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 <log.h>
  11 #include <reset.h>
  12 #include <serial.h>
  13 #include <watchdog.h>
  14 #include <asm/io.h>
  15 #include <asm/arch/stm32.h>
  16 #include <linux/bitops.h>
  17 #include <linux/delay.h>
  18 #include "serial_stm32.h"
  19 #include <dm/device_compat.h>
  20
  21 static void _stm32_serial_setbrg(fdt_addr_t base,
  22                                  struct stm32_uart_info *uart_info,
  23                                  u32 clock_rate,
  24                                  int baudrate)
  25 {
  26         bool stm32f4 = uart_info->stm32f4;
  27         u32 int_div, mantissa, fraction, oversampling;
  28
  29         int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
  30
  31         if (int_div < 16) {
  32                 oversampling = 8;
  33                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  34         } else {
  35                 oversampling = 16;
  36                 clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
  37         }
  38
  39         mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT;
  40         fraction = int_div % oversampling;
  41
  42         writel(mantissa | fraction, base + BRR_OFFSET(stm32f4));
  43 }
  44
  45 static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
  46 {
  47         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
  48
  49         _stm32_serial_setbrg(plat->base, plat->uart_info,
  50                              plat->clock_rate, baudrate);
  51
  52         return 0;
  53 }
  54
  55 static int stm32_serial_setconfig(struct udevice *dev, uint serial_config)
  56 {
  57         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
  58         bool stm32f4 = plat->uart_info->stm32f4;
  59         u8 uart_enable_bit = plat->uart_info->uart_enable_bit;
  60         u32 cr1 = plat->base + CR1_OFFSET(stm32f4);
  61         u32 config = 0;
  62         uint parity = SERIAL_GET_PARITY(serial_config);
  63         uint bits = SERIAL_GET_BITS(serial_config);
  64         uint stop = SERIAL_GET_STOP(serial_config);
  65
  66         /*
  67          * only parity config is implemented, check if other serial settings
  68          * are the default one.
  69          * (STM32F4 serial IP didn't support parity setting)
  70          */
  71         if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP || stm32f4)
  72                 return -ENOTSUPP; /* not supported in driver*/
  73
  74         clrbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
  75         /* update usart configuration (uart need to be disable)
  76          * PCE: parity check enable
  77          * PS : '0' : Even / '1' : Odd
  78          * M[1:0] = '00' : 8 Data bits
  79          * M[1:0] = '01' : 9 Data bits with parity
  80          */
  81         switch (parity) {
  82         default:
  83         case SERIAL_PAR_NONE:
  84                 config = 0;
  85                 break;
  86         case SERIAL_PAR_ODD:
  87                 config = USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0;
  88                 break;
  89         case SERIAL_PAR_EVEN:
  90                 config = USART_CR1_PCE | USART_CR1_M0;
  91                 break;
  92         }
  93
  94         clrsetbits_le32(cr1,
  95                         USART_CR1_PCE | USART_CR1_PS | USART_CR1_M1 |
  96                         USART_CR1_M0,
  97                         config);
  98         setbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
  99
 100         return 0;
 101 }
 102
 103 static int stm32_serial_getc(struct udevice *dev)
 104 {
 105         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
 106         bool stm32f4 = plat->uart_info->stm32f4;
 107         fdt_addr_t base = plat->base;
 108         u32 isr = readl(base + ISR_OFFSET(stm32f4));
 109
 110         if ((isr & USART_ISR_RXNE) == 0)
 111                 return -EAGAIN;
 112
 113         if (isr & (USART_ISR_PE | USART_ISR_ORE | USART_ISR_FE)) {
 114                 if (!stm32f4)
 115                         setbits_le32(base + ICR_OFFSET,
 116                                      USART_ICR_PCECF | USART_ICR_ORECF |
 117                                      USART_ICR_FECF);
 118                 else
 119                         readl(base + RDR_OFFSET(stm32f4));
 120                 return -EIO;
 121         }
 122
 123         return readl(base + RDR_OFFSET(stm32f4));
 124 }
 125
 126 static int _stm32_serial_putc(fdt_addr_t base,
 127                               struct stm32_uart_info *uart_info,
 128                               const char c)
 129 {
 130         bool stm32f4 = uart_info->stm32f4;
 131
 132         if ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE) == 0)
 133                 return -EAGAIN;
 134
 135         writel(c, base + TDR_OFFSET(stm32f4));
 136
 137         return 0;
 138 }
 139
 140 static int stm32_serial_putc(struct udevice *dev, const char c)
 141 {
 142         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
 143
 144         return _stm32_serial_putc(plat->base, plat->uart_info, c);
 145 }
 146
 147 static int stm32_serial_pending(struct udevice *dev, bool input)
 148 {
 149         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
 150         bool stm32f4 = plat->uart_info->stm32f4;
 151         fdt_addr_t base = plat->base;
 152
 153         if (input)
 154                 return readl(base + ISR_OFFSET(stm32f4)) &
 155                         USART_ISR_RXNE ? 1 : 0;
 156         else
 157                 return readl(base + ISR_OFFSET(stm32f4)) &
 158                         USART_ISR_TXE ? 0 : 1;
 159 }
 160
 161 static void _stm32_serial_init(fdt_addr_t base,
 162                                struct stm32_uart_info *uart_info)
 163 {
 164         bool stm32f4 = uart_info->stm32f4;
 165         u8 uart_enable_bit = uart_info->uart_enable_bit;
 166
 167         /* Disable uart-> enable fifo -> enable uart */
 168         clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 169                      BIT(uart_enable_bit));
 170         if (uart_info->has_fifo)
 171                 setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_FIFOEN);
 172         setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
 173                      BIT(uart_enable_bit));
 174 }
 175
 176 static int stm32_serial_probe(struct udevice *dev)
 177 {
 178         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
 179         struct clk clk;
 180         struct reset_ctl reset;
 181         int ret;
 182
 183         plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
 184
 185         ret = clk_get_by_index(dev, 0, &clk);
 186         if (ret < 0)
 187                 return ret;
 188
 189         ret = clk_enable(&clk);
 190         if (ret) {
 191                 dev_err(dev, "failed to enable clock\n");
 192                 return ret;
 193         }
 194
 195         ret = reset_get_by_index(dev, 0, &reset);
 196         if (!ret) {
 197                 reset_assert(&reset);
 198                 udelay(2);
 199                 reset_deassert(&reset);
 200         }
 201
 202         plat->clock_rate = clk_get_rate(&clk);
 203         if (!plat->clock_rate) {
 204                 clk_disable(&clk);
 205                 return -EINVAL;
 206         };
 207
 208         _stm32_serial_init(plat->base, plat->uart_info);
 209
 210         return 0;
 211 }
 212
 213 static const struct udevice_id stm32_serial_id[] = {
 214         { .compatible = "st,stm32-uart", .data = (ulong)&stm32f4_info},
 215         { .compatible = "st,stm32f7-uart", .data = (ulong)&stm32f7_info},
 216         { .compatible = "st,stm32h7-uart", .data = (ulong)&stm32h7_info},
 217         {}
 218 };
 219
 220 static int stm32_serial_ofdata_to_platdata(struct udevice *dev)
 221 {
 222         struct stm32x7_serial_platdata *plat = dev_get_plat(dev);
 223
 224         plat->base = dev_read_addr(dev);
 225         if (plat->base == FDT_ADDR_T_NONE)
 226                 return -EINVAL;
 227
 228         return 0;
 229 }
 230
 231 static const struct dm_serial_ops stm32_serial_ops = {
 232         .putc = stm32_serial_putc,
 233         .pending = stm32_serial_pending,
 234         .getc = stm32_serial_getc,
 235         .setbrg = stm32_serial_setbrg,
 236         .setconfig = stm32_serial_setconfig
 237 };
 238
 239 U_BOOT_DRIVER(serial_stm32) = {
 240         .name = "serial_stm32",
 241         .id = UCLASS_SERIAL,
 242         .of_match = of_match_ptr(stm32_serial_id),
 243         .ofdata_to_platdata = of_match_ptr(stm32_serial_ofdata_to_platdata),
 244         .plat_auto      = sizeof(struct stm32x7_serial_platdata),
 245         .ops = &stm32_serial_ops,
 246         .probe = stm32_serial_probe,
 247 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 248         .flags = DM_FLAG_PRE_RELOC,
 249 #endif
 250 };
 251
 252 #ifdef CONFIG_DEBUG_UART_STM32
 253 #include <debug_uart.h>
 254 static inline struct stm32_uart_info *_debug_uart_info(void)
 255 {
 256         struct stm32_uart_info *uart_info;
 257
 258 #if defined(CONFIG_STM32F4)
 259         uart_info = &stm32f4_info;
 260 #elif defined(CONFIG_STM32F7)
 261         uart_info = &stm32f7_info;
 262 #else
 263         uart_info = &stm32h7_info;
 264 #endif
 265         return uart_info;
 266 }
 267
 268 static inline void _debug_uart_init(void)
 269 {
 270         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 271         struct stm32_uart_info *uart_info = _debug_uart_info();
 272
 273         _stm32_serial_init(base, uart_info);
 274         _stm32_serial_setbrg(base, uart_info,
 275                              CONFIG_DEBUG_UART_CLOCK,
 276                              CONFIG_BAUDRATE);
 277 }
 278
 279 static inline void _debug_uart_putc(int c)
 280 {
 281         fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
 282         struct stm32_uart_info *uart_info = _debug_uart_info();
 283
 284         while (_stm32_serial_putc(base, uart_info, c) == -EAGAIN)
 285                 ;
 286 }
 287
 288 DEBUG_UART_FUNCS
 289 #endif