diff options
Diffstat (limited to 'arch/sh/kernel/cpu/sh2/smp-j2.c')
| -rw-r--r-- | arch/sh/kernel/cpu/sh2/smp-j2.c | 138 |
1 files changed, 138 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 000000000000..9a5fce6b5a32 --- /dev/null +++ b/arch/sh/kernel/cpu/sh2/smp-j2.c @@ -0,0 +1,138 @@ +/* + * SMP support for J2 processor + * + * Copyright (C) 2015-2016 Smart Energy Instruments, Inc. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/cpumask.h> +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/sched.h> +#include <linux/delay.h> +#include <linux/cpu.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <asm/sections.h> +#include <asm/cmpxchg.h> + +#define J2_CPU_LIMIT 2 + +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) +{ + pr_info("j2_smp_setup finished\n"); +} + +static void j2_prepare_cpus(unsigned int max_cpus) +{ + struct device_node *np; + unsigned i; + + for (i=max_cpus; i<NR_CPUS; i++) { + set_cpu_possible(i, false); + set_cpu_present(i, false); + } + + np = of_find_compatible_node(NULL, NULL, "jcore,ipi-controller"); + if (!np) return; + j2_ipi_irq = irq_of_parse_and_map(np, 0); + j2_ipi_trigger = of_iomap(np, 0); + + np = of_find_compatible_node(NULL, NULL, "jcore,cpuid-mmio"); + if (!np) return; + sh2_cpuid_addr = of_iomap(np, 0); + + request_irq(j2_ipi_irq, j2_ipi_interrupt_handler, IRQF_PERCPU, + "ipi", (void *)j2_ipi_interrupt_handler); + + pr_info("j2_prepare_cpus finished\n"); +} + +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_nocache(regs[0], sizeof(u32)); + initpc = ioremap_nocache(regs[1], sizeof(u32)); + + __raw_writel(entry_point, initpc); + __raw_writel(1, release); + + iounmap(initpc); + iounmap(release); + + pr_info("j2_start_cpu(%u) finished\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); |