sparc: Support for GRLIB APBUART serial port

This patch adds support for the APBUART serial port from Aeroflex
Gaisler's IP library GRLIB. It is currently used in all LEON3 designs
(SPARC V8) but can be used on other platforms as well (which support OF).

Signed-off-by: Kristoffer Glembo <kristoffer@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 710 insertions, 0 deletions

diff --git a/drivers/serial/apbuart.c b/drivers/serial/apbuart.c
new file mode 100644
index 00000000000..8a343045131
--- /dev/null
+++ b/drivers/serial/apbuart.c
@@ -0,0 +1,710 @@
+/*
+ *  Driver for GRLIB serial ports (APBUART)
+ *
+ *  Based on linux/drivers/serial/amba.c
+ *
+ *  Copyright (C) 2000 Deep Blue Solutions Ltd.
+ *  Copyright (C) 2003 Konrad Eisele <eiselekd@web.de>
+ *  Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB
+ *  Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com>
+ *  Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB
+ */
+
+#if defined(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/kthread.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/serial_core.h>
+#include <asm/irq.h>
+#include <asm/oplib.h>
+
+#include "apbuart.h"
+
+#define SERIAL_APBUART_MAJOR	TTY_MAJOR
+#define SERIAL_APBUART_MINOR	64
+#define UART_DUMMY_RSR_RX	0x8000	/* for ignore all read */
+
+static void apbuart_tx_chars(struct uart_port *port);
+
+static void apbuart_stop_tx(struct uart_port *port)
+{
+	unsigned int cr;
+
+	cr = UART_GET_CTRL(port);
+	cr &= ~UART_CTRL_TI;
+	UART_PUT_CTRL(port, cr);
+}
+
+static void apbuart_start_tx(struct uart_port *port)
+{
+	unsigned int cr;
+
+	cr = UART_GET_CTRL(port);
+	cr |= UART_CTRL_TI;
+	UART_PUT_CTRL(port, cr);
+
+	if (UART_GET_STATUS(port) & UART_STATUS_THE)
+		apbuart_tx_chars(port);
+}
+
+static void apbuart_stop_rx(struct uart_port *port)
+{
+	unsigned int cr;
+
+	cr = UART_GET_CTRL(port);
+	cr &= ~(UART_CTRL_RI);
+	UART_PUT_CTRL(port, cr);
+}
+
+static void apbuart_enable_ms(struct uart_port *port)
+{
+	/* No modem status change interrupts for APBUART */
+}
+
+static void apbuart_rx_chars(struct uart_port *port)
+{
+	struct tty_struct *tty = port->state->port.tty;
+	unsigned int status, ch, rsr, flag;
+	unsigned int max_chars = port->fifosize;
+
+	status = UART_GET_STATUS(port);
+
+	while (UART_RX_DATA(status) && (max_chars--)) {
+
+		ch = UART_GET_CHAR(port);
+		flag = TTY_NORMAL;
+
+		port->icount.rx++;
+
+		rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;
+		UART_PUT_STATUS(port, 0);
+		if (rsr & UART_STATUS_ERR) {
+
+			if (rsr & UART_STATUS_BR) {
+				rsr &= ~(UART_STATUS_FE | UART_STATUS_PE);
+				port->icount.brk++;
+				if (uart_handle_break(port))
+					goto ignore_char;
+			} else if (rsr & UART_STATUS_PE) {
+				port->icount.parity++;
+			} else if (rsr & UART_STATUS_FE) {
+				port->icount.frame++;
+			}
+			if (rsr & UART_STATUS_OE)
+				port->icount.overrun++;
+
+			rsr &= port->read_status_mask;
+
+			if (rsr & UART_STATUS_PE)
+				flag = TTY_PARITY;
+			else if (rsr & UART_STATUS_FE)
+				flag = TTY_FRAME;
+		}
+
+		if (uart_handle_sysrq_char(port, ch))
+			goto ignore_char;
+
+		uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag);
+
+
+	      ignore_char:
+		status = UART_GET_STATUS(port);
+	}
+
+	tty_flip_buffer_push(tty);
+}
+
+static void apbuart_tx_chars(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+	int count;
+
+	if (port->x_char) {
+		UART_PUT_CHAR(port, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		apbuart_stop_tx(port);
+		return;
+	}
+
+	/* amba: fill FIFO */
+	count = port->fifosize >> 1;
+	do {
+		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		apbuart_stop_tx(port);
+}
+
+static irqreturn_t apbuart_int(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	unsigned int status;
+
+	spin_lock(&port->lock);
+
+	status = UART_GET_STATUS(port);
+	if (status & UART_STATUS_DR)
+		apbuart_rx_chars(port);
+	if (status & UART_STATUS_THE)
+		apbuart_tx_chars(port);
+
+	spin_unlock(&port->lock);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned int apbuart_tx_empty(struct uart_port *port)
+{
+	unsigned int status = UART_GET_STATUS(port);
+	return status & UART_STATUS_THE ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int apbuart_get_mctrl(struct uart_port *port)
+{
+	/* The GRLIB APBUART handles flow control in hardware */
+	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+}
+
+static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* The GRLIB APBUART handles flow control in hardware */
+}
+
+static void apbuart_break_ctl(struct uart_port *port, int break_state)
+{
+	/* We don't support sending break */
+}
+
+static int apbuart_startup(struct uart_port *port)
+{
+	int retval;
+	unsigned int cr;
+
+	/* Allocate the IRQ */
+	retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port);
+	if (retval)
+		return retval;
+
+	/* Finally, enable interrupts */
+	cr = UART_GET_CTRL(port);
+	UART_PUT_CTRL(port,
+		      cr | UART_CTRL_RE | UART_CTRL_TE |
+		      UART_CTRL_RI | UART_CTRL_TI);
+
+	return 0;
+}
+
+static void apbuart_shutdown(struct uart_port *port)
+{
+	unsigned int cr;
+
+	/* disable all interrupts, disable the port */
+	cr = UART_GET_CTRL(port);
+	UART_PUT_CTRL(port,
+		      cr & ~(UART_CTRL_RE | UART_CTRL_TE |
+			     UART_CTRL_RI | UART_CTRL_TI));
+
+	/* Free the interrupt */
+	free_irq(port->irq, port);
+}
+
+static void apbuart_set_termios(struct uart_port *port,
+				struct ktermios *termios, struct ktermios *old)
+{
+	unsigned int cr;
+	unsigned long flags;
+	unsigned int baud, quot;
+
+	/* Ask the core to calculate the divisor for us. */
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
+	if (baud == 0)
+		panic("invalid baudrate %i\n", port->uartclk / 16);
+
+	/* uart_get_divisor calc a *16 uart freq, apbuart is *8 */
+	quot = (uart_get_divisor(port, baud)) * 2;
+	cr = UART_GET_CTRL(port);
+	cr &= ~(UART_CTRL_PE | UART_CTRL_PS);
+
+	if (termios->c_cflag & PARENB) {
+		cr |= UART_CTRL_PE;
+		if ((termios->c_cflag & PARODD))
+			cr |= UART_CTRL_PS;
+	}
+
+	/* Enable flow control. */
+	if (termios->c_cflag & CRTSCTS)
+		cr |= UART_CTRL_FL;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* Update the per-port timeout. */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = UART_STATUS_OE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
+
+	/* Characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
+
+	/* Ignore all characters if CREAD is not set. */
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |= UART_DUMMY_RSR_RX;
+
+	/* Set baud rate */
+	quot -= 1;
+	UART_PUT_SCAL(port, quot);
+	UART_PUT_CTRL(port, cr);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *apbuart_type(struct uart_port *port)
+{
+	return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL;
+}
+
+static void apbuart_release_port(struct uart_port *port)
+{
+	release_mem_region(port->mapbase, 0x100);
+}
+
+static int apbuart_request_port(struct uart_port *port)
+{
+	return request_mem_region(port->mapbase, 0x100, "grlib-apbuart")
+	    != NULL ? 0 : -EBUSY;
+	return 0;
+}
+
+/* Configure/autoconfigure the port */
+static void apbuart_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE) {
+		port->type = PORT_APBUART;
+		apbuart_request_port(port);
+	}
+}
+
+/* Verify the new serial_struct (for TIOCSSERIAL) */
+static int apbuart_verify_port(struct uart_port *port,
+			       struct serial_struct *ser)
+{
+	int ret = 0;
+	if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART)
+		ret = -EINVAL;
+	if (ser->irq < 0 || ser->irq >= NR_IRQS)
+		ret = -EINVAL;
+	if (ser->baud_base < 9600)
+		ret = -EINVAL;
+	return ret;
+}
+
+static struct uart_ops grlib_apbuart_ops = {
+	.tx_empty = apbuart_tx_empty,
+	.set_mctrl = apbuart_set_mctrl,
+	.get_mctrl = apbuart_get_mctrl,
+	.stop_tx = apbuart_stop_tx,
+	.start_tx = apbuart_start_tx,
+	.stop_rx = apbuart_stop_rx,
+	.enable_ms = apbuart_enable_ms,
+	.break_ctl = apbuart_break_ctl,
+	.startup = apbuart_startup,
+	.shutdown = apbuart_shutdown,
+	.set_termios = apbuart_set_termios,
+	.type = apbuart_type,
+	.release_port = apbuart_release_port,
+	.request_port = apbuart_request_port,
+	.config_port = apbuart_config_port,
+	.verify_port = apbuart_verify_port,
+};
+
+static struct uart_port grlib_apbuart_ports[UART_NR];
+static struct device_node *grlib_apbuart_nodes[UART_NR];
+
+static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber)
+{
+	int ctrl, loop = 0;
+	int status;
+	int fifosize;
+	unsigned long flags;
+
+	ctrl = UART_GET_CTRL(port);
+
+	/*
+	 * Enable the transceiver and wait for it to be ready to send data.
+	 * Clear interrupts so that this process will not be externally
+	 * interrupted in the middle (which can cause the transceiver to
+	 * drain prematurely).
+	 */
+
+	local_irq_save(flags);
+
+	UART_PUT_CTRL(port, ctrl | UART_CTRL_TE);
+
+	while (!UART_TX_READY(UART_GET_STATUS(port)))
+		loop++;
+
+	/*
+	 * Disable the transceiver so data isn't actually sent during the
+	 * actual test.
+	 */
+
+	UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE));
+
+	fifosize = 1;
+	UART_PUT_CHAR(port, 0);
+
+	/*
+	 * So long as transmitting a character increments the tranceivier FIFO
+	 * length the FIFO must be at least that big. These bytes will
+	 * automatically drain off of the FIFO.
+	 */
+
+	status = UART_GET_STATUS(port);
+	while (((status >> 20) & 0x3F) == fifosize) {
+		fifosize++;
+		UART_PUT_CHAR(port, 0);
+		status = UART_GET_STATUS(port);
+	}
+
+	fifosize--;
+
+	UART_PUT_CTRL(port, ctrl);
+	local_irq_restore(flags);
+
+	if (fifosize == 0)
+		fifosize = 1;
+
+	return fifosize;
+}
+
+static void apbuart_flush_fifo(struct uart_port *port)
+{
+	int i;
+
+	for (i = 0; i < port->fifosize; i++)
+		UART_GET_CHAR(port);
+}
+
+
+/* ======================================================================== */
+/* Console driver, if enabled                                               */
+/* ======================================================================== */
+
+#ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
+
+static void apbuart_console_putchar(struct uart_port *port, int ch)
+{
+	unsigned int status;
+	do {
+		status = UART_GET_STATUS(port);
+	} while (!UART_TX_READY(status));
+	UART_PUT_CHAR(port, ch);
+}
+
+static void
+apbuart_console_write(struct console *co, const char *s, unsigned int count)
+{
+	struct uart_port *port = &grlib_apbuart_ports[co->index];
+	unsigned int status, old_cr, new_cr;
+
+	/* First save the CR then disable the interrupts */
+	old_cr = UART_GET_CTRL(port);
+	new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI);
+	UART_PUT_CTRL(port, new_cr);
+
+	uart_console_write(port, s, count, apbuart_console_putchar);
+
+	/*
+	 *      Finally, wait for transmitter to become empty
+	 *      and restore the TCR
+	 */
+	do {
+		status = UART_GET_STATUS(port);
+	} while (!UART_TX_READY(status));
+	UART_PUT_CTRL(port, old_cr);
+}
+
+static void __init
+apbuart_console_get_options(struct uart_port *port, int *baud,
+			    int *parity, int *bits)
+{
+	if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) {
+
+		unsigned int quot, status;
+		status = UART_GET_STATUS(port);
+
+		*parity = 'n';
+		if (status & UART_CTRL_PE) {
+			if ((status & UART_CTRL_PS) == 0)
+				*parity = 'e';
+			else
+				*parity = 'o';
+		}
+
+		*bits = 8;
+		quot = UART_GET_SCAL(port) / 8;
+		*baud = port->uartclk / (16 * (quot + 1));
+	}
+}
+
+static int __init apbuart_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 38400;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n",
+		 co, co->index, options);
+
+	/*
+	 * Check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index >= grlib_apbuart_port_nr)
+		co->index = 0;
+
+	port = &grlib_apbuart_ports[co->index];
+
+	spin_lock_init(&port->lock);
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		apbuart_console_get_options(port, &baud, &parity, &bits);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver grlib_apbuart_driver;
+
+static struct console grlib_apbuart_console = {
+	.name = "ttyS",
+	.write = apbuart_console_write,
+	.device = uart_console_device,
+	.setup = apbuart_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &grlib_apbuart_driver,
+};
+
+
+static void grlib_apbuart_configure(void);
+
+static int __init apbuart_console_init(void)
+{
+	grlib_apbuart_configure();
+	register_console(&grlib_apbuart_console);
+	return 0;
+}
+
+console_initcall(apbuart_console_init);
+
+#define APBUART_CONSOLE	(&grlib_apbuart_console)
+#else
+#define APBUART_CONSOLE	NULL
+#endif
+
+static struct uart_driver grlib_apbuart_driver = {
+	.owner = THIS_MODULE,
+	.driver_name = "serial",
+	.dev_name = "ttyS",
+	.major = SERIAL_APBUART_MAJOR,
+	.minor = SERIAL_APBUART_MINOR,
+	.nr = UART_NR,
+	.cons = APBUART_CONSOLE,
+};
+
+
+/* ======================================================================== */
+/* OF Platform Driver                                                       */
+/* ======================================================================== */
+
+static int __devinit apbuart_probe(struct of_device *op,
+				   const struct of_device_id *match)
+{
+	int i = -1;
+	struct uart_port *port = NULL;
+
+	i = 0;
+	for (i = 0; i < grlib_apbuart_port_nr; i++) {
+		if (op->node == grlib_apbuart_nodes[i])
+			break;
+	}
+
+	port = &grlib_apbuart_ports[i];
+	port->dev = &op->dev;
+
+	uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port);
+
+	apbuart_flush_fifo((struct uart_port *) port);
+
+	printk(KERN_INFO "grlib-apbuart at 0x%x, irq %d\n",
+	       port->mapbase, port->irq);
+	return 0;
+
+}
+
+static struct of_device_id __initdata apbuart_match[] = {
+	{
+	 .name = "GAISLER_APBUART",
+	 },
+	{},
+};
+
+static struct of_platform_driver grlib_apbuart_of_driver = {
+	.match_table = apbuart_match,
+	.probe = apbuart_probe,
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = "grlib-apbuart",
+		   },
+};
+
+
+static void grlib_apbuart_configure(void)
+{
+	static int enum_done;
+	struct device_node *np;
+	struct uart_port *port = NULL;
+
+	int node;
+	int freq_khz;
+	int v = 0, d = 0;
+	unsigned int addr;
+	int irq, line;
+	struct amba_prom_registers *regs;
+
+	if (enum_done)
+		return;
+
+	/* Get bus frequency */
+	node = prom_getchild(prom_root_node);
+	freq_khz = prom_getint(node, "clock-frequency");
+
+	line = 0;
+	for_each_matching_node(np, apbuart_match) {
+
+		int *vendor = (int *) of_get_property(np, "vendor", NULL);
+		int *device = (int *) of_get_property(np, "device", NULL);
+		int *irqs = (int *) of_get_property(np, "interrupts", NULL);
+		regs = (struct amba_prom_registers *)
+		    of_get_property(np, "reg", NULL);
+
+		if (vendor)
+			v = *vendor;
+		if (device)
+			d = *device;
+
+		if (!irqs || !regs)
+			return;
+
+		grlib_apbuart_nodes[line] = np;
+
+		addr = regs->phys_addr;
+		irq = *irqs;
+
+		port = &grlib_apbuart_ports[line];
+
+		port->mapbase = addr;
+		port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
+		port->irq = irq;
+		port->iotype = UPIO_MEM;
+		port->ops = &grlib_apbuart_ops;
+		port->flags = UPF_BOOT_AUTOCONF;
+		port->line = line;
+		port->uartclk = freq_khz * 1000;
+		port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
+		line++;
+
+		/* We support maximum UART_NR uarts ... */
+		if (line == UART_NR)
+			break;
+
+	}
+
+	enum_done = 1;
+
+	grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
+}
+
+static int __init grlib_apbuart_init(void)
+{
+	int ret;
+
+	/* Find all APBUARTS in device the tree and initialize their ports */
+	grlib_apbuart_configure();
+
+	printk(KERN_INFO "Serial: GRLIB APBUART driver\n");
+
+	ret = uart_register_driver(&grlib_apbuart_driver);
+
+	if (ret) {
+		printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
+		       __FILE__, ret);
+		return ret;
+	}
+
+	ret = of_register_driver(&grlib_apbuart_of_driver, &of_platform_bus_type);
+
+	if (ret) {
+		printk(KERN_ERR
+		       "%s: of_register_platform_driver failed (%i)\n",
+		       __FILE__, ret);
+		uart_unregister_driver(&grlib_apbuart_driver);
+		return ret;
+	}
+
+	return ret;
+}
+
+static void __exit grlib_apbuart_exit(void)
+{
+	int i;
+
+	for (i = 0; i < grlib_apbuart_port_nr; i++)
+		uart_remove_one_port(&grlib_apbuart_driver,
+				     &grlib_apbuart_ports[i]);
+
+	uart_unregister_driver(&grlib_apbuart_driver);
+
+}
+
+module_init(grlib_apbuart_init);
+module_exit(grlib_apbuart_exit);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB");
+MODULE_DESCRIPTION("GRLIB APBUART serial driver");
+MODULE_VERSION("2.1");
+MODULE_LICENSE("GPL");