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/*
* 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, 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 = __pa_symbol(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;
}
}
static const struct smp_operations bcm63138_smp_ops __initconst = {
.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);
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