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author | Wolfgang Muees <wolfgang.mues@auerswald.de> | 2009-04-06 19:00:53 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-07 08:31:06 -0700 |
commit | 93b61bddc13d9acf1fe341b39d826e80f3182d1e (patch) | |
tree | 54a5b574ada4b619a9cba845bee1e4205d62176c /drivers | |
parent | 42c78b2bf51bafb4cfa98dfecc28dd9b8bcd04b0 (diff) | |
download | linux-3.10-93b61bddc13d9acf1fe341b39d826e80f3182d1e.tar.gz linux-3.10-93b61bddc13d9acf1fe341b39d826e80f3182d1e.tar.bz2 linux-3.10-93b61bddc13d9acf1fe341b39d826e80f3182d1e.zip |
Blackfin SPI Driver: Make mmc_spi driver work on Blackfin
1. Rewrite of the non-dma data transfer functions to use only ONE mode
of TIMOD (TIMOD=0x1). With TIMOD=0, it was not possible to set the TX
bit pattern. So the TDBR = 0xFFFF inside the read calls won't work.
2. Clear SPI_RDBR before reading and before duplex transfer.
Otherwise the garbage data in RDBR will get read. Since mmc_spi uses a
lot of duplex transfers, this is the main cause of mmc_spi failure.
3. Poll RXS for transfer completion. Polling SPIF or TXS cannot
guarantee transfer completion. This may interrupt a transfer before it
is finished. Also this may leave garbage data in buffer and affect
next transfer.
[Yi Li <yi.li@analog.com>: add a field "u16 idle_tx_val" in "struct
bfin5xx_spi_chip" to specify the value to transmit if no TX value
is supplied.]
Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/spi/spi_bfin5xx.c | 250 |
1 files changed, 108 insertions, 142 deletions
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index 6aa084e445e..e1d9eae1fae 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -45,6 +45,9 @@ MODULE_LICENSE("GPL"); #define QUEUE_RUNNING 0 #define QUEUE_STOPPED 1 +/* Value to send if no TX value is supplied */ +#define SPI_IDLE_TXVAL 0x0000 + struct driver_data { /* Driver model hookup */ struct platform_device *pdev; @@ -112,6 +115,7 @@ struct chip_data { u8 cs_change_per_word; u16 cs_chg_udelay; /* Some devices require > 255usec delay */ u32 cs_gpio; + u16 idle_tx_val; void (*write) (struct driver_data *); void (*read) (struct driver_data *); void (*duplex) (struct driver_data *); @@ -226,134 +230,126 @@ static void bfin_spi_restore_state(struct driver_data *drv_data) bfin_spi_cs_active(drv_data, chip); } -/* used to kick off transfer in rx mode */ -static unsigned short bfin_spi_dummy_read(struct driver_data *drv_data) +/* used to kick off transfer in rx mode and read unwanted RX data */ +static inline void bfin_spi_dummy_read(struct driver_data *drv_data) { - unsigned short tmp; - tmp = read_RDBR(drv_data); - return tmp; + (void) read_RDBR(drv_data); } static void bfin_spi_null_writer(struct driver_data *drv_data) { u8 n_bytes = drv_data->n_bytes; + u16 tx_val = drv_data->cur_chip->idle_tx_val; + + /* clear RXS (we check for RXS inside the loop) */ + bfin_spi_dummy_read(drv_data); while (drv_data->tx < drv_data->tx_end) { - write_TDBR(drv_data, 0); - while ((read_STAT(drv_data) & BIT_STAT_TXS)) - cpu_relax(); + write_TDBR(drv_data, tx_val); drv_data->tx += n_bytes; + /* wait until transfer finished. + checking SPIF or TXS may not guarantee transfer completion */ + while (!(read_STAT(drv_data) & BIT_STAT_RXS)) + cpu_relax(); + /* discard RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); } } static void bfin_spi_null_reader(struct driver_data *drv_data) { u8 n_bytes = drv_data->n_bytes; + u16 tx_val = drv_data->cur_chip->idle_tx_val; + + /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { + write_TDBR(drv_data, tx_val); + drv_data->rx += n_bytes; while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); bfin_spi_dummy_read(drv_data); - drv_data->rx += n_bytes; } } static void bfin_spi_u8_writer(struct driver_data *drv_data) { - dev_dbg(&drv_data->pdev->dev, - "cr8-s is 0x%x\n", read_STAT(drv_data)); + /* clear RXS (we check for RXS inside the loop) */ + bfin_spi_dummy_read(drv_data); while (drv_data->tx < drv_data->tx_end) { - write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); - while (read_STAT(drv_data) & BIT_STAT_TXS) + write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); + /* wait until transfer finished. + checking SPIF or TXS may not guarantee transfer completion */ + while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - ++drv_data->tx; + /* discard RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); } - - /* poll for SPI completion before return */ - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); } static void bfin_spi_u8_cs_chg_writer(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; + /* clear RXS (we check for RXS inside the loop) */ + bfin_spi_dummy_read(drv_data); + while (drv_data->tx < drv_data->tx_end) { bfin_spi_cs_active(drv_data, chip); - - write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); - while (read_STAT(drv_data) & BIT_STAT_TXS) - cpu_relax(); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) + write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); + /* make sure transfer finished before deactiving CS */ + while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - + bfin_spi_dummy_read(drv_data); bfin_spi_cs_deactive(drv_data, chip); - - ++drv_data->tx; } } static void bfin_spi_u8_reader(struct driver_data *drv_data) { - dev_dbg(&drv_data->pdev->dev, - "cr-8 is 0x%x\n", read_STAT(drv_data)); - - /* poll for SPI completion before start */ - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); - - /* clear TDBR buffer before read(else it will be shifted out) */ - write_TDBR(drv_data, 0xFFFF); + u16 tx_val = drv_data->cur_chip->idle_tx_val; + /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); - while (drv_data->rx < drv_data->rx_end - 1) { + while (drv_data->rx < drv_data->rx_end) { + write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - *(u8 *) (drv_data->rx) = read_RDBR(drv_data); - ++drv_data->rx; + *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); } - - while (!(read_STAT(drv_data) & BIT_STAT_RXS)) - cpu_relax(); - *(u8 *) (drv_data->rx) = read_SHAW(drv_data); - ++drv_data->rx; } static void bfin_spi_u8_cs_chg_reader(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; + u16 tx_val = chip->idle_tx_val; + + /* discard old RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { bfin_spi_cs_active(drv_data, chip); - read_RDBR(drv_data); /* kick off */ - + write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); - - *(u8 *) (drv_data->rx) = read_SHAW(drv_data); + *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); bfin_spi_cs_deactive(drv_data, chip); - - ++drv_data->rx; } } static void bfin_spi_u8_duplex(struct driver_data *drv_data) { - /* in duplex mode, clk is triggered by writing of TDBR */ + /* discard old RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); + while (drv_data->rx < drv_data->rx_end) { - write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); + write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - *(u8 *) (drv_data->rx) = read_RDBR(drv_data); - ++drv_data->rx; - ++drv_data->tx; + *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); } } @@ -361,130 +357,102 @@ static void bfin_spi_u8_cs_chg_duplex(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; + /* discard old RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); + while (drv_data->rx < drv_data->rx_end) { bfin_spi_cs_active(drv_data, chip); - - write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); - - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); + write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - *(u8 *) (drv_data->rx) = read_RDBR(drv_data); - + *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); bfin_spi_cs_deactive(drv_data, chip); - - ++drv_data->rx; - ++drv_data->tx; } } static void bfin_spi_u16_writer(struct driver_data *drv_data) { - dev_dbg(&drv_data->pdev->dev, - "cr16 is 0x%x\n", read_STAT(drv_data)); + /* clear RXS (we check for RXS inside the loop) */ + bfin_spi_dummy_read(drv_data); while (drv_data->tx < drv_data->tx_end) { write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); - while ((read_STAT(drv_data) & BIT_STAT_TXS)) - cpu_relax(); drv_data->tx += 2; + /* wait until transfer finished. + checking SPIF or TXS may not guarantee transfer completion */ + while (!(read_STAT(drv_data) & BIT_STAT_RXS)) + cpu_relax(); + /* discard RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); } - - /* poll for SPI completion before return */ - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); } static void bfin_spi_u16_cs_chg_writer(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; + /* clear RXS (we check for RXS inside the loop) */ + bfin_spi_dummy_read(drv_data); + while (drv_data->tx < drv_data->tx_end) { bfin_spi_cs_active(drv_data, chip); - write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); - while ((read_STAT(drv_data) & BIT_STAT_TXS)) - cpu_relax(); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) + drv_data->tx += 2; + /* make sure transfer finished before deactiving CS */ + while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - + bfin_spi_dummy_read(drv_data); bfin_spi_cs_deactive(drv_data, chip); - - drv_data->tx += 2; } } static void bfin_spi_u16_reader(struct driver_data *drv_data) { - dev_dbg(&drv_data->pdev->dev, - "cr-16 is 0x%x\n", read_STAT(drv_data)); - - /* poll for SPI completion before start */ - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); - - /* clear TDBR buffer before read(else it will be shifted out) */ - write_TDBR(drv_data, 0xFFFF); + u16 tx_val = drv_data->cur_chip->idle_tx_val; + /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); - while (drv_data->rx < (drv_data->rx_end - 2)) { + while (drv_data->rx < drv_data->rx_end) { + write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += 2; } - - while (!(read_STAT(drv_data) & BIT_STAT_RXS)) - cpu_relax(); - *(u16 *) (drv_data->rx) = read_SHAW(drv_data); - drv_data->rx += 2; } static void bfin_spi_u16_cs_chg_reader(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; + u16 tx_val = chip->idle_tx_val; - /* poll for SPI completion before start */ - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); - - /* clear TDBR buffer before read(else it will be shifted out) */ - write_TDBR(drv_data, 0xFFFF); - - bfin_spi_cs_active(drv_data, chip); + /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); - while (drv_data->rx < drv_data->rx_end - 2) { - bfin_spi_cs_deactive(drv_data, chip); - + while (drv_data->rx < drv_data->rx_end) { + bfin_spi_cs_active(drv_data, chip); + write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); - bfin_spi_cs_active(drv_data, chip); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += 2; + bfin_spi_cs_deactive(drv_data, chip); } - bfin_spi_cs_deactive(drv_data, chip); - - while (!(read_STAT(drv_data) & BIT_STAT_RXS)) - cpu_relax(); - *(u16 *) (drv_data->rx) = read_SHAW(drv_data); - drv_data->rx += 2; } static void bfin_spi_u16_duplex(struct driver_data *drv_data) { - /* in duplex mode, clk is triggered by writing of TDBR */ - while (drv_data->tx < drv_data->tx_end) { + /* discard old RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); + + while (drv_data->rx < drv_data->rx_end) { write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); + drv_data->tx += 2; while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += 2; - drv_data->tx += 2; } } @@ -492,20 +460,18 @@ static void bfin_spi_u16_cs_chg_duplex(struct driver_data *drv_data) { struct chip_data *chip = drv_data->cur_chip; - while (drv_data->tx < drv_data->tx_end) { - bfin_spi_cs_active(drv_data, chip); + /* discard old RX data and clear RXS */ + bfin_spi_dummy_read(drv_data); + while (drv_data->rx < drv_data->rx_end) { + bfin_spi_cs_active(drv_data, chip); write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); - while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) - cpu_relax(); + drv_data->tx += 2; while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); - - bfin_spi_cs_deactive(drv_data, chip); - drv_data->rx += 2; - drv_data->tx += 2; + bfin_spi_cs_deactive(drv_data, chip); } } @@ -682,6 +648,13 @@ static void bfin_spi_pump_transfers(unsigned long data) return; } + if (transfer->len == 0) { + /* Move to next transfer of this msg */ + message->state = bfin_spi_next_transfer(drv_data); + /* Schedule next transfer tasklet */ + tasklet_schedule(&drv_data->pump_transfers); + } + if (transfer->tx_buf != NULL) { drv_data->tx = (void *)transfer->tx_buf; drv_data->tx_end = drv_data->tx + transfer->len; @@ -837,9 +810,6 @@ static void bfin_spi_pump_transfers(unsigned long data) (unsigned long) (drv_data->rx + drv_data->len_in_bytes)); - /* clear tx reg soformer data is not shifted out */ - write_TDBR(drv_data, 0xFFFF); - dma_config |= WNR; dma_start_addr = (unsigned long)drv_data->rx; cr |= BIT_CTL_TIMOD_DMA_RX | BIT_CTL_SENDOPT; @@ -881,6 +851,11 @@ static void bfin_spi_pump_transfers(unsigned long data) /* IO mode write then read */ dev_dbg(&drv_data->pdev->dev, "doing IO transfer\n"); + /* we always use SPI_WRITE mode. SPI_READ mode + seems to have problems with setting up the + output value in TDBR prior to the transfer. */ + write_CTRL(drv_data, (cr | CFG_SPI_WRITE)); + if (full_duplex) { /* full duplex mode */ BUG_ON((drv_data->tx_end - drv_data->tx) != @@ -888,9 +863,6 @@ static void bfin_spi_pump_transfers(unsigned long data) dev_dbg(&drv_data->pdev->dev, "IO duplex: cr is 0x%x\n", cr); - /* set SPI transfer mode */ - write_CTRL(drv_data, (cr | CFG_SPI_WRITE)); - drv_data->duplex(drv_data); if (drv_data->tx != drv_data->tx_end) @@ -900,9 +872,6 @@ static void bfin_spi_pump_transfers(unsigned long data) dev_dbg(&drv_data->pdev->dev, "IO write: cr is 0x%x\n", cr); - /* set SPI transfer mode */ - write_CTRL(drv_data, (cr | CFG_SPI_WRITE)); - drv_data->write(drv_data); if (drv_data->tx != drv_data->tx_end) @@ -912,9 +881,6 @@ static void bfin_spi_pump_transfers(unsigned long data) dev_dbg(&drv_data->pdev->dev, "IO read: cr is 0x%x\n", cr); - /* set SPI transfer mode */ - write_CTRL(drv_data, (cr | CFG_SPI_READ)); - drv_data->read(drv_data); if (drv_data->rx != drv_data->rx_end) tranf_success = 0; @@ -934,7 +900,6 @@ static void bfin_spi_pump_transfers(unsigned long data) } /* Schedule next transfer tasklet */ tasklet_schedule(&drv_data->pump_transfers); - } } @@ -1092,6 +1057,7 @@ static int bfin_spi_setup(struct spi_device *spi) chip->cs_change_per_word = chip_info->cs_change_per_word; chip->cs_chg_udelay = chip_info->cs_chg_udelay; chip->cs_gpio = chip_info->cs_gpio; + chip->idle_tx_val = chip_info->idle_tx_val; } /* translate common spi framework into our register */ |