1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * HSM extension and cpu_ops implementation. 4 * 5 * Copyright (c) 2020 Western Digital Corporation or its affiliates. 6 */ 7 8 #include <linux/init.h> 9 #include <linux/mm.h> 10 #include <linux/sched/task_stack.h> 11 #include <asm/cpu_ops.h> 12 #include <asm/cpu_ops_sbi.h> 13 #include <asm/sbi.h> 14 #include <asm/smp.h> 15 16 extern char secondary_start_sbi[]; 17 const struct cpu_operations cpu_ops_sbi; 18 19 /* 20 * Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can 21 * be invoked from multiple threads in parallel. Define a per cpu data 22 * to handle that. 23 */ 24 static DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data); 25 26 static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr, 27 unsigned long priv) 28 { 29 struct sbiret ret; 30 31 ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START, 32 hartid, saddr, priv, 0, 0, 0); 33 if (ret.error) 34 return sbi_err_map_linux_errno(ret.error); 35 else 36 return 0; 37 } 38 39 #ifdef CONFIG_HOTPLUG_CPU 40 static int sbi_hsm_hart_stop(void) 41 { 42 struct sbiret ret; 43 44 ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0); 45 46 if (ret.error) 47 return sbi_err_map_linux_errno(ret.error); 48 else 49 return 0; 50 } 51 52 static int sbi_hsm_hart_get_status(unsigned long hartid) 53 { 54 struct sbiret ret; 55 56 ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS, 57 hartid, 0, 0, 0, 0, 0); 58 if (ret.error) 59 return sbi_err_map_linux_errno(ret.error); 60 else 61 return ret.value; 62 } 63 #endif 64 65 static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle) 66 { 67 unsigned long boot_addr = __pa_symbol(secondary_start_sbi); 68 unsigned long hartid = cpuid_to_hartid_map(cpuid); 69 unsigned long hsm_data; 70 struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid); 71 72 /* Make sure tidle is updated */ 73 smp_mb(); 74 bdata->task_ptr = tidle; 75 bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE; 76 /* Make sure boot data is updated */ 77 smp_mb(); 78 hsm_data = __pa(bdata); 79 return sbi_hsm_hart_start(hartid, boot_addr, hsm_data); 80 } 81 82 static int sbi_cpu_prepare(unsigned int cpuid) 83 { 84 if (!cpu_ops_sbi.cpu_start) { 85 pr_err("cpu start method not defined for CPU [%d]\n", cpuid); 86 return -ENODEV; 87 } 88 return 0; 89 } 90 91 #ifdef CONFIG_HOTPLUG_CPU 92 static int sbi_cpu_disable(unsigned int cpuid) 93 { 94 if (!cpu_ops_sbi.cpu_stop) 95 return -EOPNOTSUPP; 96 return 0; 97 } 98 99 static void sbi_cpu_stop(void) 100 { 101 int ret; 102 103 ret = sbi_hsm_hart_stop(); 104 pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret); 105 } 106 107 static int sbi_cpu_is_stopped(unsigned int cpuid) 108 { 109 int rc; 110 unsigned long hartid = cpuid_to_hartid_map(cpuid); 111 112 rc = sbi_hsm_hart_get_status(hartid); 113 114 if (rc == SBI_HSM_STATE_STOPPED) 115 return 0; 116 return rc; 117 } 118 #endif 119 120 const struct cpu_operations cpu_ops_sbi = { 121 .name = "sbi", 122 .cpu_prepare = sbi_cpu_prepare, 123 .cpu_start = sbi_cpu_start, 124 #ifdef CONFIG_HOTPLUG_CPU 125 .cpu_disable = sbi_cpu_disable, 126 .cpu_stop = sbi_cpu_stop, 127 .cpu_is_stopped = sbi_cpu_is_stopped, 128 #endif 129 }; 130