2 * Serial Port driver for a NWP uart device
4 * Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/init.h>
13 #include <linux/export.h>
14 #include <linux/console.h>
15 #include <linux/serial.h>
16 #include <linux/serial_reg.h>
17 #include <linux/serial_core.h>
18 #include <linux/tty.h>
19 #include <linux/tty_flip.h>
20 #include <linux/irqreturn.h>
21 #include <linux/mutex.h>
22 #include <linux/of_platform.h>
23 #include <linux/of_device.h>
24 #include <linux/nwpserial.h>
28 #define NWPSERIAL_NR 2
30 #define NWPSERIAL_STATUS_RXVALID 0x1
31 #define NWPSERIAL_STATUS_TXFULL 0x2
33 struct nwpserial_port {
34 struct uart_port port;
40 static DEFINE_MUTEX(nwpserial_mutex);
41 static struct nwpserial_port nwpserial_ports[NWPSERIAL_NR];
43 static void wait_for_bits(struct nwpserial_port *up, int bits)
45 unsigned int status, tmout = 10000;
47 /* Wait up to 10ms for the character(s) to be sent. */
49 status = dcr_read(up->dcr_host, UART_LSR);
54 } while ((status & bits) != bits);
57 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
58 static void nwpserial_console_putchar(struct uart_port *port, int c)
60 struct nwpserial_port *up;
61 up = container_of(port, struct nwpserial_port, port);
62 /* check if tx buffer is full */
63 wait_for_bits(up, UART_LSR_THRE);
64 dcr_write(up->dcr_host, UART_TX, c);
69 nwpserial_console_write(struct console *co, const char *s, unsigned int count)
71 struct nwpserial_port *up = &nwpserial_ports[co->index];
76 locked = spin_trylock_irqsave(&up->port.lock, flags);
78 spin_lock_irqsave(&up->port.lock, flags);
80 /* save and disable interrupt */
81 up->ier = dcr_read(up->dcr_host, UART_IER);
82 dcr_write(up->dcr_host, UART_IER, up->ier & ~UART_IER_RDI);
84 uart_console_write(&up->port, s, count, nwpserial_console_putchar);
86 /* wait for transmitter to become empty */
87 while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
90 /* restore interrupt state */
91 dcr_write(up->dcr_host, UART_IER, up->ier);
94 spin_unlock_irqrestore(&up->port.lock, flags);
97 static struct uart_driver nwpserial_reg;
98 static struct console nwpserial_console = {
100 .write = nwpserial_console_write,
101 .device = uart_console_device,
102 .flags = CON_PRINTBUFFER,
104 .data = &nwpserial_reg,
106 #define NWPSERIAL_CONSOLE (&nwpserial_console)
108 #define NWPSERIAL_CONSOLE NULL
109 #endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */
111 /**************************************************************************/
113 static int nwpserial_request_port(struct uart_port *port)
118 static void nwpserial_release_port(struct uart_port *port)
123 static void nwpserial_config_port(struct uart_port *port, int flags)
125 port->type = PORT_NWPSERIAL;
128 static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
130 struct nwpserial_port *up = dev_id;
131 struct tty_port *port = &up->port.state->port;
136 spin_lock(&up->port.lock);
138 /* check if the uart was the interrupt source. */
139 iir = dcr_read(up->dcr_host, UART_IIR);
146 up->port.icount.rx++;
147 ch = dcr_read(up->dcr_host, UART_RX);
148 if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
149 tty_insert_flip_char(port, ch, TTY_NORMAL);
150 } while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);
152 spin_unlock(&up->port.lock);
153 tty_flip_buffer_push(port);
154 spin_lock(&up->port.lock);
158 /* clear interrupt */
159 dcr_write(up->dcr_host, UART_IIR, 1);
161 spin_unlock(&up->port.lock);
165 static int nwpserial_startup(struct uart_port *port)
167 struct nwpserial_port *up;
170 up = container_of(port, struct nwpserial_port, port);
172 /* disable flow control by default */
173 up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
174 dcr_write(up->dcr_host, UART_MCR, up->mcr);
176 /* register interrupt handler */
177 err = request_irq(up->port.irq, nwpserial_interrupt,
178 IRQF_SHARED, "nwpserial", up);
182 /* enable interrupts */
183 up->ier = UART_IER_RDI;
184 dcr_write(up->dcr_host, UART_IER, up->ier);
186 /* enable receiving */
187 up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;
192 static void nwpserial_shutdown(struct uart_port *port)
194 struct nwpserial_port *up;
195 up = container_of(port, struct nwpserial_port, port);
197 /* disable receiving */
198 up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
200 /* disable interrupts from this port */
202 dcr_write(up->dcr_host, UART_IER, up->ier);
205 free_irq(up->port.irq, up);
208 static int nwpserial_verify_port(struct uart_port *port,
209 struct serial_struct *ser)
214 static const char *nwpserial_type(struct uart_port *port)
216 return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
219 static void nwpserial_set_termios(struct uart_port *port,
220 struct ktermios *termios, struct ktermios *old)
222 struct nwpserial_port *up;
223 up = container_of(port, struct nwpserial_port, port);
225 up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID
226 | NWPSERIAL_STATUS_TXFULL;
228 up->port.ignore_status_mask = 0;
229 /* ignore all characters if CREAD is not set */
230 if ((termios->c_cflag & CREAD) == 0)
231 up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
233 /* Copy back the old hardware settings */
235 tty_termios_copy_hw(termios, old);
238 static void nwpserial_break_ctl(struct uart_port *port, int ctl)
243 static void nwpserial_stop_rx(struct uart_port *port)
245 struct nwpserial_port *up;
246 up = container_of(port, struct nwpserial_port, port);
247 /* don't forward any more data (like !CREAD) */
248 up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
251 static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
253 /* check if tx buffer is full */
254 wait_for_bits(up, UART_LSR_THRE);
255 dcr_write(up->dcr_host, UART_TX, c);
256 up->port.icount.tx++;
259 static void nwpserial_start_tx(struct uart_port *port)
261 struct nwpserial_port *up;
262 struct circ_buf *xmit;
263 up = container_of(port, struct nwpserial_port, port);
264 xmit = &up->port.state->xmit;
267 nwpserial_putchar(up, up->port.x_char);
271 while (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port))) {
272 nwpserial_putchar(up, xmit->buf[xmit->tail]);
273 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
277 static unsigned int nwpserial_get_mctrl(struct uart_port *port)
282 static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
287 static void nwpserial_stop_tx(struct uart_port *port)
292 static unsigned int nwpserial_tx_empty(struct uart_port *port)
294 struct nwpserial_port *up;
297 up = container_of(port, struct nwpserial_port, port);
299 spin_lock_irqsave(&up->port.lock, flags);
300 ret = dcr_read(up->dcr_host, UART_LSR);
301 spin_unlock_irqrestore(&up->port.lock, flags);
303 return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
306 static struct uart_ops nwpserial_pops = {
307 .tx_empty = nwpserial_tx_empty,
308 .set_mctrl = nwpserial_set_mctrl,
309 .get_mctrl = nwpserial_get_mctrl,
310 .stop_tx = nwpserial_stop_tx,
311 .start_tx = nwpserial_start_tx,
312 .stop_rx = nwpserial_stop_rx,
313 .break_ctl = nwpserial_break_ctl,
314 .startup = nwpserial_startup,
315 .shutdown = nwpserial_shutdown,
316 .set_termios = nwpserial_set_termios,
317 .type = nwpserial_type,
318 .release_port = nwpserial_release_port,
319 .request_port = nwpserial_request_port,
320 .config_port = nwpserial_config_port,
321 .verify_port = nwpserial_verify_port,
324 static struct uart_driver nwpserial_reg = {
325 .owner = THIS_MODULE,
326 .driver_name = "nwpserial",
331 .cons = NWPSERIAL_CONSOLE,
334 int nwpserial_register_port(struct uart_port *port)
336 struct nwpserial_port *up = NULL;
339 static int first = 1;
342 struct device_node *dn;
344 mutex_lock(&nwpserial_mutex);
346 dn = port->dev->of_node;
351 dcr_base = dcr_resource_start(dn, 0);
353 /* find matching entry */
354 for (i = 0; i < NWPSERIAL_NR; i++)
355 if (nwpserial_ports[i].port.iobase == dcr_base) {
356 up = &nwpserial_ports[i];
360 /* we didn't find a mtching entry, search for a free port */
362 for (i = 0; i < NWPSERIAL_NR; i++)
363 if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
364 nwpserial_ports[i].port.iobase == 0) {
365 up = &nwpserial_ports[i];
375 uart_register_driver(&nwpserial_reg);
378 up->port.membase = port->membase;
379 up->port.irq = port->irq;
380 up->port.uartclk = port->uartclk;
381 up->port.fifosize = port->fifosize;
382 up->port.regshift = port->regshift;
383 up->port.iotype = port->iotype;
384 up->port.flags = port->flags;
385 up->port.mapbase = port->mapbase;
386 up->port.private_data = port->private_data;
389 up->port.dev = port->dev;
391 if (up->port.iobase != dcr_base) {
392 up->port.ops = &nwpserial_pops;
393 up->port.fifosize = 16;
395 spin_lock_init(&up->port.lock);
397 up->port.iobase = dcr_base;
398 dcr_len = dcr_resource_len(dn, 0);
400 up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
401 if (!DCR_MAP_OK(up->dcr_host)) {
402 printk(KERN_ERR "Cannot map DCR resources for NWPSERIAL");
407 ret = uart_add_one_port(&nwpserial_reg, &up->port);
412 mutex_unlock(&nwpserial_mutex);
416 EXPORT_SYMBOL(nwpserial_register_port);
418 void nwpserial_unregister_port(int line)
420 struct nwpserial_port *up = &nwpserial_ports[line];
421 mutex_lock(&nwpserial_mutex);
422 uart_remove_one_port(&nwpserial_reg, &up->port);
424 up->port.type = PORT_UNKNOWN;
426 mutex_unlock(&nwpserial_mutex);
428 EXPORT_SYMBOL(nwpserial_unregister_port);
430 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
431 static int __init nwpserial_console_init(void)
433 struct nwpserial_port *up = NULL;
434 struct device_node *dn;
440 /* search for a free port */
441 for (i = 0; i < NWPSERIAL_NR; i++)
442 if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
443 up = &nwpserial_ports[i];
450 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
454 dn = of_find_node_by_path(name);
458 spin_lock_init(&up->port.lock);
459 up->port.ops = &nwpserial_pops;
460 up->port.type = PORT_NWPSERIAL;
461 up->port.fifosize = 16;
463 dcr_base = dcr_resource_start(dn, 0);
464 dcr_len = dcr_resource_len(dn, 0);
465 up->port.iobase = dcr_base;
467 up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
468 if (!DCR_MAP_OK(up->dcr_host)) {
469 printk("Cannot map DCR resources for SERIAL");
472 register_console(&nwpserial_console);
475 console_initcall(nwpserial_console_init);
476 #endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */