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> --- 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 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev