[e230fb4] | 1 | /* |
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| 2 | * Copyright (c) 2012 Sebastian Huber. All rights reserved. |
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| 3 | * |
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| 4 | * embedded brains GmbH |
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| 5 | * Obere Lagerstr. 30 |
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| 6 | * 82178 Puchheim |
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| 7 | * Germany |
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| 8 | * <rtems@embedded-brains.de> |
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| 9 | * |
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| 10 | * The license and distribution terms for this file may be |
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| 11 | * found in the file LICENSE in this distribution or at |
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[c499856] | 12 | * http://www.rtems.org/license/LICENSE. |
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[e230fb4] | 13 | */ |
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| 14 | |
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| 15 | #include <libchip/sersupp.h> |
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| 16 | |
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| 17 | #include <bsp.h> |
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[228ece9] | 18 | #include <bsp/io.h> |
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| 19 | #include <bsp/rcc.h> |
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[e230fb4] | 20 | #include <bsp/irq.h> |
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| 21 | #include <bsp/usart.h> |
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| 22 | #include <bsp/stm32f4.h> |
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| 23 | |
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| 24 | static volatile stm32f4_usart *usart_get_regs(const console_tbl *ct) |
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| 25 | { |
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| 26 | return (stm32f4_usart *) ct->ulCtrlPort1; |
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| 27 | } |
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| 28 | |
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| 29 | #if 0 |
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| 30 | static rtems_vector_number usart_get_irq_number(const console_tbl *ct) |
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| 31 | { |
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| 32 | return ct->ulIntVector; |
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| 33 | } |
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| 34 | #endif |
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| 35 | |
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[228ece9] | 36 | static const stm32f4_rcc_index usart_rcc_index [] = { |
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| 37 | STM32F4_RCC_USART1, |
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| 38 | STM32F4_RCC_USART2, |
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| 39 | STM32F4_RCC_USART3, |
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| 40 | STM32F4_RCC_UART4, |
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| 41 | STM32F4_RCC_UART5, |
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[1485a58] | 42 | #ifdef STM32F4_FAMILY_F4XXXX |
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[228ece9] | 43 | STM32F4_RCC_USART6 |
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[1485a58] | 44 | #endif /* STM32F4_FAMILY_F4XXXX */ |
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[228ece9] | 45 | }; |
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| 46 | |
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| 47 | static stm32f4_rcc_index usart_get_rcc_index(const console_tbl *ct) |
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| 48 | { |
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| 49 | return usart_rcc_index [ct->ulCtrlPort2]; |
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| 50 | } |
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| 51 | |
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[e230fb4] | 52 | static const uint8_t usart_pclk_index [] = { 1, 0, 0, 0, 0, 1 }; |
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| 53 | |
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| 54 | static const uint32_t usart_pclk_by_index [] = { |
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| 55 | STM32F4_PCLK1, |
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| 56 | STM32F4_PCLK2 |
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| 57 | }; |
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| 58 | |
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| 59 | static uint32_t usart_get_pclk(const console_tbl *ct) |
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| 60 | { |
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| 61 | return usart_pclk_by_index [usart_pclk_index [ct->ulCtrlPort2]]; |
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| 62 | } |
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| 63 | |
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| 64 | static uint32_t usart_get_baud(const console_tbl *ct) |
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| 65 | { |
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| 66 | return ct->ulClock; |
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| 67 | } |
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| 68 | |
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| 69 | /* |
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| 70 | * a = 8 * (2 - CR1[OVER8]) |
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| 71 | * |
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| 72 | * usartdiv = div_mantissa + div_fraction / a |
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| 73 | * |
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| 74 | * baud = pclk / (a * usartdiv) |
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| 75 | * |
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| 76 | * usartdiv = pclk / (a * baud) |
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| 77 | * |
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| 78 | * Calculation in integer arithmetic: |
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| 79 | * |
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| 80 | * 1. div_mantissa = pclk / (a * baud) |
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| 81 | * |
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| 82 | * 2. div_fraction = pclk / (baud - a * div_mantissa) |
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| 83 | */ |
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| 84 | static uint32_t usart_get_bbr( |
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| 85 | volatile stm32f4_usart *usart, |
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| 86 | uint32_t pclk, |
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| 87 | uint32_t baud |
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| 88 | ) |
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| 89 | { |
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| 90 | uint32_t a = 8 * (2 - ((usart->cr1 & STM32F4_USART_CR1_OVER8) != 0)); |
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| 91 | uint32_t div_mantissa_low = pclk / (a * baud); |
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| 92 | uint32_t div_fraction_low = pclk / (baud - a * div_mantissa_low); |
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| 93 | uint32_t div_mantissa_high; |
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| 94 | uint32_t div_fraction_high; |
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| 95 | uint32_t high_err; |
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| 96 | uint32_t low_err; |
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| 97 | uint32_t div_mantissa; |
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| 98 | uint32_t div_fraction; |
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| 99 | |
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| 100 | if (div_fraction_low < a - 1) { |
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| 101 | div_mantissa_high = div_fraction_low; |
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| 102 | div_fraction_high = div_fraction_low + 1; |
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| 103 | } else { |
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| 104 | div_mantissa_high = div_fraction_low + 1; |
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| 105 | div_fraction_high = 0; |
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| 106 | } |
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| 107 | |
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| 108 | high_err = pclk - baud * (a * div_mantissa_high + div_fraction_high); |
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| 109 | low_err = baud * (a * div_mantissa_low + div_fraction_low) - pclk; |
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| 110 | |
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| 111 | if (low_err < high_err) { |
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| 112 | div_mantissa = div_mantissa_low; |
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| 113 | div_fraction = div_fraction_low; |
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| 114 | } else { |
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| 115 | div_mantissa = div_mantissa_high; |
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| 116 | div_fraction = div_fraction_high; |
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| 117 | } |
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| 118 | |
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| 119 | return STM32F4_USART_BBR_DIV_MANTISSA(div_mantissa) |
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| 120 | | STM32F4_USART_BBR_DIV_FRACTION(div_fraction); |
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| 121 | } |
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| 122 | |
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| 123 | static void usart_initialize(int minor) |
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| 124 | { |
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| 125 | const console_tbl *ct = Console_Port_Tbl [minor]; |
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| 126 | volatile stm32f4_usart *usart = usart_get_regs(ct); |
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| 127 | uint32_t pclk = usart_get_pclk(ct); |
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| 128 | uint32_t baud = usart_get_baud(ct); |
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[228ece9] | 129 | stm32f4_rcc_index rcc_index = usart_get_rcc_index(ct); |
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[e230fb4] | 130 | |
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[228ece9] | 131 | stm32f4_rcc_set_clock(rcc_index, true); |
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[e230fb4] | 132 | |
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| 133 | usart->cr1 = 0; |
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| 134 | usart->cr2 = 0; |
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| 135 | usart->cr3 = 0; |
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| 136 | usart->bbr = usart_get_bbr(usart, pclk, baud); |
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| 137 | usart->cr1 = STM32F4_USART_CR1_UE |
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| 138 | | STM32F4_USART_CR1_TE |
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| 139 | | STM32F4_USART_CR1_RE; |
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| 140 | } |
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| 141 | |
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| 142 | static int usart_first_open(int major, int minor, void *arg) |
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| 143 | { |
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| 144 | rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *) arg; |
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| 145 | struct rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1; |
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| 146 | const console_tbl *ct = Console_Port_Tbl [minor]; |
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| 147 | console_data *cd = &Console_Port_Data [minor]; |
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| 148 | |
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| 149 | cd->termios_data = tty; |
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| 150 | rtems_termios_set_initial_baud(tty, ct->ulClock); |
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| 151 | |
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| 152 | return 0; |
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| 153 | } |
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| 154 | |
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| 155 | static int usart_last_close(int major, int minor, void *arg) |
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| 156 | { |
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| 157 | return 0; |
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| 158 | } |
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| 159 | |
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| 160 | static int usart_read_polled(int minor) |
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| 161 | { |
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| 162 | const console_tbl *ct = Console_Port_Tbl [minor]; |
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| 163 | volatile stm32f4_usart *usart = usart_get_regs(ct); |
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| 164 | |
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| 165 | if ((usart->sr & STM32F4_USART_SR_RXNE) != 0) { |
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| 166 | return STM32F4_USART_DR_GET(usart->dr); |
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| 167 | } else { |
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| 168 | return -1; |
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| 169 | } |
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| 170 | } |
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| 171 | |
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| 172 | static void usart_write_polled(int minor, char c) |
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| 173 | { |
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| 174 | const console_tbl *ct = Console_Port_Tbl [minor]; |
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| 175 | volatile stm32f4_usart *usart = usart_get_regs(ct); |
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| 176 | |
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| 177 | while ((usart->sr & STM32F4_USART_SR_TXE) == 0) { |
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| 178 | /* Wait */ |
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| 179 | } |
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| 180 | |
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| 181 | usart->dr = STM32F4_USART_DR(c); |
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| 182 | } |
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| 183 | |
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| 184 | static ssize_t usart_write_support_polled( |
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| 185 | int minor, |
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| 186 | const char *s, |
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| 187 | size_t n |
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| 188 | ) |
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| 189 | { |
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| 190 | ssize_t i = 0; |
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| 191 | |
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| 192 | for (i = 0; i < n; ++i) { |
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| 193 | usart_write_polled(minor, s [i]); |
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| 194 | } |
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| 195 | |
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| 196 | return n; |
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| 197 | } |
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| 198 | |
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| 199 | static int usart_set_attributes(int minor, const struct termios *term) |
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| 200 | { |
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| 201 | return -1; |
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| 202 | } |
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| 203 | |
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[c8bd3cd] | 204 | const console_fns stm32f4_usart_fns = { |
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[e230fb4] | 205 | .deviceProbe = libchip_serial_default_probe, |
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| 206 | .deviceFirstOpen = usart_first_open, |
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| 207 | .deviceLastClose = usart_last_close, |
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| 208 | .deviceRead = usart_read_polled, |
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| 209 | .deviceWrite = usart_write_support_polled, |
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| 210 | .deviceInitialize = usart_initialize, |
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| 211 | .deviceWritePolled = usart_write_polled, |
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| 212 | .deviceSetAttributes = usart_set_attributes, |
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| 213 | .deviceOutputUsesInterrupts = false |
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| 214 | }; |
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