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 <[email protected]>
   7  */
   8 #include <clk.h>
   9 #include <dm.h>
  10 #include <errno.h>
  11 #include <malloc.h>
  12 #include <watchdog.h>
  13 #include <serial.h>
  14 #include <debug_uart.h>
  15 #include <asm/global_data.h>
  16 #include <linux/compiler.h>
  17 #include <linux/delay.h>
  18
  19 #include <asm/io.h>
  20 #if CONFIG_IS_ENABLED(DM_SERIAL)
  21 #include <asm/arch/atmel_serial.h>
  22 #endif
  23 #include <asm/arch/clk.h>
  24 #include <asm/arch/hardware.h>
  25
  26 #include "atmel_usart.h"
  27
  28 DECLARE_GLOBAL_DATA_PTR;
  29
  30 #if !CONFIG_IS_ENABLED(DM_SERIAL)
  31 static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id,
  32                                          int baudrate)
  33 {
  34         unsigned long divisor;
  35         unsigned long usart_hz;
  36
  37         /*
  38          *              Master Clock
  39          * Baud Rate = --------------
  40          *                16 * CD
  41          */
  42         usart_hz = get_usart_clk_rate(id);
  43         divisor = (usart_hz / 16 + baudrate / 2) / baudrate;
  44         writel(USART3_BF(CD, divisor), &usart->brgr);
  45 }
  46
  47 static void atmel_serial_init_internal(atmel_usart3_t *usart)
  48 {
  49         /*
  50          * Just in case: drain transmitter register
  51          * 1000us is enough for baudrate >= 9600
  52          */
  53         if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY)))
  54                 __udelay(1000);
  55
  56         writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
  57 }
  58
  59 static void atmel_serial_activate(atmel_usart3_t *usart)
  60 {
  61         writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
  62                            | USART3_BF(USCLKS, USART3_USCLKS_MCK)
  63                            | USART3_BF(CHRL, USART3_CHRL_8)
  64                            | USART3_BF(PAR, USART3_PAR_NONE)
  65                            | USART3_BF(NBSTOP, USART3_NBSTOP_1)),
  66                            &usart->mr);
  67         writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
  68         /* 100us is enough for the new settings to be settled */
  69         __udelay(100);
  70 }
  71
  72 static void atmel_serial_setbrg(void)
  73 {
  74         atmel_serial_setbrg_internal((atmel_usart3_t *)CFG_USART_BASE,
  75                                      CFG_USART_ID, gd->baudrate);
  76 }
  77
  78 static int atmel_serial_init(void)
  79 {
  80         atmel_usart3_t *usart = (atmel_usart3_t *)CFG_USART_BASE;
  81
  82         atmel_serial_init_internal(usart);
  83         serial_setbrg();
  84         atmel_serial_activate(usart);
  85
  86         return 0;
  87 }
  88
  89 static void atmel_serial_putc(char c)
  90 {
  91         atmel_usart3_t *usart = (atmel_usart3_t *)CFG_USART_BASE;
  92
  93         if (c == '\n')
  94                 serial_putc('\r');
  95
  96         while (!(readl(&usart->csr) & USART3_BIT(TXRDY)));
  97         writel(c, &usart->thr);
  98 }
  99
 100 static int atmel_serial_getc(void)
 101 {
 102         atmel_usart3_t *usart = (atmel_usart3_t *)CFG_USART_BASE;
 103
 104         while (!(readl(&usart->csr) & USART3_BIT(RXRDY)))
 105                  schedule();
 106         return readl(&usart->rhr);
 107 }
 108
 109 static int atmel_serial_tstc(void)
 110 {
 111         atmel_usart3_t *usart = (atmel_usart3_t *)CFG_USART_BASE;
 112         return (readl(&usart->csr) & USART3_BIT(RXRDY)) != 0;
 113 }
 114
 115 static struct serial_device atmel_serial_drv = {
 116         .name   = "atmel_serial",
 117         .start  = atmel_serial_init,
 118         .stop   = NULL,
 119         .setbrg = atmel_serial_setbrg,
 120         .putc   = atmel_serial_putc,
 121         .puts   = default_serial_puts,
 122         .getc   = atmel_serial_getc,
 123         .tstc   = atmel_serial_tstc,
 124 };
 125
 126 void atmel_serial_initialize(void)
 127 {
 128         serial_register(&atmel_serial_drv);
 129 }
 130
 131 __weak struct serial_device *default_serial_console(void)
 132 {
 133         return &atmel_serial_drv;
 134 }
 135 #else
 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         return 0;
 256 }
 257 #endif
 258
 259 static int atmel_serial_probe(struct udevice *dev)
 260 {
 261         struct atmel_serial_plat *plat = dev_get_plat(dev);
 262         struct atmel_serial_priv *priv = dev_get_priv(dev);
 263         int ret;
 264 #if CONFIG_IS_ENABLED(OF_CONTROL)
 265         fdt_addr_t addr_base;
 266
 267         addr_base = dev_read_addr(dev);
 268         if (addr_base == FDT_ADDR_T_NONE)
 269                 return -ENODEV;
 270
 271         plat->base_addr = (uint32_t)addr_base;
 272 #endif
 273         priv->usart = (atmel_usart3_t *)plat->base_addr;
 274
 275         ret = atmel_serial_enable_clk(dev);
 276         if (ret)
 277                 return ret;
 278
 279         _atmel_serial_init(priv->usart, priv->usart_clk_rate, gd->baudrate);
 280
 281         return 0;
 282 }
 283
 284 #if CONFIG_IS_ENABLED(OF_CONTROL)
 285 static const struct udevice_id atmel_serial_ids[] = {
 286         {
 287                 .compatible = "atmel,at91sam9260-dbgu",
 288                 .data = CLK_TYPE_DBGU,
 289         },
 290         {
 291                 .compatible = "atmel,at91sam9260-usart",
 292                 .data = CLK_TYPE_NORMAL,
 293         },
 294         { }
 295 };
 296 #endif
 297
 298 U_BOOT_DRIVER(serial_atmel) = {
 299         .name   = "serial_atmel",
 300         .id     = UCLASS_SERIAL,
 301 #if CONFIG_IS_ENABLED(OF_CONTROL)
 302         .of_match = atmel_serial_ids,
 303         .plat_auto      = sizeof(struct atmel_serial_plat),
 304 #endif
 305         .probe = atmel_serial_probe,
 306         .ops    = &atmel_serial_ops,
 307 #if !CONFIG_IS_ENABLED(OF_CONTROL)
 308         .flags = DM_FLAG_PRE_RELOC,
 309 #endif
 310         .priv_auto      = sizeof(struct atmel_serial_priv),
 311 };
 312 #endif
 313
 314 #ifdef CONFIG_DEBUG_UART_ATMEL
 315 static inline void _debug_uart_init(void)
 316 {
 317         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_VAL(DEBUG_UART_BASE);
 318
 319         _atmel_serial_init(usart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 320 }
 321
 322 static inline void _debug_uart_putc(int ch)
 323 {
 324         atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_VAL(DEBUG_UART_BASE);
 325
 326         while (!(readl(&usart->csr) & USART3_BIT(TXRDY)))
 327                 ;
 328
 329         writel(ch, &usart->thr);
 330 }
 331
 332 DEBUG_UART_FUNCS
 333 #endif