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| author | Heiner Kallweit <hkallweit1@gmail.com> | 2016-10-27 21:27:56 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2016-10-28 20:39:47 +0200 |
| commit | e508cea45bc31de87b35180a9ba5ef9572ffde3f (patch) | |
| tree | 2dbb4a80450a4693d6eefba97ec05a16469d6b7e /drivers/spi/spi-fsl-espi.c | |
| parent | spi: fsl-espi: extend and improve transfer error handling (diff) | |
| download | linux-e508cea45bc31de87b35180a9ba5ef9572ffde3f.tar.xz linux-e508cea45bc31de87b35180a9ba5ef9572ffde3f.zip | |
spi: fsl-espi: make better use of the RX FIFO
So far an interrupt is triggered whenever there's at least one byte
in the RX FIFO. This results in a unnecessarily high number of
interrupts.
Change this to generate an interrupt if
- RX FIFO is half full (except if all bytes to read fit into the
RX FIFO anyway)
- end of transfer has been reached
This way the number of interrupts can be significantly reduced.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-fsl-espi.c')
| -rw-r--r-- | drivers/spi/spi-fsl-espi.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index a9593f9691ec..239f0362df61 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -55,9 +55,10 @@ #define CSMODE_CG(x) ((x) << 3) #define FSL_ESPI_FIFO_SIZE 32 +#define FSL_ESPI_RXTHR 15 /* Default mode/csmode for eSPI controller */ -#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3)) +#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(FSL_ESPI_RXTHR)) #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \ | CSMODE_AFT(0) | CSMODE_CG(1)) @@ -263,6 +264,7 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) { struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master); + u32 mask; int ret; mpc8xxx_spi->rx_len = t->len; @@ -277,8 +279,11 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPCOM, (SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1))); - /* enable rx ints */ - fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, SPIM_RNE); + /* enable interrupts */ + mask = SPIM_DON; + if (mpc8xxx_spi->rx_len > FSL_ESPI_FIFO_SIZE) + mask |= SPIM_RXT; + fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, mask); /* Prevent filling the fifo from getting interrupted */ spin_lock_irq(&mpc8xxx_spi->lock); |