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/* sunhv.c: Serial driver for SUN4V hypervisor console.
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* Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/tty_flip.h>
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#include <linux/major.h>
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#include <linux/circ_buf.h>
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#include <linux/serial.h>
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#include <linux/sysrq.h>
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#include <linux/console.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/of_device.h>
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#include <asm/hypervisor.h>
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#include <asm/spitfire.h>
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#if defined(CONFIG_MAGIC_SYSRQ)
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#include <linux/serial_core.h>
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#define CON_BREAK ((long)-1)
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#define CON_HUP ((long)-2)
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#define IGNORE_BREAK 0x1
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#define IGNORE_ALL 0x2
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static char *con_write_page;
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static char *con_read_page;
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static int hung_up = 0;
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static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
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while (!uart_circ_empty(xmit)) {
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long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
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while (!uart_circ_empty(xmit)) {
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unsigned long ra = __pa(xmit->buf + xmit->tail);
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unsigned long len, status, sent;
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len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
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status = sun4v_con_write(ra, len, &sent);
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xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
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port->icount.tx += sent;
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static int receive_chars_getchar(struct uart_port *port, struct tty_struct *tty)
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int saw_console_brk = 0;
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long c = sun4v_con_getchar(&status);
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if (status == HV_EWOULDBLOCK)
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if (uart_handle_break(port))
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uart_handle_dcd_change(port, 0);
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uart_handle_dcd_change(port, 1);
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uart_handle_sysrq_char(port, c);
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if (uart_handle_sysrq_char(port, c))
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tty_insert_flip_char(tty, c, TTY_NORMAL);
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return saw_console_brk;
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static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
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int saw_console_brk = 0;
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while (limit-- > 0) {
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unsigned long ra = __pa(con_read_page);
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unsigned long bytes_read, i;
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long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
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if (stat != HV_EOK) {
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if (stat == CON_BREAK) {
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if (uart_handle_break(port))
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} else if (stat == CON_HUP) {
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uart_handle_dcd_change(port, 0);
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/* HV_EWOULDBLOCK, etc. */
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uart_handle_dcd_change(port, 1);
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for (i = 0; i < bytes_read; i++)
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uart_handle_sysrq_char(port, con_read_page[i]);
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port->icount.rx += bytes_read;
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tty_insert_flip_string(tty, con_read_page, bytes_read);
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return saw_console_brk;
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void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
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int (*receive_chars)(struct uart_port *port, struct tty_struct *tty);
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static struct sunhv_ops bychar_ops = {
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.transmit_chars = transmit_chars_putchar,
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.receive_chars = receive_chars_getchar,
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static struct sunhv_ops bywrite_ops = {
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.transmit_chars = transmit_chars_write,
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.receive_chars = receive_chars_read,
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static struct sunhv_ops *sunhv_ops = &bychar_ops;
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static struct tty_struct *receive_chars(struct uart_port *port)
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struct tty_struct *tty = NULL;
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if (port->state != NULL) /* Unopened serial console */
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tty = port->state->port.tty;
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if (sunhv_ops->receive_chars(port, tty))
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static void transmit_chars(struct uart_port *port)
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struct circ_buf *xmit;
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xmit = &port->state->xmit;
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if (uart_circ_empty(xmit) || uart_tx_stopped(port))
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sunhv_ops->transmit_chars(port, xmit);
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if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
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uart_write_wakeup(port);
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static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
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struct uart_port *port = dev_id;
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struct tty_struct *tty;
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spin_lock_irqsave(&port->lock, flags);
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tty = receive_chars(port);
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transmit_chars(port);
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spin_unlock_irqrestore(&port->lock, flags);
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tty_flip_buffer_push(tty);
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/* port->lock is not held. */
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static unsigned int sunhv_tx_empty(struct uart_port *port)
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/* Transmitter is always empty for us. If the circ buffer
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* is non-empty or there is an x_char pending, our caller
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* will do the right thing and ignore what we return here.
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/* port->lock held by caller. */
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static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
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/* port->lock is held by caller and interrupts are disabled. */
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static unsigned int sunhv_get_mctrl(struct uart_port *port)
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return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
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/* port->lock held by caller. */
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static void sunhv_stop_tx(struct uart_port *port)
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/* port->lock held by caller. */
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static void sunhv_start_tx(struct uart_port *port)
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transmit_chars(port);
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/* port->lock is not held. */
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static void sunhv_send_xchar(struct uart_port *port, char ch)
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spin_lock_irqsave(&port->lock, flags);
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while (limit-- > 0) {
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long status = sun4v_con_putchar(ch);
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if (status == HV_EOK)
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spin_unlock_irqrestore(&port->lock, flags);
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/* port->lock held by caller. */
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static void sunhv_stop_rx(struct uart_port *port)
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/* port->lock held by caller. */
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static void sunhv_enable_ms(struct uart_port *port)
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/* port->lock is not held. */
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static void sunhv_break_ctl(struct uart_port *port, int break_state)
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spin_lock_irqsave(&port->lock, flags);
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while (limit-- > 0) {
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long status = sun4v_con_putchar(CON_BREAK);
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if (status == HV_EOK)
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spin_unlock_irqrestore(&port->lock, flags);
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/* port->lock is not held. */
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static int sunhv_startup(struct uart_port *port)
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/* port->lock is not held. */
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static void sunhv_shutdown(struct uart_port *port)
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/* port->lock is not held. */
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static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
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struct ktermios *old)
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unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
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unsigned int quot = uart_get_divisor(port, baud);
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unsigned int iflag, cflag;
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spin_lock_irqsave(&port->lock, flags);
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iflag = termios->c_iflag;
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cflag = termios->c_cflag;
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port->ignore_status_mask = 0;
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port->ignore_status_mask |= IGNORE_BREAK;
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if ((cflag & CREAD) == 0)
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port->ignore_status_mask |= IGNORE_ALL;
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uart_update_timeout(port, cflag,
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(port->uartclk / (16 * quot)));
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spin_unlock_irqrestore(&port->lock, flags);
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static const char *sunhv_type(struct uart_port *port)
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return "SUN4V HCONS";
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static void sunhv_release_port(struct uart_port *port)
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static int sunhv_request_port(struct uart_port *port)
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static void sunhv_config_port(struct uart_port *port, int flags)
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static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
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static struct uart_ops sunhv_pops = {
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.tx_empty = sunhv_tx_empty,
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.set_mctrl = sunhv_set_mctrl,
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.get_mctrl = sunhv_get_mctrl,
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.stop_tx = sunhv_stop_tx,
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.start_tx = sunhv_start_tx,
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.send_xchar = sunhv_send_xchar,
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.stop_rx = sunhv_stop_rx,
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.enable_ms = sunhv_enable_ms,
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.break_ctl = sunhv_break_ctl,
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.startup = sunhv_startup,
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.shutdown = sunhv_shutdown,
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.set_termios = sunhv_set_termios,
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.release_port = sunhv_release_port,
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.request_port = sunhv_request_port,
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.config_port = sunhv_config_port,
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.verify_port = sunhv_verify_port,
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static struct uart_driver sunhv_reg = {
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.owner = THIS_MODULE,
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.driver_name = "sunhv",
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static struct uart_port *sunhv_port;
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/* Copy 's' into the con_write_page, decoding "\n" into
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* "\r\n" along the way. We have to return two lengths
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* because the caller needs to know how much to advance
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* 's' and also how many bytes to output via con_write_page.
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static int fill_con_write_page(const char *s, unsigned int n,
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unsigned long *page_bytes)
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const char *orig_s = s;
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char *p = con_write_page;
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int left = PAGE_SIZE;
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*page_bytes = p - con_write_page;
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static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
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struct uart_port *port = sunhv_port;
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local_irq_save(flags);
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} else if (oops_in_progress) {
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locked = spin_trylock(&port->lock);
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spin_lock(&port->lock);
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unsigned long ra = __pa(con_write_page);
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unsigned long page_bytes;
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unsigned int cpy = fill_con_write_page(s, n,
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while (page_bytes > 0) {
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unsigned long written;
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stat = sun4v_con_write(ra, page_bytes,
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page_bytes -= written;
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spin_unlock(&port->lock);
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local_irq_restore(flags);
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static inline void sunhv_console_putchar(struct uart_port *port, char c)
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while (limit-- > 0) {
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long status = sun4v_con_putchar(c);
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if (status == HV_EOK)
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static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
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struct uart_port *port = sunhv_port;
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local_irq_save(flags);
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} else if (oops_in_progress) {
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locked = spin_trylock(&port->lock);
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spin_lock(&port->lock);
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for (i = 0; i < n; i++) {
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sunhv_console_putchar(port, '\r');
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sunhv_console_putchar(port, *s++);
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spin_unlock(&port->lock);
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local_irq_restore(flags);
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static struct console sunhv_console = {
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.write = sunhv_console_write_bychar,
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.device = uart_console_device,
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.flags = CON_PRINTBUFFER,
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static int __devinit hv_probe(struct platform_device *op, const struct of_device_id *match)
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struct uart_port *port;
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if (op->archdata.irqs[0] == 0xffffffff)
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port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
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if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
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con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
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con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
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goto out_free_con_write_page;
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sunhv_console.write = sunhv_console_write_paged;
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sunhv_ops = &bywrite_ops;
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port->ops = &sunhv_pops;
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port->type = PORT_SUNHV;
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port->uartclk = ( 29491200 / 16 ); /* arbitrary */
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port->membase = (unsigned char __iomem *) __pa(port);
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port->irq = op->archdata.irqs[0];
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port->dev = &op->dev;
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err = sunserial_register_minors(&sunhv_reg, 1);
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goto out_free_con_read_page;
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sunserial_console_match(&sunhv_console, op->dev.of_node,
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&sunhv_reg, port->line, false);
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err = uart_add_one_port(&sunhv_reg, port);
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goto out_unregister_driver;
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err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
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goto out_remove_port;
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dev_set_drvdata(&op->dev, port);
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uart_remove_one_port(&sunhv_reg, port);
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out_unregister_driver:
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sunserial_unregister_minors(&sunhv_reg, 1);
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out_free_con_read_page:
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kfree(con_read_page);
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out_free_con_write_page:
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kfree(con_write_page);
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static int __devexit hv_remove(struct platform_device *dev)
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struct uart_port *port = dev_get_drvdata(&dev->dev);
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free_irq(port->irq, port);
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uart_remove_one_port(&sunhv_reg, port);
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sunserial_unregister_minors(&sunhv_reg, 1);
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dev_set_drvdata(&dev->dev, NULL);
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static const struct of_device_id hv_match[] = {
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.compatible = "SUNW,sun4v-console",
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MODULE_DEVICE_TABLE(of, hv_match);
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static struct of_platform_driver hv_driver = {
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.owner = THIS_MODULE,
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.of_match_table = hv_match,
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.remove = __devexit_p(hv_remove),
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static int __init sunhv_init(void)
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if (tlb_type != hypervisor)
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return of_register_platform_driver(&hv_driver);
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static void __exit sunhv_exit(void)
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of_unregister_platform_driver(&hv_driver);
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module_init(sunhv_init);
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module_exit(sunhv_exit);
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MODULE_AUTHOR("David S. Miller");
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MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
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MODULE_VERSION("2.0");
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MODULE_LICENSE("GPL");