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Commit 9c1fbac6 authored by Samuel Holland's avatar Samuel Holland Committed by Greg Kroah-Hartman
Browse files

bus: sunxi-rsb: Support atomic transfers 



[ Upstream commit 077686da0e2162c4ea5ae0df205849c2a7a84479 ]

When communicating with a PMIC during system poweroff (pm_power_off()),
IRQs are disabled and we are in a RCU read-side critical section, so we
cannot use wait_for_completion_io_timeout(). Instead, poll the status
register for transfer completion.

Fixes: d787dcdb ("bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus")
Signed-off-by: default avatarSamuel Holland <samuel@sholland.org>
Reviewed-by: default avatarJernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20221114015749.28490-3-samuel@sholland.org


Signed-off-by: default avatarJernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 347875ff

drivers/bus/sunxi-rsb.c

+21 −8
Original line number Diff line number Diff line
@@ -268,6 +268,9 @@ EXPORT_SYMBOL_GPL(sunxi_rsb_driver_register); 
/* common code that starts a transfer */

static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)

{

	u32 int_mask, status;

	bool timeout;



	if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) {

		dev_dbg(rsb->dev, "RSB transfer still in progress\n");

		return -EBUSY;
@@ -275,13 +278,23 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) 


	reinit_completion(&rsb->complete);



	writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER,

	       rsb->regs + RSB_INTE);

	int_mask = RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER;

	writel(int_mask, rsb->regs + RSB_INTE);

	writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB,

	       rsb->regs + RSB_CTRL);



	if (!wait_for_completion_io_timeout(&rsb->complete,

					    msecs_to_jiffies(100))) {

	if (irqs_disabled()) {

		timeout = readl_poll_timeout_atomic(rsb->regs + RSB_INTS,

						    status, (status & int_mask),

						    10, 100000);

		writel(status, rsb->regs + RSB_INTS);

	} else {

		timeout = !wait_for_completion_io_timeout(&rsb->complete,

							  msecs_to_jiffies(100));

		status = rsb->status;

	}



	if (timeout) {

		dev_dbg(rsb->dev, "RSB timeout\n");



		/* abort the transfer */
@@ -293,18 +306,18 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) 
		return -ETIMEDOUT;

	}



	if (rsb->status & RSB_INTS_LOAD_BSY) {

	if (status & RSB_INTS_LOAD_BSY) {

		dev_dbg(rsb->dev, "RSB busy\n");

		return -EBUSY;

	}



	if (rsb->status & RSB_INTS_TRANS_ERR) {

		if (rsb->status & RSB_INTS_TRANS_ERR_ACK) {

	if (status & RSB_INTS_TRANS_ERR) {

		if (status & RSB_INTS_TRANS_ERR_ACK) {

			dev_dbg(rsb->dev, "RSB slave nack\n");

			return -EINVAL;

		}



		if (rsb->status & RSB_INTS_TRANS_ERR_DATA) {

		if (status & RSB_INTS_TRANS_ERR_DATA) {

			dev_dbg(rsb->dev, "RSB transfer data error\n");

			return -EIO;

		}