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bus: sunxi-rsb: Support atomic transfers

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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: d787dcdb9c ("bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20221114015749.28490-3-samuel@sholland.org
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
This commit is contained in:
Samuel Holland 2022-11-13 19:57:48 -06:00 committed by Jernej Skrabec
parent 5f4696ddca
commit 077686da0e
1 changed files with 21 additions and 8 deletions
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29
drivers/bus/sunxi-rsb.c
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@ -267,6 +267,9 @@ 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;
@ -274,13 +277,23 @@ 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 */
@ -292,18 +305,18 @@ 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;
}