diff options
Diffstat (limited to 'arch/arm/mach-versatile/dcscb.c')
| -rw-r--r-- | arch/arm/mach-versatile/dcscb.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/arm/mach-versatile/dcscb.c b/arch/arm/mach-versatile/dcscb.c new file mode 100644 index 000000000000..d8797350996d --- /dev/null +++ b/arch/arm/mach-versatile/dcscb.c @@ -0,0 +1,173 @@ +// 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); |