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| author | Akinobu Mita <akinobu.mita@gmail.com> | 2017-03-22 09:18:26 +0900 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2017-03-24 18:50:23 +0000 |
| commit | 812613591cb652344186c4cd912304ed02138566 (patch) | |
| tree | 256955ff7a022f11ec2a9977be3415fb6e793e70 /drivers/spi/spi-omap2-mcspi.c | |
| parent | fafd67940774733fa97f4b09412aea6981b82e0a (diff) | |
| download | lwn-812613591cb652344186c4cd912304ed02138566.tar.gz lwn-812613591cb652344186c4cd912304ed02138566.zip | |
spi: omap2-mcspi: poll OMAP2_MCSPI_CHSTAT_RXS for PIO transfer
When running the spi-loopback-test with slower clock rate like 10 KHz,
the test for 251 bytes transfer was failed. This failure triggered an
spi-omap2-mcspi's error message "DMA RX last word empty".
This message means that PIO for reading the remaining bytes due to the
DMA transfer length reduction is failed. This problem can be fixed by
polling OMAP2_MCSPI_CHSTAT_RXS bit in channel status register to wait
until the receive buffer register is filled.
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-omap2-mcspi.c')
| -rw-r--r-- | drivers/spi/spi-omap2-mcspi.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 79800e991ccd..7275223dbcd4 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -454,6 +454,8 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, int elements = 0; int word_len, element_count; struct omap2_mcspi_cs *cs = spi->controller_state; + void __iomem *chstat_reg = cs->base + OMAP2_MCSPI_CHSTAT0; + mcspi = spi_master_get_devdata(spi->master); mcspi_dma = &mcspi->dma_channels[spi->chip_select]; count = xfer->len; @@ -549,8 +551,8 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, if (l & OMAP2_MCSPI_CHCONF_TURBO) { elements--; - if (likely(mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHSTAT0) - & OMAP2_MCSPI_CHSTAT_RXS)) { + if (!mcspi_wait_for_reg_bit(chstat_reg, + OMAP2_MCSPI_CHSTAT_RXS)) { u32 w; w = mcspi_read_cs_reg(spi, OMAP2_MCSPI_RX0); @@ -568,8 +570,7 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer, return count; } } - if (likely(mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHSTAT0) - & OMAP2_MCSPI_CHSTAT_RXS)) { + if (!mcspi_wait_for_reg_bit(chstat_reg, OMAP2_MCSPI_CHSTAT_RXS)) { u32 w; w = mcspi_read_cs_reg(spi, OMAP2_MCSPI_RX0); |