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SubjectRe: [PATCH v3 3/3] bus: sunxi-rsb: Clear interrupt status before each transfer
Date
Hi Samuel,

Dne ponedeljek, 14. november 2022 ob 02:57:49 CET je Samuel Holland
napisal(a):
> Currently, the driver clears the interrupt status bits after anything
> could have set them. However, this requires duplicating the same logic
> in several places.
>
> Instead of clearing the status flags in the interrupt handler, disable
> all further interrupts by clearing the RSB_CTRL_GLOBAL_INT_ENB bit.

where is this bit cleared?

> Then we can delay the status register write until the start of the next
> transfer, so it only has to be done in one place.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
>
> Changes in v3:
> - Add a patch refactoring how the status bits are cleared
>
> drivers/bus/sunxi-rsb.c | 20 +++++---------------
> 1 file changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
> index 3aa91aed3bf7..cb622e60897b 100644
> --- a/drivers/bus/sunxi-rsb.c
> +++ b/drivers/bus/sunxi-rsb.c
> @@ -279,6 +279,7 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)
>
> int_mask = RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR |
RSB_INTS_TRANS_OVER;
> writel(int_mask, rsb->regs + RSB_INTE);
> + writel(int_mask, rsb->regs + RSB_INTS);

Wouldn't be better to clear status before enabling interrupts? Unless global
interrupt flag is cleared beforehand, but I don't see that anywhere.

Best regards,
Jernej

> writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB,
> rsb->regs + RSB_CTRL);
>
> @@ -286,7 +287,6 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)
> 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));
> @@ -296,12 +296,9 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)
> if (timeout) {
> dev_dbg(rsb->dev, "RSB timeout\n");
>
> - /* abort the transfer */
> + /* abort the transfer and disable interrupts */
> writel(RSB_CTRL_ABORT_TRANS, rsb->regs + RSB_CTRL);
>
> - /* clear any interrupt flags */
> - writel(readl(rsb->regs + RSB_INTS), rsb->regs +
RSB_INTS);
> -
> return -ETIMEDOUT;
> }
>
> @@ -503,15 +500,11 @@ EXPORT_SYMBOL_GPL(__devm_regmap_init_sunxi_rsb);
> static irqreturn_t sunxi_rsb_irq(int irq, void *dev_id)
> {
> struct sunxi_rsb *rsb = dev_id;
> - u32 status;
>
> - status = readl(rsb->regs + RSB_INTS);
> - rsb->status = status;
> + /* disable interrupts */
> + writel(0, rsb->regs + RSB_CTRL);
>
> - /* Clear interrupts */
> - status &= (RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR |
> - RSB_INTS_TRANS_OVER);
> - writel(status, rsb->regs + RSB_INTS);
> + rsb->status = readl(rsb->regs + RSB_INTS);
>
> complete(&rsb->complete);
>
> @@ -532,9 +525,6 @@ static int sunxi_rsb_init_device_mode(struct sunxi_rsb
> *rsb) if (reg & RSB_DMCR_DEVICE_START)
> ret = -ETIMEDOUT;
>
> - /* clear interrupt status bits */
> - writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
> -
> return ret;
> }




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