[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 <mingkai...@freescale.com> wrote: > For Freescale's eSPI controller, the max transaction length one time > is limitted by the SPCOM[TRANSLEN] field which is 0xFFFF. 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 <mingkai...@freescale.com> 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 0xFFFF 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_espi_do_one_msg; > diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h > index af56071..0729cbd 100644 > --- a/include/linux/spi/spi.h > +++ b/include/linux/spi/spi.h > @@ -261,6 +261,7 @@ struct spi_master { > #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ > #define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ > #define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ > +#define SPI_MASTER_TRANS_LIMIT BIT(3) /* have trans length limit */ > > /* Setup mode and clock, etc (spi driver may call many times). > * > -- > 1.6.4 > > > -- Grant Likely, B.Sc., P.Eng. 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