diff options
Diffstat (limited to 'arch/arm/mach-bcm/bcm63xx_smp.c')
| -rw-r--r-- | arch/arm/mach-bcm/bcm63xx_smp.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/arm/mach-bcm/bcm63xx_smp.c b/arch/arm/mach-bcm/bcm63xx_smp.c new file mode 100644 index 000000000000..3f014f18cea5 --- /dev/null +++ b/arch/arm/mach-bcm/bcm63xx_smp.c @@ -0,0 +1,169 @@ +/* + * Broadcom BCM63138 DSL SoCs SMP support code + * + * Copyright (C) 2015, Broadcom Corporation + * + * Licensed under the terms of the GPLv2 + */ + +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> + +#include <asm/cacheflush.h> +#include <asm/smp_scu.h> +#include <asm/smp_plat.h> +#include <asm/vfp.h> + +#include "bcm63xx_smp.h" + +/* Size of mapped Cortex A9 SCU address space */ +#define CORTEX_A9_SCU_SIZE 0x58 + +/* + * Enable the Cortex A9 Snoop Control Unit + * + * By the time this is called we already know there are multiple + * cores present. We assume we're running on a Cortex A9 processor, + * so any trouble getting the base address register or getting the + * SCU base is a problem. + * + * Return 0 if successful or an error code otherwise. + */ +static int __init scu_a9_enable(void) +{ + unsigned long config_base; + void __iomem *scu_base; + unsigned int i, ncores; + + if (!scu_a9_has_base()) { + pr_err("no configuration base address register!\n"); + return -ENXIO; + } + + /* Config base address register value is zero for uniprocessor */ + config_base = scu_a9_get_base(); + if (!config_base) { + pr_err("hardware reports only one core\n"); + return -ENOENT; + } + + scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE); + if (!scu_base) { + pr_err("failed to remap config base (%lu/%u) for SCU\n", + config_base, CORTEX_A9_SCU_SIZE); + return -ENOMEM; + } + + scu_enable(scu_base); + + ncores = scu_base ? scu_get_core_count(scu_base) : 1; + + if (ncores > nr_cpu_ids) { + pr_warn("SMP: %u cores greater than maximum (%u), clipping\n", + ncores, nr_cpu_ids); + ncores = nr_cpu_ids; + } + + /* The BCM63138 SoC has two Cortex-A9 CPUs, CPU0 features a complete + * and fully functional VFP unit that can be used, but CPU1 does not. + * Since we will not be able to trap kernel-mode NEON to force + * migration to CPU0, just do not advertise VFP support at all. + * + * This will make vfp_init bail out and do not attempt to use VFP at + * all, for kernel-mode NEON, we do not want to introduce any + * conditionals in hot-paths, so we just restrict the system to UP. + */ +#ifdef CONFIG_VFP + if (ncores > 1) { + pr_warn("SMP: secondary CPUs lack VFP unit, disabling VFP\n"); + vfp_disable(); + +#ifdef CONFIG_KERNEL_MODE_NEON + WARN(1, "SMP: kernel-mode NEON enabled, restricting to UP\n"); + ncores = 1; +#endif + } +#endif + + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); + + iounmap(scu_base); /* That's the last we'll need of this */ + + return 0; +} + +static const struct of_device_id bcm63138_bootlut_ids[] = { + { .compatible = "brcm,bcm63138-bootlut", }, + { /* sentinel */ }, +}; + +#define BOOTLUT_RESET_VECT 0x20 + +static int bcm63138_smp_boot_secondary(unsigned int cpu, + struct task_struct *idle) +{ + void __iomem *bootlut_base; + struct device_node *dn; + int ret = 0; + u32 val; + + dn = of_find_matching_node(NULL, bcm63138_bootlut_ids); + if (!dn) { + pr_err("SMP: unable to find bcm63138 boot LUT node\n"); + return -ENODEV; + } + + bootlut_base = of_iomap(dn, 0); + of_node_put(dn); + + if (!bootlut_base) { + pr_err("SMP: unable to remap boot LUT base register\n"); + return -ENOMEM; + } + + /* Locate the secondary CPU node */ + dn = of_get_cpu_node(cpu_logical_map(cpu), NULL); + if (!dn) { + pr_err("SMP: failed to locate secondary CPU%d node\n", cpu); + ret = -ENODEV; + goto out; + } + + /* Write the secondary init routine to the BootLUT reset vector */ + val = virt_to_phys(bcm63138_secondary_startup); + writel_relaxed(val, bootlut_base + BOOTLUT_RESET_VECT); + + /* Power up the core, will jump straight to its reset vector when we + * return + */ + ret = bcm63xx_pmb_power_on_cpu(dn); + if (ret) + goto out; +out: + iounmap(bootlut_base); + + return ret; +} + +static void __init bcm63138_smp_prepare_cpus(unsigned int max_cpus) +{ + int ret; + + ret = scu_a9_enable(); + if (ret) { + pr_warn("SMP: Cortex-A9 SCU setup failed\n"); + return; + } +} + +struct smp_operations bcm63138_smp_ops __initdata = { + .smp_prepare_cpus = bcm63138_smp_prepare_cpus, + .smp_boot_secondary = bcm63138_smp_boot_secondary, +}; + +CPU_METHOD_OF_DECLARE(bcm63138_smp, "brcm,bcm63138", &bcm63138_smp_ops); |