1 /* 2 * Copyright 2012-2022, Haiku, Inc. All rights reserved. 3 * Distributed under the terms of the MIT License. 4 * 5 * Authors: 6 * Ithamar R. Adema <ithamar@upgrade-android.com> 7 */ 8 9 #include <boot/arch/arm/arch_cpu.h> 10 #include <kernel/arch/arm/arch_cpu.h> 11 12 #include <OS.h> 13 #include <boot/platform.h> 14 #include <boot/stdio.h> 15 #include <boot/kernel_args.h> 16 #include <boot/stage2.h> 17 #include <arch/cpu.h> 18 #include <arch_kernel.h> 19 #include <arch_system_info.h> 20 #include <string.h> 21 22 23 #define TRACE_CPU 24 #ifdef TRACE_CPU 25 # define TRACE(x...) dprintf(x) 26 #else 27 # define TRACE(x...) ; 28 #endif 29 30 31 /*! Detect ARM core version and features. 32 Please note the fact that ARM7 and ARMv7 are two different things ;) 33 ARMx is a specific ARM CPU core instance, while ARMvX refers to the 34 ARM architecture specification version.... 35 36 Most of the architecture versions we're detecting here we will probably 37 never run on, just included for completeness sake... ARMv5 and up are 38 the likely ones for us to support (as they all have some kind of MMU). 39 */ 40 static status_t 41 check_cpu_features() 42 { 43 uint32 result = 0; 44 int arch = 0; 45 int variant = 0; 46 int part = 0; 47 int revision = 0; 48 int implementor = 0; 49 50 asm volatile("MRC p15, 0, %[c1out], c0, c0, 0":[c1out] "=r" (result)); 51 52 implementor = (result >> 24) & 0xff; 53 54 switch ((result >> 12) & 0xf) { 55 case 0: /* early ARMv3 or even older */ 56 arch = ARCH_ARM_PRE_ARM7; 57 break; 58 59 case 7: /* ARM7 processor */ 60 arch = (result & (1 << 23)) ? ARCH_ARM_v4T : ARCH_ARM_v3; 61 variant = (result >> 16) & 0x7f; 62 part = (result >> 4) & 0xfff; 63 revision = result & 0xf; 64 break; 65 66 default: 67 revision = result & 0xf; 68 part = (result >> 4) & 0xfff; 69 switch((result >> 16) & 0xf) { 70 case 1: arch = ARCH_ARM_v4; break; 71 case 2: arch = ARCH_ARM_v4T; break; 72 case 3: arch = ARCH_ARM_v5; break; 73 case 4: arch = ARCH_ARM_v5T; break; 74 case 5: arch = ARCH_ARM_v5TE; break; 75 case 6: arch = ARCH_ARM_v5TEJ; break; 76 case 7: arch = ARCH_ARM_v6; break; 77 case 0xf: 78 arch = ARCH_ARM_v7; 79 // TODO ... or later. We apparently need to scan the 80 // CPUID registers to decide. 81 break; 82 } 83 variant = (result >> 20) & 0xf; 84 break; 85 } 86 87 TRACE("%s: implementor=0x%x('%c'), arch=%d, variant=0x%x, part=0x%x, revision=0x%x\n", 88 __func__, implementor, implementor, arch, variant, part, revision); 89 90 return (arch < ARCH_ARM_v5) ? B_ERROR : B_OK; 91 } 92 93 94 status_t 95 boot_arch_cpu_init(void) 96 { 97 status_t err = check_cpu_features(); 98 if (err != B_OK) { 99 panic("Retire your old Acorn and get something modern to boot!\n"); 100 return err; 101 } 102 103 return B_OK; 104 } 105 106 107 void 108 arch_ucode_load(BootVolume& volume) 109 { 110 // NOP on arm currently 111 } 112