2 * Driver for AMAZONASC serial ports
4 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5 * Based on drivers/serial/serial_s3c2400.c
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * Copyright (C) 2004 Infineon IFAP DC COM CPE
22 * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
23 * Copyright (C) 2007 John Crispin <blogic@openwrt.org>
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/signal.h>
29 #include <linux/sched.h>
30 #include <linux/interrupt.h>
31 #include <linux/tty.h>
32 #include <linux/tty_flip.h>
33 #include <linux/major.h>
34 #include <linux/string.h>
35 #include <linux/fcntl.h>
36 #include <linux/ptrace.h>
37 #include <linux/ioport.h>
39 #include <linux/slab.h>
40 #include <linux/init.h>
41 #include <linux/circ_buf.h>
42 #include <linux/serial.h>
43 #include <linux/serial_core.h>
44 #include <linux/console.h>
45 #include <linux/sysrq.h>
46 #include <linux/irq.h>
47 #include <linux/platform_device.h>
49 #include <asm/system.h>
51 #include <asm/uaccess.h>
52 #include <asm/bitops.h>
53 #include <asm/amazon/amazon.h>
54 #include <asm/amazon/irq.h>
55 #include <asm/amazon/serial.h>
57 #define PORT_AMAZONASC 111
59 #include <linux/serial_core.h>
63 #define UART_DUMMY_UER_RX 1
65 #define SERIAL_AMAZONASC_MAJOR TTY_MAJOR
66 #define CALLOUT_AMAZONASC_MAJOR TTYAUX_MAJOR
67 #define SERIAL_AMAZONASC_MINOR 64
68 #define SERIAL_AMAZONASC_NR UART_NR
70 static void amazonasc_tx_chars(struct uart_port *port);
71 static struct uart_port amazonasc_ports[UART_NR];
72 static struct uart_driver amazonasc_reg;
73 static unsigned int uartclk = 0;
75 static void amazonasc_stop_tx(struct uart_port *port)
77 /* fifo underrun shuts up after firing once */
81 static void amazonasc_start_tx(struct uart_port *port)
85 local_irq_save(flags);
86 amazonasc_tx_chars(port);
87 local_irq_restore(flags);
92 static void amazonasc_stop_rx(struct uart_port *port)
94 /* clear the RX enable bit */
95 amazon_writel(ASCWHBCON_CLRREN, AMAZON_ASC_WHBCON);
98 static void amazonasc_enable_ms(struct uart_port *port)
100 /* no modem signals */
104 #include <linux/version.h>
107 amazonasc_rx_chars(struct uart_port *port)
109 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 31))
110 struct tty_struct *tty = port->state->port.tty;
112 struct tty_struct *tty = port->info->port.tty;
114 unsigned int ch = 0, rsr = 0, fifocnt;
116 fifocnt = amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
119 u8 flag = TTY_NORMAL;
120 ch = amazon_readl(AMAZON_ASC_RBUF);
121 rsr = (amazon_readl(AMAZON_ASC_CON) & ASCCON_ANY) | UART_DUMMY_UER_RX;
122 tty_flip_buffer_push(tty);
126 * Note that the error handling code is
127 * out of the main execution path
129 if (rsr & ASCCON_ANY) {
130 if (rsr & ASCCON_PE) {
131 port->icount.parity++;
132 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLRPE, ASCWHBCON_CLRPE);
133 } else if (rsr & ASCCON_FE) {
134 port->icount.frame++;
135 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLRFE, ASCWHBCON_CLRFE);
137 if (rsr & ASCCON_OE) {
138 port->icount.overrun++;
139 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLROE, ASCWHBCON_CLROE);
142 rsr &= port->read_status_mask;
146 else if (rsr & ASCCON_FE)
150 if ((rsr & port->ignore_status_mask) == 0)
151 tty_insert_flip_char(tty, ch, flag);
155 * Overrun is special, since it's reported
156 * immediately, and doesn't affect the current
159 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
162 tty_flip_buffer_push(tty);
168 static void amazonasc_tx_chars(struct uart_port *port)
170 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 31))
171 struct circ_buf *xmit = &port->state->xmit;
173 struct circ_buf *xmit = &port->info->xmit;
176 if (uart_tx_stopped(port)) {
177 amazonasc_stop_tx(port);
181 while (((amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK)
182 >> ASCFSTAT_TXFFLOFF) != AMAZONASC_TXFIFO_FULL)
185 amazon_writel(port->x_char, AMAZON_ASC_TBUF);
191 if (uart_circ_empty(xmit))
194 amazon_writel(xmit->buf[xmit->tail], AMAZON_ASC_TBUF);
195 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
199 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
200 uart_write_wakeup(port);
203 static irqreturn_t amazonasc_tx_int(int irq, void *port)
205 amazon_writel(ASC_IRNCR_TIR, AMAZON_ASC_IRNCR1);
206 amazonasc_start_tx(port);
208 /* clear any pending interrupts */
209 amazon_writel_masked(AMAZON_ASC_WHBCON,
210 (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE),
211 (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE));
216 static irqreturn_t amazonasc_er_int(int irq, void *port)
218 /* clear any pending interrupts */
219 amazon_writel_masked(AMAZON_ASC_WHBCON,
220 (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE),
221 (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE));
226 static irqreturn_t amazonasc_rx_int(int irq, void *port)
228 amazon_writel(ASC_IRNCR_RIR, AMAZON_ASC_IRNCR1);
229 amazonasc_rx_chars((struct uart_port *) port);
233 static u_int amazonasc_tx_empty(struct uart_port *port)
238 * FSTAT tells exactly how many bytes are in the FIFO.
239 * The question is whether we really need to wait for all
240 * 16 bytes to be transmitted before reporting that the
241 * transmitter is empty.
243 status = amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
244 return status ? 0 : TIOCSER_TEMT;
247 static u_int amazonasc_get_mctrl(struct uart_port *port)
249 /* no modem control signals - the readme says to pretend all are set */
250 return TIOCM_CTS|TIOCM_CAR|TIOCM_DSR;
253 static void amazonasc_set_mctrl(struct uart_port *port, u_int mctrl)
255 /* no modem control - just return */
259 static void amazonasc_break_ctl(struct uart_port *port, int break_state)
261 /* no way to send a break */
265 static int amazonasc_startup(struct uart_port *port)
267 unsigned int con = 0;
271 /* this assumes: CON.BRS = CON.FDE = 0 */
273 uartclk = amazon_get_fpi_hz();
275 amazonasc_ports[0].uartclk = uartclk;
277 local_irq_save(flags);
279 /* this setup was probably already done in u-boot */
280 /* ASC and GPIO Port 1 bits 3 and 4 share the same pins
281 * P1.3 (RX) in, Alternate 10
282 * P1.4 (TX) in, Alternate 10
284 amazon_writel_masked(AMAZON_GPIO_P1_DIR, 0x18, 0x10); //P1.4 output, P1.3 input
285 amazon_writel_masked(AMAZON_GPIO_P1_ALTSEL0, 0x18, 0x18); //ALTSETL0 11
286 amazon_writel_masked(AMAZON_GPIO_P1_ALTSEL1, 0x18, 0); //ALTSETL1 00
287 amazon_writel_masked(AMAZON_GPIO_P1_OD, 0x18, 0x10);
290 amazon_writel_masked(AMAZON_ASC_CLC, AMAZON_ASC_CLC_DISS, 0);
291 amazon_writel_masked(AMAZON_ASC_CLC, ASCCLC_RMCMASK, 1 << ASCCLC_RMCOFFSET);
293 /* asynchronous mode */
294 con = ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_OEN | ASCCON_PEN;
296 /* choose the line - there's only one */
297 amazon_writel(0, AMAZON_ASC_PISEL);
298 amazon_writel(((AMAZONASC_TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) | ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
300 amazon_writel(((AMAZONASC_RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK) | ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
304 amazon_writel_masked(AMAZON_ASC_CON, con, con);
306 retval = request_irq(AMAZONASC_RIR, amazonasc_rx_int, 0, "asc_rx", port);
308 printk("failed to request amazonasc_rx_int\n");
311 retval = request_irq(AMAZONASC_TIR, amazonasc_tx_int, 0, "asc_tx", port);
313 printk("failed to request amazonasc_tx_int\n");
317 retval = request_irq(AMAZONASC_EIR, amazonasc_er_int, 0, "asc_er", port);
319 printk("failed to request amazonasc_er_int\n");
323 local_irq_restore(flags);
327 free_irq(AMAZONASC_TIR, port);
330 free_irq(AMAZONASC_RIR, port);
331 local_irq_restore(flags);
335 static void amazonasc_shutdown(struct uart_port *port)
337 free_irq(AMAZONASC_RIR, port);
338 free_irq(AMAZONASC_TIR, port);
339 free_irq(AMAZONASC_EIR, port);
341 * disable the baudrate generator to disable the ASC
343 amazon_writel(0, AMAZON_ASC_CON);
345 /* flush and then disable the fifos */
346 amazon_writel_masked(AMAZON_ASC_RXFCON, ASCRXFCON_RXFFLU, ASCRXFCON_RXFFLU);
347 amazon_writel_masked(AMAZON_ASC_RXFCON, ASCRXFCON_RXFEN, 0);
348 amazon_writel_masked(AMAZON_ASC_TXFCON, ASCTXFCON_TXFFLU, ASCTXFCON_TXFFLU);
349 amazon_writel_masked(AMAZON_ASC_TXFCON, ASCTXFCON_TXFEN, 0);
352 static void amazonasc_set_termios(struct uart_port *port, struct ktermios *new, struct ktermios *old)
356 unsigned int baud, quot;
357 unsigned int con = 0;
360 cflag = new->c_cflag;
361 iflag = new->c_iflag;
363 /* byte size and parity */
364 switch (cflag & CSIZE) {
365 /* 7 bits are always with parity */
366 case CS7: con = ASCCON_M_7ASYNCPAR; break;
367 /* the ASC only suports 7 and 8 bits */
372 con = ASCCON_M_8ASYNCPAR;
374 con = ASCCON_M_8ASYNC;
379 if (cflag & PARENB) {
380 if (!(cflag & PARODD))
386 port->read_status_mask = ASCCON_OE;
388 port->read_status_mask |= ASCCON_FE | ASCCON_PE;
390 port->ignore_status_mask = 0;
392 port->ignore_status_mask |= ASCCON_FE | ASCCON_PE;
394 if (iflag & IGNBRK) {
396 * If we're ignoring parity and break indicators,
397 * ignore overruns too (for real raw support).
400 port->ignore_status_mask |= ASCCON_OE;
404 * Ignore all characters if CREAD is not set.
406 if ((cflag & CREAD) == 0)
407 port->ignore_status_mask |= UART_DUMMY_UER_RX;
409 /* set error signals - framing, parity and overrun */
413 /* enable the receiver */
417 local_irq_save(flags);
420 amazon_writel(con, AMAZON_ASC_CON);
422 /* Set baud rate - take a divider of 2 into account */
423 baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
424 quot = uart_get_divisor(port, baud);
427 /* the next 3 probably already happened when we set CON above */
428 /* disable the baudrate generator */
429 amazon_writel_masked(AMAZON_ASC_CON, ASCCON_R, 0);
430 /* make sure the fractional divider is off */
431 amazon_writel_masked(AMAZON_ASC_CON, ASCCON_FDE, 0);
432 /* set up to use divisor of 2 */
433 amazon_writel_masked(AMAZON_ASC_CON, ASCCON_BRS, 0);
434 /* now we can write the new baudrate into the register */
435 amazon_writel(quot, AMAZON_ASC_BTR);
436 /* turn the baudrate generator back on */
437 amazon_writel_masked(AMAZON_ASC_CON, ASCCON_R, ASCCON_R);
439 local_irq_restore(flags);
442 static const char *amazonasc_type(struct uart_port *port)
444 return port->type == PORT_AMAZONASC ? "AMAZONASC" : NULL;
448 * Release the memory region(s) being used by 'port'
450 static void amazonasc_release_port(struct uart_port *port)
456 * Request the memory region(s) being used by 'port'
458 static int amazonasc_request_port(struct uart_port *port)
464 * Configure/autoconfigure the port.
466 static void amazonasc_config_port(struct uart_port *port, int flags)
468 if (flags & UART_CONFIG_TYPE) {
469 port->type = PORT_AMAZONASC;
470 amazonasc_request_port(port);
475 * verify the new serial_struct (for TIOCSSERIAL).
477 static int amazonasc_verify_port(struct uart_port *port, struct serial_struct *ser)
480 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMAZONASC)
482 if (ser->irq < 0 || ser->irq >= NR_IRQS)
484 if (ser->baud_base < 9600)
489 static struct uart_ops amazonasc_pops = {
490 .tx_empty = amazonasc_tx_empty,
491 .set_mctrl = amazonasc_set_mctrl,
492 .get_mctrl = amazonasc_get_mctrl,
493 .stop_tx = amazonasc_stop_tx,
494 .start_tx = amazonasc_start_tx,
495 .stop_rx = amazonasc_stop_rx,
496 .enable_ms = amazonasc_enable_ms,
497 .break_ctl = amazonasc_break_ctl,
498 .startup = amazonasc_startup,
499 .shutdown = amazonasc_shutdown,
500 .set_termios = amazonasc_set_termios,
501 .type = amazonasc_type,
502 .release_port = amazonasc_release_port,
503 .request_port = amazonasc_request_port,
504 .config_port = amazonasc_config_port,
505 .verify_port = amazonasc_verify_port,
508 static struct uart_port amazonasc_ports[UART_NR] = {
510 membase: (void *)AMAZON_ASC,
512 iotype: SERIAL_IO_MEM,
513 irq: AMAZONASC_RIR, /* RIR */
514 uartclk: 0, /* filled in dynamically */
516 unused: { AMAZONASC_TIR, AMAZONASC_EIR}, /* xmit/error/xmit-buffer-empty IRQ */
517 type: PORT_AMAZONASC,
518 ops: &amazonasc_pops,
519 flags: ASYNC_BOOT_AUTOCONF,
523 static void amazonasc_console_write(struct console *co, const char *s, u_int count)
527 local_irq_save(flags);
528 for (i = 0; i < count;)
530 /* wait until the FIFO is not full */
533 fifocnt = (amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK)
534 >> ASCFSTAT_TXFFLOFF;
535 } while (fifocnt == AMAZONASC_TXFIFO_FULL);
542 amazon_writel('\r', AMAZON_ASC_TBUF);
545 fifocnt = (amazon_readl(AMAZON_ASC_FSTAT) &
546 ASCFSTAT_TXFFLMASK) >> ASCFSTAT_TXFFLOFF;
547 } while (fifocnt == AMAZONASC_TXFIFO_FULL);
549 amazon_writel(s[i], AMAZON_ASC_TBUF);
553 local_irq_restore(flags);
557 amazonasc_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits)
561 lcr_h = amazon_readl(AMAZON_ASC_CON);
562 /* do this only if the ASC is turned on */
563 if (lcr_h & ASCCON_R) {
564 u_int quot, div, fdiv, frac;
567 if ((lcr_h & ASCCON_MODEMASK) == ASCCON_M_7ASYNCPAR ||
568 (lcr_h & ASCCON_MODEMASK) == ASCCON_M_8ASYNCPAR) {
569 if (lcr_h & ASCCON_ODD)
575 if ((lcr_h & ASCCON_MODEMASK) == ASCCON_M_7ASYNCPAR)
580 quot = amazon_readl(AMAZON_ASC_BTR) + 1;
582 /* this gets hairy if the fractional divider is used */
583 if (lcr_h & ASCCON_FDE)
586 fdiv = amazon_readl(AMAZON_ASC_FDV);
593 div = lcr_h & ASCCON_BRS ? 3 : 2;
597 * This doesn't work exactly because we use integer
598 * math to calculate baud which results in rounding
599 * errors when we try to go from quot -> baud !!
600 * Try to make this work for both the fractional divider
601 * and the simple divider. Also try to avoid rounding
602 * errors using integer math.
605 *baud = frac * (port->uartclk / (div * 512 * 16 * quot));
606 if (*baud > 1100 && *baud < 2400)
608 if (*baud > 2300 && *baud < 4800)
610 if (*baud > 4700 && *baud < 9600)
612 if (*baud > 9500 && *baud < 19200)
614 if (*baud > 19000 && *baud < 38400)
616 if (*baud > 38400 && *baud < 57600)
618 if (*baud > 57600 && *baud < 115200)
620 if (*baud > 115200 && *baud < 230400)
625 static int __init amazonasc_console_setup(struct console *co, char *options)
627 struct uart_port *port;
633 /* this assumes: CON.BRS = CON.FDE = 0 */
635 uartclk = amazon_get_fpi_hz();
637 port = &amazonasc_ports[0];
638 amazonasc_ports[0].uartclk = uartclk;
639 amazonasc_ports[0].type = PORT_AMAZONASC;
642 uart_parse_options(options, &baud, &parity, &bits, &flow);
645 return uart_set_options(port, co, baud, parity, bits, flow);
648 static struct uart_driver amazonasc_reg;
649 static struct console amazonasc_console = {
651 write: amazonasc_console_write,
652 device: uart_console_device,
653 setup: amazonasc_console_setup,
654 flags: CON_PRINTBUFFER,
656 data: &amazonasc_reg,
659 static struct uart_driver amazonasc_reg = {
660 .owner = THIS_MODULE,
661 .driver_name = "serial",
666 .cons = &amazonasc_console,
669 static int __init amazon_asc_probe(struct platform_device *dev)
672 uart_register_driver(&amazonasc_reg);
673 res = uart_add_one_port(&amazonasc_reg, &amazonasc_ports[0]);
677 static int amazon_asc_remove(struct platform_device *dev)
679 uart_unregister_driver(&amazonasc_reg);
683 static struct platform_driver amazon_asc_driver = {
684 .probe = amazon_asc_probe,
685 .remove = amazon_asc_remove,
687 .name = "amazon_asc",
688 .owner = THIS_MODULE,
692 static int __init amazon_asc_init(void)
694 int ret = platform_driver_register(&amazon_asc_driver);
696 printk(KERN_WARNING "amazon_asc: error registering platfom driver!\n");
700 static void __exit amazon_asc_cleanup(void)
702 platform_driver_unregister(&amazon_asc_driver);
705 module_init(amazon_asc_init);
706 module_exit(amazon_asc_cleanup);
708 MODULE_AUTHOR("Gary Jennejohn, Felix Fietkau, John Crispin");
709 MODULE_DESCRIPTION("MIPS AMAZONASC serial port driver");
710 MODULE_LICENSE("GPL");