drivers/serial/serial_stm32.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
   4  * Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
   5  */
   6
   7 #include <common.h>
   8 #include <clk.h>
   9 #include <dm.h>
  10 #include <reset.h>
  11 #include <serial.h>
  12 #include <watchdog.h>
  13 #include <asm/io.h>
  14 #include <asm/arch/stm32.h>
  15 #include "serial_stm32.h"
  16
  17 static void _stm32_serial_setbrg(fdt_addr_t base,
  18                                  struct stm32_uart_info *uart_info,
  19                                  u32 clock_rate,
  20                                  int baudrate)
  21 {
  22         bool stm32f4 = uart_info->stm32f4;
  23         u32 int_div, mantissa, fraction, oversampling;
  24
  25         int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
  26
  27         if (int_div < 16) {
  28                 oversampling = 8;
  29                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  30         } else {
  31                 oversampling = 16;
  32                 clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  33         }
  34
  35         mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT;
  36         fraction = int_div % oversampling;
  37
  38         writel(mantissa | fraction, base + BRR_OFFSET(stm32f4));
  39 }
  40
  41 static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
  42 {
  43         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
  44
  45         _stm32_serial_setbrg(plat->base, plat->uart_info,
  46                              plat->clock_rate, baudrate);
  47
  48         return 0;
  49 }
  50
  51 static int stm32_serial_setconfig(struct udevice *dev, uint serial_config)
  52 {
  53         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
  54         bool stm32f4 = plat->uart_info->stm32f4;
  55         u8 uart_enable_bit = plat->uart_info->uart_enable_bit;
  56         u32 cr1 = plat->base + CR1_OFFSET(stm32f4);
  57         u32 config = 0;
  58         uint parity = SERIAL_GET_PARITY(serial_config);
  59         uint bits = SERIAL_GET_BITS(serial_config);
  60         uint stop = SERIAL_GET_STOP(serial_config);
  61
  62         /*
  63          * only parity config is implemented, check if other serial settings
  64          * are the default one.
  65          * (STM32F4 serial IP didn't support parity setting)
  66          */
  67         if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP || stm32f4)
  68                 return -ENOTSUPP; /* not supported in driver*/
  69
  70         clrbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
  71         /* update usart configuration (uart need to be disable)
  72          * PCE: parity check enable
  73          * PS : '0' : Even / '1' : Odd
  74          * M[1:0] = '00' : 8 Data bits
  75          * M[1:0] = '01' : 9 Data bits with parity
  76          */
  77         switch (parity) {
  78         default:
  79         case SERIAL_PAR_NONE:
  80                 config = 0;
  81                 break;
  82         case SERIAL_PAR_ODD:
  83                 config = USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0;
  84                 break;
  85         case SERIAL_PAR_EVEN:
  86                 config = USART_CR1_PCE | USART_CR1_M0;
  87                 break;
  88         }
  89
  90         clrsetbits_le32(cr1,
  91                         USART_CR1_PCE | USART_CR1_PS | USART_CR1_M1 |
  92                         USART_CR1_M0,
  93                         config);
  94         setbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
  95
  96         return 0;
  97 }
  98
  99 static int stm32_serial_getc(struct udevice *dev)
 100 {
 101         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
 102         bool stm32f4 = plat->uart_info->stm32f4;
 103         fdt_addr_t base = plat->base;
 104         u32 isr = readl(base + ISR_OFFSET(stm32f4));
 105
 106         if ((isr & USART_ISR_RXNE) == 0)
 107                 return -EAGAIN;
 108
 109         if (isr & (USART_ISR_PE | USART_ISR_ORE | USART_ISR_FE)) {
 110                 if (!stm32f4)
 111                         setbits_le32(base + ICR_OFFSET,
 112                                      USART_ICR_PCECF | USART_ICR_ORECF |
 113                                      USART_ICR_FECF);
 114                 else
 115                         readl(base + RDR_OFFSET(stm32f4));
 116                 return -EIO;
 117         }
 118
 119         return readl(base + RDR_OFFSET(stm32f4));
 120 }
 121
 122 static int _stm32_serial_putc(fdt_addr_t base,
 123                               struct stm32_uart_info *uart_info,
 124                               const char c)
 125 {
 126         bool stm32f4 = uart_info->stm32f4;
 127
 128         if ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE) == 0)
 129                 return -EAGAIN;
 130
 131         writel(c, base + TDR_OFFSET(stm32f4));
 132
 133         return 0;
 134 }
 135
 136 static int stm32_serial_putc(struct udevice *dev, const char c)
 137 {
 138         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
 139
 140         return _stm32_serial_putc(plat->base, plat->uart_info, c);
 141 }
 142
 143 static int stm32_serial_pending(struct udevice *dev, bool input)
 144 {
 145         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
 146         bool stm32f4 = plat->uart_info->stm32f4;
 147         fdt_addr_t base = plat->base;
 148
 149         if (input)
 150                 return readl(base + ISR_OFFSET(stm32f4)) &
 151                         USART_ISR_RXNE ? 1 : 0;
 152         else
 153                 return readl(base + ISR_OFFSET(stm32f4)) &
 154                         USART_ISR_TXE ? 0 : 1;
 155 }
 156
 157 static void _stm32_serial_init(fdt_addr_t base,
 158                                struct stm32_uart_info *uart_info)
 159 {
 160         bool stm32f4 = uart_info->stm32f4;
 161         u8 uart_enable_bit = uart_info->uart_enable_bit;
 162
 163         /* Disable uart-> enable fifo -> enable uart */
 164         clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 165                      BIT(uart_enable_bit));
 166         if (uart_info->has_fifo)
 167                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_FIFOEN);
 168         setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 169                      BIT(uart_enable_bit));
 170 }
 171
 172 static int stm32_serial_probe(struct udevice *dev)
 173 {
 174         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
 175         struct clk clk;
 176         struct reset_ctl reset;
 177         int ret;
 178
 179         plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
 180
 181         ret = clk_get_by_index(dev, 0, &clk);
 182         if (ret < 0)
 183                 return ret;
 184
 185         ret = clk_enable(&clk);
 186         if (ret) {
 187                 dev_err(dev, "failed to enable clock\n");
 188                 return ret;
 189         }
 190
 191         ret = reset_get_by_index(dev, 0, &reset);
 192         if (!ret) {
 193                 reset_assert(&reset);
 194                 udelay(2);
 195                 reset_deassert(&reset);
 196         }
 197
 198         plat->clock_rate = clk_get_rate(&clk);
 199         if (!plat->clock_rate) {
 200                 clk_disable(&clk);
 201                 return -EINVAL;
 202         };
 203
 204         _stm32_serial_init(plat->base, plat->uart_info);
 205
 206         return 0;
 207 }
 208
 209 static const struct udevice_id stm32_serial_id[] = {
 210         { .compatible = "st,stm32-uart", .data = (ulong)&stm32f4_info},
 211         { .compatible = "st,stm32f7-uart", .data = (ulong)&stm32f7_info},
 212         { .compatible = "st,stm32h7-uart", .data = (ulong)&stm32h7_info},
 213         {}
 214 };
 215
 216 static int stm32_serial_ofdata_to_platdata(struct udevice *dev)
 217 {
 218         struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
 219
 220         plat->base = devfdt_get_addr(dev);
 221         if (plat->base == FDT_ADDR_T_NONE)
 222                 return -EINVAL;
 223
 224         return 0;
 225 }
 226
 227 static const struct dm_serial_ops stm32_serial_ops = {
 228         .putc = stm32_serial_putc,
 229         .pending = stm32_serial_pending,
 230         .getc = stm32_serial_getc,
 231         .setbrg = stm32_serial_setbrg,
 232         .setconfig = stm32_serial_setconfig
 233 };
 234
 235 U_BOOT_DRIVER(serial_stm32) = {
 236         .name = "serial_stm32",
 237         .id = UCLASS_SERIAL,
 238         .of_match = of_match_ptr(stm32_serial_id),
 239         .ofdata_to_platdata = of_match_ptr(stm32_serial_ofdata_to_platdata),
 240         .platdata_auto_alloc_size = sizeof(struct stm32x7_serial_platdata),
 241         .ops = &stm32_serial_ops,
 242         .probe = stm32_serial_probe,
 243 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 244         .flags = DM_FLAG_PRE_RELOC,
 245 #endif
 246 };
 247
 248 #ifdef CONFIG_DEBUG_UART_STM32
 249 #include <debug_uart.h>
 250 static inline struct stm32_uart_info *_debug_uart_info(void)
 251 {
 252         struct stm32_uart_info *uart_info;
 253
 254 #if defined(CONFIG_STM32F4)
 255         uart_info = &stm32f4_info;
 256 #elif defined(CONFIG_STM32F7)
 257         uart_info = &stm32f7_info;
 258 #else
 259         uart_info = &stm32h7_info;
 260 #endif
 261         return uart_info;
 262 }
 263
 264 static inline void _debug_uart_init(void)
 265 {
 266         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 267         struct stm32_uart_info *uart_info = _debug_uart_info();
 268
 269         _stm32_serial_init(base, uart_info);
 270         _stm32_serial_setbrg(base, uart_info,
 271                              CONFIG_DEBUG_UART_CLOCK,
 272                              CONFIG_BAUDRATE);
 273 }
 274
 275 static inline void _debug_uart_putc(int c)
 276 {
 277         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 278         struct stm32_uart_info *uart_info = _debug_uart_info();
 279
 280         while (_stm32_serial_putc(base, uart_info, c) == -EAGAIN)
 281                 ;
 282 }
 283
 284 DEBUG_UART_FUNCS
 285 #endif