On 3/21/25 4:40 PM, André Draszik wrote:
> acpm_dequeue_by_polling() uses a loop counter and assumes that each
> iteration of the loop takes 20us. It may take longer, though, because
> usleep_range() may sleep a different amount.
>
> Switch to using ktime_get() / ktime_after() to detect the timeout
> condition more reliably.
>
> This change also makes the code easier to follow and it allows us to
> adjust the sleep without having to adjust the loop counter exit
> condition. This will come in useful in a follow-up patch that changes
> the delays.
>
> Signed-off-by: André Draszik <andre.draszik@xxxxxxxxxx>
> ---
> drivers/firmware/samsung/exynos-acpm.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/firmware/samsung/exynos-acpm.c b/drivers/firmware/samsung/exynos-acpm.c
> index a85b2dbdd9f0d7b1f327f54a0a283e4f32587a98..d7ed6b77a957af5db5beba7deecce13ac7b30fd2 100644
> --- a/drivers/firmware/samsung/exynos-acpm.c
> +++ b/drivers/firmware/samsung/exynos-acpm.c
> @@ -32,8 +32,7 @@
>
> #define ACPM_PROTOCOL_SEQNUM GENMASK(21, 16)
>
> -/* The unit of counter is 20 us. 5000 * 20 = 100 ms */
> -#define ACPM_POLL_TIMEOUT 5000
> +#define ACPM_POLL_TIMEOUT_US (100 * USEC_PER_MSEC)
> #define ACPM_TX_TIMEOUT_US 500000
>
> #define ACPM_GS101_INITDATA_BASE 0xa000
> @@ -284,12 +283,13 @@ static int acpm_dequeue_by_polling(struct acpm_chan *achan,
> const struct acpm_xfer *xfer)
> {
> struct device *dev = achan->acpm->dev;
> - unsigned int cnt_20us = 0;
> + ktime_t timeout;
#include <linux/ktime.h>
> u32 seqnum;
> int ret;
>
> seqnum = FIELD_GET(ACPM_PROTOCOL_SEQNUM, xfer->txd[0]);
>
> + timeout = ktime_add_us(ktime_get(), ACPM_POLL_TIMEOUT_US);
> do {
> ret = acpm_get_rx(achan, xfer);
> if (ret)
> @@ -300,11 +300,10 @@ static int acpm_dequeue_by_polling(struct acpm_chan *achan,
>
> /* Determined experimentally. */
> usleep_range(20, 30);
> - cnt_20us++;
> - } while (cnt_20us < ACPM_POLL_TIMEOUT);
> + } while (!ktime_after(ktime_get(), timeout));
ktime_before()
With these addressed:
Reviewed-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
