c7754d465b
Hypervisor interfaces need to be negotiated in order to use some API calls reliably. So add a small set of interfaces to request API versions and query current settings. This allows us to fix some bugs in the hypervisor console: 1) If we can negotiate API group CORE of at least major 1 minor 1 we can use con_read and con_write which can improve console performance quite a bit. 2) When we do a console write request, we should hold the spinlock around the whole request, not a byte at a time. What would happen is that it's easy for output from different cpus to get mixed with each other. 3) Use consistent udelay() based polling, udelay(1) each loop with a limit of 1000 polls to handle stuck hypervisor console. Signed-off-by: David S. Miller <davem@davemloft.net>
665 lines
14 KiB
C
665 lines
14 KiB
C
/* sunhv.c: Serial driver for SUN4V hypervisor console.
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*
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* Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
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*/
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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.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 <asm/hypervisor.h>
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#include <asm/spitfire.h>
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#include <asm/prom.h>
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#include <asm/of_device.h>
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#include <asm/irq.h>
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#if defined(CONFIG_MAGIC_SYSRQ)
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#define SUPPORT_SYSRQ
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#endif
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#include <linux/serial_core.h>
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#include "suncore.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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{
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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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if (status != HV_EOK)
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break;
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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port->icount.tx++;
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}
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}
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static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
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{
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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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UART_XMIT_SIZE);
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status = sun4v_con_write(ra, len, &sent);
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if (status != HV_EOK)
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break;
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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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}
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}
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static int receive_chars_getchar(struct uart_port *port, struct tty_struct *tty)
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{
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int saw_console_brk = 0;
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int limit = 10000;
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while (limit-- > 0) {
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long status;
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long c = sun4v_con_getchar(&status);
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if (status == HV_EWOULDBLOCK)
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break;
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if (c == CON_BREAK) {
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if (uart_handle_break(port))
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continue;
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saw_console_brk = 1;
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c = 0;
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}
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if (c == CON_HUP) {
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hung_up = 1;
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uart_handle_dcd_change(port, 0);
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} else if (hung_up) {
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hung_up = 0;
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uart_handle_dcd_change(port, 1);
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}
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if (tty == NULL) {
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uart_handle_sysrq_char(port, c);
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continue;
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}
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port->icount.rx++;
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if (uart_handle_sysrq_char(port, c))
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continue;
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tty_insert_flip_char(tty, c, TTY_NORMAL);
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}
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return saw_console_brk;
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}
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static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
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{
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int saw_console_brk = 0;
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int limit = 10000;
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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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bytes_read = 0;
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if (stat == CON_BREAK) {
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if (uart_handle_break(port))
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continue;
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saw_console_brk = 1;
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*con_read_page = 0;
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bytes_read = 1;
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} else if (stat == CON_HUP) {
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hung_up = 1;
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uart_handle_dcd_change(port, 0);
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continue;
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} else {
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/* HV_EWOULDBLOCK, etc. */
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break;
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}
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}
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if (hung_up) {
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hung_up = 0;
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uart_handle_dcd_change(port, 1);
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}
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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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if (tty == NULL)
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continue;
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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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}
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return saw_console_brk;
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}
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struct sunhv_ops {
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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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};
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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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};
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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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};
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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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{
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struct tty_struct *tty = NULL;
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if (port->info != NULL) /* Unopened serial console */
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tty = port->info->tty;
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if (sunhv_ops->receive_chars(port, tty))
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sun_do_break();
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return tty;
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}
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static void transmit_chars(struct uart_port *port)
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{
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struct circ_buf *xmit;
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if (!port->info)
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return;
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xmit = &port->info->xmit;
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if (uart_circ_empty(xmit) || uart_tx_stopped(port))
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return;
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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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}
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static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
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{
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struct uart_port *port = dev_id;
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struct tty_struct *tty;
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unsigned long flags;
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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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if (tty)
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tty_flip_buffer_push(tty);
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return IRQ_HANDLED;
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}
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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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{
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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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*/
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return TIOCSER_TEMT;
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}
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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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{
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return;
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}
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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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{
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return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
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}
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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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{
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return;
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}
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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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{
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struct circ_buf *xmit = &port->info->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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if (status != HV_EOK)
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break;
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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port->icount.tx++;
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}
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}
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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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{
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unsigned long flags;
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int limit = 10000;
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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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break;
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udelay(1);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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}
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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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{
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}
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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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{
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}
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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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{
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if (break_state) {
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unsigned long flags;
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int limit = 10000;
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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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break;
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udelay(1);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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}
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}
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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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{
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return 0;
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}
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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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{
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}
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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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{
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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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unsigned long flags;
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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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if (iflag & IGNBRK)
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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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/* XXX */
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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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}
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static const char *sunhv_type(struct uart_port *port)
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{
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return "SUN4V HCONS";
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}
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static void sunhv_release_port(struct uart_port *port)
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{
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}
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static int sunhv_request_port(struct uart_port *port)
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{
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return 0;
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}
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static void sunhv_config_port(struct uart_port *port, int flags)
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{
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}
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static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
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{
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return -EINVAL;
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}
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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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.type = sunhv_type,
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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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};
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static struct uart_driver sunhv_reg = {
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.owner = THIS_MODULE,
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.driver_name = "serial",
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.dev_name = "ttyS",
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.major = TTY_MAJOR,
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};
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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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*/
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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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{
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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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while (n--) {
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if (*s == '\n') {
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if (left < 2)
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break;
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*p++ = '\r';
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left--;
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} else if (left < 1)
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break;
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*p++ = *s++;
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left--;
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}
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*page_bytes = p - con_write_page;
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return s - orig_s;
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}
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static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
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{
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struct uart_port *port = sunhv_port;
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unsigned long flags;
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spin_lock_irqsave(&port->lock, flags);
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while (n > 0) {
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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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&page_bytes);
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n -= cpy;
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s += cpy;
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while (page_bytes > 0) {
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unsigned long written;
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int limit = 1000000;
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while (limit--) {
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unsigned long stat;
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stat = sun4v_con_write(ra, page_bytes,
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&written);
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if (stat == HV_EOK)
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break;
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udelay(1);
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}
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if (limit <= 0)
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break;
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page_bytes -= written;
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ra += written;
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}
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}
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static inline void sunhv_console_putchar(struct uart_port *port, char c)
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{
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int limit = 1000000;
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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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break;
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udelay(1);
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}
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}
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static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
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{
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struct uart_port *port = sunhv_port;
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unsigned long flags;
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int i;
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spin_lock_irqsave(&port->lock, flags);
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for (i = 0; i < n; i++) {
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if (*s == '\n')
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sunhv_console_putchar(port, '\r');
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sunhv_console_putchar(port, *s++);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static struct console sunhv_console = {
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.name = "ttyHV",
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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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.index = -1,
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.data = &sunhv_reg,
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};
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static inline struct console *SUNHV_CONSOLE(void)
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{
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if (con_is_present())
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return NULL;
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sunhv_console.index = 0;
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return &sunhv_console;
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}
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static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
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{
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struct uart_port *port;
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unsigned long minor;
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int err;
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if (op->irqs[0] == 0xffffffff)
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return -ENODEV;
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port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
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if (unlikely(!port))
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return -ENOMEM;
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minor = 1;
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if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
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minor >= 1) {
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err = -ENOMEM;
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con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!con_write_page)
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goto out_free_port;
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con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!con_read_page)
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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->irqs[0];
|
|
|
|
port->dev = &op->dev;
|
|
|
|
sunhv_reg.minor = sunserial_current_minor;
|
|
sunhv_reg.nr = 1;
|
|
|
|
err = uart_register_driver(&sunhv_reg);
|
|
if (err)
|
|
goto out_free_con_read_page;
|
|
|
|
sunhv_reg.tty_driver->name_base = sunhv_reg.minor - 64;
|
|
sunserial_current_minor += 1;
|
|
|
|
sunhv_reg.cons = SUNHV_CONSOLE();
|
|
|
|
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;
|
|
|
|
dev_set_drvdata(&op->dev, port);
|
|
|
|
return 0;
|
|
|
|
out_remove_port:
|
|
uart_remove_one_port(&sunhv_reg, port);
|
|
|
|
out_unregister_driver:
|
|
sunserial_current_minor -= 1;
|
|
uart_unregister_driver(&sunhv_reg);
|
|
|
|
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 __devexit hv_remove(struct of_device *dev)
|
|
{
|
|
struct uart_port *port = dev_get_drvdata(&dev->dev);
|
|
|
|
free_irq(port->irq, port);
|
|
|
|
uart_remove_one_port(&sunhv_reg, port);
|
|
|
|
sunserial_current_minor -= 1;
|
|
uart_unregister_driver(&sunhv_reg);
|
|
|
|
kfree(port);
|
|
sunhv_port = NULL;
|
|
|
|
dev_set_drvdata(&dev->dev, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct of_device_id hv_match[] = {
|
|
{
|
|
.name = "console",
|
|
.compatible = "qcn",
|
|
},
|
|
{
|
|
.name = "console",
|
|
.compatible = "SUNW,sun4v-console",
|
|
},
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, hv_match);
|
|
|
|
static struct of_platform_driver hv_driver = {
|
|
.name = "hv",
|
|
.match_table = hv_match,
|
|
.probe = hv_probe,
|
|
.remove = __devexit_p(hv_remove),
|
|
};
|
|
|
|
static int __init sunhv_init(void)
|
|
{
|
|
if (tlb_type != hypervisor)
|
|
return -ENODEV;
|
|
|
|
return of_register_driver(&hv_driver, &of_bus_type);
|
|
}
|
|
|
|
static void __exit sunhv_exit(void)
|
|
{
|
|
of_unregister_driver(&hv_driver);
|
|
}
|
|
|
|
module_init(sunhv_init);
|
|
module_exit(sunhv_exit);
|
|
|
|
MODULE_AUTHOR("David S. Miller");
|
|
MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
|
|
MODULE_VERSION("2.0");
|
|
MODULE_LICENSE("GPL");
|