1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Created by: Nicolas Pitre, October 2012 4 * Copyright: (C) 2012-2013 Linaro Limited 5 * 6 * Some portions of this file were originally written by Achin Gupta 7 * Copyright: (C) 2012 ARM Limited 8 */ 9 10#include <linux/delay.h> 11#include <linux/init.h> 12#include <linux/io.h> 13#include <linux/kernel.h> 14#include <linux/of_address.h> 15#include <linux/of_irq.h> 16#include <linux/errno.h> 17#include <linux/irqchip/arm-gic.h> 18 19#include <asm/mcpm.h> 20#include <asm/proc-fns.h> 21#include <asm/cacheflush.h> 22#include <asm/cputype.h> 23#include <asm/cp15.h> 24 25#include <linux/arm-cci.h> 26 27#include "spc.h" 28 29/* SCC conf registers */ 30#define RESET_CTRL 0x018 31#define RESET_A15_NCORERESET(cpu) (1 << (2 + (cpu))) 32#define RESET_A7_NCORERESET(cpu) (1 << (16 + (cpu))) 33 34#define A15_CONF 0x400 35#define A7_CONF 0x500 36#define SYS_INFO 0x700 37#define SPC_BASE 0xb00 38 39static void __iomem *scc; 40 41#define TC2_CLUSTERS 2 42#define TC2_MAX_CPUS_PER_CLUSTER 3 43 44static unsigned int tc2_nr_cpus[TC2_CLUSTERS]; 45 46static int tc2_pm_cpu_powerup(unsigned int cpu, unsigned int cluster) 47{ 48 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); 49 if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) 50 return -EINVAL; 51 ve_spc_set_resume_addr(cluster, cpu, 52 __pa_symbol(mcpm_entry_point)); 53 ve_spc_cpu_wakeup_irq(cluster, cpu, true); 54 return 0; 55} 56 57static int tc2_pm_cluster_powerup(unsigned int cluster) 58{ 59 pr_debug("%s: cluster %u\n", __func__, cluster); 60 if (cluster >= TC2_CLUSTERS) 61 return -EINVAL; 62 ve_spc_powerdown(cluster, false); 63 return 0; 64} 65 66static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster) 67{ 68 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); 69 BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); 70 ve_spc_cpu_wakeup_irq(cluster, cpu, true); 71 /* 72 * If the CPU is committed to power down, make sure 73 * the power controller will be in charge of waking it 74 * up upon IRQ, ie IRQ lines are cut from GIC CPU IF 75 * to the CPU by disabling the GIC CPU IF to prevent wfi 76 * from completing execution behind power controller back 77 */ 78 gic_cpu_if_down(0); 79} 80 81static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster) 82{ 83 pr_debug("%s: cluster %u\n", __func__, cluster); 84 BUG_ON(cluster >= TC2_CLUSTERS); 85 ve_spc_powerdown(cluster, true); 86 ve_spc_global_wakeup_irq(true); 87} 88 89static void tc2_pm_cpu_cache_disable(void) 90{ 91 v7_exit_coherency_flush(louis); 92} 93 94static void tc2_pm_cluster_cache_disable(void) 95{ 96 if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) { 97 /* 98 * On the Cortex-A15 we need to disable 99 * L2 prefetching before flushing the cache. 100 */ 101 asm volatile( 102 "mcr p15, 1, %0, c15, c0, 3 \n\t" 103 "isb \n\t" 104 "dsb " 105 : : "r" (0x400) ); 106 } 107 108 v7_exit_coherency_flush(all); 109 cci_disable_port_by_cpu(read_cpuid_mpidr()); 110} 111 112static int tc2_core_in_reset(unsigned int cpu, unsigned int cluster) 113{ 114 u32 mask = cluster ? 115 RESET_A7_NCORERESET(cpu) 116 : RESET_A15_NCORERESET(cpu); 117 118 return !(readl_relaxed(scc + RESET_CTRL) & mask); 119} 120 121#define POLL_MSEC 10 122#define TIMEOUT_MSEC 1000 123 124static int tc2_pm_wait_for_powerdown(unsigned int cpu, unsigned int cluster) 125{ 126 unsigned tries; 127 128 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); 129 BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); 130 131 for (tries = 0; tries < TIMEOUT_MSEC / POLL_MSEC; ++tries) { 132 pr_debug("%s(cpu=%u, cluster=%u): RESET_CTRL = 0x%08X\n", 133 __func__, cpu, cluster, 134 readl_relaxed(scc + RESET_CTRL)); 135 136 /* 137 * We need the CPU to reach WFI, but the power 138 * controller may put the cluster in reset and 139 * power it off as soon as that happens, before 140 * we have a chance to see STANDBYWFI. 141 * 142 * So we need to check for both conditions: 143 */ 144 if (tc2_core_in_reset(cpu, cluster) || 145 ve_spc_cpu_in_wfi(cpu, cluster)) 146 return 0; /* success: the CPU is halted */ 147 148 /* Otherwise, wait and retry: */ 149 msleep(POLL_MSEC); 150 } 151 152 return -ETIMEDOUT; /* timeout */ 153} 154 155static void tc2_pm_cpu_suspend_prepare(unsigned int cpu, unsigned int cluster) 156{ 157 ve_spc_set_resume_addr(cluster, cpu, __pa_symbol(mcpm_entry_point)); 158} 159 160static void tc2_pm_cpu_is_up(unsigned int cpu, unsigned int cluster) 161{ 162 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); 163 BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); 164 ve_spc_cpu_wakeup_irq(cluster, cpu, false); 165 ve_spc_set_resume_addr(cluster, cpu, 0); 166} 167 168static void tc2_pm_cluster_is_up(unsigned int cluster) 169{ 170 pr_debug("%s: cluster %u\n", __func__, cluster); 171 BUG_ON(cluster >= TC2_CLUSTERS); 172 ve_spc_powerdown(cluster, false); 173 ve_spc_global_wakeup_irq(false); 174} 175 176static const struct mcpm_platform_ops tc2_pm_power_ops = { 177 .cpu_powerup = tc2_pm_cpu_powerup, 178 .cluster_powerup = tc2_pm_cluster_powerup, 179 .cpu_suspend_prepare = tc2_pm_cpu_suspend_prepare, 180 .cpu_powerdown_prepare = tc2_pm_cpu_powerdown_prepare, 181 .cluster_powerdown_prepare = tc2_pm_cluster_powerdown_prepare, 182 .cpu_cache_disable = tc2_pm_cpu_cache_disable, 183 .cluster_cache_disable = tc2_pm_cluster_cache_disable, 184 .wait_for_powerdown = tc2_pm_wait_for_powerdown, 185 .cpu_is_up = tc2_pm_cpu_is_up, 186 .cluster_is_up = tc2_pm_cluster_is_up, 187}; 188 189/* 190 * Enable cluster-level coherency, in preparation for turning on the MMU. 191 */ 192static void __naked tc2_pm_power_up_setup(unsigned int affinity_level) 193{ 194 asm volatile (" \n" 195" cmp r0, #1 \n" 196" bxne lr \n" 197" b cci_enable_port_for_self "); 198} 199 200static int __init tc2_pm_init(void) 201{ 202 unsigned int mpidr, cpu, cluster; 203 int ret, irq; 204 u32 a15_cluster_id, a7_cluster_id, sys_info; 205 struct device_node *np; 206 207 /* 208 * The power management-related features are hidden behind 209 * SCC registers. We need to extract runtime information like 210 * cluster ids and number of CPUs really available in clusters. 211 */ 212 np = of_find_compatible_node(NULL, NULL, 213 "arm,vexpress-scc,v2p-ca15_a7"); 214 scc = of_iomap(np, 0); 215 if (!scc) 216 return -ENODEV; 217 218 a15_cluster_id = readl_relaxed(scc + A15_CONF) & 0xf; 219 a7_cluster_id = readl_relaxed(scc + A7_CONF) & 0xf; 220 if (a15_cluster_id >= TC2_CLUSTERS || a7_cluster_id >= TC2_CLUSTERS) 221 return -EINVAL; 222 223 sys_info = readl_relaxed(scc + SYS_INFO); 224 tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf; 225 tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf; 226 227 irq = irq_of_parse_and_map(np, 0); 228 229 /* 230 * A subset of the SCC registers is also used to communicate 231 * with the SPC (power controller). We need to be able to 232 * drive it very early in the boot process to power up 233 * processors, so we initialize the SPC driver here. 234 */ 235 ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq); 236 if (ret) 237 return ret; 238 239 if (!cci_probed()) 240 return -ENODEV; 241 242 mpidr = read_cpuid_mpidr(); 243 cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); 244 cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); 245 pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); 246 if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) { 247 pr_err("%s: boot CPU is out of bound!\n", __func__); 248 return -EINVAL; 249 } 250 251 ret = mcpm_platform_register(&tc2_pm_power_ops); 252 if (!ret) { 253 mcpm_sync_init(tc2_pm_power_up_setup); 254 /* test if we can (re)enable the CCI on our own */ 255 BUG_ON(mcpm_loopback(tc2_pm_cluster_cache_disable) != 0); 256 pr_info("TC2 power management initialized\n"); 257 } 258 return ret; 259} 260 261early_initcall(tc2_pm_init); 262