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Commit 913f536c authored by Icenowy Zheng's avatar Icenowy Zheng Committed by Mark Brown
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spi: sun6i: Allow transfers larger than FIFO size 



The spi-sun6i driver have the same problem that spi-sun4i used to have
-- SPI transfers are limited to one FIFO depth.

This commit fixes this problem in the same way it's fixed in spi-sun4i.
See commit 19673791 ("spi: sun4i: Allow transfers larger than FIFO size")
for more information.

The sun6i SPI controllers features changeable interrupt trigger level, but I
set it to 3/4 of fifo depth, as same as the the sun4i SPI controllers.

Signed-off-by: default avatarIcenowy Zheng <icenowy@aosc.xyz>
Acked-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent c1ae3cfa

drivers/spi/spi-sun6i.c

+81 −9
Original line number Diff line number Diff line
@@ -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);
@@ -190,6 +226,17 @@ static int sun6i_spi_transfer_one(struct spi_master *master, 
	sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,

			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;

}