aboutsummaryrefslogtreecommitdiffstats
path: root/libmaple/rcc.c
blob: 891453924a9487f363dbd200d8d7b31d1f1636c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/******************************************************************************
 * The MIT License
 *
 * Copyright (c) 2010 Perry Hung.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *****************************************************************************/

/**
 * @brief Implements pretty much only the basic clock setup on the
 *        stm32, clock enable/disable and peripheral reset commands.
 */

#include "libmaple.h"
#include "flash.h"
#include "rcc.h"

enum {
    APB1,
    APB2,
    AHB
};

struct rcc_dev_info {
    const uint8 clk_domain;
    const uint8 line_num;
};

/* device descriptor tables  */
static const struct rcc_dev_info rcc_dev_table[] = {
    [RCC_GPIOA]  = { .clk_domain = APB2, .line_num = 2 },
    [RCC_GPIOB]  = { .clk_domain = APB2, .line_num = 3 },
    [RCC_GPIOC]  = { .clk_domain = APB2, .line_num = 4 },
    [RCC_GPIOD]  = { .clk_domain = APB2, .line_num = 5 },
    [RCC_GPIOE]  = { .clk_domain = APB2, .line_num = 6 }, // High-density only
    [RCC_GPIOF]  = { .clk_domain = APB2, .line_num = 7 }, // High-density only
    [RCC_GPIOG]  = { .clk_domain = APB2, .line_num = 8 }, // High-density only
    [RCC_AFIO]   = { .clk_domain = APB2, .line_num = 0 },
    [RCC_ADC1]   = { .clk_domain = APB2, .line_num = 9 },
    [RCC_ADC2]   = { .clk_domain = APB2, .line_num = 10 },
    [RCC_USART1] = { .clk_domain = APB2, .line_num = 14 },
    [RCC_USART2] = { .clk_domain = APB1, .line_num = 17 },
    [RCC_USART3] = { .clk_domain = APB1, .line_num = 18 },
    [RCC_USART4] = { .clk_domain = APB1, .line_num = 19 }, // High-density only
    [RCC_USART5] = { .clk_domain = APB1, .line_num = 20 }, // High-density only
    [RCC_TIMER1] = { .clk_domain = APB2, .line_num = 11 },
    [RCC_TIMER2] = { .clk_domain = APB1, .line_num = 0 },
    [RCC_TIMER3] = { .clk_domain = APB1, .line_num = 1 },
    [RCC_TIMER4] = { .clk_domain = APB1, .line_num = 2 },
    [RCC_TIMER5] = { .clk_domain = APB1, .line_num = 3 }, // High-density only
    [RCC_TIMER6] = { .clk_domain = APB1, .line_num = 4 }, // High-density only
    [RCC_TIMER7] = { .clk_domain = APB1, .line_num = 5 }, // High-density only
    [RCC_TIMER8] = { .clk_domain = APB2, .line_num = 13 }, // High-density only
    [RCC_SPI1]   = { .clk_domain = APB2, .line_num = 12 },
    [RCC_SPI2]   = { .clk_domain = APB1, .line_num = 14 },
    [RCC_FSMC]   = { .clk_domain = AHB,  .line_num = 8 }, // High-density only
    [RCC_DAC]    = { .clk_domain = APB1, .line_num = 9 }, // High-density only
    [RCC_DMA1]   = { .clk_domain = AHB,  .line_num = 0 },
    [RCC_DMA2]   = { .clk_domain = AHB,  .line_num = 1 }, // High-density only
};

/**
 * @brief Initialize the clock control system. Initializes the system
 *        clock source to use the PLL driven by an external oscillator
 * @param sysclk_src system clock source, must be PLL
 * @param pll_src pll clock source, must be HSE
 * @param pll_mul pll multiplier
 */
void rcc_clk_init(uint32 sysclk_src, uint32 pll_src, uint32 pll_mul) {
    /* Assume that we're going to clock the chip off the PLL, fed by
     * the HSE */
    ASSERT(sysclk_src == RCC_CLKSRC_PLL &&
           pll_src    == RCC_PLLSRC_HSE);

    uint32 cfgr = 0;
    uint32 cr = RCC_READ_CR();

    cfgr =  (pll_src | pll_mul);
    RCC_WRITE_CFGR(cfgr);

    /* Turn on the HSE  */
    cr |= RCC_CR_HSEON;
    RCC_WRITE_CR(cr);
    while (!(RCC_READ_CR() & RCC_CR_HSERDY))
        ;

    /* Now the PLL  */
    cr |= RCC_CR_PLLON;
    RCC_WRITE_CR(cr);
    while (!(RCC_READ_CR() & RCC_CR_PLLRDY))
        ;

    /* Finally, let's switch over to the PLL  */
    cfgr &= ~RCC_CFGR_SW;
    cfgr |= RCC_CFGR_SW_PLL;
    RCC_WRITE_CFGR(cfgr);
    while ((RCC_READ_CFGR() & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL)
        ;
}

/**
 * @brief Turn on the clock line on a device
 * @param dev_num device to turn on
 */
void rcc_clk_enable(uint32 dev_num) {
    static const uint32 enable_regs[] = {
        [APB1] = RCC_APB1ENR,
        [APB2] = RCC_APB2ENR,
        [AHB] = RCC_AHBENR,
    };

    uint8 clk_domain = rcc_dev_table[dev_num].clk_domain;

    __set_bits(enable_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
}

/**
 * @brief Set the divider on a device prescaler
 * @param prescaler prescaler to set
 * @param divider prescaler divider
 */
void rcc_set_prescaler(uint32 prescaler, uint32 divider) {
    static const uint32 masks[] = {
        [RCC_PRESCALER_AHB] = RCC_CFGR_HPRE,
        [RCC_PRESCALER_APB1] = RCC_CFGR_PPRE1,
        [RCC_PRESCALER_APB2] = RCC_CFGR_PPRE2,
        [RCC_PRESCALER_USB] = RCC_CFGR_USBPRE,
        [RCC_PRESCALER_ADC] = RCC_CFGR_ADCPRE,
    };

    uint32 cfgr = RCC_READ_CFGR();

    cfgr &= ~masks[prescaler];
    cfgr |= divider;
    RCC_WRITE_CFGR(cfgr);
}

/**
 * @brief reset a device
 * @param dev_num device to reset
 */
void rcc_reset_dev(uint32 dev_num) {
    static const uint32 reset_regs[] = {
        [APB1] = RCC_APB1RSTR,
        [APB2] = RCC_APB2RSTR,
    };

    uint8 clk_domain = rcc_dev_table[dev_num].clk_domain;

    __set_bits(reset_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
    __clear_bits(reset_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
}