1 // SPDX-License-Identifier: BSD-2-Clause 2 /* 3 * Copyright (c) 2016, Linaro Limited 4 */ 5 6 #include <initcall.h> 7 #include <io.h> 8 #include <keep.h> 9 #include <kernel/interrupt.h> 10 #include <kernel/misc.h> 11 #include <kernel/spinlock.h> 12 #include <mm/core_memprot.h> 13 #include <mm/core_mmu.h> 14 #include <platform_config.h> 15 #include <rng_support.h> 16 17 #define RNG_OUTPUT_L 0x0000 18 #define RNG_OUTPUT_H 0x0004 19 #define RNG_STATUS 0x0008 20 # define RNG_READY BIT(0) 21 # define SHUTDOWN_OFLO BIT(1) 22 #define RNG_INTMASK 0x000C 23 #define RNG_INTACK 0x0010 24 #define RNG_CONTROL 0x0014 25 # define ENABLE_TRNG BIT(10) 26 #define RNG_CONFIG 0x0018 27 #define RNG_ALARMCNT 0x001C 28 #define RNG_FROENABLE 0x0020 29 #define RNG_FRODETUNE 0x0024 30 #define RNG_ALARMMASK 0x0028 31 #define RNG_ALARMSTOP 0x002C 32 #define RNG_LFSR_L 0x0030 33 #define RNG_LFSR_M 0x0034 34 #define RNG_LFSR_H 0x0038 35 #define RNG_COUNT 0x003C 36 #define RNG_OPTIONS 0x0078 37 #define RNG_EIP_REV 0x007C 38 #define RNG_MMR_STATUS_EN 0x1FD8 39 #define RNG_REV 0x1FE0 40 #define RNG_SYS_CONFIG_REG 0x1FE4 41 # define RNG_AUTOIDLE BIT(0) 42 #define RNG_MMR_STATUS_SET 0x1FEC 43 #define RNG_SOFT_RESET_REG 0x1FF0 44 # define RNG_SOFT_RESET BIT(0) 45 #define RNG_IRQ_EOI_REG 0x1FF4 46 #define RNG_IRQSTATUS 0x1FF8 47 48 #define RNG_CONTROL_STARTUP_CYCLES_SHIFT 16 49 #define RNG_CONTROL_STARTUP_CYCLES_MASK GENMASK_32(31, 16) 50 51 #define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT 16 52 #define RNG_CONFIG_MAX_REFIL_CYCLES_MASK GENMASK_32(31, 16) 53 #define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT 0 54 #define RNG_CONFIG_MIN_REFIL_CYCLES_MASK GENMASK_32(7, 0) 55 56 #define RNG_ALARMCNT_ALARM_TH_SHIFT 0 57 #define RNG_ALARMCNT_ALARM_TH_MASK GENMASK_32(7, 0) 58 #define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT 16 59 #define RNG_ALARMCNT_SHUTDOWN_TH_MASK GENMASK_32(20, 16) 60 61 #define RNG_CONTROL_STARTUP_CYCLES 0xff 62 #define RNG_CONFIG_MIN_REFIL_CYCLES 0x21 63 #define RNG_CONFIG_MAX_REFIL_CYCLES 0x22 64 #define RNG_ALARM_THRESHOLD 0xff 65 #define RNG_SHUTDOWN_THRESHOLD 0x4 66 67 #define RNG_FRO_MASK GENMASK_32(23, 0) 68 69 #define RNG_REG_SIZE 0x2000 70 71 register_phys_mem(MEM_AREA_IO_SEC, RNG_BASE, RNG_REG_SIZE); 72 73 static unsigned int rng_lock = SPINLOCK_UNLOCK; 74 75 uint8_t hw_get_random_byte(void) 76 { 77 static int pos; 78 static union { 79 uint32_t val[2]; 80 uint8_t byte[8]; 81 } random; 82 vaddr_t rng = (vaddr_t)phys_to_virt(RNG_BASE, MEM_AREA_IO_SEC); 83 uint8_t ret; 84 85 uint32_t exceptions = thread_mask_exceptions(THREAD_EXCP_ALL); 86 cpu_spin_lock(&rng_lock); 87 88 if (!pos) { 89 /* Is the result ready (available)? */ 90 while (!(read32(rng + RNG_STATUS) & RNG_READY)) { 91 /* Is the shutdown threshold reached? */ 92 if (read32(rng + RNG_STATUS) & SHUTDOWN_OFLO) { 93 uint32_t alarm = read32(rng + RNG_ALARMSTOP); 94 uint32_t tuning = read32(rng + RNG_FRODETUNE); 95 /* Clear the alarm events */ 96 write32(0x0, rng + RNG_ALARMMASK); 97 write32(0x0, rng + RNG_ALARMSTOP); 98 /* De-tune offending FROs */ 99 write32(tuning ^ alarm, rng + RNG_FRODETUNE); 100 /* Re-enable the shut down FROs */ 101 write32(RNG_FRO_MASK, rng + RNG_FROENABLE); 102 /* Clear the shutdown overflow event */ 103 write32(SHUTDOWN_OFLO, rng + RNG_INTACK); 104 105 DMSG("Fixed FRO shutdown\n"); 106 } 107 } 108 /* Read random value */ 109 random.val[0] = read32(rng + RNG_OUTPUT_L); 110 random.val[1] = read32(rng + RNG_OUTPUT_H); 111 /* Acknowledge read complete */ 112 write32(RNG_READY, rng + RNG_INTACK); 113 } 114 115 ret = random.byte[pos]; 116 117 pos = (pos + 1) % 8; 118 119 cpu_spin_unlock(&rng_lock); 120 thread_set_exceptions(exceptions); 121 122 return ret; 123 } 124 125 static TEE_Result dra7_rng_init(void) 126 { 127 vaddr_t rng = (vaddr_t)phys_to_virt(RNG_BASE, MEM_AREA_IO_SEC); 128 uint32_t val; 129 130 /* Execute a software reset */ 131 write32(RNG_SOFT_RESET, rng + RNG_SOFT_RESET_REG); 132 133 /* Wait for the software reset completion by polling */ 134 while (read32(rng + RNG_SOFT_RESET_REG) & RNG_SOFT_RESET) 135 ; 136 137 /* Switch to low-power operating mode */ 138 write32(RNG_AUTOIDLE, rng + RNG_SYS_CONFIG_REG); 139 140 /* 141 * Select the number of clock input cycles to the 142 * FROs between two samples 143 */ 144 val = 0; 145 146 /* Ensure initial latency */ 147 val |= RNG_CONFIG_MIN_REFIL_CYCLES << 148 RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT; 149 val |= RNG_CONFIG_MAX_REFIL_CYCLES << 150 RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT; 151 write32(val, rng + RNG_CONFIG); 152 153 /* Configure the desired FROs */ 154 write32(0x0, rng + RNG_FRODETUNE); 155 156 /* Enable all FROs */ 157 write32(0xffffff, rng + RNG_FROENABLE); 158 159 /* 160 * Select the maximum number of samples after 161 * which if a repeating pattern is still detected, an 162 * alarm event is generated 163 */ 164 val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT; 165 166 /* 167 * Set the shutdown threshold to the number of FROs 168 * allowed to be shut downed 169 */ 170 val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT; 171 write32(val, rng + RNG_ALARMCNT); 172 173 /* Enable the RNG module */ 174 val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT; 175 val |= ENABLE_TRNG; 176 write32(val, rng + RNG_CONTROL); 177 178 IMSG("DRA7x TRNG initialized"); 179 180 return TEE_SUCCESS; 181 } 182 driver_init(dra7_rng_init); 183