1 /* 2 * Broadcom BCM63138 DSL SoCs SMP support code 3 * 4 * Copyright (C) 2015, Broadcom Corporation 5 * 6 * Licensed under the terms of the GPLv2 7 */ 8 9 #include <linux/delay.h> 10 #include <linux/init.h> 11 #include <linux/smp.h> 12 #include <linux/io.h> 13 #include <linux/of.h> 14 #include <linux/of_address.h> 15 16 #include <asm/cacheflush.h> 17 #include <asm/smp_scu.h> 18 #include <asm/smp_plat.h> 19 #include <asm/vfp.h> 20 21 #include "bcm63xx_smp.h" 22 23 /* Size of mapped Cortex A9 SCU address space */ 24 #define CORTEX_A9_SCU_SIZE 0x58 25 26 /* 27 * Enable the Cortex A9 Snoop Control Unit 28 * 29 * By the time this is called we already know there are multiple 30 * cores present. We assume we're running on a Cortex A9 processor, 31 * so any trouble getting the base address register or getting the 32 * SCU base is a problem. 33 * 34 * Return 0 if successful or an error code otherwise. 35 */ 36 static int __init scu_a9_enable(void) 37 { 38 unsigned long config_base; 39 void __iomem *scu_base; 40 unsigned int i, ncores; 41 42 if (!scu_a9_has_base()) { 43 pr_err("no configuration base address register!\n"); 44 return -ENXIO; 45 } 46 47 /* Config base address register value is zero for uniprocessor */ 48 config_base = scu_a9_get_base(); 49 if (!config_base) { 50 pr_err("hardware reports only one core\n"); 51 return -ENOENT; 52 } 53 54 scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE); 55 if (!scu_base) { 56 pr_err("failed to remap config base (%lu/%u) for SCU\n", 57 config_base, CORTEX_A9_SCU_SIZE); 58 return -ENOMEM; 59 } 60 61 scu_enable(scu_base); 62 63 ncores = scu_base ? scu_get_core_count(scu_base) : 1; 64 65 if (ncores > nr_cpu_ids) { 66 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n", 67 ncores, nr_cpu_ids); 68 ncores = nr_cpu_ids; 69 } 70 71 /* The BCM63138 SoC has two Cortex-A9 CPUs, CPU0 features a complete 72 * and fully functional VFP unit that can be used, but CPU1 does not. 73 * Since we will not be able to trap kernel-mode NEON to force 74 * migration to CPU0, just do not advertise VFP support at all. 75 * 76 * This will make vfp_init bail out and do not attempt to use VFP at 77 * all, for kernel-mode NEON, we do not want to introduce any 78 * conditionals in hot-paths, so we just restrict the system to UP. 79 */ 80 #ifdef CONFIG_VFP 81 if (ncores > 1) { 82 pr_warn("SMP: secondary CPUs lack VFP unit, disabling VFP\n"); 83 vfp_disable(); 84 85 #ifdef CONFIG_KERNEL_MODE_NEON 86 WARN(1, "SMP: kernel-mode NEON enabled, restricting to UP\n"); 87 ncores = 1; 88 #endif 89 } 90 #endif 91 92 for (i = 0; i < ncores; i++) 93 set_cpu_possible(i, true); 94 95 iounmap(scu_base); /* That's the last we'll need of this */ 96 97 return 0; 98 } 99 100 static const struct of_device_id bcm63138_bootlut_ids[] = { 101 { .compatible = "brcm,bcm63138-bootlut", }, 102 { /* sentinel */ }, 103 }; 104 105 #define BOOTLUT_RESET_VECT 0x20 106 107 static int bcm63138_smp_boot_secondary(unsigned int cpu, 108 struct task_struct *idle) 109 { 110 void __iomem *bootlut_base; 111 struct device_node *dn; 112 int ret = 0; 113 u32 val; 114 115 dn = of_find_matching_node(NULL, bcm63138_bootlut_ids); 116 if (!dn) { 117 pr_err("SMP: unable to find bcm63138 boot LUT node\n"); 118 return -ENODEV; 119 } 120 121 bootlut_base = of_iomap(dn, 0); 122 of_node_put(dn); 123 124 if (!bootlut_base) { 125 pr_err("SMP: unable to remap boot LUT base register\n"); 126 return -ENOMEM; 127 } 128 129 /* Locate the secondary CPU node */ 130 dn = of_get_cpu_node(cpu, NULL); 131 if (!dn) { 132 pr_err("SMP: failed to locate secondary CPU%d node\n", cpu); 133 ret = -ENODEV; 134 goto out; 135 } 136 137 /* Write the secondary init routine to the BootLUT reset vector */ 138 val = virt_to_phys(secondary_startup); 139 writel_relaxed(val, bootlut_base + BOOTLUT_RESET_VECT); 140 141 /* Power up the core, will jump straight to its reset vector when we 142 * return 143 */ 144 ret = bcm63xx_pmb_power_on_cpu(dn); 145 if (ret) 146 goto out; 147 out: 148 iounmap(bootlut_base); 149 150 return ret; 151 } 152 153 static void __init bcm63138_smp_prepare_cpus(unsigned int max_cpus) 154 { 155 int ret; 156 157 ret = scu_a9_enable(); 158 if (ret) { 159 pr_warn("SMP: Cortex-A9 SCU setup failed\n"); 160 return; 161 } 162 } 163 164 static const struct smp_operations bcm63138_smp_ops __initconst = { 165 .smp_prepare_cpus = bcm63138_smp_prepare_cpus, 166 .smp_boot_secondary = bcm63138_smp_boot_secondary, 167 }; 168 169 CPU_METHOD_OF_DECLARE(bcm63138_smp, "brcm,bcm63138", &bcm63138_smp_ops); 170