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 #define LOG_CATEGORY UCLASS_SERIAL
   8
   9 #include <common.h>
  10 #include <clk.h>
  11 #include <dm.h>
  12 #include <log.h>
  13 #include <reset.h>
  14 #include <serial.h>
  15 #include <watchdog.h>
  16 #include <asm/io.h>
  17 #include <asm/arch/stm32.h>
  18 #include <dm/device_compat.h>
  19 #include <linux/bitops.h>
  20 #include <linux/delay.h>
  21 #include "serial_stm32.h"
  22 #include <dm/device_compat.h>
  23
  24 static void _stm32_serial_setbrg(fdt_addr_t base,
  25                                  struct stm32_uart_info *uart_info,
  26                                  u32 clock_rate,
  27                                  int baudrate)
  28 {
  29         bool stm32f4 = uart_info->stm32f4;
  30         u32 int_div, mantissa, fraction, oversampling;
  31
  32         int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
  33
  34         if (int_div < 16) {
  35                 oversampling = 8;
  36                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  37         } else {
  38                 oversampling = 16;
  39                 clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  40         }
  41
  42         mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT;
  43         fraction = int_div % oversampling;
  44
  45         writel(mantissa | fraction, base + BRR_OFFSET(stm32f4));
  46 }
  47
  48 static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
  49 {
  50         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
  51
  52         _stm32_serial_setbrg(plat->base, plat->uart_info,
  53                              plat->clock_rate, baudrate);
  54
  55         return 0;
  56 }
  57
  58 static int stm32_serial_setconfig(struct udevice *dev, uint serial_config)
  59 {
  60         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
  61         bool stm32f4 = plat->uart_info->stm32f4;
  62         u8 uart_enable_bit = plat->uart_info->uart_enable_bit;
  63         u32 cr1 = plat->base + CR1_OFFSET(stm32f4);
  64         u32 config = 0;
  65         uint parity = SERIAL_GET_PARITY(serial_config);
  66         uint bits = SERIAL_GET_BITS(serial_config);
  67         uint stop = SERIAL_GET_STOP(serial_config);
  68
  69         /*
  70          * only parity config is implemented, check if other serial settings
  71          * are the default one.
  72          * (STM32F4 serial IP didn't support parity setting)
  73          */
  74         if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP || stm32f4)
  75                 return -ENOTSUPP; /* not supported in driver*/
  76
  77         clrbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
  78         /* update usart configuration (uart need to be disable)
  79          * PCE: parity check enable
  80          * PS : '0' : Even / '1' : Odd
  81          * M[1:0] = '00' : 8 Data bits
  82          * M[1:0] = '01' : 9 Data bits with parity
  83          */
  84         switch (parity) {
  85         default:
  86         case SERIAL_PAR_NONE:
  87                 config = 0;
  88                 break;
  89         case SERIAL_PAR_ODD:
  90                 config = USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0;
  91                 break;
  92         case SERIAL_PAR_EVEN:
  93                 config = USART_CR1_PCE | USART_CR1_M0;
  94                 break;
  95         }
  96
  97         clrsetbits_le32(cr1,
  98                         USART_CR1_PCE | USART_CR1_PS | USART_CR1_M1 |
  99                         USART_CR1_M0,
 100                         config);
 101         setbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
 102
 103         return 0;
 104 }
 105
 106 static int stm32_serial_getc(struct udevice *dev)
 107 {
 108         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
 109         bool stm32f4 = plat->uart_info->stm32f4;
 110         fdt_addr_t base = plat->base;
 111         u32 isr = readl(base + ISR_OFFSET(stm32f4));
 112
 113         if ((isr & USART_ISR_RXNE) == 0)
 114                 return -EAGAIN;
 115
 116         if (isr & (USART_ISR_PE | USART_ISR_ORE | USART_ISR_FE)) {
 117                 if (!stm32f4)
 118                         setbits_le32(base + ICR_OFFSET,
 119                                      USART_ICR_PCECF | USART_ICR_ORECF |
 120                                      USART_ICR_FECF);
 121                 else
 122                         readl(base + RDR_OFFSET(stm32f4));
 123                 return -EIO;
 124         }
 125
 126         return readl(base + RDR_OFFSET(stm32f4));
 127 }
 128
 129 static int _stm32_serial_putc(fdt_addr_t base,
 130                               struct stm32_uart_info *uart_info,
 131                               const char c)
 132 {
 133         bool stm32f4 = uart_info->stm32f4;
 134
 135         if ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE) == 0)
 136                 return -EAGAIN;
 137
 138         writel(c, base + TDR_OFFSET(stm32f4));
 139
 140         return 0;
 141 }
 142
 143 static int stm32_serial_putc(struct udevice *dev, const char c)
 144 {
 145         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
 146
 147         return _stm32_serial_putc(plat->base, plat->uart_info, c);
 148 }
 149
 150 static int stm32_serial_pending(struct udevice *dev, bool input)
 151 {
 152         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
 153         bool stm32f4 = plat->uart_info->stm32f4;
 154         fdt_addr_t base = plat->base;
 155
 156         if (input)
 157                 return readl(base + ISR_OFFSET(stm32f4)) &
 158                         USART_ISR_RXNE ? 1 : 0;
 159         else
 160                 return readl(base + ISR_OFFSET(stm32f4)) &
 161                         USART_ISR_TXE ? 0 : 1;
 162 }
 163
 164 static void _stm32_serial_init(fdt_addr_t base,
 165                                struct stm32_uart_info *uart_info)
 166 {
 167         bool stm32f4 = uart_info->stm32f4;
 168         u8 uart_enable_bit = uart_info->uart_enable_bit;
 169
 170         /* Disable uart-> enable fifo -> enable uart */
 171         clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 172                      BIT(uart_enable_bit));
 173         if (uart_info->has_fifo)
 174                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_FIFOEN);
 175         setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 176                      BIT(uart_enable_bit));
 177 }
 178
 179 static int stm32_serial_probe(struct udevice *dev)
 180 {
 181         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
 182         struct clk clk;
 183         struct reset_ctl reset;
 184         int ret;
 185
 186         plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
 187
 188         ret = clk_get_by_index(dev, 0, &clk);
 189         if (ret < 0)
 190                 return ret;
 191
 192         ret = clk_enable(&clk);
 193         if (ret) {
 194                 dev_err(dev, "failed to enable clock\n");
 195                 return ret;
 196         }
 197
 198         ret = reset_get_by_index(dev, 0, &reset);
 199         if (!ret) {
 200                 reset_assert(&reset);
 201                 udelay(2);
 202                 reset_deassert(&reset);
 203         }
 204
 205         plat->clock_rate = clk_get_rate(&clk);
 206         if (!plat->clock_rate) {
 207                 clk_disable(&clk);
 208                 return -EINVAL;
 209         };
 210
 211         _stm32_serial_init(plat->base, plat->uart_info);
 212
 213         return 0;
 214 }
 215
 216 static const struct udevice_id stm32_serial_id[] = {
 217         { .compatible = "st,stm32-uart", .data = (ulong)&stm32f4_info},
 218         { .compatible = "st,stm32f7-uart", .data = (ulong)&stm32f7_info},
 219         { .compatible = "st,stm32h7-uart", .data = (ulong)&stm32h7_info},
 220         {}
 221 };
 222
 223 static int stm32_serial_of_to_plat(struct udevice *dev)
 224 {
 225         struct stm32x7_serial_plat *plat = dev_get_plat(dev);
 226
 227         plat->base = dev_read_addr(dev);
 228         if (plat->base == FDT_ADDR_T_NONE)
 229                 return -EINVAL;
 230
 231         return 0;
 232 }
 233
 234 static const struct dm_serial_ops stm32_serial_ops = {
 235         .putc = stm32_serial_putc,
 236         .pending = stm32_serial_pending,
 237         .getc = stm32_serial_getc,
 238         .setbrg = stm32_serial_setbrg,
 239         .setconfig = stm32_serial_setconfig
 240 };
 241
 242 U_BOOT_DRIVER(serial_stm32) = {
 243         .name = "serial_stm32",
 244         .id = UCLASS_SERIAL,
 245         .of_match = of_match_ptr(stm32_serial_id),
 246         .of_to_plat = of_match_ptr(stm32_serial_of_to_plat),
 247         .plat_auto      = sizeof(struct stm32x7_serial_plat),
 248         .ops = &stm32_serial_ops,
 249         .probe = stm32_serial_probe,
 250 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 251         .flags = DM_FLAG_PRE_RELOC,
 252 #endif
 253 };
 254
 255 #ifdef CONFIG_DEBUG_UART_STM32
 256 #include <debug_uart.h>
 257 static inline struct stm32_uart_info *_debug_uart_info(void)
 258 {
 259         struct stm32_uart_info *uart_info;
 260
 261 #if defined(CONFIG_STM32F4)
 262         uart_info = &stm32f4_info;
 263 #elif defined(CONFIG_STM32F7)
 264         uart_info = &stm32f7_info;
 265 #else
 266         uart_info = &stm32h7_info;
 267 #endif
 268         return uart_info;
 269 }
 270
 271 static inline void _debug_uart_init(void)
 272 {
 273         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 274         struct stm32_uart_info *uart_info = _debug_uart_info();
 275
 276         _stm32_serial_init(base, uart_info);
 277         _stm32_serial_setbrg(base, uart_info,
 278                              CONFIG_DEBUG_UART_CLOCK,
 279                              CONFIG_BAUDRATE);
 280 }
 281
 282 static inline void _debug_uart_putc(int c)
 283 {
 284         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 285         struct stm32_uart_info *uart_info = _debug_uart_info();
 286
 287         while (_stm32_serial_putc(base, uart_info, c) == -EAGAIN)
 288                 ;
 289 }
 290
 291 DEBUG_UART_FUNCS
 292 #endif