diff options
Diffstat (limited to 'libmaple/rcc.c')
-rw-r--r-- | libmaple/rcc.c | 235 |
1 files changed, 152 insertions, 83 deletions
diff --git a/libmaple/rcc.c b/libmaple/rcc.c index bb423b9..4f13b0d 100644 --- a/libmaple/rcc.c +++ b/libmaple/rcc.c @@ -23,107 +23,176 @@ * ****************************************************************************/ /** - * @file rcc.c - * - * @brief Implements pretty much only the basic clock setup on the maple, - * exposes a handful of clock enable/disable and peripheral reset commands. + * @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" -static void set_ahb_prescaler(uint32 divider) { - uint32 cfgr = __read(RCC_CFGR); - - cfgr &= ~HPRE; - - switch (divider) { - case SYSCLK_DIV_1: - cfgr |= SYSCLK_DIV_1; - break; - default: - ASSERT(0); - } +/* registers */ +#define RCC_BASE 0x40021000 +#define RCC_CR (RCC_BASE + 0x0) +#define RCC_CFGR (RCC_BASE + 0x4) +#define RCC_CIR (RCC_BASE + 0x8) +#define RCC_APB2RSTR (RCC_BASE + 0xC) +#define RCC_APB1RSTR (RCC_BASE + 0x10) +#define RCC_AHBENR (RCC_BASE + 0x14) +#define RCC_APB2ENR (RCC_BASE + 0x18) +#define RCC_APB1ENR (RCC_BASE + 0x1C) +#define RCC_BDCR (RCC_BASE + 0x20) +#define RCC_CSR (RCC_BASE + 0x24) +#define RCC_AHBSTR (RCC_BASE + 0x28) +#define RCC_CFGR2 (RCC_BASE + 0x2C) + +#define RCC_CFGR_USBPRE (0x1 << 22) +#define RCC_CFGR_ADCPRE (0x3 << 14) +#define RCC_CFGR_PPRE1 (0x7 << 8) +#define RCC_CFGR_PPRE2 (0x7 << 11) +#define RCC_CFGR_HPRE (0xF << 4) +#define RCC_CFGR_PLLSRC (0x1 << 16) + +#define RCC_CFGR_SWS (0x3 << 2) +#define RCC_CFGR_SWS_PLL (0x2 << 2) +#define RCC_CFGR_SWS_HSE (0x1 << 2) + +#define RCC_CFGR_SW (0x3 << 0) +#define RCC_CFGR_SW_PLL (0x2 << 0) +#define RCC_CFGR_SW_HSE (0x1 << 0) + +/* CR status bits */ +#define RCC_CR_HSEON (0x1 << 16) +#define RCC_CR_HSERDY (0x1 << 17) +#define RCC_CR_PLLON (0x1 << 24) +#define RCC_CR_PLLRDY (0x1 << 25) + +#define RCC_WRITE_CFGR(val) __write(RCC_CFGR, val) +#define RCC_READ_CFGR() __read(RCC_CFGR) + +#define RCC_WRITE_CR(val) __write(RCC_CR, val) +#define RCC_READ_CR() __read(RCC_CR) + +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_AFIO] = { .clk_domain = APB2, .line_num = 0 }, + [RCC_ADC1] = { .clk_domain = APB2, .line_num = 9 }, + [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_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 }, +}; - __write(RCC_CFGR, cfgr); +/** + * @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) + ; } -static void set_apb1_prescaler(uint32 divider) { - uint32 cfgr = __read(RCC_CFGR); - cfgr &= ~PPRE1; - switch (divider) { - case HCLK_DIV_2: - cfgr |= HCLK_DIV_2; - break; - default: - ASSERT(0); - } - - __write(RCC_CFGR, cfgr); -} - -static void set_apb2_prescaler(uint32 divider) { - uint32 cfgr = __read(RCC_CFGR); - - cfgr &= ~PPRE2; +/** + * @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, + }; - switch (divider) { - case HCLK_DIV_1: - cfgr |= HCLK_DIV_1; - break; - default: - ASSERT(0); - } + uint8 clk_domain = rcc_dev_table[dev_num].clk_domain; - __write(RCC_CFGR, cfgr); + __set_bits(enable_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num)); } -/* FIXME: magic numbers */ -static void pll_init(void) { - uint32 cfgr; - cfgr = __read(RCC_CFGR); - cfgr &= (~PLLMUL | PLL_INPUT_CLK_HSE); - - /* pll multiplier 9, input clock hse */ - __write(RCC_CFGR, cfgr | PLL_MUL_9 | PLL_INPUT_CLK_HSE); - - /* enable pll */ - __set_bits(RCC_CR, PLLON); - while(!__get_bits(RCC_CR, PLLRDY)) { - asm volatile("nop"); - } - - /* select pll for system clock source */ - cfgr = __read(RCC_CFGR); - cfgr &= ~RCC_CFGR_SW; - __write(RCC_CFGR, cfgr | RCC_CFGR_SW_PLL); - - while (__get_bits(RCC_CFGR, 0x00000008) != 0x8) { - asm volatile("nop"); - } +/** + * @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); } -static void hse_init(void) { - __set_bits(RCC_CR, HSEON); - while (!HSERDY) { - asm volatile("nop"); - } -} -void rcc_init(void) { - hse_init(); - set_ahb_prescaler(SYSCLK_DIV_1); - set_apb1_prescaler(HCLK_DIV_2); - set_apb2_prescaler(HCLK_DIV_1); - pll_init(); -} +/** + * @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; -void rcc_set_adc_prescaler(uint32 divider) { - uint32 cfgr = __read(RCC_CFGR); - cfgr &= ~ADCPRE; - __write(RCC_CFGR, cfgr | PCLK2_DIV_2); + __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)); } |