Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 32e22409 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: sh_mobile: terminate DMA reads properly 



DMA read requests could miss proper termination, so two more bytes would
have been read via PIO overwriting the end of the buffer with wrong
data. Make DMA stop handling more readable while we are here.

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent d5fd120e

drivers/i2c/busses/i2c-sh_mobile.c

+11 −1
Original line number Diff line number Diff line
@@ -139,6 +139,7 @@ struct sh_mobile_i2c_data { 
	int pos;

	int sr;

	bool send_stop;

	bool stop_after_dma;



	struct resource *res;

	struct dma_chan *dma_tx;
@@ -407,7 +408,7 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) 


	if (pd->pos == pd->msg->len) {

		/* Send stop if we haven't yet (DMA case) */

		if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY))

		if (pd->send_stop && pd->stop_after_dma)

			i2c_op(pd, OP_TX_STOP, 0);

		return 1;

	}
@@ -449,6 +450,13 @@ static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) 
		real_pos = pd->pos - 2;



		if (pd->pos == pd->msg->len) {

			if (pd->stop_after_dma) {

				/* Simulate PIO end condition after DMA transfer */

				i2c_op(pd, OP_RX_STOP, 0);

				pd->pos++;

				break;

			}



			if (real_pos < 0) {

				i2c_op(pd, OP_RX_STOP, 0);

				break;
@@ -536,6 +544,7 @@ static void sh_mobile_i2c_dma_callback(void *data) 


	sh_mobile_i2c_dma_unmap(pd);

	pd->pos = pd->msg->len;

	pd->stop_after_dma = true;



	iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);

}
@@ -726,6 +735,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, 
		bool do_start = pd->send_stop || !i;

		msg = &msgs[i];

		pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;

		pd->stop_after_dma = false;



		err = start_ch(pd, msg, do_start);

		if (err)