1 files changed, 655 insertions, 0 deletions

diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c
new file mode 100644
index 000000000..f8503f8fc
--- /dev/null
+++ b/drivers/tty/serial/sunhv.c
@@ -0,0 +1,655 @@
+// SPDX-License-Identifier: GPL-2.0
+/* sunhv.c: Serial driver for SUN4V hypervisor console.
+ *
+ * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/major.h>
+#include <linux/circ_buf.h>
+#include <linux/serial.h>
+#include <linux/sysrq.h>
+#include <linux/console.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/of_device.h>
+
+#include <asm/hypervisor.h>
+#include <asm/spitfire.h>
+#include <asm/prom.h>
+#include <asm/irq.h>
+#include <asm/setup.h>
+
+#if defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial_core.h>
+#include <linux/sunserialcore.h>
+
+#define CON_BREAK	((long)-1)
+#define CON_HUP		((long)-2)
+
+#define IGNORE_BREAK	0x1
+#define IGNORE_ALL	0x2
+
+static char *con_write_page;
+static char *con_read_page;
+
+static int hung_up = 0;
+
+static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
+{
+	while (!uart_circ_empty(xmit)) {
+		long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
+
+		if (status != HV_EOK)
+			break;
+
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+	}
+}
+
+static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
+{
+	while (!uart_circ_empty(xmit)) {
+		unsigned long ra = __pa(xmit->buf + xmit->tail);
+		unsigned long len, status, sent;
+
+		len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
+				      UART_XMIT_SIZE);
+		status = sun4v_con_write(ra, len, &sent);
+		if (status != HV_EOK)
+			break;
+		xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
+		port->icount.tx += sent;
+	}
+}
+
+static int receive_chars_getchar(struct uart_port *port)
+{
+	int saw_console_brk = 0;
+	int limit = 10000;
+
+	while (limit-- > 0) {
+		long status;
+		long c = sun4v_con_getchar(&status);
+
+		if (status == HV_EWOULDBLOCK)
+			break;
+
+		if (c == CON_BREAK) {
+			if (uart_handle_break(port))
+				continue;
+			saw_console_brk = 1;
+			c = 0;
+		}
+
+		if (c == CON_HUP) {
+			hung_up = 1;
+			uart_handle_dcd_change(port, 0);
+		} else if (hung_up) {
+			hung_up = 0;
+			uart_handle_dcd_change(port, 1);
+		}
+
+		if (port->state == NULL) {
+			uart_handle_sysrq_char(port, c);
+			continue;
+		}
+
+		port->icount.rx++;
+
+		if (uart_handle_sysrq_char(port, c))
+			continue;
+
+		tty_insert_flip_char(&port->state->port, c, TTY_NORMAL);
+	}
+
+	return saw_console_brk;
+}
+
+static int receive_chars_read(struct uart_port *port)
+{
+	static int saw_console_brk;
+	int limit = 10000;
+
+	while (limit-- > 0) {
+		unsigned long ra = __pa(con_read_page);
+		unsigned long bytes_read, i;
+		long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
+
+		if (stat != HV_EOK) {
+			bytes_read = 0;
+
+			if (stat == CON_BREAK) {
+				if (saw_console_brk)
+					sun_do_break();
+
+				if (uart_handle_break(port))
+					continue;
+				saw_console_brk = 1;
+				*con_read_page = 0;
+				bytes_read = 1;
+			} else if (stat == CON_HUP) {
+				hung_up = 1;
+				uart_handle_dcd_change(port, 0);
+				continue;
+			} else {
+				/* HV_EWOULDBLOCK, etc.  */
+				break;
+			}
+		}
+
+		if (hung_up) {
+			hung_up = 0;
+			uart_handle_dcd_change(port, 1);
+		}
+
+		if (port->sysrq != 0 &&  *con_read_page) {
+			for (i = 0; i < bytes_read; i++)
+				uart_handle_sysrq_char(port, con_read_page[i]);
+			saw_console_brk = 0;
+		}
+
+		if (port->state == NULL)
+			continue;
+
+		port->icount.rx += bytes_read;
+
+		tty_insert_flip_string(&port->state->port, con_read_page,
+				bytes_read);
+	}
+
+	return saw_console_brk;
+}
+
+struct sunhv_ops {
+	void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
+	int (*receive_chars)(struct uart_port *port);
+};
+
+static const struct sunhv_ops bychar_ops = {
+	.transmit_chars = transmit_chars_putchar,
+	.receive_chars = receive_chars_getchar,
+};
+
+static const struct sunhv_ops bywrite_ops = {
+	.transmit_chars = transmit_chars_write,
+	.receive_chars = receive_chars_read,
+};
+
+static const struct sunhv_ops *sunhv_ops = &bychar_ops;
+
+static struct tty_port *receive_chars(struct uart_port *port)
+{
+	struct tty_port *tport = NULL;
+
+	if (port->state != NULL)		/* Unopened serial console */
+		tport = &port->state->port;
+
+	if (sunhv_ops->receive_chars(port))
+		sun_do_break();
+
+	return tport;
+}
+
+static void transmit_chars(struct uart_port *port)
+{
+	struct circ_buf *xmit;
+
+	if (!port->state)
+		return;
+
+	xmit = &port->state->xmit;
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+		return;
+
+	sunhv_ops->transmit_chars(port, xmit);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+}
+
+static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct tty_port *tport;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	tport = receive_chars(port);
+	transmit_chars(port);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	if (tport)
+		tty_flip_buffer_push(tport);
+
+	return IRQ_HANDLED;
+}
+
+/* port->lock is not held.  */
+static unsigned int sunhv_tx_empty(struct uart_port *port)
+{
+	/* Transmitter is always empty for us.  If the circ buffer
+	 * is non-empty or there is an x_char pending, our caller
+	 * will do the right thing and ignore what we return here.
+	 */
+	return TIOCSER_TEMT;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	return;
+}
+
+/* port->lock is held by caller and interrupts are disabled.  */
+static unsigned int sunhv_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_stop_tx(struct uart_port *port)
+{
+	return;
+}
+
+/* port->lock held by caller.  */
+static void sunhv_start_tx(struct uart_port *port)
+{
+	transmit_chars(port);
+}
+
+/* port->lock is not held.  */
+static void sunhv_send_xchar(struct uart_port *port, char ch)
+{
+	unsigned long flags;
+	int limit = 10000;
+
+	if (ch == __DISABLED_CHAR)
+		return;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	while (limit-- > 0) {
+		long status = sun4v_con_putchar(ch);
+		if (status == HV_EOK)
+			break;
+		udelay(1);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* port->lock held by caller.  */
+static void sunhv_stop_rx(struct uart_port *port)
+{
+}
+
+/* port->lock is not held.  */
+static void sunhv_break_ctl(struct uart_port *port, int break_state)
+{
+	if (break_state) {
+		unsigned long flags;
+		int limit = 10000;
+
+		spin_lock_irqsave(&port->lock, flags);
+
+		while (limit-- > 0) {
+			long status = sun4v_con_putchar(CON_BREAK);
+			if (status == HV_EOK)
+				break;
+			udelay(1);
+		}
+
+		spin_unlock_irqrestore(&port->lock, flags);
+	}
+}
+
+/* port->lock is not held.  */
+static int sunhv_startup(struct uart_port *port)
+{
+	return 0;
+}
+
+/* port->lock is not held.  */
+static void sunhv_shutdown(struct uart_port *port)
+{
+}
+
+/* port->lock is not held.  */
+static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
+			      struct ktermios *old)
+{
+	unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
+	unsigned int quot = uart_get_divisor(port, baud);
+	unsigned int iflag, cflag;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	iflag = termios->c_iflag;
+	cflag = termios->c_cflag;
+
+	port->ignore_status_mask = 0;
+	if (iflag & IGNBRK)
+		port->ignore_status_mask |= IGNORE_BREAK;
+	if ((cflag & CREAD) == 0)
+		port->ignore_status_mask |= IGNORE_ALL;
+
+	/* XXX */
+	uart_update_timeout(port, cflag,
+			    (port->uartclk / (16 * quot)));
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *sunhv_type(struct uart_port *port)
+{
+	return "SUN4V HCONS";
+}
+
+static void sunhv_release_port(struct uart_port *port)
+{
+}
+
+static int sunhv_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+static void sunhv_config_port(struct uart_port *port, int flags)
+{
+}
+
+static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	return -EINVAL;
+}
+
+static const struct uart_ops sunhv_pops = {
+	.tx_empty	= sunhv_tx_empty,
+	.set_mctrl	= sunhv_set_mctrl,
+	.get_mctrl	= sunhv_get_mctrl,
+	.stop_tx	= sunhv_stop_tx,
+	.start_tx	= sunhv_start_tx,
+	.send_xchar	= sunhv_send_xchar,
+	.stop_rx	= sunhv_stop_rx,
+	.break_ctl	= sunhv_break_ctl,
+	.startup	= sunhv_startup,
+	.shutdown	= sunhv_shutdown,
+	.set_termios	= sunhv_set_termios,
+	.type		= sunhv_type,
+	.release_port	= sunhv_release_port,
+	.request_port	= sunhv_request_port,
+	.config_port	= sunhv_config_port,
+	.verify_port	= sunhv_verify_port,
+};
+
+static struct uart_driver sunhv_reg = {
+	.owner			= THIS_MODULE,
+	.driver_name		= "sunhv",
+	.dev_name		= "ttyHV",
+	.major			= TTY_MAJOR,
+};
+
+static struct uart_port *sunhv_port;
+
+void sunhv_migrate_hvcons_irq(int cpu)
+{
+	/* Migrate hvcons irq to param cpu */
+	irq_force_affinity(sunhv_port->irq, cpumask_of(cpu));
+}
+
+/* Copy 's' into the con_write_page, decoding "\n" into
+ * "\r\n" along the way.  We have to return two lengths
+ * because the caller needs to know how much to advance
+ * 's' and also how many bytes to output via con_write_page.
+ */
+static int fill_con_write_page(const char *s, unsigned int n,
+			       unsigned long *page_bytes)
+{
+	const char *orig_s = s;
+	char *p = con_write_page;
+	int left = PAGE_SIZE;
+
+	while (n--) {
+		if (*s == '\n') {
+			if (left < 2)
+				break;
+			*p++ = '\r';
+			left--;
+		} else if (left < 1)
+			break;
+		*p++ = *s++;
+		left--;
+	}
+	*page_bytes = p - con_write_page;
+	return s - orig_s;
+}
+
+static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
+{
+	struct uart_port *port = sunhv_port;
+	unsigned long flags;
+	int locked = 1;
+
+	if (port->sysrq || oops_in_progress)
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	else
+		spin_lock_irqsave(&port->lock, flags);
+
+	while (n > 0) {
+		unsigned long ra = __pa(con_write_page);
+		unsigned long page_bytes;
+		unsigned int cpy = fill_con_write_page(s, n,
+						       &page_bytes);
+
+		n -= cpy;
+		s += cpy;
+		while (page_bytes > 0) {
+			unsigned long written;
+			int limit = 1000000;
+
+			while (limit--) {
+				unsigned long stat;
+
+				stat = sun4v_con_write(ra, page_bytes,
+						       &written);
+				if (stat == HV_EOK)
+					break;
+				udelay(1);
+			}
+			if (limit < 0)
+				break;
+			page_bytes -= written;
+			ra += written;
+		}
+	}
+
+	if (locked)
+		spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static inline void sunhv_console_putchar(struct uart_port *port, char c)
+{
+	int limit = 1000000;
+
+	while (limit-- > 0) {
+		long status = sun4v_con_putchar(c);
+		if (status == HV_EOK)
+			break;
+		udelay(1);
+	}
+}
+
+static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
+{
+	struct uart_port *port = sunhv_port;
+	unsigned long flags;
+	int i, locked = 1;
+
+	if (port->sysrq || oops_in_progress)
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	else
+		spin_lock_irqsave(&port->lock, flags);
+
+	for (i = 0; i < n; i++) {
+		if (*s == '\n')
+			sunhv_console_putchar(port, '\r');
+		sunhv_console_putchar(port, *s++);
+	}
+
+	if (locked)
+		spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static struct console sunhv_console = {
+	.name	=	"ttyHV",
+	.write	=	sunhv_console_write_bychar,
+	.device	=	uart_console_device,
+	.flags	=	CON_PRINTBUFFER,
+	.index	=	-1,
+	.data	=	&sunhv_reg,
+};
+
+static int hv_probe(struct platform_device *op)
+{
+	struct uart_port *port;
+	unsigned long minor;
+	int err;
+
+	if (op->archdata.irqs[0] == 0xffffffff)
+		return -ENODEV;
+
+	port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
+	if (unlikely(!port))
+		return -ENOMEM;
+
+	minor = 1;
+	if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
+	    minor >= 1) {
+		err = -ENOMEM;
+		con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+		if (!con_write_page)
+			goto out_free_port;
+
+		con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+		if (!con_read_page)
+			goto out_free_con_write_page;
+
+		sunhv_console.write = sunhv_console_write_paged;
+		sunhv_ops = &bywrite_ops;
+	}
+
+	sunhv_port = port;
+
+	port->line = 0;
+	port->ops = &sunhv_pops;
+	port->type = PORT_SUNHV;
+	port->uartclk = ( 29491200 / 16 ); /* arbitrary */
+
+	port->membase = (unsigned char __iomem *) __pa(port);
+
+	port->irq = op->archdata.irqs[0];
+
+	port->dev = &op->dev;
+
+	err = sunserial_register_minors(&sunhv_reg, 1);
+	if (err)
+		goto out_free_con_read_page;
+
+	sunserial_console_match(&sunhv_console, op->dev.of_node,
+				&sunhv_reg, port->line, false);
+
+	err = uart_add_one_port(&sunhv_reg, port);
+	if (err)
+		goto out_unregister_driver;
+
+	err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
+	if (err)
+		goto out_remove_port;
+
+	platform_set_drvdata(op, port);
+
+	return 0;
+
+out_remove_port:
+	uart_remove_one_port(&sunhv_reg, port);
+
+out_unregister_driver:
+	sunserial_unregister_minors(&sunhv_reg, 1);
+
+out_free_con_read_page:
+	kfree(con_read_page);
+
+out_free_con_write_page:
+	kfree(con_write_page);
+
+out_free_port:
+	kfree(port);
+	sunhv_port = NULL;
+	return err;
+}
+
+static int hv_remove(struct platform_device *dev)
+{
+	struct uart_port *port = platform_get_drvdata(dev);
+
+	free_irq(port->irq, port);
+
+	uart_remove_one_port(&sunhv_reg, port);
+
+	sunserial_unregister_minors(&sunhv_reg, 1);
+	kfree(con_read_page);
+	kfree(con_write_page);
+	kfree(port);
+	sunhv_port = NULL;
+
+	return 0;
+}
+
+static const struct of_device_id hv_match[] = {
+	{
+		.name = "console",
+		.compatible = "qcn",
+	},
+	{
+		.name = "console",
+		.compatible = "SUNW,sun4v-console",
+	},
+	{},
+};
+
+static struct platform_driver hv_driver = {
+	.driver = {
+		.name = "hv",
+		.of_match_table = hv_match,
+	},
+	.probe		= hv_probe,
+	.remove		= hv_remove,
+};
+
+static int __init sunhv_init(void)
+{
+	if (tlb_type != hypervisor)
+		return -ENODEV;
+
+	return platform_driver_register(&hv_driver);
+}
+device_initcall(sunhv_init);
+
+#if 0 /* ...def MODULE ; never supported as such */
+MODULE_AUTHOR("David S. Miller");
+MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
+MODULE_VERSION("2.0");
+MODULE_LICENSE("GPL");
+#endif