* [PATCH] loongarch: time: Derive max_delta from prcfg1 tmrbits
@ 2025-01-02 14:05 Jiaxun Yang
2025-01-03 2:36 ` Huacai Chen
0 siblings, 1 reply; 3+ messages in thread
From: Jiaxun Yang @ 2025-01-02 14:05 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui; +Cc: loongarch, linux-kernel, Jiaxun Yang
As per arch spec, maximum timer bits is configurable and
should not be hardcoded in any way.
Use prcfg1 tmrbits to determine clockevent's max_delta
to be conformance.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
LA32R doesn't have prcfg, maybe we should handle this
during cpu-probe and save it in cpuinfo_loongarch,
What's your opinion, Huacai?
---
arch/loongarch/include/asm/loongarch.h | 1 -
arch/loongarch/kernel/time.c | 7 ++++++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index 64ad277e096edd7d77af6f37e234d68e571764a4..a3cc4f8d4c4a0b0521ef2b76c87fa57eca417d75 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -466,7 +466,6 @@
#define LOONGARCH_CSR_TCFG 0x41 /* Timer config */
#define CSR_TCFG_VAL_SHIFT 2
-#define CSR_TCFG_VAL_WIDTH 48
#define CSR_TCFG_VAL (_ULCAST_(0x3fffffffffff) << CSR_TCFG_VAL_SHIFT)
#define CSR_TCFG_PERIOD_SHIFT 1
#define CSR_TCFG_PERIOD (_ULCAST_(0x1) << CSR_TCFG_PERIOD_SHIFT)
diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
index a07d7eff4dc5fb0f41f5fad02698ff7a84c7bc8a..bde2297f139c2d5e26894a2ebc1748cc6fef3146 100644
--- a/arch/loongarch/kernel/time.c
+++ b/arch/loongarch/kernel/time.c
@@ -126,16 +126,21 @@ void sync_counter(void)
int constant_clockevent_init(void)
{
+ uint32_t tmrbits;
unsigned int cpu = smp_processor_id();
#ifdef CONFIG_PREEMPT_RT
unsigned long min_delta = 100;
#else
unsigned long min_delta = 1000;
#endif
- unsigned long max_delta = (1UL << 48) - 1;
+ unsigned long max_delta;
struct clock_event_device *cd;
static int irq = 0, timer_irq_installed = 0;
+ tmrbits = read_csr_prcfg1() & CSR_CONF1_TMRBITS;
+ tmrbits = tmrbits >> CSR_CONF1_TMRBITS_SHIFT;
+ max_delta = CLOCKSOURCE_MASK(tmrbits + 1);
+
if (!timer_irq_installed) {
irq = get_percpu_irq(INT_TI);
if (irq < 0)
---
base-commit: 8155b4ef3466f0e289e8fcc9e6e62f3f4dceeac2
change-id: 20241223-la-misc-d610d14f947e
Best regards,
--
Jiaxun Yang <jiaxun.yang@flygoat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] loongarch: time: Derive max_delta from prcfg1 tmrbits
2025-01-02 14:05 [PATCH] loongarch: time: Derive max_delta from prcfg1 tmrbits Jiaxun Yang
@ 2025-01-03 2:36 ` Huacai Chen
2025-01-03 9:07 ` Jiaxun Yang
0 siblings, 1 reply; 3+ messages in thread
From: Huacai Chen @ 2025-01-03 2:36 UTC (permalink / raw)
To: Jiaxun Yang; +Cc: WANG Xuerui, loongarch, linux-kernel
Hi, Jiaxun,
On Thu, Jan 2, 2025 at 10:05 PM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
> As per arch spec, maximum timer bits is configurable and
> should not be hardcoded in any way.
>
> Use prcfg1 tmrbits to determine clockevent's max_delta
> to be conformance.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> LA32R doesn't have prcfg, maybe we should handle this
> during cpu-probe and save it in cpuinfo_loongarch,
>
> What's your opinion, Huacai?
> ---
> arch/loongarch/include/asm/loongarch.h | 1 -
> arch/loongarch/kernel/time.c | 7 ++++++-
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
> index 64ad277e096edd7d77af6f37e234d68e571764a4..a3cc4f8d4c4a0b0521ef2b76c87fa57eca417d75 100644
> --- a/arch/loongarch/include/asm/loongarch.h
> +++ b/arch/loongarch/include/asm/loongarch.h
> @@ -466,7 +466,6 @@
>
> #define LOONGARCH_CSR_TCFG 0x41 /* Timer config */
> #define CSR_TCFG_VAL_SHIFT 2
> -#define CSR_TCFG_VAL_WIDTH 48
> #define CSR_TCFG_VAL (_ULCAST_(0x3fffffffffff) << CSR_TCFG_VAL_SHIFT)
> #define CSR_TCFG_PERIOD_SHIFT 1
> #define CSR_TCFG_PERIOD (_ULCAST_(0x1) << CSR_TCFG_PERIOD_SHIFT)
> diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
> index a07d7eff4dc5fb0f41f5fad02698ff7a84c7bc8a..bde2297f139c2d5e26894a2ebc1748cc6fef3146 100644
> --- a/arch/loongarch/kernel/time.c
> +++ b/arch/loongarch/kernel/time.c
> @@ -126,16 +126,21 @@ void sync_counter(void)
>
> int constant_clockevent_init(void)
> {
> + uint32_t tmrbits;
tmr is a strange short name, you can use timer_bits or tbits for short.
> unsigned int cpu = smp_processor_id();
> #ifdef CONFIG_PREEMPT_RT
> unsigned long min_delta = 100;
> #else
> unsigned long min_delta = 1000;
> #endif
> - unsigned long max_delta = (1UL << 48) - 1;
> + unsigned long max_delta;
> struct clock_event_device *cd;
> static int irq = 0, timer_irq_installed = 0;
>
> + tmrbits = read_csr_prcfg1() & CSR_CONF1_TMRBITS;
> + tmrbits = tmrbits >> CSR_CONF1_TMRBITS_SHIFT;
> + max_delta = CLOCKSOURCE_MASK(tmrbits + 1);
I prefer to evaluate the tbits and max_delta directly when declaring them.
Huacai
> +
> if (!timer_irq_installed) {
> irq = get_percpu_irq(INT_TI);
> if (irq < 0)
>
> ---
> base-commit: 8155b4ef3466f0e289e8fcc9e6e62f3f4dceeac2
> change-id: 20241223-la-misc-d610d14f947e
>
> Best regards,
> --
> Jiaxun Yang <jiaxun.yang@flygoat.com>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] loongarch: time: Derive max_delta from prcfg1 tmrbits
2025-01-03 2:36 ` Huacai Chen
@ 2025-01-03 9:07 ` Jiaxun Yang
0 siblings, 0 replies; 3+ messages in thread
From: Jiaxun Yang @ 2025-01-03 9:07 UTC (permalink / raw)
To: Huacai Chen; +Cc: Xuerui Wang, loongarch, linux-kernel
在2025年1月3日一月 上午2:36，Huacai Chen写道：
> Hi, Jiaxun,
>
> On Thu, Jan 2, 2025 at 10:05 PM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>>
>> As per arch spec, maximum timer bits is configurable and
>> should not be hardcoded in any way.
>>
>> Use prcfg1 tmrbits to determine clockevent's max_delta
>> to be conformance.
>>
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>> ---
>> LA32R doesn't have prcfg, maybe we should handle this
>> during cpu-probe and save it in cpuinfo_loongarch,
>>
>> What's your opinion, Huacai?
>> ---
>> arch/loongarch/include/asm/loongarch.h | 1 -
>> arch/loongarch/kernel/time.c | 7 ++++++-
>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
>> index 64ad277e096edd7d77af6f37e234d68e571764a4..a3cc4f8d4c4a0b0521ef2b76c87fa57eca417d75 100644
>> --- a/arch/loongarch/include/asm/loongarch.h
>> +++ b/arch/loongarch/include/asm/loongarch.h
>> @@ -466,7 +466,6 @@
>>
>> #define LOONGARCH_CSR_TCFG 0x41 /* Timer config */
>> #define CSR_TCFG_VAL_SHIFT 2
>> -#define CSR_TCFG_VAL_WIDTH 48
>> #define CSR_TCFG_VAL (_ULCAST_(0x3fffffffffff) << CSR_TCFG_VAL_SHIFT)
>> #define CSR_TCFG_PERIOD_SHIFT 1
>> #define CSR_TCFG_PERIOD (_ULCAST_(0x1) << CSR_TCFG_PERIOD_SHIFT)
>> diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
>> index a07d7eff4dc5fb0f41f5fad02698ff7a84c7bc8a..bde2297f139c2d5e26894a2ebc1748cc6fef3146 100644
>> --- a/arch/loongarch/kernel/time.c
>> +++ b/arch/loongarch/kernel/time.c
>> @@ -126,16 +126,21 @@ void sync_counter(void)
>>
>> int constant_clockevent_init(void)
>> {
>> + uint32_t tmrbits;
> tmr is a strange short name, you can use timer_bits or tbits for short.
That’s the one from the manual :-( I’d agree with you though.
>
>> unsigned int cpu = smp_processor_id();
>> #ifdef CONFIG_PREEMPT_RT
>> unsigned long min_delta = 100;
>> #else
>> unsigned long min_delta = 1000;
>> #endif
>> - unsigned long max_delta = (1UL << 48) - 1;
>> + unsigned long max_delta;
>> struct clock_event_device *cd;
>> static int irq = 0, timer_irq_installed = 0;
>>
>> + tmrbits = read_csr_prcfg1() & CSR_CONF1_TMRBITS;
>> + tmrbits = tmrbits >> CSR_CONF1_TMRBITS_SHIFT;
>> + max_delta = CLOCKSOURCE_MASK(tmrbits + 1);
> I prefer to evaluate the tbits and max_delta directly when declaring them.
Will do in v2.
Thanks
>
>
> Huacai
>> +
>> if (!timer_irq_installed) {
>> irq = get_percpu_irq(INT_TI);
>> if (irq < 0)
>>
>> ---
>> base-commit: 8155b4ef3466f0e289e8fcc9e6e62f3f4dceeac2
>> change-id: 20241223-la-misc-d610d14f947e
>>
>> Best regards,
>> --
>> Jiaxun Yang <jiaxun.yang@flygoat.com>
>>
--
- Jiaxun
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-01-02 14:05 [PATCH] loongarch: time: Derive max_delta from prcfg1 tmrbits Jiaxun Yang
2025-01-03 2:36 ` Huacai Chen
2025-01-03 9:07 ` Jiaxun Yang
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