drivers/serial/atmel_usart.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * Modified to support C structur SoC access by
   5  * Andreas Bießmann <biessmann@corscience.de>
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9 #include <common.h>
  10 #include <dm.h>
  11 #include <errno.h>
  12 #include <watchdog.h>
  13 #include <serial.h>
  14 #include <debug_uart.h>
  15 #include <linux/compiler.h>
  16
  17 #include <asm/io.h>
  18 #ifdef CONFIG_DM_SERIAL
  19 #include <asm/arch/atmel_serial.h>
  20 #endif
  21 #include <asm/arch/clk.h>
  22 #include <asm/arch/hardware.h>
  23
  24 #include "atmel_usart.h"
  25
  26 DECLARE_GLOBAL_DATA_PTR;
  27
  28 #ifndef CONFIG_DM_SERIAL
  29 static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id,
  30                                          int baudrate)
  31 {
  32         unsigned long divisor;
  33         unsigned long usart_hz;
  34
  35         /*
  36          *              Master Clock
  37          * Baud Rate = --------------
  38          *                16 * CD
  39          */
  40         usart_hz = get_usart_clk_rate(id);
  41         divisor = (usart_hz / 16 + baudrate / 2) / baudrate;
  42         writel(USART3_BF(CD, divisor), &usart->brgr);
  43 }
  44
  45 static void atmel_serial_init_internal(atmel_usart3_t *usart)
  46 {
  47         /*
  48          * Just in case: drain transmitter register
  49          * 1000us is enough for baudrate >= 9600
  50          */
  51         if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY)))
  52                 __udelay(1000);
  53
  54         writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
  55 }
  56
  57 static void atmel_serial_activate(atmel_usart3_t *usart)
  58 {
  59         writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
  60                            | USART3_BF(USCLKS, USART3_USCLKS_MCK)
  61                            | USART3_BF(CHRL, USART3_CHRL_8)
  62                            | USART3_BF(PAR, USART3_PAR_NONE)
  63                            | USART3_BF(NBSTOP, USART3_NBSTOP_1)),
  64                            &usart->mr);
  65         writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
  66         /* 100us is enough for the new settings to be settled */
  67         __udelay(100);
  68 }
  69
  70 static void atmel_serial_setbrg(void)
  71 {
  72         atmel_serial_setbrg_internal((atmel_usart3_t *)CONFIG_USART_BASE,
  73                                      CONFIG_USART_ID, gd->baudrate);
  74 }
  75
  76 static int atmel_serial_init(void)
  77 {
  78         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
  79
  80         atmel_serial_init_internal(usart);
  81         serial_setbrg();
  82         atmel_serial_activate(usart);
  83
  84         return 0;
  85 }
  86
  87 static void atmel_serial_putc(char c)
  88 {
  89         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
  90
  91         if (c == '\n')
  92                 serial_putc('\r');
  93
  94         while (!(readl(&usart->csr) & USART3_BIT(TXRDY)));
  95         writel(c, &usart->thr);
  96 }
  97
  98 static int atmel_serial_getc(void)
  99 {
 100         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
 101
 102         while (!(readl(&usart->csr) & USART3_BIT(RXRDY)))
 103                  WATCHDOG_RESET();
 104         return readl(&usart->rhr);
 105 }
 106
 107 static int atmel_serial_tstc(void)
 108 {
 109         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
 110         return (readl(&usart->csr) & USART3_BIT(RXRDY)) != 0;
 111 }
 112
 113 static struct serial_device atmel_serial_drv = {
 114         .name   = "atmel_serial",
 115         .start  = atmel_serial_init,
 116         .stop   = NULL,
 117         .setbrg = atmel_serial_setbrg,
 118         .putc   = atmel_serial_putc,
 119         .puts   = default_serial_puts,
 120         .getc   = atmel_serial_getc,
 121         .tstc   = atmel_serial_tstc,
 122 };
 123
 124 void atmel_serial_initialize(void)
 125 {
 126         serial_register(&atmel_serial_drv);
 127 }
 128
 129 __weak struct serial_device *default_serial_console(void)
 130 {
 131         return &atmel_serial_drv;
 132 }
 133 #endif
 134
 135 #ifdef CONFIG_DM_SERIAL
 136
 137 struct atmel_serial_priv {
 138         atmel_usart3_t *usart;
 139 };
 140
 141 static void _atmel_serial_set_brg(atmel_usart3_t *usart,
 142                                   ulong usart_clk_rate, int baudrate)
 143 {
 144         unsigned long divisor;
 145
 146         divisor = (usart_clk_rate / 16 + baudrate / 2) / baudrate;
 147         writel(USART3_BF(CD, divisor), &usart->brgr);
 148 }
 149
 150 void _atmel_serial_init(atmel_usart3_t *usart,
 151                         ulong usart_clk_rate, int baudrate)
 152 {
 153         writel(USART3_BIT(RXDIS) | USART3_BIT(TXDIS), &usart->cr);
 154
 155         writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) |
 156                 USART3_BF(USCLKS, USART3_USCLKS_MCK) |
 157                 USART3_BF(CHRL, USART3_CHRL_8) |
 158                 USART3_BF(PAR, USART3_PAR_NONE) |
 159                 USART3_BF(NBSTOP, USART3_NBSTOP_1)), &usart->mr);
 160
 161         _atmel_serial_set_brg(usart, usart_clk_rate, baudrate);
 162
 163         writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
 164         writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
 165 }
 166
 167 int atmel_serial_setbrg(struct udevice *dev, int baudrate)
 168 {
 169         struct atmel_serial_priv *priv = dev_get_priv(dev);
 170
 171         _atmel_serial_set_brg(priv->usart, get_usart_clk_rate(0), baudrate);
 172
 173         return 0;
 174 }
 175
 176 static int atmel_serial_getc(struct udevice *dev)
 177 {
 178         struct atmel_serial_priv *priv = dev_get_priv(dev);
 179
 180         if (!(readl(&priv->usart->csr) & USART3_BIT(RXRDY)))
 181                 return -EAGAIN;
 182
 183         return readl(&priv->usart->rhr);
 184 }
 185
 186 static int atmel_serial_putc(struct udevice *dev, const char ch)
 187 {
 188         struct atmel_serial_priv *priv = dev_get_priv(dev);
 189
 190         if (!(readl(&priv->usart->csr) & USART3_BIT(TXRDY)))
 191                 return -EAGAIN;
 192
 193         writel(ch, &priv->usart->thr);
 194
 195         return 0;
 196 }
 197
 198 static int atmel_serial_pending(struct udevice *dev, bool input)
 199 {
 200         struct atmel_serial_priv *priv = dev_get_priv(dev);
 201         uint32_t csr = readl(&priv->usart->csr);
 202
 203         if (input)
 204                 return csr & USART3_BIT(RXRDY) ? 1 : 0;
 205         else
 206                 return csr & USART3_BIT(TXEMPTY) ? 0 : 1;
 207 }
 208
 209 static const struct dm_serial_ops atmel_serial_ops = {
 210         .putc = atmel_serial_putc,
 211         .pending = atmel_serial_pending,
 212         .getc = atmel_serial_getc,
 213         .setbrg = atmel_serial_setbrg,
 214 };
 215
 216 static int atmel_serial_probe(struct udevice *dev)
 217 {
 218         struct atmel_serial_platdata *plat = dev->platdata;
 219         struct atmel_serial_priv *priv = dev_get_priv(dev);
 220 #if CONFIG_IS_ENABLED(OF_CONTROL)
 221         fdt_addr_t addr_base;
 222
 223         addr_base = dev_get_addr(dev);
 224         if (addr_base == FDT_ADDR_T_NONE)
 225                 return -ENODEV;
 226
 227         plat->base_addr = (uint32_t)addr_base;
 228 #endif
 229         priv->usart = (atmel_usart3_t *)plat->base_addr;
 230
 231         _atmel_serial_init(priv->usart, get_usart_clk_rate(0), gd->baudrate);
 232
 233         return 0;
 234 }
 235
 236 #if CONFIG_IS_ENABLED(OF_CONTROL)
 237 static const struct udevice_id atmel_serial_ids[] = {
 238         { .compatible = "atmel,at91sam9260-usart" },
 239         { }
 240 };
 241 #endif
 242
 243 U_BOOT_DRIVER(serial_atmel) = {
 244         .name   = "serial_atmel",
 245         .id     = UCLASS_SERIAL,
 246 #if CONFIG_IS_ENABLED(OF_CONTROL)
 247         .of_match = atmel_serial_ids,
 248         .platdata_auto_alloc_size = sizeof(struct atmel_serial_platdata),
 249 #endif
 250         .probe = atmel_serial_probe,
 251         .ops    = &atmel_serial_ops,
 252         .flags = DM_FLAG_PRE_RELOC,
 253         .priv_auto_alloc_size   = sizeof(struct atmel_serial_priv),
 254 };
 255 #endif
 256
 257 #ifdef CONFIG_DEBUG_UART_ATMEL
 258 static inline void _debug_uart_init(void)
 259 {
 260         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
 261
 262         _atmel_serial_init(usart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 263 }
 264
 265 static inline void _debug_uart_putc(int ch)
 266 {
 267         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
 268
 269         while (!(readl(&usart->csr) & USART3_BIT(TXRDY)))
 270                 ;
 271
 272         writel(ch, &usart->thr);
 273 }
 274
 275 DEBUG_UART_FUNCS
 276 #endif