2 * linux/drivers/serial/21285.c
4 * Driver for the serial port on the 21285 StrongArm-110 core logic chip.
6 * Based on drivers/char/serial.c
8 * $Id: 21285.c,v 1.37 2002/07/28 10:03:27 rmk Exp $
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/ioport.h>
13 #include <linux/init.h>
14 #include <linux/console.h>
15 #include <linux/device.h>
16 #include <linux/tty_flip.h>
17 #include <linux/serial_core.h>
18 #include <linux/serial.h>
22 #include <asm/mach-types.h>
23 #include <asm/hardware/dec21285.h>
24 #include <asm/hardware.h>
26 #define BAUD_BASE (mem_fclk_21285/64)
28 #define SERIAL_21285_NAME "ttyFB"
29 #define SERIAL_21285_MAJOR 204
30 #define SERIAL_21285_MINOR 4
32 #define RXSTAT_DUMMY_READ 0x80000000
33 #define RXSTAT_FRAME (1 << 0)
34 #define RXSTAT_PARITY (1 << 1)
35 #define RXSTAT_OVERRUN (1 << 2)
36 #define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
38 #define H_UBRLCR_BREAK (1 << 0)
39 #define H_UBRLCR_PARENB (1 << 1)
40 #define H_UBRLCR_PAREVN (1 << 2)
41 #define H_UBRLCR_STOPB (1 << 3)
42 #define H_UBRLCR_FIFO (1 << 4)
44 static const char serial21285_name
[] = "Footbridge UART";
46 #define tx_enabled(port) ((port)->unused[0])
47 #define rx_enabled(port) ((port)->unused[1])
50 * The documented expression for selecting the divisor is:
51 * BAUD_BASE / baud - 1
52 * However, typically BAUD_BASE is not divisible by baud, so
53 * we want to select the divisor that gives us the minimum
54 * error. Therefore, we want:
55 * int(BAUD_BASE / baud - 0.5) ->
56 * int(BAUD_BASE / baud - (baud >> 1) / baud) ->
57 * int((BAUD_BASE - (baud >> 1)) / baud)
60 static void serial21285_stop_tx(struct uart_port
*port
)
62 if (tx_enabled(port
)) {
63 disable_irq(IRQ_CONTX
);
68 static void serial21285_start_tx(struct uart_port
*port
)
70 if (!tx_enabled(port
)) {
71 enable_irq(IRQ_CONTX
);
76 static void serial21285_stop_rx(struct uart_port
*port
)
78 if (rx_enabled(port
)) {
79 disable_irq(IRQ_CONRX
);
84 static void serial21285_enable_ms(struct uart_port
*port
)
88 static irqreturn_t
serial21285_rx_chars(int irq
, void *dev_id
)
90 struct uart_port
*port
= dev_id
;
91 struct tty_struct
*tty
= port
->info
->tty
;
92 unsigned int status
, ch
, flag
, rxs
, max_count
= 256;
94 status
= *CSR_UARTFLG
;
95 while (!(status
& 0x10) && max_count
--) {
100 rxs
= *CSR_RXSTAT
| RXSTAT_DUMMY_READ
;
101 if (unlikely(rxs
& RXSTAT_ANYERR
)) {
102 if (rxs
& RXSTAT_PARITY
)
103 port
->icount
.parity
++;
104 else if (rxs
& RXSTAT_FRAME
)
105 port
->icount
.frame
++;
106 if (rxs
& RXSTAT_OVERRUN
)
107 port
->icount
.overrun
++;
109 rxs
&= port
->read_status_mask
;
111 if (rxs
& RXSTAT_PARITY
)
113 else if (rxs
& RXSTAT_FRAME
)
117 uart_insert_char(port
, rxs
, RXSTAT_OVERRUN
, ch
, flag
);
119 status
= *CSR_UARTFLG
;
121 tty_flip_buffer_push(tty
);
126 static irqreturn_t
serial21285_tx_chars(int irq
, void *dev_id
)
128 struct uart_port
*port
= dev_id
;
129 struct circ_buf
*xmit
= &port
->info
->xmit
;
133 *CSR_UARTDR
= port
->x_char
;
138 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
)) {
139 serial21285_stop_tx(port
);
144 *CSR_UARTDR
= xmit
->buf
[xmit
->tail
];
145 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
147 if (uart_circ_empty(xmit
))
149 } while (--count
> 0 && !(*CSR_UARTFLG
& 0x20));
151 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
152 uart_write_wakeup(port
);
154 if (uart_circ_empty(xmit
))
155 serial21285_stop_tx(port
);
161 static unsigned int serial21285_tx_empty(struct uart_port
*port
)
163 return (*CSR_UARTFLG
& 8) ? 0 : TIOCSER_TEMT
;
166 /* no modem control lines */
167 static unsigned int serial21285_get_mctrl(struct uart_port
*port
)
169 return TIOCM_CAR
| TIOCM_DSR
| TIOCM_CTS
;
172 static void serial21285_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
176 static void serial21285_break_ctl(struct uart_port
*port
, int break_state
)
181 spin_lock_irqsave(&port
->lock
, flags
);
182 h_lcr
= *CSR_H_UBRLCR
;
184 h_lcr
|= H_UBRLCR_BREAK
;
186 h_lcr
&= ~H_UBRLCR_BREAK
;
187 *CSR_H_UBRLCR
= h_lcr
;
188 spin_unlock_irqrestore(&port
->lock
, flags
);
191 static int serial21285_startup(struct uart_port
*port
)
195 tx_enabled(port
) = 1;
196 rx_enabled(port
) = 1;
198 ret
= request_irq(IRQ_CONRX
, serial21285_rx_chars
, 0,
199 serial21285_name
, port
);
201 ret
= request_irq(IRQ_CONTX
, serial21285_tx_chars
, 0,
202 serial21285_name
, port
);
204 free_irq(IRQ_CONRX
, port
);
210 static void serial21285_shutdown(struct uart_port
*port
)
212 free_irq(IRQ_CONTX
, port
);
213 free_irq(IRQ_CONRX
, port
);
217 serial21285_set_termios(struct uart_port
*port
, struct termios
*termios
,
221 unsigned int baud
, quot
, h_lcr
;
224 * We don't support modem control lines.
226 termios
->c_cflag
&= ~(HUPCL
| CRTSCTS
| CMSPAR
);
227 termios
->c_cflag
|= CLOCAL
;
230 * We don't support BREAK character recognition.
232 termios
->c_iflag
&= ~(IGNBRK
| BRKINT
);
235 * Ask the core to calculate the divisor for us.
237 baud
= uart_get_baud_rate(port
, termios
, old
, 0, port
->uartclk
/16);
238 quot
= uart_get_divisor(port
, baud
);
240 switch (termios
->c_cflag
& CSIZE
) {
255 if (termios
->c_cflag
& CSTOPB
)
256 h_lcr
|= H_UBRLCR_STOPB
;
257 if (termios
->c_cflag
& PARENB
) {
258 h_lcr
|= H_UBRLCR_PARENB
;
259 if (!(termios
->c_cflag
& PARODD
))
260 h_lcr
|= H_UBRLCR_PAREVN
;
264 h_lcr
|= H_UBRLCR_FIFO
;
266 spin_lock_irqsave(&port
->lock
, flags
);
269 * Update the per-port timeout.
271 uart_update_timeout(port
, termios
->c_cflag
, baud
);
274 * Which character status flags are we interested in?
276 port
->read_status_mask
= RXSTAT_OVERRUN
;
277 if (termios
->c_iflag
& INPCK
)
278 port
->read_status_mask
|= RXSTAT_FRAME
| RXSTAT_PARITY
;
281 * Which character status flags should we ignore?
283 port
->ignore_status_mask
= 0;
284 if (termios
->c_iflag
& IGNPAR
)
285 port
->ignore_status_mask
|= RXSTAT_FRAME
| RXSTAT_PARITY
;
286 if (termios
->c_iflag
& IGNBRK
&& termios
->c_iflag
& IGNPAR
)
287 port
->ignore_status_mask
|= RXSTAT_OVERRUN
;
290 * Ignore all characters if CREAD is not set.
292 if ((termios
->c_cflag
& CREAD
) == 0)
293 port
->ignore_status_mask
|= RXSTAT_DUMMY_READ
;
298 *CSR_L_UBRLCR
= quot
& 0xff;
299 *CSR_M_UBRLCR
= (quot
>> 8) & 0x0f;
300 *CSR_H_UBRLCR
= h_lcr
;
303 spin_unlock_irqrestore(&port
->lock
, flags
);
306 static const char *serial21285_type(struct uart_port
*port
)
308 return port
->type
== PORT_21285
? "DC21285" : NULL
;
311 static void serial21285_release_port(struct uart_port
*port
)
313 release_mem_region(port
->mapbase
, 32);
316 static int serial21285_request_port(struct uart_port
*port
)
318 return request_mem_region(port
->mapbase
, 32, serial21285_name
)
319 != NULL
? 0 : -EBUSY
;
322 static void serial21285_config_port(struct uart_port
*port
, int flags
)
324 if (flags
& UART_CONFIG_TYPE
&& serial21285_request_port(port
) == 0)
325 port
->type
= PORT_21285
;
329 * verify the new serial_struct (for TIOCSSERIAL).
331 static int serial21285_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
334 if (ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_21285
)
336 if (ser
->irq
!= NO_IRQ
)
338 if (ser
->baud_base
!= port
->uartclk
/ 16)
343 static struct uart_ops serial21285_ops
= {
344 .tx_empty
= serial21285_tx_empty
,
345 .get_mctrl
= serial21285_get_mctrl
,
346 .set_mctrl
= serial21285_set_mctrl
,
347 .stop_tx
= serial21285_stop_tx
,
348 .start_tx
= serial21285_start_tx
,
349 .stop_rx
= serial21285_stop_rx
,
350 .enable_ms
= serial21285_enable_ms
,
351 .break_ctl
= serial21285_break_ctl
,
352 .startup
= serial21285_startup
,
353 .shutdown
= serial21285_shutdown
,
354 .set_termios
= serial21285_set_termios
,
355 .type
= serial21285_type
,
356 .release_port
= serial21285_release_port
,
357 .request_port
= serial21285_request_port
,
358 .config_port
= serial21285_config_port
,
359 .verify_port
= serial21285_verify_port
,
362 static struct uart_port serial21285_port
= {
363 .mapbase
= 0x42000160,
367 .ops
= &serial21285_ops
,
368 .flags
= UPF_BOOT_AUTOCONF
,
371 static void serial21285_setup_ports(void)
373 serial21285_port
.uartclk
= mem_fclk_21285
/ 4;
376 #ifdef CONFIG_SERIAL_21285_CONSOLE
377 static void serial21285_console_putchar(struct uart_port
*port
, int ch
)
379 while (*CSR_UARTFLG
& 0x20)
385 serial21285_console_write(struct console
*co
, const char *s
,
388 uart_console_write(&serial21285_port
, s
, count
, serial21285_console_putchar
);
392 serial21285_get_options(struct uart_port
*port
, int *baud
,
393 int *parity
, int *bits
)
395 if (*CSR_UARTCON
== 1) {
399 switch (tmp
& 0x60) {
415 if (tmp
& H_UBRLCR_PARENB
) {
417 if (tmp
& H_UBRLCR_PAREVN
)
421 tmp
= *CSR_L_UBRLCR
| (*CSR_M_UBRLCR
<< 8);
423 *baud
= port
->uartclk
/ (16 * (tmp
+ 1));
427 static int __init
serial21285_console_setup(struct console
*co
, char *options
)
429 struct uart_port
*port
= &serial21285_port
;
435 if (machine_is_personal_server())
439 * Check whether an invalid uart number has been specified, and
440 * if so, search for the first available port that does have
444 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
446 serial21285_get_options(port
, &baud
, &parity
, &bits
);
448 return uart_set_options(port
, co
, baud
, parity
, bits
, flow
);
451 static struct uart_driver serial21285_reg
;
453 static struct console serial21285_console
=
455 .name
= SERIAL_21285_NAME
,
456 .write
= serial21285_console_write
,
457 .device
= uart_console_device
,
458 .setup
= serial21285_console_setup
,
459 .flags
= CON_PRINTBUFFER
,
461 .data
= &serial21285_reg
,
464 static int __init
rs285_console_init(void)
466 serial21285_setup_ports();
467 register_console(&serial21285_console
);
470 console_initcall(rs285_console_init
);
472 #define SERIAL_21285_CONSOLE &serial21285_console
474 #define SERIAL_21285_CONSOLE NULL
477 static struct uart_driver serial21285_reg
= {
478 .owner
= THIS_MODULE
,
479 .driver_name
= "ttyFB",
481 .major
= SERIAL_21285_MAJOR
,
482 .minor
= SERIAL_21285_MINOR
,
484 .cons
= SERIAL_21285_CONSOLE
,
487 static int __init
serial21285_init(void)
491 printk(KERN_INFO
"Serial: 21285 driver $Revision: 1.37 $\n");
493 serial21285_setup_ports();
495 ret
= uart_register_driver(&serial21285_reg
);
497 uart_add_one_port(&serial21285_reg
, &serial21285_port
);
502 static void __exit
serial21285_exit(void)
504 uart_remove_one_port(&serial21285_reg
, &serial21285_port
);
505 uart_unregister_driver(&serial21285_reg
);
508 module_init(serial21285_init
);
509 module_exit(serial21285_exit
);
511 MODULE_LICENSE("GPL");
512 MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver $Revision: 1.37 $");
513 MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR
, SERIAL_21285_MINOR
);