Hi Peng,
On 24-01-22, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
>
> To i.MX95 System counter module, we use Read register space to get
> the counter, not the Control register space to get the counter, because
> System Manager firmware not allow Linux to read Control register space.
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/clocksource/timer-imx-sysctr.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
> index 5a7a951c4efc..3d3bc16388ed 100644
> --- a/drivers/clocksource/timer-imx-sysctr.c
> +++ b/drivers/clocksource/timer-imx-sysctr.c
> @@ -8,9 +8,12 @@
> #include "timer-of.h"
>
> #define CMP_OFFSET 0x10000
> +#define RD_OFFSET 0x20000
>
> #define CNTCV_LO 0x8
> #define CNTCV_HI 0xc
> +#define CNTCV_LO_IMX95 (RD_OFFSET + 0x8)
> +#define CNTCV_HI_IMX95 (RD_OFFSET + 0xc)
> #define CMPCV_LO (CMP_OFFSET + 0x20)
> #define CMPCV_HI (CMP_OFFSET + 0x24)
> #define CMPCR (CMP_OFFSET + 0x2c)
> @@ -22,6 +25,8 @@
>
> static void __iomem *sys_ctr_base __ro_after_init;
> static u32 cmpcr __ro_after_init;
> +static u32 cntcv_hi = CNTCV_HI;
> +static u32 cntcv_lo = CNTCV_LO;
>
> static void sysctr_timer_enable(bool enable)
> {
> @@ -43,9 +48,9 @@ static inline u64 sysctr_read_counter(void)
> u32 cnt_hi, tmp_hi, cnt_lo;
>
> do {
> - cnt_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
> - cnt_lo = readl_relaxed(sys_ctr_base + CNTCV_LO);
> - tmp_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
> + cnt_hi = readl_relaxed(sys_ctr_base + cntcv_hi);
> + cnt_lo = readl_relaxed(sys_ctr_base + cntcv_lo);
> + tmp_hi = readl_relaxed(sys_ctr_base + cntcv_hi);
> } while (tmp_hi != cnt_hi);
>
> return ((u64) cnt_hi << 32) | cnt_lo;
> @@ -139,6 +144,11 @@ static int __init sysctr_timer_init(struct device_node *np)
> to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV;
> }
>
> + if (of_device_is_compatible(np, "nxp,imx95-sysctr-timer")) {
> + cntcv_hi = CNTCV_HI_IMX95;
> + cntcv_lo = CNTCV_LO_IMX95;
> + }
I'm not a fan of this, since TIMER_OF_DECLARE() can do the compat check.
So instead of using fallback bindings just use the correct binding
within the dts file. Also I'm not a fan of this clobal variable setting
albeit there is just one instance _yet_ we really should instead rework
this driver a bit and instead provide a i.MX95 specific
sysctr_read_counter() function. This is clearly a bit more work but IMO
a cleaner approach. Also afterwards once you add i.MX9x which is again a
bit different would gain from this work.
Regards,
Marco
> +
> sys_ctr_base = timer_of_base(&to_sysctr);
> cmpcr = readl(sys_ctr_base + CMPCR);
> cmpcr &= ~SYS_CTR_EN;
> --
> 2.37.1
>
>
>
