.erase = m25p80_erase;
> flash->mtd.read = m25p80_read;
>
> + if (spi->master->flags & SPI_MASTER_TRANS_LIMIT)
> + flash->mtd.read = m25p80_page_read;
> +
> /* sst flash chips use AAI word program */
> if (info->jedec_id >> 16 == 0xbf)
> flash->mtd.write = sst_write;
> diff --git a/drivers/spi/spi_fsl_espi.c b/drivers/spi/spi_fsl_espi.c
> index 61987cf..e15b7dc 100644
> --- a/drivers/spi/spi_fsl_espi.c
> +++ b/drivers/spi/spi_fsl_espi.c
> @@ -470,6 +470,7 @@ static struct spi_master * __devinit
> fsl_espi_probe(struct device *dev,
> goto err_probe;
>
> master->setup = fsl_espi_setup;
> + master->flags = SPI_MASTER_TRANS_LIMIT;
>
> mpc8xxx_spi = spi_master_get_devdata(master);
> mpc8xxx_spi->spi_do_one_msg = fsl