1 // SPDX-License-Identifier: GPL-2.0+
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
8 #include <environment.h>
10 #include <stdio_dev.h>
12 #include <linux/compiler.h>
15 DECLARE_GLOBAL_DATA_PTR;
17 static struct serial_device *serial_devices;
18 static struct serial_device *serial_current;
20 * Table with supported baudrates (defined in config_xyz.h)
22 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
25 * serial_null() - Void registration routine of a serial driver
27 * This routine implements a void registration routine of a serial
28 * driver. The registration routine of a particular driver is aliased
29 * to this empty function in case the driver is not compiled into
32 static void serial_null(void)
37 * on_baudrate() - Update the actual baudrate when the env var changes
39 * This will check for a valid baudrate and only apply it if valid.
41 static int on_baudrate(const char *name, const char *value, enum env_op op,
49 case env_op_overwrite:
51 * Switch to new baudrate if new baudrate is supported
53 baudrate = simple_strtoul(value, NULL, 10);
55 /* Not actually changing */
56 if (gd->baudrate == baudrate)
59 for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
60 if (baudrate == baudrate_table[i])
63 if (i == ARRAY_SIZE(baudrate_table)) {
64 if ((flags & H_FORCE) == 0)
65 printf("## Baudrate %d bps not supported\n",
69 if ((flags & H_INTERACTIVE) != 0) {
70 printf("## Switch baudrate to %d"
71 " bps and press ENTER ...\n", baudrate);
75 gd->baudrate = baudrate;
81 if ((flags & H_INTERACTIVE) != 0)
89 printf("## Baudrate may not be deleted\n");
95 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
98 * serial_initfunc() - Forward declare of driver registration routine
99 * @name: Name of the real driver registration routine.
101 * This macro expands onto forward declaration of a driver registration
102 * routine, which is then used below in serial_initialize() function.
103 * The declaration is made weak and aliases to serial_null() so in case
104 * the driver is not compiled in, the function is still declared and can
105 * be used, but aliases to serial_null() and thus is optimized away.
107 #define serial_initfunc(name) \
109 __attribute__((weak, alias("serial_null")));
111 serial_initfunc(atmel_serial_initialize);
112 serial_initfunc(au1x00_serial_initialize);
113 serial_initfunc(mcf_serial_initialize);
114 serial_initfunc(mpc85xx_serial_initialize);
115 serial_initfunc(mpc8xx_serial_initialize);
116 serial_initfunc(mxc_serial_initialize);
117 serial_initfunc(ns16550_serial_initialize);
118 serial_initfunc(pl01x_serial_initialize);
119 serial_initfunc(pxa_serial_initialize);
120 serial_initfunc(sh_serial_initialize);
123 * serial_register() - Register serial driver with serial driver core
124 * @dev: Pointer to the serial driver structure
126 * This function registers the serial driver supplied via @dev with
127 * serial driver core, thus making U-Boot aware of it and making it
128 * available for U-Boot to use. On platforms that still require manual
129 * relocation of constant variables, relocation of the supplied structure
132 void serial_register(struct serial_device *dev)
134 #ifdef CONFIG_NEEDS_MANUAL_RELOC
136 dev->start += gd->reloc_off;
138 dev->stop += gd->reloc_off;
140 dev->setbrg += gd->reloc_off;
142 dev->getc += gd->reloc_off;
144 dev->tstc += gd->reloc_off;
146 dev->putc += gd->reloc_off;
148 dev->puts += gd->reloc_off;
151 dev->next = serial_devices;
152 serial_devices = dev;
156 * serial_initialize() - Register all compiled-in serial port drivers
158 * This function registers all serial port drivers that are compiled
159 * into the U-Boot binary with the serial core, thus making them
160 * available to U-Boot to use. Lastly, this function assigns a default
161 * serial port to the serial core. That serial port is then used as a
164 void serial_initialize(void)
166 atmel_serial_initialize();
167 au1x00_serial_initialize();
168 mcf_serial_initialize();
169 mpc85xx_serial_initialize();
170 mpc8xx_serial_initialize();
171 mxc_serial_initialize();
172 ns16550_serial_initialize();
173 pl01x_serial_initialize();
174 pxa_serial_initialize();
175 sh_serial_initialize();
177 serial_assign(default_serial_console()->name);
180 static int serial_stub_start(struct stdio_dev *sdev)
182 struct serial_device *dev = sdev->priv;
187 static int serial_stub_stop(struct stdio_dev *sdev)
189 struct serial_device *dev = sdev->priv;
194 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
196 struct serial_device *dev = sdev->priv;
201 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
203 struct serial_device *dev = sdev->priv;
208 static int serial_stub_getc(struct stdio_dev *sdev)
210 struct serial_device *dev = sdev->priv;
215 static int serial_stub_tstc(struct stdio_dev *sdev)
217 struct serial_device *dev = sdev->priv;
223 * serial_stdio_init() - Register serial ports with STDIO core
225 * This function generates a proxy driver for each serial port driver.
226 * These proxy drivers then register with the STDIO core, making the
227 * serial drivers available as STDIO devices.
229 void serial_stdio_init(void)
231 struct stdio_dev dev;
232 struct serial_device *s = serial_devices;
235 memset(&dev, 0, sizeof(dev));
237 strcpy(dev.name, s->name);
238 dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
240 dev.start = serial_stub_start;
241 dev.stop = serial_stub_stop;
242 dev.putc = serial_stub_putc;
243 dev.puts = serial_stub_puts;
244 dev.getc = serial_stub_getc;
245 dev.tstc = serial_stub_tstc;
248 stdio_register(&dev);
255 * serial_assign() - Select the serial output device by name
256 * @name: Name of the serial driver to be used as default output
258 * This function configures the serial output multiplexing by
259 * selecting which serial device will be used as default. In case
260 * the STDIO "serial" device is selected as stdin/stdout/stderr,
261 * the serial device previously configured by this function will be
262 * used for the particular operation.
264 * Returns 0 on success, negative on error.
266 int serial_assign(const char *name)
268 struct serial_device *s;
270 for (s = serial_devices; s; s = s->next) {
271 if (strcmp(s->name, name))
281 * serial_reinit_all() - Reinitialize all compiled-in serial ports
283 * This function reinitializes all serial ports that are compiled
284 * into U-Boot by calling their serial_start() functions.
286 void serial_reinit_all(void)
288 struct serial_device *s;
290 for (s = serial_devices; s; s = s->next)
295 * get_current() - Return pointer to currently selected serial port
297 * This function returns a pointer to currently selected serial port.
298 * The currently selected serial port is altered by serial_assign()
301 * In case this function is called before relocation or before any serial
302 * port is configured, this function calls default_serial_console() to
303 * determine the serial port. Otherwise, the configured serial port is
306 * Returns pointer to the currently selected serial port on success,
309 static struct serial_device *get_current(void)
311 struct serial_device *dev;
313 if (!(gd->flags & GD_FLG_RELOC))
314 dev = default_serial_console();
315 else if (!serial_current)
316 dev = default_serial_console();
318 dev = serial_current;
320 /* We must have a console device */
322 #ifdef CONFIG_SPL_BUILD
323 puts("Cannot find console\n");
326 panic("Cannot find console\n");
334 * serial_init() - Initialize currently selected serial port
336 * This function initializes the currently selected serial port. This
337 * usually involves setting up the registers of that particular port,
338 * enabling clock and such. This function uses the get_current() call
339 * to determine which port is selected.
341 * Returns 0 on success, negative on error.
343 int serial_init(void)
345 gd->flags |= GD_FLG_SERIAL_READY;
346 return get_current()->start();
350 * serial_setbrg() - Configure baud-rate of currently selected serial port
352 * This function configures the baud-rate of the currently selected
353 * serial port. The baud-rate is retrieved from global data within
354 * the serial port driver. This function uses the get_current() call
355 * to determine which port is selected.
357 * Returns 0 on success, negative on error.
359 void serial_setbrg(void)
361 get_current()->setbrg();
365 * serial_getc() - Read character from currently selected serial port
367 * This function retrieves a character from currently selected serial
368 * port. In case there is no character waiting on the serial port,
369 * this function will block and wait for the character to appear. This
370 * function uses the get_current() call to determine which port is
373 * Returns the character on success, negative on error.
375 int serial_getc(void)
377 return get_current()->getc();
381 * serial_tstc() - Test if data is available on currently selected serial port
383 * This function tests if one or more characters are available on
384 * currently selected serial port. This function never blocks. This
385 * function uses the get_current() call to determine which port is
388 * Returns positive if character is available, zero otherwise.
390 int serial_tstc(void)
392 return get_current()->tstc();
396 * serial_putc() - Output character via currently selected serial port
397 * @c: Single character to be output from the serial port.
399 * This function outputs a character via currently selected serial
400 * port. This character is passed to the serial port driver responsible
401 * for controlling the hardware. The hardware may still be in process
402 * of transmitting another character, therefore this function may block
403 * for a short amount of time. This function uses the get_current()
404 * call to determine which port is selected.
406 void serial_putc(const char c)
408 get_current()->putc(c);
412 * serial_puts() - Output string via currently selected serial port
413 * @s: Zero-terminated string to be output from the serial port.
415 * This function outputs a zero-terminated string via currently
416 * selected serial port. This function behaves as an accelerator
417 * in case the hardware can queue multiple characters for transfer.
418 * The whole string that is to be output is available to the function
419 * implementing the hardware manipulation. Transmitting the whole
420 * string may take some time, thus this function may block for some
421 * amount of time. This function uses the get_current() call to
422 * determine which port is selected.
424 void serial_puts(const char *s)
426 get_current()->puts(s);
430 * default_serial_puts() - Output string by calling serial_putc() in loop
431 * @s: Zero-terminated string to be output from the serial port.
433 * This function outputs a zero-terminated string by calling serial_putc()
434 * in a loop. Most drivers do not support queueing more than one byte for
435 * transfer, thus this function precisely implements their serial_puts().
437 * To optimize the number of get_current() calls, this function only
438 * calls get_current() once and then directly accesses the putc() call
439 * of the &struct serial_device .
441 void default_serial_puts(const char *s)
443 struct serial_device *dev = get_current();
448 #if CONFIG_POST & CONFIG_SYS_POST_UART
449 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
452 * uart_post_test() - Test the currently selected serial port using POST
453 * @flags: POST framework flags
455 * Do a loopback test of the currently selected serial port. This
456 * function is only useful in the context of the POST testing framwork.
457 * The serial port is first configured into loopback mode and then
458 * characters are sent through it.
460 * Returns 0 on success, value otherwise.
462 /* Mark weak until post/cpu/.../uart.c migrate over */
464 int uart_post_test(int flags)
467 int ret, saved_baud, b;
468 struct serial_device *saved_dev, *s;
470 /* Save current serial state */
472 saved_dev = serial_current;
473 saved_baud = gd->baudrate;
475 for (s = serial_devices; s; s = s->next) {
476 /* If this driver doesn't support loop back, skip it */
480 /* Test the next device */
487 /* Consume anything that happens to be queued */
488 while (serial_tstc())
491 /* Enable loop back */
494 /* Test every available baud rate */
495 for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
496 gd->baudrate = bauds[b];
500 * Stick to printable chars to avoid issues:
501 * - terminal corruption
502 * - serial program reacting to sequences and sending
503 * back random extra data
504 * - most serial drivers add in extra chars (like \r\n)
506 for (c = 0x20; c < 0x7f; ++c) {
510 /* Make sure it's the same one */
511 ret = (c != serial_getc());
517 /* Clean up the output in case it was sent */
519 ret = ('\b' != serial_getc());
527 /* Disable loop back */
530 /* XXX: There is no serial_stop() !? */
536 /* Restore previous serial state */
537 serial_current = saved_dev;
538 gd->baudrate = saved_baud;