arch/sh/kernel/cpu/sh2/smp-j2.c

Source file repositories/reference/linux-study-clean/arch/sh/kernel/cpu/sh2/smp-j2.c

File Facts

System
Linux kernel
Corpus path
arch/sh/kernel/cpu/sh2/smp-j2.c
Extension
.c
Size
3229 bytes
Lines
137
Domain
Architecture Layer
Bucket
arch/sh
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * SMP support for J2 processor
 *
 * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
 */

#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <asm/cmpxchg.h>

DEFINE_PER_CPU(unsigned, j2_ipi_messages);

extern u32 *sh2_cpuid_addr;
static u32 *j2_ipi_trigger;
static int j2_ipi_irq;

static irqreturn_t j2_ipi_interrupt_handler(int irq, void *arg)
{
	unsigned cpu = hard_smp_processor_id();
	volatile unsigned *pmsg = &per_cpu(j2_ipi_messages, cpu);
	unsigned messages, i;

	do messages = *pmsg;
	while (cmpxchg(pmsg, messages, 0) != messages);

	if (!messages) return IRQ_NONE;

	for (i=0; i<SMP_MSG_NR; i++)
		if (messages & (1U<<i))
			smp_message_recv(i);

	return IRQ_HANDLED;
}

static void j2_smp_setup(void)
{
}

static void j2_prepare_cpus(unsigned int max_cpus)
{
	struct device_node *np;
	unsigned i, max = 1;

	np = of_find_compatible_node(NULL, NULL, "jcore,ipi-controller");
	if (!np)
		goto out;

	j2_ipi_irq = irq_of_parse_and_map(np, 0);
	j2_ipi_trigger = of_iomap(np, 0);
	if (!j2_ipi_irq || !j2_ipi_trigger)
		goto out;

	np = of_find_compatible_node(NULL, NULL, "jcore,cpuid-mmio");
	if (!np)
		goto out;

	sh2_cpuid_addr = of_iomap(np, 0);
	if (!sh2_cpuid_addr)
		goto out;

	if (request_irq(j2_ipi_irq, j2_ipi_interrupt_handler, IRQF_PERCPU,
			"ipi", (void *)j2_ipi_interrupt_handler) != 0)
		goto out;

	max = max_cpus;
out:
	/* Disable any cpus past max_cpus, or all secondaries if we didn't
	 * get the necessary resources to support SMP. */
	for (i=max; i<NR_CPUS; i++) {
		set_cpu_possible(i, false);
		set_cpu_present(i, false);
	}
}

static void j2_start_cpu(unsigned int cpu, unsigned long entry_point)
{
	struct device_node *np;
	u32 regs[2];
	void __iomem *release, *initpc;

	if (!cpu) return;

	np = of_get_cpu_node(cpu, NULL);
	if (!np) return;

	if (of_property_read_u32_array(np, "cpu-release-addr", regs, 2)) return;

Annotation

Implementation Notes