linux/drivers/tty/serial/sunhv.c
Andy Shevchenko 30336ef6f1 Revert "serial: sunhv: Initialize lock for non-registered console"
This reverts commit 0f87aa66e8.

There has been a quick fix against uninitialised lock revealed by
the commit f743061a85 ("serial: core: Initialise spin lock before use
in uart_configure_port()"). Since we have now better fix in serial core,
this may be safely reverted.

Fixes: 0f87aa66e8 ("serial: sunhv: Initialize lock for non-registered console")
Depends-on: f743061a85 ("serial: core: Initialise spin lock before use in uart_configure_port()")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200711135346.71171-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 18:21:49 +02:00

653 lines
13 KiB
C

// 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>
#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->has_sysrq = 1;
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