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;
132 struct tty_struct *tty = port->tty;
137 spin_lock(&up->port.lock);
139 /* check if the uart was the interrupt source. */
140 iir = dcr_read(up->dcr_host, UART_IIR);
147 up->port.icount.rx++;
148 ch = dcr_read(up->dcr_host, UART_RX);
149 if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
150 tty_insert_flip_char(port, ch, TTY_NORMAL);
151 } while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);
153 tty_flip_buffer_push(tty);
156 /* clear interrupt */
157 dcr_write(up->dcr_host, UART_IIR, 1);
159 spin_unlock(&up->port.lock);
163 static int nwpserial_startup(struct uart_port *port)
165 struct nwpserial_port *up;
168 up = container_of(port, struct nwpserial_port, port);
170 /* disable flow control by default */
171 up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
172 dcr_write(up->dcr_host, UART_MCR, up->mcr);
174 /* register interrupt handler */
175 err = request_irq(up->port.irq, nwpserial_interrupt,
176 IRQF_SHARED, "nwpserial", up);
180 /* enable interrupts */
181 up->ier = UART_IER_RDI;
182 dcr_write(up->dcr_host, UART_IER, up->ier);
184 /* enable receiving */
185 up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;
190 static void nwpserial_shutdown(struct uart_port *port)
192 struct nwpserial_port *up;
193 up = container_of(port, struct nwpserial_port, port);
195 /* disable receiving */
196 up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
198 /* disable interrupts from this port */
200 dcr_write(up->dcr_host, UART_IER, up->ier);
203 free_irq(up->port.irq, port);
206 static int nwpserial_verify_port(struct uart_port *port,
207 struct serial_struct *ser)
212 static const char *nwpserial_type(struct uart_port *port)
214 return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
217 static void nwpserial_set_termios(struct uart_port *port,
218 struct ktermios *termios, struct ktermios *old)
220 struct nwpserial_port *up;
221 up = container_of(port, struct nwpserial_port, port);
223 up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID
224 | NWPSERIAL_STATUS_TXFULL;
226 up->port.ignore_status_mask = 0;
227 /* ignore all characters if CREAD is not set */
228 if ((termios->c_cflag & CREAD) == 0)
229 up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
231 /* Copy back the old hardware settings */
233 tty_termios_copy_hw(termios, old);
236 static void nwpserial_break_ctl(struct uart_port *port, int ctl)
241 static void nwpserial_enable_ms(struct uart_port *port)
246 static void nwpserial_stop_rx(struct uart_port *port)
248 struct nwpserial_port *up;
249 up = container_of(port, struct nwpserial_port, port);
250 /* don't forward any more data (like !CREAD) */
251 up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
254 static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
256 /* check if tx buffer is full */
257 wait_for_bits(up, UART_LSR_THRE);
258 dcr_write(up->dcr_host, UART_TX, c);
259 up->port.icount.tx++;
262 static void nwpserial_start_tx(struct uart_port *port)
264 struct nwpserial_port *up;
265 struct circ_buf *xmit;
266 up = container_of(port, struct nwpserial_port, port);
267 xmit = &up->port.state->xmit;
270 nwpserial_putchar(up, up->port.x_char);
274 while (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port))) {
275 nwpserial_putchar(up, xmit->buf[xmit->tail]);
276 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
280 static unsigned int nwpserial_get_mctrl(struct uart_port *port)
285 static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
290 static void nwpserial_stop_tx(struct uart_port *port)
295 static unsigned int nwpserial_tx_empty(struct uart_port *port)
297 struct nwpserial_port *up;
300 up = container_of(port, struct nwpserial_port, port);
302 spin_lock_irqsave(&up->port.lock, flags);
303 ret = dcr_read(up->dcr_host, UART_LSR);
304 spin_unlock_irqrestore(&up->port.lock, flags);
306 return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
309 static struct uart_ops nwpserial_pops = {
310 .tx_empty = nwpserial_tx_empty,
311 .set_mctrl = nwpserial_set_mctrl,
312 .get_mctrl = nwpserial_get_mctrl,
313 .stop_tx = nwpserial_stop_tx,
314 .start_tx = nwpserial_start_tx,
315 .stop_rx = nwpserial_stop_rx,
316 .enable_ms = nwpserial_enable_ms,
317 .break_ctl = nwpserial_break_ctl,
318 .startup = nwpserial_startup,
319 .shutdown = nwpserial_shutdown,
320 .set_termios = nwpserial_set_termios,
321 .type = nwpserial_type,
322 .release_port = nwpserial_release_port,
323 .request_port = nwpserial_request_port,
324 .config_port = nwpserial_config_port,
325 .verify_port = nwpserial_verify_port,
328 static struct uart_driver nwpserial_reg = {
329 .owner = THIS_MODULE,
330 .driver_name = "nwpserial",
335 .cons = NWPSERIAL_CONSOLE,
338 int nwpserial_register_port(struct uart_port *port)
340 struct nwpserial_port *up = NULL;
343 static int first = 1;
346 struct device_node *dn;
348 mutex_lock(&nwpserial_mutex);
350 dn = port->dev->of_node;
355 dcr_base = dcr_resource_start(dn, 0);
357 /* find matching entry */
358 for (i = 0; i < NWPSERIAL_NR; i++)
359 if (nwpserial_ports[i].port.iobase == dcr_base) {
360 up = &nwpserial_ports[i];
364 /* we didn't find a mtching entry, search for a free port */
366 for (i = 0; i < NWPSERIAL_NR; i++)
367 if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
368 nwpserial_ports[i].port.iobase == 0) {
369 up = &nwpserial_ports[i];
379 uart_register_driver(&nwpserial_reg);
382 up->port.membase = port->membase;
383 up->port.irq = port->irq;
384 up->port.uartclk = port->uartclk;
385 up->port.fifosize = port->fifosize;
386 up->port.regshift = port->regshift;
387 up->port.iotype = port->iotype;
388 up->port.flags = port->flags;
389 up->port.mapbase = port->mapbase;
390 up->port.private_data = port->private_data;
393 up->port.dev = port->dev;
395 if (up->port.iobase != dcr_base) {
396 up->port.ops = &nwpserial_pops;
397 up->port.fifosize = 16;
399 spin_lock_init(&up->port.lock);
401 up->port.iobase = dcr_base;
402 dcr_len = dcr_resource_len(dn, 0);
404 up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
405 if (!DCR_MAP_OK(up->dcr_host)) {
406 printk(KERN_ERR "Cannot map DCR resources for NWPSERIAL");
411 ret = uart_add_one_port(&nwpserial_reg, &up->port);
416 mutex_unlock(&nwpserial_mutex);
420 EXPORT_SYMBOL(nwpserial_register_port);
422 void nwpserial_unregister_port(int line)
424 struct nwpserial_port *up = &nwpserial_ports[line];
425 mutex_lock(&nwpserial_mutex);
426 uart_remove_one_port(&nwpserial_reg, &up->port);
428 up->port.type = PORT_UNKNOWN;
430 mutex_unlock(&nwpserial_mutex);
432 EXPORT_SYMBOL(nwpserial_unregister_port);
434 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
435 static int __init nwpserial_console_init(void)
437 struct nwpserial_port *up = NULL;
438 struct device_node *dn;
444 /* search for a free port */
445 for (i = 0; i < NWPSERIAL_NR; i++)
446 if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
447 up = &nwpserial_ports[i];
454 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
458 dn = of_find_node_by_path(name);
462 spin_lock_init(&up->port.lock);
463 up->port.ops = &nwpserial_pops;
464 up->port.type = PORT_NWPSERIAL;
465 up->port.fifosize = 16;
467 dcr_base = dcr_resource_start(dn, 0);
468 dcr_len = dcr_resource_len(dn, 0);
469 up->port.iobase = dcr_base;
471 up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
472 if (!DCR_MAP_OK(up->dcr_host)) {
473 printk("Cannot map DCR resources for SERIAL");
476 register_console(&nwpserial_console);
479 console_initcall(nwpserial_console_init);
480 #endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */