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/*
* Actions Semi Leopard
*
* This file is based on arm realview smp platform.
*
* Copyright 2012 Actions Semi Inc.
* Author: Actions Semi, Inc.
*
* Copyright (c) 2017 Andreas Färber
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
#define OWL_CPU1_ADDR 0x50
#define OWL_CPU1_FLAG 0x5c
#define OWL_CPUx_FLAG_BOOT 0x55aa
static void __iomem *scu_base_addr;
static void __iomem *timer_base_addr;
static int ncores;
static DEFINE_SPINLOCK(boot_lock);
static void write_pen_release(int val)
{
pen_release = val;
smp_wmb();
__cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
}
static void s500_smp_secondary_init(unsigned int cpu)
{
/*
* let the primary processor know we're out of the
* pen, then head off into the C entry point
*/
write_pen_release(-1);
spin_lock(&boot_lock);
spin_unlock(&boot_lock);
}
void owl_secondary_startup(void);
static int s500_wakeup_secondary(unsigned int cpu)
{
if (cpu > 3)
return -EINVAL;
switch (cpu) {
case 2:
case 3:
/* CPU2/3 are power-gated */
return -EINVAL;
}
/* wait for CPUx to run to WFE instruction */
udelay(200);
writel(virt_to_phys(owl_secondary_startup),
timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
writel(OWL_CPUx_FLAG_BOOT,
timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
dsb_sev();
mb();
return 0;
}
static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
int ret;
ret = s500_wakeup_secondary(cpu);
if (ret)
return ret;
udelay(10);
spin_lock(&boot_lock);
/*
* The secondary processor is waiting to be released from
* the holding pen - release it, then wait for it to flag
* that it has been released by resetting pen_release.
*/
write_pen_release(cpu_logical_map(cpu));
smp_send_reschedule(cpu);
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
if (pen_release == -1)
break;
}
writel(0, timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
writel(0, timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
spin_unlock(&boot_lock);
return pen_release != -1 ? -ENOSYS : 0;
}
static void __init s500_smp_prepare_cpus(unsigned int max_cpus)
{
struct device_node *node;
node = of_find_compatible_node(NULL, NULL, "actions,s500-timer");
if (!node) {
pr_err("%s: missing timer\n", __func__);
return;
}
timer_base_addr = of_iomap(node, 0);
if (!timer_base_addr) {
pr_err("%s: could not map timer registers\n", __func__);
return;
}
if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
if (!node) {
pr_err("%s: missing scu\n", __func__);
return;
}
scu_base_addr = of_iomap(node, 0);
if (!scu_base_addr) {
pr_err("%s: could not map scu registers\n", __func__);
return;
}
/*
* While the number of cpus is gathered from dt, also get the
* number of cores from the scu to verify this value when
* booting the cores.
*/
ncores = scu_get_core_count(scu_base_addr);
pr_debug("%s: ncores %d\n", __func__, ncores);
scu_enable(scu_base_addr);
}
}
static const struct smp_operations s500_smp_ops __initconst = {
.smp_prepare_cpus = s500_smp_prepare_cpus,
.smp_secondary_init = s500_smp_secondary_init,
.smp_boot_secondary = s500_smp_boot_secondary,
};
CPU_METHOD_OF_DECLARE(s500_smp, "actions,s500-smp", &s500_smp_ops);
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