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SubjectRe: [PATCH] MIPS: cevt-r4k: Enable intimer for Loongson64 CPUs with extimer
Hi,

Le mer. 23 sept. 2020 à 19:02, Jiaxun Yang <jiaxun.yang@flygoat.com> a
écrit :
> Loongson64C and Loongson64G have extimer feature, which is a
> timer sharing Cause.TI with cevt-r4k (named intimer).
>
> To ensure the cevt-r4k's usability, we need to add a callback for
> clock device to switch intimer.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> arch/mips/include/asm/cpu-features.h | 4 ++++
> arch/mips/include/asm/cpu.h | 1 +
> arch/mips/kernel/cevt-r4k.c | 25 +++++++++++++++++++++++++
> arch/mips/kernel/cpu-probe.c | 6 +++++-
> 4 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/cpu-features.h
> b/arch/mips/include/asm/cpu-features.h
> index 78cf7e300f12..aec458eee2a5 100644
> --- a/arch/mips/include/asm/cpu-features.h
> +++ b/arch/mips/include/asm/cpu-features.h
> @@ -576,6 +576,10 @@
> # define cpu_has_gsexcex __opt(MIPS_CPU_GSEXCEX)
> #endif
>
> +#ifndef cpu_has_extimer
> +# define cpu_has_extimer __opt(MIPS_CPU_EXTIMER)
> +#endif
> +
> #ifdef CONFIG_SMP
> /*
> * Some systems share FTLB RAMs between threads within a core
> (siblings in
> diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
> index 388a82f28a87..854e1b44254b 100644
> --- a/arch/mips/include/asm/cpu.h
> +++ b/arch/mips/include/asm/cpu.h
> @@ -429,6 +429,7 @@ enum cpu_type_enum {
> #define MIPS_CPU_MAC_2008_ONLY BIT_ULL(60) /* CPU Only support
> MAC2008 Fused multiply-add instruction */
> #define MIPS_CPU_FTLBPAREX BIT_ULL(61) /* CPU has FTLB parity
> exception */
> #define MIPS_CPU_GSEXCEX BIT_ULL(62) /* CPU has GSExc exception */
> +#define MIPS_CPU_EXTIMER BIT_ULL(63) /* CPU has External Timer
> (Loongson) */
>
> /*
> * CPU ASE encodings
> diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
> index 995ad9e69ded..fae49e9215b4 100644
> --- a/arch/mips/kernel/cevt-r4k.c
> +++ b/arch/mips/kernel/cevt-r4k.c
> @@ -15,6 +15,8 @@
>
> #include <asm/time.h>
> #include <asm/cevt-r4k.h>
> +#include <asm/cpu-features.h>
> +#include <asm/mipsregs.h>
>
> static int mips_next_event(unsigned long delta,
> struct clock_event_device *evt)
> @@ -294,6 +296,24 @@ core_initcall(r4k_register_cpufreq_notifier);
>
> #endif /* !CONFIG_CPU_FREQ */
>
> +#ifdef CONFIG_CPU_LOONGSON64
> +static int c0_compare_int_enable(struct clock_event_device *cd)
> +{
> + if (cpu_has_extimer)
> + set_c0_config6(LOONGSON_CONF6_INTIMER);
> +
> + return 0;
> +}
> +
> +static int c0_compare_int_disable(struct clock_event_device *cd)
> +{
> + if (cpu_has_extimer)
> + clear_c0_config6(LOONGSON_CONF6_INTIMER);
> +
> + return 0;
> +}
> +#endif

static int __maybe_unused c0_compare_int_enable(...)
{
...
}

without the #ifdef.

Or better, move these two to loongson64 board code, with "extern int
c0_compare_int_enable" in a header somewhere.

> +
> int r4k_clockevent_init(void)
> {
> unsigned long flags = IRQF_PERCPU | IRQF_TIMER | IRQF_SHARED;
> @@ -329,6 +349,11 @@ int r4k_clockevent_init(void)
> cd->set_next_event = mips_next_event;
> cd->event_handler = mips_event_handler;
>
> +#ifdef CONFIG_CPU_LOONGSON64
> + cd->set_state_oneshot = c0_compare_int_enable;
> + cd->set_state_shutdown = c0_compare_int_disable;
> +#endif
> +

if (IS_ENABLED(CONFIG_CPU_LOONGSON64)) {
cd->set_state_oneshot = ...;
}

Although I think this is still incorrect: here you check whether the
kernel supports this CPU, instead of checking what CPU you're running
on.

Cheers,
-Paul

> clockevents_config_and_register(cd, mips_hpt_frequency, min_delta,
> 0x7fffffff);
> if (cp0_timer_irq_installed)
> diff --git a/arch/mips/kernel/cpu-probe.c
> b/arch/mips/kernel/cpu-probe.c
> index 6be23f205e74..4f1e9ef2644e 100644
> --- a/arch/mips/kernel/cpu-probe.c
> +++ b/arch/mips/kernel/cpu-probe.c
> @@ -2030,6 +2030,9 @@ static inline void decode_cpucfg(struct
> cpuinfo_mips *c)
> if (cfg2 & LOONGSON_CFG2_LEXT2)
> c->ases |= MIPS_ASE_LOONGSON_EXT2;
>
> + if (cfg2 & LOONGSON_CFG2_LLFTP)
> + c->options |= MIPS_CPU_EXTIMER;
> +
> if (cfg2 & LOONGSON_CFG2_LSPW) {
> c->options |= MIPS_CPU_LDPTE;
> c->guest.options |= MIPS_CPU_LDPTE;
> @@ -2088,7 +2091,8 @@ static inline void cpu_probe_loongson(struct
> cpuinfo_mips *c, unsigned int cpu)
> * Also some early Loongson-3A2000 had wrong TLB type in Config
> * register, we correct it here.
> */
> - c->options |= MIPS_CPU_FTLB | MIPS_CPU_TLBINV | MIPS_CPU_LDPTE;
> + c->options |= MIPS_CPU_FTLB | MIPS_CPU_TLBINV | MIPS_CPU_LDPTE |
> + MIPS_CPU_EXTIMER;
> c->writecombine = _CACHE_UNCACHED_ACCELERATED;
> c->ases |= (MIPS_ASE_LOONGSON_MMI | MIPS_ASE_LOONGSON_CAM |
> MIPS_ASE_LOONGSON_EXT | MIPS_ASE_LOONGSON_EXT2);
> --
> 2.28.0
>


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