1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (C) 2025 Arm Ltd. */ 3 4 #include <asm/mpam.h> 5 6 #include <linux/arm_mpam.h> 7 #include <linux/cpu_pm.h> 8 #include <linux/jump_label.h> 9 #include <linux/percpu.h> 10 11 DEFINE_STATIC_KEY_FALSE(mpam_enabled); 12 DEFINE_PER_CPU(u64, arm64_mpam_default); 13 DEFINE_PER_CPU(u64, arm64_mpam_current); 14 15 u64 arm64_mpam_global_default; 16 17 static int mpam_pm_notifier(struct notifier_block *self, 18 unsigned long cmd, void *v) 19 { 20 u64 regval; 21 int cpu = smp_processor_id(); 22 23 switch (cmd) { 24 case CPU_PM_EXIT: 25 /* 26 * Don't use mpam_thread_switch() as the system register 27 * value has changed under our feet. 28 */ 29 regval = READ_ONCE(per_cpu(arm64_mpam_current, cpu)); 30 write_sysreg_s(regval | MPAM1_EL1_MPAMEN, SYS_MPAM1_EL1); 31 if (system_supports_sme()) { 32 write_sysreg_s(regval & (MPAMSM_EL1_PARTID_D | MPAMSM_EL1_PMG_D), 33 SYS_MPAMSM_EL1); 34 } 35 isb(); 36 37 write_sysreg_s(regval, SYS_MPAM0_EL1); 38 39 return NOTIFY_OK; 40 default: 41 return NOTIFY_DONE; 42 } 43 } 44 45 static struct notifier_block mpam_pm_nb = { 46 .notifier_call = mpam_pm_notifier, 47 }; 48 49 static int __init arm64_mpam_register_cpus(void) 50 { 51 u64 mpamidr = read_sanitised_ftr_reg(SYS_MPAMIDR_EL1); 52 u16 partid_max = FIELD_GET(MPAMIDR_EL1_PARTID_MAX, mpamidr); 53 u8 pmg_max = FIELD_GET(MPAMIDR_EL1_PMG_MAX, mpamidr); 54 55 if (!system_supports_mpam()) 56 return 0; 57 58 cpu_pm_register_notifier(&mpam_pm_nb); 59 return mpam_register_requestor(partid_max, pmg_max); 60 } 61 /* Must occur before mpam_msc_driver_init() from subsys_initcall() */ 62 arch_initcall(arm64_mpam_register_cpus) 63