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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-20 19:03:22 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-20 19:03:22 (GMT) |
commit | 3aad3f03b2b6d2d977b985c49274cdb78a1593e5 (patch) | |
tree | e2955fe687fcd9c26f82d57a3c818e05406964ed /drivers/spi/spi-bcm63xx.c | |
parent | 10b6339e93244156fac901560117e94bf9dca120 (diff) | |
parent | 095c3752e673c0ba039a2f67fd867297fde75ae7 (diff) | |
download | linux-3aad3f03b2b6d2d977b985c49274cdb78a1593e5.tar.xz |
Merge tag 'spi-for-linus' of git://git.secretlab.ca/git/linux
Pull SPI changes from Grant Likely:
"Changes to both core spi code and spi device drivers. The driver
changes are the usual set of bug fixes and platform enablement.
Core code changes include:
- More intelligent assignment of SPI bus numbers when using DT
- Common mechanism for using gpios as CS lines
- Pull checks for bits_per_word and transfer speed out of drivers and
into core code
- Ensure temporary DMA buffers are DMA safe"
* tag 'spi-for-linus' of git://git.secretlab.ca/git/linux: (50 commits)
spi: Document cs_gpios and cs_gpio in kernel-doc
spi/of: Fix initialization of cs_gpios array
spi/pxa2xx: add support for Lynxpoint SPI controllers
spi/pxa2xx: add support for Intel Low Power Subsystem SPI
spi/pxa2xx: add support for SPI_LOOP
spi/pxa2xx: add support for runtime PM
spi/pxa2xx: add support for DMA engine
spi/pxa2xx: break out the private DMA API usage into a separate file
spi/ath79: add shutdown handler
spi/mips-lantiq: set SPI_MASTER_HALF_DUPLEX flag
spi/mips-lantiq: make use of spi_finalize_current_message
spi/bcm63xx: work around inability to keep CS up
spi/davinci: use request_threaded_irq() to fix deadlock
spi/orion: Use module_platform_driver()
spi/bcm63xx: reject transfers unable to transfer
spi: Ensure memory used for spi_write_then_read() is DMA safe
spi/spi-mpc512x-psc: init mode bits supported by the driver
spi/mpc512x-psc: don't use obsolet cell-index property
spi: Remove erroneous __init, __exit and __exit_p() references in drivers
spi/s3c64xx: fix checkpatch warnings and error
...
Diffstat (limited to 'drivers/spi/spi-bcm63xx.c')
-rw-r--r-- | drivers/spi/spi-bcm63xx.c | 179 |
1 files changed, 125 insertions, 54 deletions
diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c index f44ab55..9578af7 100644 --- a/drivers/spi/spi-bcm63xx.c +++ b/drivers/spi/spi-bcm63xx.c @@ -37,6 +37,8 @@ #define PFX KBUILD_MODNAME +#define BCM63XX_SPI_MAX_PREPEND 15 + struct bcm63xx_spi { struct completion done; @@ -49,16 +51,10 @@ struct bcm63xx_spi { unsigned int msg_type_shift; unsigned int msg_ctl_width; - /* Data buffers */ - const unsigned char *tx_ptr; - unsigned char *rx_ptr; - /* data iomem */ u8 __iomem *tx_io; const u8 __iomem *rx_io; - int remaining_bytes; - struct clk *clk; struct platform_device *pdev; }; @@ -175,24 +171,17 @@ static int bcm63xx_spi_setup(struct spi_device *spi) return 0; } -/* Fill the TX FIFO with as many bytes as possible */ -static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs) -{ - u8 size; - - /* Fill the Tx FIFO with as many bytes as possible */ - size = bs->remaining_bytes < bs->fifo_size ? bs->remaining_bytes : - bs->fifo_size; - memcpy_toio(bs->tx_io, bs->tx_ptr, size); - bs->remaining_bytes -= size; -} - -static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi, - struct spi_transfer *t) +static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *first, + unsigned int num_transfers) { struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master); u16 msg_ctl; u16 cmd; + u8 rx_tail; + unsigned int i, timeout = 0, prepend_len = 0, len = 0; + struct spi_transfer *t = first; + bool do_rx = false; + bool do_tx = false; /* Disable the CMD_DONE interrupt */ bcm_spi_writeb(bs, 0, SPI_INT_MASK); @@ -200,25 +189,45 @@ static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi, dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n", t->tx_buf, t->rx_buf, t->len); - /* Transmitter is inhibited */ - bs->tx_ptr = t->tx_buf; - bs->rx_ptr = t->rx_buf; + if (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND) + prepend_len = t->len; - if (t->tx_buf) { - bs->remaining_bytes = t->len; - bcm63xx_spi_fill_tx_fifo(bs); + /* prepare the buffer */ + for (i = 0; i < num_transfers; i++) { + if (t->tx_buf) { + do_tx = true; + memcpy_toio(bs->tx_io + len, t->tx_buf, t->len); + + /* don't prepend more than one tx */ + if (t != first) + prepend_len = 0; + } + + if (t->rx_buf) { + do_rx = true; + /* prepend is half-duplex write only */ + if (t == first) + prepend_len = 0; + } + + len += t->len; + + t = list_entry(t->transfer_list.next, struct spi_transfer, + transfer_list); } + len -= prepend_len; + init_completion(&bs->done); /* Fill in the Message control register */ - msg_ctl = (t->len << SPI_BYTE_CNT_SHIFT); + msg_ctl = (len << SPI_BYTE_CNT_SHIFT); - if (t->rx_buf && t->tx_buf) + if (do_rx && do_tx && prepend_len == 0) msg_ctl |= (SPI_FD_RW << bs->msg_type_shift); - else if (t->rx_buf) + else if (do_rx) msg_ctl |= (SPI_HD_R << bs->msg_type_shift); - else if (t->tx_buf) + else if (do_tx) msg_ctl |= (SPI_HD_W << bs->msg_type_shift); switch (bs->msg_ctl_width) { @@ -232,14 +241,41 @@ static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi, /* Issue the transfer */ cmd = SPI_CMD_START_IMMEDIATE; - cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT); + cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT); cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT); bcm_spi_writew(bs, cmd, SPI_CMD); /* Enable the CMD_DONE interrupt */ bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK); - return t->len - bs->remaining_bytes; + timeout = wait_for_completion_timeout(&bs->done, HZ); + if (!timeout) + return -ETIMEDOUT; + + /* read out all data */ + rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL); + + if (do_rx && rx_tail != len) + return -EIO; + + if (!rx_tail) + return 0; + + len = 0; + t = first; + /* Read out all the data */ + for (i = 0; i < num_transfers; i++) { + if (t->rx_buf) + memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len); + + if (t != first || prepend_len == 0) + len += t->len; + + t = list_entry(t->transfer_list.next, struct spi_transfer, + transfer_list); + } + + return 0; } static int bcm63xx_spi_prepare_transfer(struct spi_master *master) @@ -264,41 +300,76 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master, struct spi_message *m) { struct bcm63xx_spi *bs = spi_master_get_devdata(master); - struct spi_transfer *t; + struct spi_transfer *t, *first = NULL; struct spi_device *spi = m->spi; int status = 0; - unsigned int timeout = 0; - + unsigned int n_transfers = 0, total_len = 0; + bool can_use_prepend = false; + + /* + * This SPI controller does not support keeping CS active after a + * transfer. + * Work around this by merging as many transfers we can into one big + * full-duplex transfers. + */ list_for_each_entry(t, &m->transfers, transfer_list) { - unsigned int len = t->len; - u8 rx_tail; - status = bcm63xx_spi_check_transfer(spi, t); if (status < 0) goto exit; - /* configure adapter for a new transfer */ - bcm63xx_spi_setup_transfer(spi, t); + if (!first) + first = t; + + n_transfers++; + total_len += t->len; + + if (n_transfers == 2 && !first->rx_buf && !t->tx_buf && + first->len <= BCM63XX_SPI_MAX_PREPEND) + can_use_prepend = true; + else if (can_use_prepend && t->tx_buf) + can_use_prepend = false; + + /* we can only transfer one fifo worth of data */ + if ((can_use_prepend && + total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) || + (!can_use_prepend && total_len > bs->fifo_size)) { + dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n", + total_len, bs->fifo_size); + status = -EINVAL; + goto exit; + } + + /* all combined transfers have to have the same speed */ + if (t->speed_hz != first->speed_hz) { + dev_err(&spi->dev, "unable to change speed between transfers\n"); + status = -EINVAL; + goto exit; + } - while (len) { - /* send the data */ - len -= bcm63xx_txrx_bufs(spi, t); + /* CS will be deasserted directly after transfer */ + if (t->delay_usecs) { + dev_err(&spi->dev, "unable to keep CS asserted after transfer\n"); + status = -EINVAL; + goto exit; + } + + if (t->cs_change || + list_is_last(&t->transfer_list, &m->transfers)) { + /* configure adapter for a new transfer */ + bcm63xx_spi_setup_transfer(spi, first); - timeout = wait_for_completion_timeout(&bs->done, HZ); - if (!timeout) { - status = -ETIMEDOUT; + /* send the data */ + status = bcm63xx_txrx_bufs(spi, first, n_transfers); + if (status) goto exit; - } - /* read out all data */ - rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL); + m->actual_length += total_len; - /* Read out all the data */ - if (rx_tail) - memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail); + first = NULL; + n_transfers = 0; + total_len = 0; + can_use_prepend = false; } - - m->actual_length += t->len; } exit: m->status = status; |