1 // SPDX-License-Identifier: GPL-2.0-only
3 * arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
5 * Created by: Nicolas Pitre, May 2012
6 * Copyright: (C) 2012-2013 Linaro Limited
9 #include <linux/init.h>
10 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/of_address.h>
14 #include <linux/vexpress.h>
15 #include <linux/arm-cci.h>
18 #include <asm/proc-fns.h>
19 #include <asm/cacheflush.h>
20 #include <asm/cputype.h>
26 #define SYS_SWRESET 0x8
28 #define RST_STAT1 0x10
29 #define EAG_CFG_R 0x20
30 #define EAG_CFG_W 0x24
31 #define KFC_CFG_R 0x28
32 #define KFC_CFG_W 0x2c
33 #define DCS_CFG_R 0x30
35 static void __iomem *dcscb_base;
36 static int dcscb_allcpus_mask[2];
38 static int dcscb_cpu_powerup(unsigned int cpu, unsigned int cluster)
40 unsigned int rst_hold, cpumask = (1 << cpu);
42 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
43 if (cluster >= 2 || !(cpumask & dcscb_allcpus_mask[cluster]))
46 rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
47 rst_hold &= ~(cpumask | (cpumask << 4));
48 writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
52 static int dcscb_cluster_powerup(unsigned int cluster)
54 unsigned int rst_hold;
56 pr_debug("%s: cluster %u\n", __func__, cluster);
60 /* remove cluster reset and add individual CPU's reset */
61 rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
62 rst_hold &= ~(1 << 8);
63 rst_hold |= dcscb_allcpus_mask[cluster];
64 writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
68 static void dcscb_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
70 unsigned int rst_hold;
72 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
73 BUG_ON(cluster >= 2 || !((1 << cpu) & dcscb_allcpus_mask[cluster]));
75 rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
76 rst_hold |= (1 << cpu);
77 writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
80 static void dcscb_cluster_powerdown_prepare(unsigned int cluster)
82 unsigned int rst_hold;
84 pr_debug("%s: cluster %u\n", __func__, cluster);
87 rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
89 writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
92 static void dcscb_cpu_cache_disable(void)
94 /* Disable and flush the local CPU cache. */
95 v7_exit_coherency_flush(louis);
98 static void dcscb_cluster_cache_disable(void)
100 /* Flush all cache levels for this cluster. */
101 v7_exit_coherency_flush(all);
104 * A full outer cache flush could be needed at this point
105 * on platforms with such a cache, depending on where the
106 * outer cache sits. In some cases the notion of a "last
107 * cluster standing" would need to be implemented if the
108 * outer cache is shared across clusters. In any case, when
109 * the outer cache needs flushing, there is no concurrent
110 * access to the cache controller to worry about and no
111 * special locking besides what is already provided by the
112 * MCPM state machinery is needed.
116 * Disable cluster-level coherency by masking
117 * incoming snoops and DVM messages:
119 cci_disable_port_by_cpu(read_cpuid_mpidr());
122 static const struct mcpm_platform_ops dcscb_power_ops = {
123 .cpu_powerup = dcscb_cpu_powerup,
124 .cluster_powerup = dcscb_cluster_powerup,
125 .cpu_powerdown_prepare = dcscb_cpu_powerdown_prepare,
126 .cluster_powerdown_prepare = dcscb_cluster_powerdown_prepare,
127 .cpu_cache_disable = dcscb_cpu_cache_disable,
128 .cluster_cache_disable = dcscb_cluster_cache_disable,
131 extern void dcscb_power_up_setup(unsigned int affinity_level);
133 static int __init dcscb_init(void)
135 struct device_node *node;
142 node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
145 dcscb_base = of_iomap(node, 0);
148 return -EADDRNOTAVAIL;
149 cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
150 dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
151 dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
153 ret = mcpm_platform_register(&dcscb_power_ops);
155 ret = mcpm_sync_init(dcscb_power_up_setup);
161 pr_info("VExpress DCSCB support installed\n");
164 * Future entries into the kernel can now go
165 * through the cluster entry vectors.
167 vexpress_flags_set(__pa_symbol(mcpm_entry_point));
172 early_initcall(dcscb_init);