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// SPDX-License-Identifier: GPL-2.0-only
/*
* dcscb.c - Dual Cluster System Configuration Block
*
* Created by: Nicolas Pitre, May 2012
* Copyright: (C) 2012-2013 Linaro Limited
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/of_address.h>
#include <linux/vexpress.h>
#include <linux/arm-cci.h>
#include <asm/mcpm.h>
#include <asm/proc-fns.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <asm/cp15.h>
#include "vexpress.h"
#define RST_HOLD0 0x0
#define RST_HOLD1 0x4
#define SYS_SWRESET 0x8
#define RST_STAT0 0xc
#define RST_STAT1 0x10
#define EAG_CFG_R 0x20
#define EAG_CFG_W 0x24
#define KFC_CFG_R 0x28
#define KFC_CFG_W 0x2c
#define DCS_CFG_R 0x30
static void __iomem *dcscb_base;
static int dcscb_allcpus_mask[2];
static int dcscb_cpu_powerup(unsigned int cpu, unsigned int cluster)
{
unsigned int rst_hold, cpumask = (1 << cpu);
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
if (cluster >= 2 || !(cpumask & dcscb_allcpus_mask[cluster]))
return -EINVAL;
rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
rst_hold &= ~(cpumask | (cpumask << 4));
writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
return 0;
}
static int dcscb_cluster_powerup(unsigned int cluster)
{
unsigned int rst_hold;
pr_debug("%s: cluster %u\n", __func__, cluster);
if (cluster >= 2)
return -EINVAL;
/* remove cluster reset and add individual CPU's reset */
rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
rst_hold &= ~(1 << 8);
rst_hold |= dcscb_allcpus_mask[cluster];
writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
return 0;
}
static void dcscb_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
{
unsigned int rst_hold;
pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
BUG_ON(cluster >= 2 || !((1 << cpu) & dcscb_allcpus_mask[cluster]));
rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
rst_hold |= (1 << cpu);
writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
}
static void dcscb_cluster_powerdown_prepare(unsigned int cluster)
{
unsigned int rst_hold;
pr_debug("%s: cluster %u\n", __func__, cluster);
BUG_ON(cluster >= 2);
rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
rst_hold |= (1 << 8);
writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
}
static void dcscb_cpu_cache_disable(void)
{
/* Disable and flush the local CPU cache. */
v7_exit_coherency_flush(louis);
}
static void dcscb_cluster_cache_disable(void)
{
/* Flush all cache levels for this cluster. */
v7_exit_coherency_flush(all);
/*
* A full outer cache flush could be needed at this point
* on platforms with such a cache, depending on where the
* outer cache sits. In some cases the notion of a "last
* cluster standing" would need to be implemented if the
* outer cache is shared across clusters. In any case, when
* the outer cache needs flushing, there is no concurrent
* access to the cache controller to worry about and no
* special locking besides what is already provided by the
* MCPM state machinery is needed.
*/
/*
* Disable cluster-level coherency by masking
* incoming snoops and DVM messages:
*/
cci_disable_port_by_cpu(read_cpuid_mpidr());
}
static const struct mcpm_platform_ops dcscb_power_ops = {
.cpu_powerup = dcscb_cpu_powerup,
.cluster_powerup = dcscb_cluster_powerup,
.cpu_powerdown_prepare = dcscb_cpu_powerdown_prepare,
.cluster_powerdown_prepare = dcscb_cluster_powerdown_prepare,
.cpu_cache_disable = dcscb_cpu_cache_disable,
.cluster_cache_disable = dcscb_cluster_cache_disable,
};
extern void dcscb_power_up_setup(unsigned int affinity_level);
static int __init dcscb_init(void)
{
struct device_node *node;
unsigned int cfg;
int ret;
if (!cci_probed())
return -ENODEV;
node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
if (!node)
return -ENODEV;
dcscb_base = of_iomap(node, 0);
of_node_put(node);
if (!dcscb_base)
return -EADDRNOTAVAIL;
cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
ret = mcpm_platform_register(&dcscb_power_ops);
if (!ret)
ret = mcpm_sync_init(dcscb_power_up_setup);
if (ret) {
iounmap(dcscb_base);
return ret;
}
pr_info("VExpress DCSCB support installed\n");
/*
* Future entries into the kernel can now go
* through the cluster entry vectors.
*/
vexpress_flags_set(__pa_symbol(mcpm_entry_point));
return 0;
}
early_initcall(dcscb_init);
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