1 files changed, 136 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh2/smp-j2.c b/arch/sh/kernel/cpu/sh2/smp-j2.c
new file mode 100644
index 000000000..d0d5d8145
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh2/smp-j2.c
@@ -0,0 +1,136 @@
+// 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;
+	release = ioremap(regs[0], sizeof(u32));
+	initpc = ioremap(regs[1], sizeof(u32));
+
+	__raw_writel(entry_point, initpc);
+	__raw_writel(1, release);
+
+	iounmap(initpc);
+	iounmap(release);
+
+	pr_info("J2 SMP: requested start of cpu %u\n", cpu);
+}
+
+static unsigned int j2_smp_processor_id(void)
+{
+	return __raw_readl(sh2_cpuid_addr);
+}
+
+static void j2_send_ipi(unsigned int cpu, unsigned int message)
+{
+	volatile unsigned *pmsg;
+	unsigned old;
+	unsigned long val;
+
+	/* There is only one IPI interrupt shared by all messages, so
+	 * we keep a separate interrupt flag per message type in sw. */
+	pmsg = &per_cpu(j2_ipi_messages, cpu);
+	do old = *pmsg;
+	while (cmpxchg(pmsg, old, old|(1U<<message)) != old);
+
+	/* Generate the actual interrupt by writing to CCRn bit 28. */
+	val = __raw_readl(j2_ipi_trigger + cpu);
+	__raw_writel(val | (1U<<28), j2_ipi_trigger + cpu);
+}
+
+static struct plat_smp_ops j2_smp_ops = {
+	.smp_setup		= j2_smp_setup,
+	.prepare_cpus		= j2_prepare_cpus,
+	.start_cpu		= j2_start_cpu,
+	.smp_processor_id	= j2_smp_processor_id,
+	.send_ipi		= j2_send_ipi,
+	.cpu_die		= native_cpu_die,
+	.cpu_disable		= native_cpu_disable,
+	.play_dead		= native_play_dead,
+};
+
+CPU_METHOD_OF_DECLARE(j2_cpu_method, "jcore,spin-table", &j2_smp_ops);