On Fri, 1 Mar 2024 at 19:23, Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote:
>
> The delays used with the various atomic polling loops are already at the
> maximum value of ~10µs, as documented for read_poll_timeout_atomic().
> Hence reduce the delays from 10 to 1 µs. Increase PDRESR_RETRIES
> accordingly, to retain the old (generous) timeout value.
>
> Measurements on R-Car V3U, S4, V4H, and V4M show that the first three
> polling loops rarely (never?) loop, so the actual delay does not matter.
> The fourth loop (for SYSCISCR in rcar_gen4_sysc_power()) typically ran
> for one or two cycles with the old delay. With the reduced delay, it
> typically runs for two to 17 cycles, and finishes earlier than before,
> which can reduce loop time up to a factor of three.
>
> While at it, rename the SYSCISR_{TIMEOUT,DELAY_US} definitions to
> SYSCISCR_{TIMEOUT,DELAY_US}, to match the register name they apply to.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Applied for next, thanks!
Kind regards
Uffe
> ---
> drivers/pmdomain/renesas/rcar-gen4-sysc.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pmdomain/renesas/rcar-gen4-sysc.c b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> index 728248659a97e8cc..66409cff2083fcd8 100644
> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> @@ -50,13 +50,13 @@
> #define SYSCSR_BUSY GENMASK(1, 0) /* All bit sets is not busy */
>
> #define SYSCSR_TIMEOUT 10000
> -#define SYSCSR_DELAY_US 10
> +#define SYSCSR_DELAY_US 1
>
> -#define PDRESR_RETRIES 1000
> -#define PDRESR_DELAY_US 10
> +#define PDRESR_RETRIES 10000
> +#define PDRESR_DELAY_US 1
>
> -#define SYSCISR_TIMEOUT 10000
> -#define SYSCISR_DELAY_US 10
> +#define SYSCISCR_TIMEOUT 10000
> +#define SYSCISCR_DELAY_US 1
>
> #define RCAR_GEN4_PD_ALWAYS_ON 64
> #define NUM_DOMAINS_EACH_REG BITS_PER_TYPE(u32)
> @@ -97,7 +97,7 @@ static int clear_irq_flags(unsigned int reg_idx, unsigned int isr_mask)
>
> ret = readl_poll_timeout_atomic(rcar_gen4_sysc_base + SYSCISCR(reg_idx),
> val, !(val & isr_mask),
> - SYSCISR_DELAY_US, SYSCISR_TIMEOUT);
> + SYSCISCR_DELAY_US, SYSCISCR_TIMEOUT);
> if (ret < 0) {
> pr_err("\n %s : Can not clear IRQ flags in SYSCISCR", __func__);
> return -EIO;
> @@ -157,7 +157,7 @@ static int rcar_gen4_sysc_power(u8 pdr, bool on)
> /* Wait until the power shutoff or resume request has completed * */
> ret = readl_poll_timeout_atomic(rcar_gen4_sysc_base + SYSCISCR(reg_idx),
> val, (val & isr_mask),
> - SYSCISR_DELAY_US, SYSCISR_TIMEOUT);
> + SYSCISCR_DELAY_US, SYSCISCR_TIMEOUT);
> if (ret < 0) {
> ret = -EIO;
> goto out;
> --
> 2.34.1
>
