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Commit 713a3a94 authored by Ulrich Hecht's avatar Ulrich Hecht Committed by Greg Kroah-Hartman
Browse files

i2c: sh_mobile: implement atomic transfers 



[ Upstream commit a49cc1fe9d64a2dc4e19b599204f403e5d25f44b ]

Implements atomic transfers to fix reboot/shutdown on r8a7790 Lager and
similar boards.

Signed-off-by: default avatarUlrich Hecht <uli+renesas@fpond.eu>
Tested-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
[wsa: some whitespace fixing]
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 37a048d7

drivers/i2c/busses/i2c-sh_mobile.c

+66 −20
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ struct sh_mobile_i2c_data { 
	int sr;

	bool send_stop;

	bool stop_after_dma;

	bool atomic_xfer;



	struct resource *res;

	struct dma_chan *dma_tx;
@@ -333,11 +334,13 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op 
		ret = iic_rd(pd, ICDR);

		break;

	case OP_RX_STOP: /* enable DTE interrupt, issue stop */

		if (!pd->atomic_xfer)

			iic_wr(pd, ICIC,

			       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);

		iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);

		break;

	case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */

		if (!pd->atomic_xfer)

			iic_wr(pd, ICIC,

			       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);

		ret = iic_rd(pd, ICDR);
@@ -435,6 +438,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) 


	if (wakeup) {

		pd->sr |= SW_DONE;

		if (!pd->atomic_xfer)

			wake_up(&pd->wait);

	}
@@ -587,6 +591,9 @@ static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, 
	pd->pos = -1;

	pd->sr = 0;



	if (pd->atomic_xfer)

		return;



	pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8);

	if (pd->dma_buf)

		sh_mobile_i2c_xfer_dma(pd);
@@ -643,15 +650,13 @@ static int poll_busy(struct sh_mobile_i2c_data *pd) 
	return i ? 0 : -ETIMEDOUT;

}



static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,

			      struct i2c_msg *msgs,

			      int num)

static int sh_mobile_xfer(struct sh_mobile_i2c_data *pd,

			 struct i2c_msg *msgs, int num)

{

	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);

	struct i2c_msg	*msg;

	int err = 0;

	int i;

	long timeout;

	long time_left;



	/* Wake up device and enable clock */

	pm_runtime_get_sync(pd->dev);
@@ -668,15 +673,35 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 
		if (do_start)

			i2c_op(pd, OP_START);



		if (pd->atomic_xfer) {

			unsigned long j = jiffies + pd->adap.timeout;



			time_left = time_before_eq(jiffies, j);

			while (time_left &&

			       !(pd->sr & (ICSR_TACK | SW_DONE))) {

				unsigned char sr = iic_rd(pd, ICSR);



				if (sr & (ICSR_AL   | ICSR_TACK |

					  ICSR_WAIT | ICSR_DTE)) {

					sh_mobile_i2c_isr(0, pd);

					udelay(150);

				} else {

					cpu_relax();

				}

				time_left = time_before_eq(jiffies, j);

			}

		} else {

			/* The interrupt handler takes care of the rest... */

		timeout = wait_event_timeout(pd->wait,

			time_left = wait_event_timeout(pd->wait,

					pd->sr & (ICSR_TACK | SW_DONE),

				       adapter->timeout);

					pd->adap.timeout);



		/* 'stop_after_dma' tells if DMA transfer was complete */

		i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg, pd->stop_after_dma);

			/* 'stop_after_dma' tells if DMA xfer was complete */

			i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg,

						 pd->stop_after_dma);

		}



		if (!timeout) {

		if (!time_left) {

			dev_err(pd->dev, "Transfer request timed out\n");

			if (pd->dma_direction != DMA_NONE)

				sh_mobile_i2c_cleanup_dma(pd);
@@ -702,6 +727,26 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 
	return err ?: num;

}



static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,

			      struct i2c_msg *msgs,

			      int num)

{

	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);



	pd->atomic_xfer = false;

	return sh_mobile_xfer(pd, msgs, num);

}



static int sh_mobile_i2c_xfer_atomic(struct i2c_adapter *adapter,

				     struct i2c_msg *msgs,

				     int num)

{

	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);



	pd->atomic_xfer = true;

	return sh_mobile_xfer(pd, msgs, num);

}



static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
@@ -710,6 +755,7 @@ static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) 
static const struct i2c_algorithm sh_mobile_i2c_algorithm = {

	.functionality = sh_mobile_i2c_func,

	.master_xfer = sh_mobile_i2c_xfer,

	.master_xfer_atomic = sh_mobile_i2c_xfer_atomic,

};



static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = {