[PATCH 04/10] timer: cadence-ttc: Add timer_early functions

[Stefan Roese]

Hi Simon,
Hi Michal,

On 25.09.22 16:15, Simon Glass wrote:
> Hi Stefan,
> 
> On Wed, 21 Sept 2022 at 08:06, Stefan Roese <sr at denx.de> wrote:
>>
>> Currently this timer driver provides timer_get_boot_us() to support the
>> BOOTSTAGE functionality. This patch adds the timer_early functions so
>> that the "normal" timer functions can be used, when CONFIG_TIMER_EARLY
>> is enabled.
>>
>> timer_get_boot_us() will get removed in a follow-up patch, once the
>> BOOTSTAGE interface is migrated to timer_get_us().
>>
>> Signed-off-by: Stefan Roese <sr at denx.de>
>> Cc: Michal Simek <michal.simek at xilinx.com>
>> ---
>>   drivers/timer/cadence-ttc.c | 25 +++++++++++++++++++++++++
>>   1 file changed, 25 insertions(+)
>>
>> diff --git a/drivers/timer/cadence-ttc.c b/drivers/timer/cadence-ttc.c
>> index 2eff45060ad6..e26c7923a140 100644
>> --- a/drivers/timer/cadence-ttc.c
>> +++ b/drivers/timer/cadence-ttc.c
>> @@ -58,6 +58,31 @@ ulong timer_get_boot_us(void)
>>   }
>>   #endif
>>
>> +unsigned long notrace timer_early_get_rate(void)
>> +{
>> +       return 1;
>> +}
>> +
>> +u64 notrace timer_early_get_count(void)
>> +{
>> +       u64 ticks = 0;
>> +       u32 rate = 1;
>> +       u64 us;
>> +       int ret;
>> +
>> +       ret = dm_timer_init();
> 
> I don't think you can call this if you want to support bootstage,
> since driver model may not be inited.

Yes, thanks for noticing. Still, this code is copied from the original
timer_get_boot_us() function in this driver. Which also has problems
with early timer access AFAICT.

Michal, you are the author of the timer_get_boot_us() implementation
in commit 56c0e646c4f6a ("timer: cadence: Implement timer_get_boot_us").
How is this supposed to work in the early boot phase, before DM is
initialized?

Thanks,
Stefan

>> +       if (!ret) {
>> +               /* The timer is available */
>> +               rate = timer_get_rate(gd->timer);
>> +               timer_get_count(gd->timer, &ticks);
>> +       } else {
>> +               return 0;
>> +       }
>> +
>> +       us = (ticks * 1000) / rate;
>> +       return us;
>> +}
>> +
>>   static u64 cadence_ttc_get_count(struct udevice *dev)
>>   {
>>          struct cadence_ttc_priv *priv = dev_get_priv(dev);
>> --
>> 2.37.3
>>
> 
> REgards,
> Simon

Viele Grüße,
Stefan Roese

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