1 /******************************************************************************
2 *
3 * Copyright (C) 2022-2023 Maxim Integrated Products, Inc. (now owned by
4 * Analog Devices, Inc.),
5 * Copyright (C) 2023-2024 Analog Devices, Inc.
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 ******************************************************************************/
20
21 #include <string.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include "max32675.h"
25 #include "gcr_regs.h"
26 #include "mxc_sys.h"
27 #include "pwrseq_regs.h"
28
29 extern void (*const __vector_table[])(void);
30
31 extern void (*const __isr_vector[])(void);
32
33 uint32_t SystemCoreClock = HIRC_FREQ;
34
35 /*
36 The libc implementation from GCC 11+ depends on _getpid and _kill in some places.
37 There is no concept of processes/PIDs in the baremetal PeriphDrivers, therefore
38 we implement stub functions that return an error code to resolve linker warnings.
39 */
_getpid(void)40 __weak int _getpid(void)
41 {
42 return E_NOT_SUPPORTED;
43 }
44
_kill(void)45 __weak int _kill(void)
46 {
47 return E_NOT_SUPPORTED;
48 }
49
SystemCoreClockUpdate(void)50 __weak void SystemCoreClockUpdate(void)
51 {
52 uint32_t base_freq, div, clk_src;
53
54 // Get the clock source and frequency
55 clk_src = (MXC_GCR->clkctrl & MXC_F_GCR_CLKCTRL_SYSCLK_SEL);
56 switch (clk_src) {
57 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_EXTCLK:
58 base_freq = EXTCLK_FREQ;
59 break;
60 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_ERFO:
61 base_freq = ERFO_FREQ;
62 break;
63 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_INRO:
64 base_freq = INRO_FREQ;
65 break;
66 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_IPO:
67 base_freq = IPO_FREQ;
68 break;
69 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_IBRO:
70 base_freq = IBRO_FREQ;
71 break;
72 case MXC_S_GCR_CLKCTRL_SYSCLK_SEL_ERTCO:
73 base_freq = ERTCO_FREQ;
74 break;
75 default:
76 // Codes 001 and 111 are reserved.
77 // This code should never execute, however, initialize to safe value.
78 base_freq = HIRC_FREQ;
79 break;
80 }
81 // Get the clock divider
82 if (clk_src == MXC_S_GCR_CLKCTRL_SYSCLK_SEL_IPO) {
83 uint32_t ovr = (MXC_PWRSEQ->lpcn & MXC_F_PWRSEQ_LPCN_OVR);
84 switch (ovr) {
85 case MXC_S_PWRSEQ_LPCN_OVR_0_9V:
86 base_freq = base_freq >> 3;
87 break;
88 case MXC_S_PWRSEQ_LPCN_OVR_1_0V:
89 base_freq = base_freq >> 1;
90 break;
91 case MXC_S_PWRSEQ_LPCN_OVR_1_1V:
92 default:
93 /* Nothing to do here.
94 OVR = 1.1V means the clock runs full speed. */
95 break;
96 }
97
98 base_freq = base_freq >> ((MXC_GCR->clkctrl & MXC_F_GCR_CLKCTRL_IPO_DIV) >>
99 MXC_F_GCR_CLKCTRL_IPO_DIV_POS);
100 }
101 div = (MXC_GCR->clkctrl & MXC_F_GCR_CLKCTRL_SYSCLK_DIV) >> MXC_F_GCR_CLKCTRL_SYSCLK_DIV_POS;
102
103 SystemCoreClock = base_freq >> div;
104 }
105
106 /* This function is called before C runtime initialization and can be
107 * implemented by the application for early initializations. If a value other
108 * than '0' is returned, the C runtime initialization will be skipped.
109 *
110 * You may over-ride this function in your program by defining a custom
111 * PreInit(), but care should be taken to reproduce the initialization steps
112 * or a non-functional system may result.
113 */
PreInit(void)114 __weak int PreInit(void)
115 {
116 /* Do nothing */
117 return 0;
118 }
119
120 /* This function can be implemented by the application to initialize the board */
Board_Init(void)121 __weak int Board_Init(void)
122 {
123 /* Do nothing */
124 return 0;
125 }
126
127 /* This function is called just before control is transferred to main().
128 *
129 * You may over-ride this function in your program by defining a custom
130 * SystemInit(), but care should be taken to reproduce the initialization
131 * steps or a non-functional system may result.
132 */
SystemInit(void)133 __weak void SystemInit(void)
134 {
135 /* Configure the interrupt controller to use the application vector table in */
136 /* the application space */
137 #if defined(__CC_ARM) || defined(__GNUC__)
138 /* IAR sets the VTOR pointer incorrectly and causes stack corruption */
139 SCB->VTOR = (uint32_t)__isr_vector;
140 #endif /* __CC_ARM || __GNUC__ */
141
142 #if defined __ICCARM__
143 SCB->VTOR = (uint32_t)__vector_table;
144 #endif
145
146 /* Make sure interrupts are enabled. */
147 __enable_irq();
148
149 /* Enable FPU on Cortex-M4, which occupies coprocessor slots 10 & 11 */
150 /* Grant full access, per "Table B3-24 CPACR bit assignments". */
151 /* DDI0403D "ARMv7-M Architecture Reference Manual" */
152 SCB->CPACR |= SCB_CPACR_CP10_Msk | SCB_CPACR_CP11_Msk;
153 __DSB();
154 __ISB();
155
156 /* Change system clock source to the main high-speed clock */
157 MXC_SYS_Clock_Select(MXC_SYS_CLOCK_IPO);
158 SystemCoreClockUpdate();
159
160 MXC_SYS_ClockEnable(MXC_SYS_PERIPH_CLOCK_GPIO0);
161 MXC_SYS_ClockEnable(MXC_SYS_PERIPH_CLOCK_GPIO1);
162
163 Board_Init();
164 }
165
166 #if defined(__CC_ARM)
167 /* Global variable initialization does not occur until post scatterload in Keil tools.*/
168
169 /* External function called after our post scatterload function implementation. */
170 extern void $Super$$__main_after_scatterload(void);
171
172 /**
173 * @brief Initialization function for SystemCoreClock and Board_Init.
174 * @details $Sub$$__main_after_scatterload is called during system startup in the Keil
175 * toolset. Global variable and static variable space must be set up by the compiler
176 * prior to using these memory spaces. Setting up the SystemCoreClock and Board_Init
177 * require global memory for variable storage and are called from this function in
178 * the Keil tool chain.
179 */
$Sub$$__main_after_scatterload(void)180 void $Sub$$__main_after_scatterload(void)
181 {
182 SystemInit();
183 $Super$$__main_after_scatterload();
184 while (1) {}
185 }
186 #endif /* __CC_ARM */
187
