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Diffstat (limited to 'arch/sh/kernel/cpu/sh2/smp-j2.c')
-rw-r--r--arch/sh/kernel/cpu/sh2/smp-j2.c136
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);