drivers/serial/atmel_usart.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2004-2006 Atmel Corporation
   4  *
   5  * Modified to support C structur SoC access by
   6  * Andreas Bießmann <biessmann@corscience.de>
   7  */
   8 #include <common.h>
   9 #include <clk.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 enum serial_clk_type {
 137         CLK_TYPE_NORMAL = 0,
 138         CLK_TYPE_DBGU,
 139 };
 140
 141 struct atmel_serial_priv {
 142         atmel_usart3_t *usart;
 143         ulong usart_clk_rate;
 144 };
 145
 146 static void _atmel_serial_set_brg(atmel_usart3_t *usart,
 147                                   ulong usart_clk_rate, int baudrate)
 148 {
 149         unsigned long divisor;
 150
 151         divisor = (usart_clk_rate / 16 + baudrate / 2) / baudrate;
 152         writel(USART3_BF(CD, divisor), &usart->brgr);
 153 }
 154
 155 void _atmel_serial_init(atmel_usart3_t *usart,
 156                         ulong usart_clk_rate, int baudrate)
 157 {
 158         writel(USART3_BIT(RXDIS) | USART3_BIT(TXDIS), &usart->cr);
 159
 160         writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) |
 161                 USART3_BF(USCLKS, USART3_USCLKS_MCK) |
 162                 USART3_BF(CHRL, USART3_CHRL_8) |
 163                 USART3_BF(PAR, USART3_PAR_NONE) |
 164                 USART3_BF(NBSTOP, USART3_NBSTOP_1)), &usart->mr);
 165
 166         _atmel_serial_set_brg(usart, usart_clk_rate, baudrate);
 167
 168         writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
 169         writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
 170 }
 171
 172 int atmel_serial_setbrg(struct udevice *dev, int baudrate)
 173 {
 174         struct atmel_serial_priv *priv = dev_get_priv(dev);
 175
 176         _atmel_serial_set_brg(priv->usart, priv->usart_clk_rate, baudrate);
 177
 178         return 0;
 179 }
 180
 181 static int atmel_serial_getc(struct udevice *dev)
 182 {
 183         struct atmel_serial_priv *priv = dev_get_priv(dev);
 184
 185         if (!(readl(&priv->usart->csr) & USART3_BIT(RXRDY)))
 186                 return -EAGAIN;
 187
 188         return readl(&priv->usart->rhr);
 189 }
 190
 191 static int atmel_serial_putc(struct udevice *dev, const char ch)
 192 {
 193         struct atmel_serial_priv *priv = dev_get_priv(dev);
 194
 195         if (!(readl(&priv->usart->csr) & USART3_BIT(TXRDY)))
 196                 return -EAGAIN;
 197
 198         writel(ch, &priv->usart->thr);
 199
 200         return 0;
 201 }
 202
 203 static int atmel_serial_pending(struct udevice *dev, bool input)
 204 {
 205         struct atmel_serial_priv *priv = dev_get_priv(dev);
 206         uint32_t csr = readl(&priv->usart->csr);
 207
 208         if (input)
 209                 return csr & USART3_BIT(RXRDY) ? 1 : 0;
 210         else
 211                 return csr & USART3_BIT(TXEMPTY) ? 0 : 1;
 212 }
 213
 214 static const struct dm_serial_ops atmel_serial_ops = {
 215         .putc = atmel_serial_putc,
 216         .pending = atmel_serial_pending,
 217         .getc = atmel_serial_getc,
 218         .setbrg = atmel_serial_setbrg,
 219 };
 220
 221 #if defined(CONFIG_SPL_BUILD) && !defined(CONFIG_SPL_CLK)
 222 static int atmel_serial_enable_clk(struct udevice *dev)
 223 {
 224         struct atmel_serial_priv *priv = dev_get_priv(dev);
 225
 226         /* Use fixed clock value in SPL */
 227         priv->usart_clk_rate = CONFIG_SPL_UART_CLOCK;
 228
 229         return 0;
 230 }
 231 #else
 232 static int atmel_serial_enable_clk(struct udevice *dev)
 233 {
 234         struct atmel_serial_priv *priv = dev_get_priv(dev);
 235         struct clk clk;
 236         ulong clk_rate;
 237         int ret;
 238
 239         ret = clk_get_by_index(dev, 0, &clk);
 240         if (ret)
 241                 return -EINVAL;
 242
 243         if (dev_get_driver_data(dev) == CLK_TYPE_NORMAL) {
 244                 ret = clk_enable(&clk);
 245                 if (ret)
 246                         return ret;
 247         }
 248
 249         clk_rate = clk_get_rate(&clk);
 250         if (!clk_rate)
 251                 return -EINVAL;
 252
 253         priv->usart_clk_rate = clk_rate;
 254
 255         clk_free(&clk);
 256
 257         return 0;
 258 }
 259 #endif
 260
 261 static int atmel_serial_probe(struct udevice *dev)
 262 {
 263         struct atmel_serial_platdata *plat = dev->platdata;
 264         struct atmel_serial_priv *priv = dev_get_priv(dev);
 265         int ret;
 266 #if CONFIG_IS_ENABLED(OF_CONTROL)
 267         fdt_addr_t addr_base;
 268
 269         addr_base = devfdt_get_addr(dev);
 270         if (addr_base == FDT_ADDR_T_NONE)
 271                 return -ENODEV;
 272
 273         plat->base_addr = (uint32_t)addr_base;
 274 #endif
 275         priv->usart = (atmel_usart3_t *)plat->base_addr;
 276
 277         ret = atmel_serial_enable_clk(dev);
 278         if (ret)
 279                 return ret;
 280
 281         _atmel_serial_init(priv->usart, priv->usart_clk_rate, gd->baudrate);
 282
 283         return 0;
 284 }
 285
 286 #if CONFIG_IS_ENABLED(OF_CONTROL)
 287 static const struct udevice_id atmel_serial_ids[] = {
 288         {
 289                 .compatible = "atmel,at91sam9260-dbgu",
 290                 .data = CLK_TYPE_DBGU,
 291         },
 292         {
 293                 .compatible = "atmel,at91sam9260-usart",
 294                 .data = CLK_TYPE_NORMAL,
 295         },
 296         { }
 297 };
 298 #endif
 299
 300 U_BOOT_DRIVER(serial_atmel) = {
 301         .name   = "serial_atmel",
 302         .id     = UCLASS_SERIAL,
 303 #if CONFIG_IS_ENABLED(OF_CONTROL)
 304         .of_match = atmel_serial_ids,
 305         .platdata_auto_alloc_size = sizeof(struct atmel_serial_platdata),
 306 #endif
 307         .probe = atmel_serial_probe,
 308         .ops    = &atmel_serial_ops,
 309 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 310         .flags = DM_FLAG_PRE_RELOC,
 311 #endif
 312         .priv_auto_alloc_size   = sizeof(struct atmel_serial_priv),
 313 };
 314 #endif
 315
 316 #ifdef CONFIG_DEBUG_UART_ATMEL
 317 static inline void _debug_uart_init(void)
 318 {
 319         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
 320
 321         _atmel_serial_init(usart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 322 }
 323
 324 static inline void _debug_uart_putc(int ch)
 325 {
 326         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
 327
 328         while (!(readl(&usart->csr) & USART3_BIT(TXRDY)))
 329                 ;
 330
 331         writel(ch, &usart->thr);
 332 }
 333
 334 DEBUG_UART_FUNCS
 335 #endif