1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver for KS8695 serial ports
5 * Based on drivers/serial/serial_amba.c, by Kam Lee.
7 * Copyright 2002-2005 Micrel Inc.
9 #include <linux/module.h>
10 #include <linux/tty.h>
11 #include <linux/tty_flip.h>
12 #include <linux/ioport.h>
13 #include <linux/init.h>
14 #include <linux/serial.h>
15 #include <linux/console.h>
16 #include <linux/sysrq.h>
17 #include <linux/device.h>
21 #include <asm/mach/irq.h>
23 #include <mach/regs-uart.h>
24 #include <mach/regs-irq.h>
26 #if defined(CONFIG_SERIAL_KS8695_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
30 #include <linux/serial_core.h>
33 #define SERIAL_KS8695_MAJOR 204
34 #define SERIAL_KS8695_MINOR 16
35 #define SERIAL_KS8695_DEVNAME "ttyAM"
37 #define SERIAL_KS8695_NR 1
40 * Access macros for the KS8695 UART
42 #define UART_GET_CHAR(p) (__raw_readl((p)->membase + KS8695_URRB) & 0xFF)
43 #define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + KS8695_URTH)
44 #define UART_GET_FCR(p) __raw_readl((p)->membase + KS8695_URFC)
45 #define UART_PUT_FCR(p, c) __raw_writel((c), (p)->membase + KS8695_URFC)
46 #define UART_GET_MSR(p) __raw_readl((p)->membase + KS8695_URMS)
47 #define UART_GET_LSR(p) __raw_readl((p)->membase + KS8695_URLS)
48 #define UART_GET_LCR(p) __raw_readl((p)->membase + KS8695_URLC)
49 #define UART_PUT_LCR(p, c) __raw_writel((c), (p)->membase + KS8695_URLC)
50 #define UART_GET_MCR(p) __raw_readl((p)->membase + KS8695_URMC)
51 #define UART_PUT_MCR(p, c) __raw_writel((c), (p)->membase + KS8695_URMC)
52 #define UART_GET_BRDR(p) __raw_readl((p)->membase + KS8695_URBD)
53 #define UART_PUT_BRDR(p, c) __raw_writel((c), (p)->membase + KS8695_URBD)
55 #define KS8695_CLR_TX_INT() __raw_writel(1 << KS8695_IRQ_UART_TX, KS8695_IRQ_VA + KS8695_INTST)
57 #define UART_DUMMY_LSR_RX 0x100
58 #define UART_PORT_SIZE (KS8695_USR - KS8695_URRB + 4)
60 static inline int tx_enabled(struct uart_port
*port
)
62 return port
->unused
[0] & 1;
65 static inline int rx_enabled(struct uart_port
*port
)
67 return port
->unused
[0] & 2;
70 static inline int ms_enabled(struct uart_port
*port
)
72 return port
->unused
[0] & 4;
75 static inline void ms_enable(struct uart_port
*port
, int enabled
)
80 port
->unused
[0] &= ~4;
83 static inline void rx_enable(struct uart_port
*port
, int enabled
)
88 port
->unused
[0] &= ~2;
91 static inline void tx_enable(struct uart_port
*port
, int enabled
)
96 port
->unused
[0] &= ~1;
101 static struct console ks8695_console
;
104 static void ks8695uart_stop_tx(struct uart_port
*port
)
106 if (tx_enabled(port
)) {
107 /* use disable_irq_nosync() and not disable_irq() to avoid self
108 * imposed deadlock by not waiting for irq handler to end,
109 * since this ks8695uart_stop_tx() is called from interrupt context.
111 disable_irq_nosync(KS8695_IRQ_UART_TX
);
116 static void ks8695uart_start_tx(struct uart_port
*port
)
118 if (!tx_enabled(port
)) {
119 enable_irq(KS8695_IRQ_UART_TX
);
124 static void ks8695uart_stop_rx(struct uart_port
*port
)
126 if (rx_enabled(port
)) {
127 disable_irq(KS8695_IRQ_UART_RX
);
132 static void ks8695uart_enable_ms(struct uart_port
*port
)
134 if (!ms_enabled(port
)) {
135 enable_irq(KS8695_IRQ_UART_MODEM_STATUS
);
140 static void ks8695uart_disable_ms(struct uart_port
*port
)
142 if (ms_enabled(port
)) {
143 disable_irq(KS8695_IRQ_UART_MODEM_STATUS
);
148 static irqreturn_t
ks8695uart_rx_chars(int irq
, void *dev_id
)
150 struct uart_port
*port
= dev_id
;
151 unsigned int status
, ch
, lsr
, flg
, max_count
= 256;
153 status
= UART_GET_LSR(port
); /* clears pending LSR interrupts */
154 while ((status
& URLS_URDR
) && max_count
--) {
155 ch
= UART_GET_CHAR(port
);
161 * Note that the error handling code is
162 * out of the main execution path
164 lsr
= UART_GET_LSR(port
) | UART_DUMMY_LSR_RX
;
165 if (unlikely(lsr
& (URLS_URBI
| URLS_URPE
| URLS_URFE
| URLS_URROE
))) {
166 if (lsr
& URLS_URBI
) {
167 lsr
&= ~(URLS_URFE
| URLS_URPE
);
169 if (uart_handle_break(port
))
173 port
->icount
.parity
++;
175 port
->icount
.frame
++;
176 if (lsr
& URLS_URROE
)
177 port
->icount
.overrun
++;
179 lsr
&= port
->read_status_mask
;
183 else if (lsr
& URLS_URPE
)
185 else if (lsr
& URLS_URFE
)
189 if (uart_handle_sysrq_char(port
, ch
))
192 uart_insert_char(port
, lsr
, URLS_URROE
, ch
, flg
);
195 status
= UART_GET_LSR(port
);
197 tty_flip_buffer_push(&port
->state
->port
);
203 static irqreturn_t
ks8695uart_tx_chars(int irq
, void *dev_id
)
205 struct uart_port
*port
= dev_id
;
206 struct circ_buf
*xmit
= &port
->state
->xmit
;
211 UART_PUT_CHAR(port
, port
->x_char
);
217 if (uart_tx_stopped(port
) || uart_circ_empty(xmit
)) {
218 ks8695uart_stop_tx(port
);
222 count
= 16; /* fifo size */
223 while (!uart_circ_empty(xmit
) && (count
-- > 0)) {
225 UART_PUT_CHAR(port
, xmit
->buf
[xmit
->tail
]);
227 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
231 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
232 uart_write_wakeup(port
);
234 if (uart_circ_empty(xmit
))
235 ks8695uart_stop_tx(port
);
240 static irqreturn_t
ks8695uart_modem_status(int irq
, void *dev_id
)
242 struct uart_port
*port
= dev_id
;
246 * clear modem interrupt by reading MSR
248 status
= UART_GET_MSR(port
);
250 if (status
& URMS_URDDCD
)
251 uart_handle_dcd_change(port
, status
& URMS_URDDCD
);
253 if (status
& URMS_URDDST
)
256 if (status
& URMS_URDCTS
)
257 uart_handle_cts_change(port
, status
& URMS_URDCTS
);
259 if (status
& URMS_URTERI
)
262 wake_up_interruptible(&port
->state
->port
.delta_msr_wait
);
267 static unsigned int ks8695uart_tx_empty(struct uart_port
*port
)
269 return (UART_GET_LSR(port
) & URLS_URTE
) ? TIOCSER_TEMT
: 0;
272 static unsigned int ks8695uart_get_mctrl(struct uart_port
*port
)
274 unsigned int result
= 0;
277 status
= UART_GET_MSR(port
);
278 if (status
& URMS_URDCD
)
280 if (status
& URMS_URDSR
)
282 if (status
& URMS_URCTS
)
284 if (status
& URMS_URRI
)
290 static void ks8695uart_set_mctrl(struct uart_port
*port
, u_int mctrl
)
294 mcr
= UART_GET_MCR(port
);
295 if (mctrl
& TIOCM_RTS
)
300 if (mctrl
& TIOCM_DTR
)
305 UART_PUT_MCR(port
, mcr
);
308 static void ks8695uart_break_ctl(struct uart_port
*port
, int break_state
)
312 lcr
= UART_GET_LCR(port
);
314 if (break_state
== -1)
319 UART_PUT_LCR(port
, lcr
);
322 static int ks8695uart_startup(struct uart_port
*port
)
326 irq_modify_status(KS8695_IRQ_UART_TX
, IRQ_NOREQUEST
, IRQ_NOAUTOEN
);
334 retval
= request_irq(KS8695_IRQ_UART_TX
, ks8695uart_tx_chars
, 0, "UART TX", port
);
338 retval
= request_irq(KS8695_IRQ_UART_RX
, ks8695uart_rx_chars
, 0, "UART RX", port
);
342 retval
= request_irq(KS8695_IRQ_UART_LINE_STATUS
, ks8695uart_rx_chars
, 0, "UART LineStatus", port
);
346 retval
= request_irq(KS8695_IRQ_UART_MODEM_STATUS
, ks8695uart_modem_status
, 0, "UART ModemStatus", port
);
353 free_irq(KS8695_IRQ_UART_LINE_STATUS
, port
);
355 free_irq(KS8695_IRQ_UART_RX
, port
);
357 free_irq(KS8695_IRQ_UART_TX
, port
);
362 static void ks8695uart_shutdown(struct uart_port
*port
)
367 free_irq(KS8695_IRQ_UART_RX
, port
);
368 free_irq(KS8695_IRQ_UART_TX
, port
);
369 free_irq(KS8695_IRQ_UART_MODEM_STATUS
, port
);
370 free_irq(KS8695_IRQ_UART_LINE_STATUS
, port
);
372 /* disable break condition and fifos */
373 UART_PUT_LCR(port
, UART_GET_LCR(port
) & ~URLC_URSBC
);
374 UART_PUT_FCR(port
, UART_GET_FCR(port
) & ~URFC_URFE
);
377 static void ks8695uart_set_termios(struct uart_port
*port
, struct ktermios
*termios
, struct ktermios
*old
)
379 unsigned int lcr
, fcr
= 0;
381 unsigned int baud
, quot
;
384 * Ask the core to calculate the divisor for us.
386 baud
= uart_get_baud_rate(port
, termios
, old
, 0, port
->uartclk
/16);
387 quot
= uart_get_divisor(port
, baud
);
389 switch (termios
->c_cflag
& CSIZE
) {
405 if (termios
->c_cflag
& CSTOPB
)
409 if (termios
->c_cflag
& PARENB
) {
410 if (termios
->c_cflag
& CMSPAR
) { /* Mark or Space parity */
411 if (termios
->c_cflag
& PARODD
)
416 else if (termios
->c_cflag
& PARODD
)
422 if (port
->fifosize
> 1)
423 fcr
= URFC_URFRT_8
| URFC_URTFR
| URFC_URRFR
| URFC_URFE
;
425 spin_lock_irqsave(&port
->lock
, flags
);
428 * Update the per-port timeout.
430 uart_update_timeout(port
, termios
->c_cflag
, baud
);
432 port
->read_status_mask
= URLS_URROE
;
433 if (termios
->c_iflag
& INPCK
)
434 port
->read_status_mask
|= (URLS_URFE
| URLS_URPE
);
435 if (termios
->c_iflag
& (IGNBRK
| BRKINT
| PARMRK
))
436 port
->read_status_mask
|= URLS_URBI
;
439 * Characters to ignore
441 port
->ignore_status_mask
= 0;
442 if (termios
->c_iflag
& IGNPAR
)
443 port
->ignore_status_mask
|= (URLS_URFE
| URLS_URPE
);
444 if (termios
->c_iflag
& IGNBRK
) {
445 port
->ignore_status_mask
|= URLS_URBI
;
447 * If we're ignoring parity and break indicators,
448 * ignore overruns too (for real raw support).
450 if (termios
->c_iflag
& IGNPAR
)
451 port
->ignore_status_mask
|= URLS_URROE
;
455 * Ignore all characters if CREAD is not set.
457 if ((termios
->c_cflag
& CREAD
) == 0)
458 port
->ignore_status_mask
|= UART_DUMMY_LSR_RX
;
460 /* first, disable everything */
461 if (UART_ENABLE_MS(port
, termios
->c_cflag
))
462 ks8695uart_enable_ms(port
);
464 ks8695uart_disable_ms(port
);
467 UART_PUT_BRDR(port
, quot
);
469 UART_PUT_LCR(port
, lcr
);
470 UART_PUT_FCR(port
, fcr
);
472 spin_unlock_irqrestore(&port
->lock
, flags
);
475 static const char *ks8695uart_type(struct uart_port
*port
)
477 return port
->type
== PORT_KS8695
? "KS8695" : NULL
;
481 * Release the memory region(s) being used by 'port'
483 static void ks8695uart_release_port(struct uart_port
*port
)
485 release_mem_region(port
->mapbase
, UART_PORT_SIZE
);
489 * Request the memory region(s) being used by 'port'
491 static int ks8695uart_request_port(struct uart_port
*port
)
493 return request_mem_region(port
->mapbase
, UART_PORT_SIZE
,
494 "serial_ks8695") != NULL
? 0 : -EBUSY
;
498 * Configure/autoconfigure the port.
500 static void ks8695uart_config_port(struct uart_port
*port
, int flags
)
502 if (flags
& UART_CONFIG_TYPE
) {
503 port
->type
= PORT_KS8695
;
504 ks8695uart_request_port(port
);
509 * verify the new serial_struct (for TIOCSSERIAL).
511 static int ks8695uart_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
515 if (ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_KS8695
)
517 if (ser
->irq
!= port
->irq
)
519 if (ser
->baud_base
< 9600)
524 static struct uart_ops ks8695uart_pops
= {
525 .tx_empty
= ks8695uart_tx_empty
,
526 .set_mctrl
= ks8695uart_set_mctrl
,
527 .get_mctrl
= ks8695uart_get_mctrl
,
528 .stop_tx
= ks8695uart_stop_tx
,
529 .start_tx
= ks8695uart_start_tx
,
530 .stop_rx
= ks8695uart_stop_rx
,
531 .enable_ms
= ks8695uart_enable_ms
,
532 .break_ctl
= ks8695uart_break_ctl
,
533 .startup
= ks8695uart_startup
,
534 .shutdown
= ks8695uart_shutdown
,
535 .set_termios
= ks8695uart_set_termios
,
536 .type
= ks8695uart_type
,
537 .release_port
= ks8695uart_release_port
,
538 .request_port
= ks8695uart_request_port
,
539 .config_port
= ks8695uart_config_port
,
540 .verify_port
= ks8695uart_verify_port
,
543 static struct uart_port ks8695uart_ports
[SERIAL_KS8695_NR
] = {
545 .membase
= KS8695_UART_VA
,
546 .mapbase
= KS8695_UART_PA
,
547 .iotype
= SERIAL_IO_MEM
,
548 .irq
= KS8695_IRQ_UART_TX
,
549 .uartclk
= KS8695_CLOCK_RATE
* 16,
551 .ops
= &ks8695uart_pops
,
552 .flags
= UPF_BOOT_AUTOCONF
,
557 #ifdef CONFIG_SERIAL_KS8695_CONSOLE
558 static void ks8695_console_putchar(struct uart_port
*port
, int ch
)
560 while (!(UART_GET_LSR(port
) & URLS_URTHRE
))
563 UART_PUT_CHAR(port
, ch
);
566 static void ks8695_console_write(struct console
*co
, const char *s
, u_int count
)
568 struct uart_port
*port
= ks8695uart_ports
+ co
->index
;
570 uart_console_write(port
, s
, count
, ks8695_console_putchar
);
573 static void __init
ks8695_console_get_options(struct uart_port
*port
, int *baud
, int *parity
, int *bits
)
577 lcr
= UART_GET_LCR(port
);
579 switch (lcr
& URLC_PARITY
) {
590 switch (lcr
& URLC_URCL
) {
604 *baud
= port
->uartclk
/ (UART_GET_BRDR(port
) & 0x0FFF);
609 static int __init
ks8695_console_setup(struct console
*co
, char *options
)
611 struct uart_port
*port
;
618 * Check whether an invalid uart number has been specified, and
619 * if so, search for the first available port that does have
622 port
= uart_get_console(ks8695uart_ports
, SERIAL_KS8695_NR
, co
);
625 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
627 ks8695_console_get_options(port
, &baud
, &parity
, &bits
);
629 return uart_set_options(port
, co
, baud
, parity
, bits
, flow
);
632 static struct uart_driver ks8695_reg
;
634 static struct console ks8695_console
= {
635 .name
= SERIAL_KS8695_DEVNAME
,
636 .write
= ks8695_console_write
,
637 .device
= uart_console_device
,
638 .setup
= ks8695_console_setup
,
639 .flags
= CON_PRINTBUFFER
,
644 static int __init
ks8695_console_init(void)
646 add_preferred_console(SERIAL_KS8695_DEVNAME
, 0, NULL
);
647 register_console(&ks8695_console
);
651 console_initcall(ks8695_console_init
);
653 #define KS8695_CONSOLE &ks8695_console
655 #define KS8695_CONSOLE NULL
658 static struct uart_driver ks8695_reg
= {
659 .owner
= THIS_MODULE
,
660 .driver_name
= "serial_ks8695",
661 .dev_name
= SERIAL_KS8695_DEVNAME
,
662 .major
= SERIAL_KS8695_MAJOR
,
663 .minor
= SERIAL_KS8695_MINOR
,
664 .nr
= SERIAL_KS8695_NR
,
665 .cons
= KS8695_CONSOLE
,
668 static int __init
ks8695uart_init(void)
672 printk(KERN_INFO
"Serial: Micrel KS8695 UART driver\n");
674 ret
= uart_register_driver(&ks8695_reg
);
678 for (i
= 0; i
< SERIAL_KS8695_NR
; i
++)
679 uart_add_one_port(&ks8695_reg
, &ks8695uart_ports
[0]);
684 static void __exit
ks8695uart_exit(void)
688 for (i
= 0; i
< SERIAL_KS8695_NR
; i
++)
689 uart_remove_one_port(&ks8695_reg
, &ks8695uart_ports
[0]);
690 uart_unregister_driver(&ks8695_reg
);
693 module_init(ks8695uart_init
);
694 module_exit(ks8695uart_exit
);
696 MODULE_DESCRIPTION("KS8695 serial port driver");
697 MODULE_AUTHOR("Micrel Inc.");
698 MODULE_LICENSE("GPL");