diff options
Diffstat (limited to 'kernel/arch/arm/mach-mvebu/platsmp.c')
| -rw-r--r-- | kernel/arch/arm/mach-mvebu/platsmp.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-mvebu/platsmp.c b/kernel/arch/arm/mach-mvebu/platsmp.c new file mode 100644 index 000000000..58cc8c157 --- /dev/null +++ b/kernel/arch/arm/mach-mvebu/platsmp.c @@ -0,0 +1,185 @@ +/* + * Symmetric Multi Processing (SMP) support for Armada XP + * + * Copyright (C) 2012 Marvell + * + * Lior Amsalem <alior@marvell.com> + * Yehuda Yitschak <yehuday@marvell.com> + * Gregory CLEMENT <gregory.clement@free-electrons.com> + * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency + * This file implements the routines for preparing the SMP infrastructure + * and waking up the secondary CPUs + */ + +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/clk.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/mbus.h> +#include <asm/cacheflush.h> +#include <asm/smp_plat.h> +#include "common.h" +#include "armada-370-xp.h" +#include "pmsu.h" +#include "coherency.h" + +#define ARMADA_XP_MAX_CPUS 4 + +#define AXP_BOOTROM_BASE 0xfff00000 +#define AXP_BOOTROM_SIZE 0x100000 + +static struct clk *get_cpu_clk(int cpu) +{ + struct clk *cpu_clk; + struct device_node *np = of_get_cpu_node(cpu, NULL); + + if (WARN(!np, "missing cpu node\n")) + return NULL; + cpu_clk = of_clk_get(np, 0); + if (WARN_ON(IS_ERR(cpu_clk))) + return NULL; + return cpu_clk; +} + +static void set_secondary_cpu_clock(unsigned int cpu) +{ + int thiscpu; + unsigned long rate; + struct clk *cpu_clk; + + thiscpu = get_cpu(); + + cpu_clk = get_cpu_clk(thiscpu); + if (!cpu_clk) + goto out; + clk_prepare_enable(cpu_clk); + rate = clk_get_rate(cpu_clk); + + cpu_clk = get_cpu_clk(cpu); + if (!cpu_clk) + goto out; + clk_set_rate(cpu_clk, rate); + clk_prepare_enable(cpu_clk); + +out: + put_cpu(); +} + +static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + int ret, hw_cpu; + + pr_info("Booting CPU %d\n", cpu); + + hw_cpu = cpu_logical_map(cpu); + set_secondary_cpu_clock(hw_cpu); + mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup); + + /* + * This is needed to wake up CPUs in the offline state after + * using CPU hotplug. + */ + arch_send_wakeup_ipi_mask(cpumask_of(cpu)); + + /* + * This is needed to take secondary CPUs out of reset on the + * initial boot. + */ + ret = mvebu_cpu_reset_deassert(hw_cpu); + if (ret) { + pr_warn("unable to boot CPU: %d\n", ret); + return ret; + } + + return 0; +} + +/* + * When a CPU is brought back online, either through CPU hotplug, or + * because of the boot of a kexec'ed kernel, the PMSU configuration + * for this CPU might be in the deep idle state, preventing this CPU + * from receiving interrupts. Here, we therefore take out the current + * CPU from this state, which was entered by armada_xp_cpu_die() + * below. + */ +static void armada_xp_secondary_init(unsigned int cpu) +{ + mvebu_v7_pmsu_idle_exit(); +} + +static void __init armada_xp_smp_init_cpus(void) +{ + unsigned int ncores = num_possible_cpus(); + + if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS) + panic("Invalid number of CPUs in DT\n"); +} + +static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus) +{ + struct device_node *node; + struct resource res; + int err; + + flush_cache_all(); + set_cpu_coherent(); + + /* + * In order to boot the secondary CPUs we need to ensure + * the bootROM is mapped at the correct address. + */ + node = of_find_compatible_node(NULL, NULL, "marvell,bootrom"); + if (!node) + panic("Cannot find 'marvell,bootrom' compatible node"); + + err = of_address_to_resource(node, 0, &res); + if (err < 0) + panic("Cannot get 'bootrom' node address"); + + if (res.start != AXP_BOOTROM_BASE || + resource_size(&res) != AXP_BOOTROM_SIZE) + panic("The address for the BootROM is incorrect"); +} + +#ifdef CONFIG_HOTPLUG_CPU +static void armada_xp_cpu_die(unsigned int cpu) +{ + /* + * CPU hotplug is implemented by putting offline CPUs into the + * deep idle sleep state. + */ + armada_370_xp_pmsu_idle_enter(true); +} + +/* + * We need a dummy function, so that platform_can_cpu_hotplug() knows + * we support CPU hotplug. However, the function does not need to do + * anything, because CPUs going offline can enter the deep idle state + * by themselves, without any help from a still alive CPU. + */ +static int armada_xp_cpu_kill(unsigned int cpu) +{ + return 1; +} +#endif + +struct smp_operations armada_xp_smp_ops __initdata = { + .smp_init_cpus = armada_xp_smp_init_cpus, + .smp_prepare_cpus = armada_xp_smp_prepare_cpus, + .smp_boot_secondary = armada_xp_boot_secondary, + .smp_secondary_init = armada_xp_secondary_init, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_die = armada_xp_cpu_die, + .cpu_kill = armada_xp_cpu_kill, +#endif +}; + +CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp", + &armada_xp_smp_ops); |