v4.19.13 snapshot.
diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c
new file mode 100644
index 0000000..63e34d8
--- /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 = "ttyS",
+ .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