Unverified Commit 2f100585 authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt
Browse files

riscv: Enable generic clockevent broadcast 



When percpu-timers are stopped by deep power saving mode, we
need system timer help to broadcast IPI_TIMER.

This is first introduced by broken x86 hardware, where the local apic
timer stops in C3 state. But many other architectures(powerpc, mips,
arm, hexagon, openrisc, sh) have supported the infrastructure to
deal with Power Management issues.

Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 95301414

arch/riscv/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ config RISCV 
	select ARCH_HAS_SET_DIRECT_MAP

	select ARCH_HAS_SET_MEMORY

	select ARCH_HAS_STRICT_KERNEL_RWX if MMU

	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST

	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX

	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT

	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
@@ -40,6 +41,7 @@ config RISCV 
	select EDAC_SUPPORT

	select GENERIC_ARCH_TOPOLOGY if SMP

	select GENERIC_ATOMIC64 if !64BIT

	select GENERIC_CLOCKEVENTS_BROADCAST if SMP

	select GENERIC_EARLY_IOREMAP

	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO

	select GENERIC_IOREMAP

arch/riscv/kernel/smp.c

+16 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
 */



#include <linux/cpu.h>

#include <linux/clockchips.h>

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/profile.h>
@@ -27,6 +28,7 @@ enum ipi_message_type { 
	IPI_CALL_FUNC,

	IPI_CPU_STOP,

	IPI_IRQ_WORK,

	IPI_TIMER,

	IPI_MAX

};
@@ -176,6 +178,12 @@ void handle_IPI(struct pt_regs *regs) 
			irq_work_run();

		}



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

		if (ops & (1 << IPI_TIMER)) {

			stats[IPI_TIMER]++;

			tick_receive_broadcast();

		}

#endif

		BUG_ON((ops >> IPI_MAX) != 0);



		/* Order data access and bit testing. */
@@ -192,6 +200,7 @@ static const char * const ipi_names[] = { 
	[IPI_CALL_FUNC]		= "Function call interrupts",

	[IPI_CPU_STOP]		= "CPU stop interrupts",

	[IPI_IRQ_WORK]		= "IRQ work interrupts",

	[IPI_TIMER]		= "Timer broadcast interrupts",

};



void show_ipi_stats(struct seq_file *p, int prec)
@@ -217,6 +226,13 @@ void arch_send_call_function_single_ipi(int cpu) 
	send_ipi_single(cpu, IPI_CALL_FUNC);

}



#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

void tick_broadcast(const struct cpumask *mask)

{

	send_ipi_mask(mask, IPI_TIMER);

}

#endif



void smp_send_stop(void)

{

	unsigned long timeout;