1 /* 2 * IMX7 Secure Non-Volatile Storage 3 * 4 * Copyright (c) 2018, Impinj, Inc. 5 * 6 * Author: Andrey Smirnov <andrew.smirnov@gmail.com> 7 * 8 * This work is licensed under the terms of the GNU GPL, version 2 or later. 9 * See the COPYING file in the top-level directory. 10 * 11 * Bare minimum emulation code needed to support being able to shut 12 * down linux guest gracefully. 13 */ 14 15 #include "qemu/osdep.h" 16 #include "qemu/bitops.h" 17 #include "qemu/timer.h" 18 #include "migration/vmstate.h" 19 #include "hw/misc/imx7_snvs.h" 20 #include "qemu/cutils.h" 21 #include "qemu/module.h" 22 #include "sysemu/sysemu.h" 23 #include "sysemu/rtc.h" 24 #include "sysemu/runstate.h" 25 #include "trace.h" 26 27 #define RTC_FREQ 32768ULL 28 29 static const VMStateDescription vmstate_imx7_snvs = { 30 .name = TYPE_IMX7_SNVS, 31 .version_id = 1, 32 .minimum_version_id = 1, 33 .fields = (const VMStateField[]) { 34 VMSTATE_UINT64(tick_offset, IMX7SNVSState), 35 VMSTATE_UINT64(lpcr, IMX7SNVSState), 36 VMSTATE_END_OF_LIST() 37 } 38 }; 39 40 static uint64_t imx7_snvs_get_count(IMX7SNVSState *s) 41 { 42 uint64_t ticks = muldiv64(qemu_clock_get_ns(rtc_clock), RTC_FREQ, 43 NANOSECONDS_PER_SECOND); 44 return s->tick_offset + ticks; 45 } 46 47 static uint64_t imx7_snvs_read(void *opaque, hwaddr offset, unsigned size) 48 { 49 IMX7SNVSState *s = IMX7_SNVS(opaque); 50 uint64_t ret = 0; 51 52 switch (offset) { 53 case SNVS_LPSRTCMR: 54 ret = extract64(imx7_snvs_get_count(s), 32, 15); 55 break; 56 case SNVS_LPSRTCLR: 57 ret = extract64(imx7_snvs_get_count(s), 0, 32); 58 break; 59 case SNVS_LPCR: 60 ret = s->lpcr; 61 break; 62 } 63 64 trace_imx7_snvs_read(offset, ret, size); 65 66 return ret; 67 } 68 69 static void imx7_snvs_reset(DeviceState *dev) 70 { 71 IMX7SNVSState *s = IMX7_SNVS(dev); 72 73 s->lpcr = 0; 74 } 75 76 static void imx7_snvs_write(void *opaque, hwaddr offset, 77 uint64_t v, unsigned size) 78 { 79 trace_imx7_snvs_write(offset, v, size); 80 81 IMX7SNVSState *s = IMX7_SNVS(opaque); 82 83 uint64_t new_value = 0, snvs_count = 0; 84 85 if (offset == SNVS_LPSRTCMR || offset == SNVS_LPSRTCLR) { 86 snvs_count = imx7_snvs_get_count(s); 87 } 88 89 switch (offset) { 90 case SNVS_LPSRTCMR: 91 new_value = deposit64(snvs_count, 32, 32, v); 92 break; 93 case SNVS_LPSRTCLR: 94 new_value = deposit64(snvs_count, 0, 32, v); 95 break; 96 case SNVS_LPCR: { 97 s->lpcr = v; 98 99 const uint32_t mask = SNVS_LPCR_TOP | SNVS_LPCR_DP_EN; 100 101 if ((v & mask) == mask) { 102 qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN); 103 } 104 break; 105 } 106 } 107 108 if (offset == SNVS_LPSRTCMR || offset == SNVS_LPSRTCLR) { 109 s->tick_offset += new_value - snvs_count; 110 } 111 } 112 113 static const struct MemoryRegionOps imx7_snvs_ops = { 114 .read = imx7_snvs_read, 115 .write = imx7_snvs_write, 116 .endianness = DEVICE_NATIVE_ENDIAN, 117 .impl = { 118 /* 119 * Our device would not work correctly if the guest was doing 120 * unaligned access. This might not be a limitation on the real 121 * device but in practice there is no reason for a guest to access 122 * this device unaligned. 123 */ 124 .min_access_size = 4, 125 .max_access_size = 4, 126 .unaligned = false, 127 }, 128 }; 129 130 static void imx7_snvs_init(Object *obj) 131 { 132 SysBusDevice *sd = SYS_BUS_DEVICE(obj); 133 IMX7SNVSState *s = IMX7_SNVS(obj); 134 struct tm tm; 135 136 memory_region_init_io(&s->mmio, obj, &imx7_snvs_ops, s, 137 TYPE_IMX7_SNVS, 0x1000); 138 139 sysbus_init_mmio(sd, &s->mmio); 140 141 qemu_get_timedate(&tm, 0); 142 s->tick_offset = mktimegm(&tm) - 143 qemu_clock_get_ns(rtc_clock) / NANOSECONDS_PER_SECOND; 144 } 145 146 static void imx7_snvs_class_init(ObjectClass *klass, void *data) 147 { 148 DeviceClass *dc = DEVICE_CLASS(klass); 149 150 dc->reset = imx7_snvs_reset; 151 dc->vmsd = &vmstate_imx7_snvs; 152 dc->desc = "i.MX7 Secure Non-Volatile Storage Module"; 153 } 154 155 static const TypeInfo imx7_snvs_info = { 156 .name = TYPE_IMX7_SNVS, 157 .parent = TYPE_SYS_BUS_DEVICE, 158 .instance_size = sizeof(IMX7SNVSState), 159 .instance_init = imx7_snvs_init, 160 .class_init = imx7_snvs_class_init, 161 }; 162 163 static void imx7_snvs_register_type(void) 164 { 165 type_register_static(&imx7_snvs_info); 166 } 167 type_init(imx7_snvs_register_type) 168