1 files changed, 690 insertions, 0 deletions

diff --git a/drivers/tty/serial/apbuart.c b/drivers/tty/serial/apbuart.c
new file mode 100644
index 000000000..e8d56e899
--- /dev/null
+++ b/drivers/tty/serial/apbuart.c
@@ -0,0 +1,690 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  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
+ */
+
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.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/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/serial_core.h>
+#include <asm/irq.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_rx_chars(struct uart_port *port)
+{
+	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);
+	}
+
+	spin_unlock(&port->lock);
+	tty_flip_buffer_push(&port->state->port);
+	spin_lock(&port->lock);
+}
+
+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 const 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,
+	.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 int grlib_apbuart_configure(void);
+
+static int __init apbuart_console_init(void)
+{
+	if (grlib_apbuart_configure())
+		return -ENODEV;
+	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 apbuart_probe(struct platform_device *op)
+{
+	int i;
+	struct uart_port *port = NULL;
+
+	for (i = 0; i < grlib_apbuart_port_nr; i++) {
+		if (op->dev.of_node == grlib_apbuart_nodes[i])
+			break;
+	}
+
+	port = &grlib_apbuart_ports[i];
+	port->dev = &op->dev;
+	port->irq = op->archdata.irqs[0];
+
+	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%llx, irq %d\n",
+	       (unsigned long long) port->mapbase, port->irq);
+	return 0;
+}
+
+static const struct of_device_id apbuart_match[] = {
+	{
+	 .name = "GAISLER_APBUART",
+	 },
+	{
+	 .name = "01_00c",
+	 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, apbuart_match);
+
+static struct platform_driver grlib_apbuart_of_driver = {
+	.probe = apbuart_probe,
+	.driver = {
+		.name = "grlib-apbuart",
+		.of_match_table = apbuart_match,
+	},
+};
+
+
+static int __init grlib_apbuart_configure(void)
+{
+	struct device_node *np;
+	int line = 0;
+
+	for_each_matching_node(np, apbuart_match) {
+		const int *ampopts;
+		const u32 *freq_hz;
+		const struct amba_prom_registers *regs;
+		struct uart_port *port;
+		unsigned long addr;
+
+		ampopts = of_get_property(np, "ampopts", NULL);
+		if (ampopts && (*ampopts == 0))
+			continue; /* Ignore if used by another OS instance */
+		regs = of_get_property(np, "reg", NULL);
+		/* Frequency of APB Bus is frequency of UART */
+		freq_hz = of_get_property(np, "freq", NULL);
+
+		if (!regs || !freq_hz || (*freq_hz == 0))
+			continue;
+
+		grlib_apbuart_nodes[line] = np;
+
+		addr = regs->phys_addr;
+
+		port = &grlib_apbuart_ports[line];
+
+		port->mapbase = addr;
+		port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
+		port->irq = 0;
+		port->iotype = UPIO_MEM;
+		port->ops = &grlib_apbuart_ops;
+		port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE);
+		port->flags = UPF_BOOT_AUTOCONF;
+		port->line = line;
+		port->uartclk = *freq_hz;
+		port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
+		line++;
+
+		/* We support maximum UART_NR uarts ... */
+		if (line == UART_NR)
+			break;
+	}
+
+	grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
+	return line ? 0 : -ENODEV;
+}
+
+static int __init grlib_apbuart_init(void)
+{
+	int ret;
+
+	/* Find all APBUARTS in device the tree and initialize their ports */
+	ret = grlib_apbuart_configure();
+	if (ret)
+		return ret;
+
+	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 = platform_driver_register(&grlib_apbuart_of_driver);
+	if (ret) {
+		printk(KERN_ERR
+		       "%s: platform_driver_register 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);
+	platform_driver_unregister(&grlib_apbuart_of_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");