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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Mon, Mar 25, 2024 at 03:22:11PM -0700, Bo Gan wrote: > On 3/25/24 9:40 AM, Jisheng Zhang wrote: > > The mtimecmp in T-Head C9xx clint only supports 32bit read/write, > > implement such support. > > > > Signed-off-by: Jisheng Zhang > > --- > > drivers/clocksource/timer-clint.c | 24 ++++++++++++++++++++++++ > > 1 file changed, 24 insertions(+) > > > > diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c > > index 4537c77e623c..71188732e8a3 100644 > > --- a/drivers/clocksource/timer-clint.c > > +++ b/drivers/clocksource/timer-clint.c > > @@ -34,6 +34,7 @@ static unsigned int clint_ipi_irq; > > static u64 __iomem *clint_timer_cmp; > > static unsigned long clint_timer_freq; > > static unsigned int clint_timer_irq; > > +static bool is_c900_clint; > > #ifdef CONFIG_SMP > > static void clint_send_ipi(unsigned int cpu) > > @@ -88,6 +89,19 @@ static int clint_clock_next_event(unsigned long delta, > > return 0; > > } > > +static int c900_clint_clock_next_event(unsigned long delta, > > + struct clock_event_device *ce) > > +{ > > + void __iomem *r = clint_timer_cmp + > > + cpuid_to_hartid_map(smp_processor_id()); > > + u64 val = clint_get_cycles64() + delta; > > + > > + csr_set(CSR_IE, IE_TIE); > Perhaps you should do a writel_relaxed(-1, r) here. just like openSBI, because the update > to mtimecmp is now split into 2 parts. > https://github.com/riscv-software-src/opensbi/blob/v1.4/lib/utils/timer/aclint_mtimer.c#L54 Thanks, I also noticed the mtimecmp update on 32bit platforms doesn't strictly follow the riscv spec: # New comparand is in a1:a0. li t0, -1 la t1, mtimecmp sw t0, 0(t1) # No smaller than old value. sw a1, 4(t1) # No smaller than new value. sw a0, 0(t1) # New value. So A new bug fix patch will be added in v2. > > > + writel_relaxed(val, r); > > + writel_relaxed(val >> 32, r + 4); > > + return 0; > > +} > > +> static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = { > > .name = "clint_clockevent", > > .features = CLOCK_EVT_FEAT_ONESHOT, > > @@ -99,6 +113,9 @@ static int clint_timer_starting_cpu(unsigned int cpu) > > { > > struct clock_event_device *ce = per_cpu_ptr(&clint_clock_event, cpu); > > + if (is_c900_clint) > > + ce->set_next_event = c900_clint_clock_next_event; > > + > > ce->cpumask = cpumask_of(cpu); > > clockevents_config_and_register(ce, clint_timer_freq, 100, ULONG_MAX); > > @@ -233,5 +250,12 @@ static int __init clint_timer_init_dt(struct device_node *np) > > return rc; > > } > > +static int __init c900_clint_timer_init_dt(struct device_node *np) > > +{ > > + is_c900_clint = true; > > + return clint_timer_init_dt(np); > > +} > > + > > TIMER_OF_DECLARE(clint_timer, "riscv,clint0", clint_timer_init_dt); > > TIMER_OF_DECLARE(clint_timer1, "sifive,clint0", clint_timer_init_dt); > > +TIMER_OF_DECLARE(clint_timer2, "thead,c900-clint", clint_timer_init_dt); > > > Better use a more generic term to describe the fact that mtimecmp doesn't support > 64-bit mmio, just like what openSBI is currently doing, instead of making it c900 specific: This has been mentioned in commit msg, but adding a code comment seems fine. > > https://github.com/riscv-software-src/opensbi/blob/v1.4/lib/utils/timer/fdt_timer_mtimer.c#L152 > > Then your `is_c900_clint` becomes something like `timecmp_64bit_mmio`. > > Bo _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv