diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-sun6i.c | 90 |
1 files changed, 81 insertions, 9 deletions
diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c index e3114832c485..6e9ca93db9bf 100644 --- a/drivers/spi/spi-sun6i.c +++ b/drivers/spi/spi-sun6i.c @@ -46,13 +46,19 @@ #define SUN6I_TFR_CTL_XCH BIT(31) #define SUN6I_INT_CTL_REG 0x10 +#define SUN6I_INT_CTL_RF_RDY BIT(0) +#define SUN6I_INT_CTL_TF_ERQ BIT(4) #define SUN6I_INT_CTL_RF_OVF BIT(8) #define SUN6I_INT_CTL_TC BIT(12) #define SUN6I_INT_STA_REG 0x14 #define SUN6I_FIFO_CTL_REG 0x18 +#define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK 0xff +#define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS 0 #define SUN6I_FIFO_CTL_RF_RST BIT(15) +#define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK 0xff +#define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS 16 #define SUN6I_FIFO_CTL_TF_RST BIT(31) #define SUN6I_FIFO_STA_REG 0x1c @@ -68,14 +74,16 @@ #define SUN6I_CLK_CTL_CDR1(div) (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8) #define SUN6I_CLK_CTL_DRS BIT(12) +#define SUN6I_MAX_XFER_SIZE 0xffffff + #define SUN6I_BURST_CNT_REG 0x30 -#define SUN6I_BURST_CNT(cnt) ((cnt) & 0xffffff) +#define SUN6I_BURST_CNT(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE) #define SUN6I_XMIT_CNT_REG 0x34 -#define SUN6I_XMIT_CNT(cnt) ((cnt) & 0xffffff) +#define SUN6I_XMIT_CNT(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE) #define SUN6I_BURST_CTL_CNT_REG 0x38 -#define SUN6I_BURST_CTL_CNT_STC(cnt) ((cnt) & 0xffffff) +#define SUN6I_BURST_CTL_CNT_STC(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE) #define SUN6I_TXDATA_REG 0x200 #define SUN6I_RXDATA_REG 0x300 @@ -105,6 +113,31 @@ static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value) writel(value, sspi->base_addr + reg); } +static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi) +{ + u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG); + + reg >>= SUN6I_FIFO_STA_TF_CNT_BITS; + + return reg & SUN6I_FIFO_STA_TF_CNT_MASK; +} + +static inline void sun6i_spi_enable_interrupt(struct sun6i_spi *sspi, u32 mask) +{ + u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG); + + reg |= mask; + sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg); +} + +static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask) +{ + u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG); + + reg &= ~mask; + sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg); +} + static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len) { u32 reg, cnt; @@ -127,10 +160,13 @@ static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len) static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi, int len) { + u32 cnt; u8 byte; - if (len > sspi->len) - len = sspi->len; + /* See how much data we can fit */ + cnt = sspi->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi); + + len = min3(len, (int)cnt, sspi->len); while (len--) { byte = sspi->tx_buf ? *sspi->tx_buf++ : 0; @@ -170,12 +206,12 @@ static int sun6i_spi_transfer_one(struct spi_master *master, struct sun6i_spi *sspi = spi_master_get_devdata(master); unsigned int mclk_rate, div, timeout; unsigned int start, end, tx_time; + unsigned int trig_level; unsigned int tx_len = 0; int ret = 0; u32 reg; - /* We don't support transfer larger than the FIFO */ - if (tfr->len > sspi->fifo_depth) + if (tfr->len > SUN6I_MAX_XFER_SIZE) return -EINVAL; reinit_completion(&sspi->done); @@ -191,6 +227,17 @@ static int sun6i_spi_transfer_one(struct spi_master *master, SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST); /* + * Setup FIFO interrupt trigger level + * Here we choose 3/4 of the full fifo depth, as it's the hardcoded + * value used in old generation of Allwinner SPI controller. + * (See spi-sun4i.c) + */ + trig_level = sspi->fifo_depth / 4 * 3; + sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG, + (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) | + (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS)); + + /* * Setup the transfer control register: Chip Select, * polarities, etc. */ @@ -274,6 +321,10 @@ static int sun6i_spi_transfer_one(struct spi_master *master, /* Enable the interrupts */ sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC); + sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TC | + SUN6I_INT_CTL_RF_RDY); + if (tx_len > sspi->fifo_depth) + sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ); /* Start the transfer */ reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); @@ -293,8 +344,6 @@ static int sun6i_spi_transfer_one(struct spi_master *master, goto out; } - sun6i_spi_drain_fifo(sspi, sspi->fifo_depth); - out: sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0); @@ -309,10 +358,33 @@ static irqreturn_t sun6i_spi_handler(int irq, void *dev_id) /* Transfer complete */ if (status & SUN6I_INT_CTL_TC) { sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC); + sun6i_spi_drain_fifo(sspi, sspi->fifo_depth); complete(&sspi->done); return IRQ_HANDLED; } + /* Receive FIFO 3/4 full */ + if (status & SUN6I_INT_CTL_RF_RDY) { + sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH); + /* Only clear the interrupt _after_ draining the FIFO */ + sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY); + return IRQ_HANDLED; + } + + /* Transmit FIFO 3/4 empty */ + if (status & SUN6I_INT_CTL_TF_ERQ) { + sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH); + + if (!sspi->len) + /* nothing left to transmit */ + sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ); + + /* Only clear the interrupt _after_ re-seeding the FIFO */ + sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ); + + return IRQ_HANDLED; + } + return IRQ_NONE; } |