// SPDX-License-Identifier: GPL-2.0-only
/*
* Created by: Nicolas Pitre, October 2012
* Copyright: (C) 2012-2013 Linaro Limited
*
* Some portions of this file were originally written by Achin Gupta
* Copyright: (C) 2012 ARM Limited
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/errno.h>
#include <linux/irqchip/arm-gic.h>
#include <asm/mcpm.h>
#include <asm/proc-fns.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <asm/cp15.h>
#include <linux/arm-cci.h>
#include "spc.h"
/* SCC conf registers */
#define RESET_CTRL 0x018
#define RESET_A15_NCORERESET(cpu) (1 << (2 + (cpu)))
#define RESET_A7_NCORERESET(cpu) (1 << (16 + (cpu)))
#define A15_CONF 0x400
#define A7_CONF 0x500
#define SYS_INFO 0x700
#define SPC_BASE 0xb00
static void __iomem *scc;
#define TC2_CLUSTERS 2
#define TC2_MAX_CPUS_PER_CLUSTER 3
static unsigned int tc2_nr_cpus[TC2_CLUSTERS];
static int tc2_pm_cpu_powerup(unsigned int cpu, unsigned int cluster)
{
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster])
return -EINVAL;
ve_spc_set_resume_addr(cluster, cpu,
__pa_symbol(mcpm_entry_point));
ve_spc_cpu_wakeup_irq(cluster, cpu, true);
return 0;
}
static int tc2_pm_cluster_powerup(unsigned int cluster)
{
pr_debug("%s: cluster %u\n", __func__, cluster);
if (cluster >= TC2_CLUSTERS)
return -EINVAL;
ve_spc_powerdown(cluster, false);
return 0;
}
static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
{
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
ve_spc_cpu_wakeup_irq(cluster, cpu, true);
/*
* If the CPU is committed to power down, make sure
* the power controller will be in charge of waking it
* up upon IRQ, ie IRQ lines are cut from GIC CPU IF
* to the CPU by disabling the GIC CPU IF to prevent wfi
* from completing execution behind power controller back
*/
gic_cpu_if_down(0);
}
static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster)
{
pr_debug("%s: cluster %u\n", __func__, cluster);
BUG_ON(cluster >= TC2_CLUSTERS);
ve_spc_powerdown(cluster, true);
ve_spc_global_wakeup_irq(true);
}
static void tc2_pm_cpu_cache_disable(void)
{
v7_exit_coherency_flush(louis);
}
static void tc2_pm_cluster_cache_disable(void)
{
if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
/*
* On the Cortex-A15 we need to disable
* L2 prefetching before flushing the cache.
*/
asm volatile(
"mcr p15, 1, %0, c15, c0, 3 \n\t"
"isb \n\t"
"dsb "
: : "r" (0x400) );
}
v7_exit_coherency_flush(all);
cci_disable_port_by_cpu(read_cpuid_mpidr());
}
static int tc2_core_in_reset(unsigned int cpu, unsigned int cluster)
{
u32 mask = cluster ?
RESET_A7_NCORERESET(cpu)
: RESET_A15_NCORERESET(cpu);
return !(readl_relaxed(scc + RESET_CTRL) & mask);
}
#define POLL_MSEC 10
#define TIMEOUT_MSEC 1000
static int tc2_pm_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
{
unsigned tries;
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
for (tries = 0; tries < TIMEOUT_MSEC / POLL_MSEC; ++tries) {
pr_debug("%s(cpu=%u, cluster=%u): RESET_CTRL = 0x%08X\n",
__func__, cpu, cluster,
readl_relaxed(scc + RESET_CTRL));
/*
* We need the CPU to reach WFI, but the power
* controller may put the cluster in reset and
* power it off as soon as that happens, before
* we have a chance to see STANDBYWFI.
*
* So we need to check for both conditions:
*/
if (tc2_core_in_reset(cpu, cluster) ||
ve_spc_cpu_in_wfi(cpu, cluster))
return 0; /* success: the CPU is halted */
/* Otherwise, wait and retry: */
msleep(POLL_MSEC);
}
return -ETIMEDOUT; /* timeout */
}
static void tc2_pm_cpu_suspend_prepare(unsigned int cpu, unsigned int cluster)
{
ve_spc_set_resume_addr(cluster, cpu, __pa_symbol(mcpm_entry_point));
}
static void tc2_pm_cpu_is_up(unsigned int cpu, unsigned int cluster)
{
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
ve_spc_cpu_wakeup_irq(cluster, cpu, false);
ve_spc_set_resume_addr(cluster, cpu, 0);
}
static void tc2_pm_cluster_is_up(unsigned int cluster)
{
pr_debug("%s: cluster %u\n", __func__, cluster);
BUG_ON(cluster >= TC2_CLUSTERS);
ve_spc_powerdown(cluster, false);
ve_spc_global_wakeup_irq(false);
}
static const struct mcpm_platform_ops tc2_pm_power_ops = {
.cpu_powerup = tc2_pm_cpu_powerup,
.cluster_powerup = tc2_pm_cluster_powerup,
.cpu_suspend_prepare = tc2_pm_cpu_suspend_prepare,
.cpu_powerdown_prepare = tc2_pm_cpu_powerdown_prepare,
.cluster_powerdown_prepare = tc2_pm_cluster_powerdown_prepare,
.cpu_cache_disable = tc2_pm_cpu_cache_disable,
.cluster_cache_disable = tc2_pm_cluster_cache_disable,
.wait_for_powerdown = tc2_pm_wait_for_powerdown,
.cpu_is_up = tc2_pm_cpu_is_up,
.cluster_is_up = tc2_pm_cluster_is_up,
};
/*
* Enable cluster-level coherency, in preparation for turning on the MMU.
*/
static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
{
asm volatile (" \n"
" cmp r0, #1 \n"
" bxne lr \n"
" b cci_enable_port_for_self ");
}
static int __init tc2_pm_init(void)
{
unsigned int mpidr, cpu, cluster;
int ret, irq;
u32 a15_cluster_id, a7_cluster_id, sys_info;
struct device_node *np;
/*
* The power management-related features are hidden behind
* SCC registers. We need to extract runtime information like
* cluster ids and number of CPUs really available in clusters.
*/
np = of_find_compatible_node(NULL, NULL,
"arm,vexpress-scc,v2p-ca15_a7");
scc = of_iomap(np, 0);
if (!scc)
return -ENODEV;
a15_cluster_id = readl_relaxed(scc + A15_CONF) & 0xf;
a7_cluster_id = readl_relaxed(scc + A7_CONF) & 0xf;
if (a15_cluster_id >= TC2_CLUSTERS || a7_cluster_id >= TC2_CLUSTERS)
return -EINVAL;
sys_info = readl_relaxed(scc + SYS_INFO);
tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf;
tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf;
irq = irq_of_parse_and_map(np, 0);
/*
* A subset of the SCC registers is also used to communicate
* with the SPC (power controller). We need to be able to
* drive it very early in the boot process to power up
* processors, so we initialize the SPC driver here.
*/
ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq);
if (ret)
return ret;
if (!cci_probed())
return -ENODEV;
mpidr = read_cpuid_mpidr();
cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) {
pr_err("%s: boot CPU is out of bound!\n", __func__);
return -EINVAL;
}
ret = mcpm_platform_register(&tc2_pm_power_ops);
if (!ret) {
mcpm_sync_init(tc2_pm_power_up_setup);
/* test if we can (re)enable the CCI on our own */
BUG_ON(mcpm_loopback(tc2_pm_cluster_cache_disable) != 0);
pr_info("TC2 power management initialized\n");
}
return ret;
}
early_initcall(tc2_pm_init);
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