1 /* 2 * Symmetric Multi Processing (SMP) support for Armada XP 3 * 4 * Copyright (C) 2012 Marvell 5 * 6 * Lior Amsalem <alior@marvell.com> 7 * Yehuda Yitschak <yehuday@marvell.com> 8 * Gregory CLEMENT <gregory.clement@free-electrons.com> 9 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> 10 * 11 * This file is licensed under the terms of the GNU General Public 12 * License version 2. This program is licensed "as is" without any 13 * warranty of any kind, whether express or implied. 14 * 15 * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency 16 * This file implements the routines for preparing the SMP infrastructure 17 * and waking up the secondary CPUs 18 */ 19 20 #include <linux/init.h> 21 #include <linux/smp.h> 22 #include <linux/clk.h> 23 #include <linux/of.h> 24 #include <linux/of_address.h> 25 #include <linux/mbus.h> 26 #include <asm/cacheflush.h> 27 #include <asm/smp_plat.h> 28 #include "common.h" 29 #include "armada-370-xp.h" 30 #include "pmsu.h" 31 #include "coherency.h" 32 33 #define AXP_BOOTROM_BASE 0xfff00000 34 #define AXP_BOOTROM_SIZE 0x100000 35 36 static struct clk *__init get_cpu_clk(int cpu) 37 { 38 struct clk *cpu_clk; 39 struct device_node *np = of_get_cpu_node(cpu, NULL); 40 41 if (WARN(!np, "missing cpu node\n")) 42 return NULL; 43 cpu_clk = of_clk_get(np, 0); 44 if (WARN_ON(IS_ERR(cpu_clk))) 45 return NULL; 46 return cpu_clk; 47 } 48 49 static void __init set_secondary_cpus_clock(void) 50 { 51 int thiscpu, cpu; 52 unsigned long rate; 53 struct clk *cpu_clk; 54 55 thiscpu = smp_processor_id(); 56 cpu_clk = get_cpu_clk(thiscpu); 57 if (!cpu_clk) 58 return; 59 clk_prepare_enable(cpu_clk); 60 rate = clk_get_rate(cpu_clk); 61 62 /* set all the other CPU clk to the same rate than the boot CPU */ 63 for_each_possible_cpu(cpu) { 64 if (cpu == thiscpu) 65 continue; 66 cpu_clk = get_cpu_clk(cpu); 67 if (!cpu_clk) 68 return; 69 clk_set_rate(cpu_clk, rate); 70 clk_prepare_enable(cpu_clk); 71 } 72 } 73 74 static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle) 75 { 76 int ret, hw_cpu; 77 78 pr_info("Booting CPU %d\n", cpu); 79 80 hw_cpu = cpu_logical_map(cpu); 81 mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup); 82 83 /* 84 * This is needed to wake up CPUs in the offline state after 85 * using CPU hotplug. 86 */ 87 arch_send_wakeup_ipi_mask(cpumask_of(cpu)); 88 89 /* 90 * This is needed to take secondary CPUs out of reset on the 91 * initial boot. 92 */ 93 ret = mvebu_cpu_reset_deassert(hw_cpu); 94 if (ret) { 95 pr_warn("unable to boot CPU: %d\n", ret); 96 return ret; 97 } 98 99 return 0; 100 } 101 102 /* 103 * When a CPU is brought back online, either through CPU hotplug, or 104 * because of the boot of a kexec'ed kernel, the PMSU configuration 105 * for this CPU might be in the deep idle state, preventing this CPU 106 * from receiving interrupts. Here, we therefore take out the current 107 * CPU from this state, which was entered by armada_xp_cpu_die() 108 * below. 109 */ 110 static void armada_xp_secondary_init(unsigned int cpu) 111 { 112 mvebu_v7_pmsu_idle_exit(); 113 } 114 115 static void __init armada_xp_smp_init_cpus(void) 116 { 117 unsigned int ncores = num_possible_cpus(); 118 119 if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS) 120 panic("Invalid number of CPUs in DT\n"); 121 } 122 123 static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus) 124 { 125 struct device_node *node; 126 struct resource res; 127 int err; 128 129 set_secondary_cpus_clock(); 130 flush_cache_all(); 131 set_cpu_coherent(); 132 133 /* 134 * In order to boot the secondary CPUs we need to ensure 135 * the bootROM is mapped at the correct address. 136 */ 137 node = of_find_compatible_node(NULL, NULL, "marvell,bootrom"); 138 if (!node) 139 panic("Cannot find 'marvell,bootrom' compatible node"); 140 141 err = of_address_to_resource(node, 0, &res); 142 if (err < 0) 143 panic("Cannot get 'bootrom' node address"); 144 145 if (res.start != AXP_BOOTROM_BASE || 146 resource_size(&res) != AXP_BOOTROM_SIZE) 147 panic("The address for the BootROM is incorrect"); 148 } 149 150 #ifdef CONFIG_HOTPLUG_CPU 151 static void armada_xp_cpu_die(unsigned int cpu) 152 { 153 /* 154 * CPU hotplug is implemented by putting offline CPUs into the 155 * deep idle sleep state. 156 */ 157 armada_370_xp_pmsu_idle_enter(true); 158 } 159 160 /* 161 * We need a dummy function, so that platform_can_cpu_hotplug() knows 162 * we support CPU hotplug. However, the function does not need to do 163 * anything, because CPUs going offline can enter the deep idle state 164 * by themselves, without any help from a still alive CPU. 165 */ 166 static int armada_xp_cpu_kill(unsigned int cpu) 167 { 168 return 1; 169 } 170 #endif 171 172 struct smp_operations armada_xp_smp_ops __initdata = { 173 .smp_init_cpus = armada_xp_smp_init_cpus, 174 .smp_prepare_cpus = armada_xp_smp_prepare_cpus, 175 .smp_boot_secondary = armada_xp_boot_secondary, 176 .smp_secondary_init = armada_xp_secondary_init, 177 #ifdef CONFIG_HOTPLUG_CPU 178 .cpu_die = armada_xp_cpu_die, 179 .cpu_kill = armada_xp_cpu_kill, 180 #endif 181 }; 182 183 CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp", 184 &armada_xp_smp_ops); 185