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path: root/drivers/spi/spi-sun4i.c
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Diffstat (limited to 'drivers/spi/spi-sun4i.c')
-rw-r--r--drivers/spi/spi-sun4i.c75
1 files changed, 67 insertions, 8 deletions
diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
index 4969dc10684a..c5cd635c28f3 100644
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -46,6 +46,8 @@
#define SUN4I_CTL_TP BIT(18)
#define SUN4I_INT_CTL_REG 0x0c
+#define SUN4I_INT_CTL_RF_F34 BIT(4)
+#define SUN4I_INT_CTL_TF_E34 BIT(12)
#define SUN4I_INT_CTL_TC BIT(16)
#define SUN4I_INT_STA_REG 0x10
@@ -61,11 +63,14 @@
#define SUN4I_CLK_CTL_CDR1(div) (((div) & SUN4I_CLK_CTL_CDR1_MASK) << 8)
#define SUN4I_CLK_CTL_DRS BIT(12)
+#define SUN4I_MAX_XFER_SIZE 0xffffff
+
#define SUN4I_BURST_CNT_REG 0x20
-#define SUN4I_BURST_CNT(cnt) ((cnt) & 0xffffff)
+#define SUN4I_BURST_CNT(cnt) ((cnt) & SUN4I_MAX_XFER_SIZE)
#define SUN4I_XMIT_CNT_REG 0x24
-#define SUN4I_XMIT_CNT(cnt) ((cnt) & 0xffffff)
+#define SUN4I_XMIT_CNT(cnt) ((cnt) & SUN4I_MAX_XFER_SIZE)
+
#define SUN4I_FIFO_STA_REG 0x28
#define SUN4I_FIFO_STA_RF_CNT_MASK 0x7f
@@ -96,6 +101,31 @@ static inline void sun4i_spi_write(struct sun4i_spi *sspi, u32 reg, u32 value)
writel(value, sspi->base_addr + reg);
}
+static inline u32 sun4i_spi_get_tx_fifo_count(struct sun4i_spi *sspi)
+{
+ u32 reg = sun4i_spi_read(sspi, SUN4I_FIFO_STA_REG);
+
+ reg >>= SUN4I_FIFO_STA_TF_CNT_BITS;
+
+ return reg & SUN4I_FIFO_STA_TF_CNT_MASK;
+}
+
+static inline void sun4i_spi_enable_interrupt(struct sun4i_spi *sspi, u32 mask)
+{
+ u32 reg = sun4i_spi_read(sspi, SUN4I_INT_CTL_REG);
+
+ reg |= mask;
+ sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, reg);
+}
+
+static inline void sun4i_spi_disable_interrupt(struct sun4i_spi *sspi, u32 mask)
+{
+ u32 reg = sun4i_spi_read(sspi, SUN4I_INT_CTL_REG);
+
+ reg &= ~mask;
+ sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, reg);
+}
+
static inline void sun4i_spi_drain_fifo(struct sun4i_spi *sspi, int len)
{
u32 reg, cnt;
@@ -118,10 +148,13 @@ static inline void sun4i_spi_drain_fifo(struct sun4i_spi *sspi, int len)
static inline void sun4i_spi_fill_fifo(struct sun4i_spi *sspi, int len)
{
+ u32 cnt;
u8 byte;
- if (len > sspi->len)
- len = sspi->len;
+ /* See how much data we can fit */
+ cnt = SUN4I_FIFO_DEPTH - sun4i_spi_get_tx_fifo_count(sspi);
+
+ len = min3(len, (int)cnt, sspi->len);
while (len--) {
byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
@@ -184,10 +217,10 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
u32 reg;
/* We don't support transfer larger than the FIFO */
- if (tfr->len > SUN4I_FIFO_DEPTH)
+ if (tfr->len > SUN4I_MAX_XFER_SIZE)
return -EMSGSIZE;
- if (tfr->tx_buf && tfr->len >= SUN4I_FIFO_DEPTH)
+ if (tfr->tx_buf && tfr->len >= SUN4I_MAX_XFER_SIZE)
return -EMSGSIZE;
reinit_completion(&sspi->done);
@@ -286,7 +319,11 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH - 1);
/* Enable the interrupts */
- sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC);
+ sun4i_spi_enable_interrupt(sspi, SUN4I_INT_CTL_TC |
+ SUN4I_INT_CTL_RF_F34);
+ /* Only enable Tx FIFO interrupt if we really need it */
+ if (tx_len > SUN4I_FIFO_DEPTH)
+ sun4i_spi_enable_interrupt(sspi, SUN4I_INT_CTL_TF_E34);
/* Start the transfer */
reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
@@ -306,7 +343,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
goto out;
}
- sun4i_spi_drain_fifo(sspi, SUN4I_FIFO_DEPTH);
out:
sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, 0);
@@ -322,10 +358,33 @@ static irqreturn_t sun4i_spi_handler(int irq, void *dev_id)
/* Transfer complete */
if (status & SUN4I_INT_CTL_TC) {
sun4i_spi_write(sspi, SUN4I_INT_STA_REG, SUN4I_INT_CTL_TC);
+ sun4i_spi_drain_fifo(sspi, SUN4I_FIFO_DEPTH);
complete(&sspi->done);
return IRQ_HANDLED;
}
+ /* Receive FIFO 3/4 full */
+ if (status & SUN4I_INT_CTL_RF_F34) {
+ sun4i_spi_drain_fifo(sspi, SUN4I_FIFO_DEPTH);
+ /* Only clear the interrupt _after_ draining the FIFO */
+ sun4i_spi_write(sspi, SUN4I_INT_STA_REG, SUN4I_INT_CTL_RF_F34);
+ return IRQ_HANDLED;
+ }
+
+ /* Transmit FIFO 3/4 empty */
+ if (status & SUN4I_INT_CTL_TF_E34) {
+ sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH);
+
+ if (!sspi->len)
+ /* nothing left to transmit */
+ sun4i_spi_disable_interrupt(sspi, SUN4I_INT_CTL_TF_E34);
+
+ /* Only clear the interrupt _after_ re-seeding the FIFO */
+ sun4i_spi_write(sspi, SUN4I_INT_STA_REG, SUN4I_INT_CTL_TF_E34);
+
+ return IRQ_HANDLED;
+ }
+
return IRQ_NONE;
}