On Friday 30 March 2012 07:24 PM, Vaibhav Hiremath wrote:
> Current OMAP code supports couple of clocksource options based
> on compilation flag (CONFIG_OMAP_32K_TIMER). The 32KHz sync-timer
> and a gptimer which can run on 32KHz or system clock (e.g 38.4 MHz).
> So there can be 3 options -
>
> 1. 32KHz sync-timer
> 2. Sys_clock based (e.g 13/19.2/26/38.4 MHz) gptimer
> 3. 32KHz based gptimer.
>
> The optional gptimer based clocksource was added so that it can
> give the high precision than sync-timer, so expected usage was 2
> and not 3.
> Unfortunately option 2, clocksource doesn't meet the requirement of
> free-running clock as per clocksource need. It stops in low power states
> when sys_clock is cut. That makes gptimer based clocksource option
> useless for OMAP2/3/4 devices with sys_clock as a clock input.
> Option 3 will still work but it is no better than 32K sync-timer
> based clocksource.
>
> So ideally we can kill the gptimer based clocksource option but there
> are some OMAP based derivative SoCs like AM33XX which doesn't have
> 32K sync-timer hardware IP and need to fallback on 32KHz based gptimer
> clocksource.
> Considering above, make sync-timer and gptimer clocksource runtime
> selectable so that both OMAP and AMXXXX continue to use the same code.
>
> Use hwmod database lookup mechanism, through which at run-time
> we can identify availability of 32k-sync timer on the device,
> else fall back to gptimer.
>
> Signed-off-by: Vaibhav Hiremath <hvaibhav@xxxxxx>
> Signed-off-by: Felipe Balbi <balbi@xxxxxx>
> CC: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Cc: Benoit Cousson <b-cousson@xxxxxx>
> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> Cc: Paul Walmsley <paul@xxxxxxxxx>
> Cc: Tarun Kanti DebBarma <tarun.kanti@xxxxxx>
> Cc: Ming Lei <tom.leiming@xxxxxxxxx>
> ---
Thanks for the change log update Vaibhav.
Some more comments.
> arch/arm/mach-omap1/timer32k.c | 6 ++-
> arch/arm/mach-omap2/timer.c | 45 +++++++++-------
> arch/arm/plat-omap/counter_32k.c | 86 ++++++++++++-----------------
> arch/arm/plat-omap/include/plat/common.h | 2 +-
> 4 files changed, 68 insertions(+), 71 deletions(-)
>
> diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c
> index a2e6d07..3f96a00 100644
> --- a/arch/arm/mach-omap1/timer32k.c
> +++ b/arch/arm/mach-omap1/timer32k.c
> @@ -72,6 +72,7 @@
>
> /* 16xx specific defines */
> #define OMAP1_32K_TIMER_BASE 0xfffb9000
> +#define OMAP1_32KSYNC_TIMER_BASE 0xfffbc410
Shouldn't you just update OMAP1_32K_TIMER_BASE ?
> #define OMAP1_32K_TIMER_CR 0x08
> #define OMAP1_32K_TIMER_TVR 0x00
> #define OMAP1_32K_TIMER_TCR 0x04
> @@ -185,7 +186,10 @@ static __init void omap_init_32k_timer(void)
> */
> bool __init omap_32k_timer_init(void)
> {
> - omap_init_clocksource_32k();
> + u32 pbase;
> +
> + pbase = cpu_is_omap16xx() ? OMAP1_32KSYNC_TIMER_BASE : NULL;
> + omap_init_clocksource_32k(pbase, SZ_1K);
If pbase is NULL, you might not want to call the init.
> omap_init_32k_timer();
>
> return true;
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index 5c9acea..f35db1a 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
> }
>
> /* Clocksource code */
> -
> -#ifdef CONFIG_OMAP_32K_TIMER
> -/*
> - * When 32k-timer is enabled, don't use GPTimer for clocksource
> - * instead, just leave default clocksource which uses the 32k
> - * sync counter. See clocksource setup in plat-omap/counter_32k.c
> - */
> -
> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
> -{
> - omap_init_clocksource_32k();
> -}
> -
> -#else
> -
> static struct omap_dm_timer clksrc;
>
> /*
> @@ -280,13 +265,33 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
> const char *fck_source)
> {
> int res;
> + struct omap_hwmod *oh;
> + const char *oh_name = "counter_32k";
> +
> + /*
> + * First check for availability for 32k-sync timer.
> + *
> + * In case of failure in finding 32k_counter module or
> + * registering it as clocksource, execution will fallback to
> + * gp-timer.
> + */
> + oh = omap_hwmod_lookup(oh_name);
> + if (oh && oh->slaves_cnt != 0) {
> + u32 pbase;
> + unsigned long size;
> +
> + pbase = oh->slaves[0]->addr->pa_start + 0x10;
Don't hardcode the offset here. This is error prone when the IP
changes so use the register define.
> + size = oh->slaves[0]->addr->pa_end -
> + oh->slaves[0]->addr->pa_start;
> + res = omap_init_clocksource_32k(pbase, size);
> + if (!res)
> + return;
> + }
>
If 'OMAP_32K_TIMER' is not selected, does omap_init_clocksource_32k()
fails too ?
> + /* Fall back to gp-timer code */
> res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
> BUG_ON(res);
>
> - pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
> - gptimer_id, clksrc.rate);
> -
> __omap_dm_timer_load_start(&clksrc,
> OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
> setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
> @@ -294,8 +299,10 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
> if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
> pr_err("Could not register clocksource %s\n",
> clocksource_gpt.name);
> + else
> + pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
> + gptimer_id, clksrc.rate);
> }
> -#endif
>
> #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src, \
> clksrc_nr, clksrc_src) \
> diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
> index 5068fe5..c1af18c 100644
> --- a/arch/arm/plat-omap/counter_32k.c
> +++ b/arch/arm/plat-omap/counter_32k.c
> @@ -35,8 +35,6 @@
> */
> static void __iomem *timer_32k_base;
>
> -#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410
> -
> static u32 notrace omap_32k_read_sched_clock(void)
> {
> return timer_32k_base ? __raw_readl(timer_32k_base) : 0;
> @@ -68,54 +66,42 @@ void read_persistent_clock(struct timespec *ts)
> *ts = *tsp;
> }
>
> -int __init omap_init_clocksource_32k(void)
> +int __init omap_init_clocksource_32k(u32 pbase, unsigned long size)
> {
> - static char err[] __initdata = KERN_ERR
> - "%s: can't register clocksource!\n";
> -
> - if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> - u32 pbase;
> - unsigned long size = SZ_4K;
> - void __iomem *base;
> - struct clk *sync_32k_ick;
> -
> - if (cpu_is_omap16xx()) {
> - pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> - size = SZ_1K;
> - } else if (cpu_is_omap2420())
> - pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> - else if (cpu_is_omap2430())
> - pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> - else if (cpu_is_omap34xx())
> - pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> - else if (cpu_is_omap44xx())
> - pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> - else
> - return -ENODEV;
Thanks for thsi clean-up. Much appreciated.
Apart from the minor comments, patch looks fine to me.
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Regards
Santosh
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