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sparc64: vcc: Add RX & TX timer for delayed LDC operation

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Add RX & TX timers to perform delayed/asynchronous LDC
read and write operations.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jag Raman 2017-08-15 17:03:02 -04:00 committed by David S. Miller
parent 8868e44a56
commit f8c553354e
2 changed files with 194 additions and 2 deletions
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1
arch/sparc/kernel/ldc.c
View file

@ -1480,6 +1480,7 @@ int ldc_rx_reset(struct ldc_channel *lp)
{
return __set_rx_head(lp, lp->rx_tail);
}
EXPORT_SYMBOL(ldc_rx_reset);
void __ldc_print(struct ldc_channel *lp, const char *caller)
{

195
drivers/tty/vcc.c
View file

@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <asm/vio.h>
#include <asm/ldc.h>
@ -52,6 +53,7 @@ struct vcc_port {
#define VCC_MAX_PORTS 1024
#define VCC_MINOR_START 0 /* must be zero */
#define VCC_BUFF_LEN VIO_VCC_MTU_SIZE
#define VCC_CTL_BREAK -1
#define VCC_CTL_HUP -2
@ -256,6 +258,185 @@ static struct vcc_port *vcc_get_ne(unsigned long index)
return port;
}
static void vcc_kick_rx(struct vcc_port *port)
{
struct vio_driver_state *vio = &port->vio;
assert_spin_locked(&port->lock);
if (!timer_pending(&port->rx_timer) && !port->removed) {
disable_irq_nosync(vio->vdev->rx_irq);
port->rx_timer.expires = (jiffies + 1);
add_timer(&port->rx_timer);
}
}
static void vcc_kick_tx(struct vcc_port *port)
{
assert_spin_locked(&port->lock);
if (!timer_pending(&port->tx_timer) && !port->removed) {
port->tx_timer.expires = (jiffies + 1);
add_timer(&port->tx_timer);
}
}
static int vcc_rx_check(struct tty_struct *tty, int size)
{
if (WARN_ON(!tty || !tty->port))
return 1;
/* tty_buffer_request_room won't sleep because it uses
* GFP_ATOMIC flag to allocate buffer
*/
if (test_bit(TTY_THROTTLED, &tty->flags) ||
(tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
return 0;
return 1;
}
static int vcc_rx(struct tty_struct *tty, char *buf, int size)
{
int len = 0;
if (WARN_ON(!tty || !tty->port))
return len;
len = tty_insert_flip_string(tty->port, buf, size);
if (len)
tty_flip_buffer_push(tty->port);
return len;
}
static int vcc_ldc_read(struct vcc_port *port)
{
struct vio_driver_state *vio = &port->vio;
struct tty_struct *tty;
struct vio_vcc pkt;
int rv = 0;
tty = port->tty;
if (!tty) {
rv = ldc_rx_reset(vio->lp);
vccdbg("VCC: reset rx q: rv=%d\n", rv);
goto done;
}
/* Read as long as LDC has incoming data. */
while (1) {
if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
vcc_kick_rx(port);
break;
}
vccdbgl(vio->lp);
rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
if (rv <= 0)
break;
vccdbg("VCC: ldc_read()=%d\n", rv);
vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
pkt.tag.type, pkt.tag.stype,
pkt.tag.stype_env, pkt.tag.sid);
if (pkt.tag.type == VIO_TYPE_DATA) {
vccdbgp(pkt);
/* vcc_rx_check ensures memory availability */
vcc_rx(tty, pkt.data, pkt.tag.stype);
} else {
pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
pkt.tag.type, pkt.tag.stype,
pkt.tag.stype_env, pkt.tag.sid);
rv = -ECONNRESET;
break;
}
WARN_ON(rv != LDC_PACKET_SIZE);
}
done:
return rv;
}
static void vcc_rx_timer(unsigned long index)
{
struct vio_driver_state *vio;
struct vcc_port *port;
unsigned long flags;
int rv;
port = vcc_get_ne(index);
if (!port)
return;
spin_lock_irqsave(&port->lock, flags);
port->rx_timer.expires = 0;
vio = &port->vio;
enable_irq(vio->vdev->rx_irq);
if (!port->tty || port->removed)
goto done;
rv = vcc_ldc_read(port);
if (rv == -ECONNRESET)
vio_conn_reset(vio);
done:
spin_unlock_irqrestore(&port->lock, flags);
vcc_put(port, false);
}
static void vcc_tx_timer(unsigned long index)
{
struct vcc_port *port;
struct vio_vcc *pkt;
unsigned long flags;
int tosend = 0;
int rv;
port = vcc_get_ne(index);
if (!port)
return;
spin_lock_irqsave(&port->lock, flags);
port->tx_timer.expires = 0;
if (!port->tty || port->removed)
goto done;
tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
if (!tosend)
goto done;
pkt = &port->buffer;
pkt->tag.type = VIO_TYPE_DATA;
pkt->tag.stype = tosend;
vccdbgl(port->vio.lp);
rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
WARN_ON(!rv);
if (rv < 0) {
vccdbg("VCC: ldc_write()=%d\n", rv);
vcc_kick_tx(port);
} else {
struct tty_struct *tty = port->tty;
port->chars_in_buffer = 0;
if (tty)
tty_wakeup(tty);
}
done:
spin_unlock_irqrestore(&port->lock, flags);
vcc_put(port, false);
}
static void vcc_event(void *arg, int event)
{
}
@ -322,7 +503,7 @@ static ssize_t vcc_sysfs_break_store(struct device *dev,
if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
rv = -EINVAL;
else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
pr_err("VCC: unable to send CTL_BREAK\n");
vcc_kick_tx(port);
spin_unlock_irqrestore(&port->lock, flags);
@ -428,6 +609,14 @@ static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
if (rv)
goto free_domain;
init_timer(&port->rx_timer);
port->rx_timer.function = vcc_rx_timer;
port->rx_timer.data = port->index;
init_timer(&port->tx_timer);
port->tx_timer.function = vcc_tx_timer;
port->tx_timer.data = port->index;
dev_set_drvdata(&vdev->dev, port);
/* It's possible to receive IRQs in the middle of vio_port_up. Disable
@ -470,6 +659,9 @@ static int vcc_remove(struct vio_dev *vdev)
if (!port)
return -ENODEV;
del_timer_sync(&port->rx_timer);
del_timer_sync(&port->tx_timer);
/* If there's a process with the device open, do a synchronous
* hangup of the TTY. This *may* cause the process to call close
* asynchronously, but it's not guaranteed.
@ -491,7 +683,6 @@ static int vcc_remove(struct vio_dev *vdev)
vio_ldc_free(&port->vio);
sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
dev_set_drvdata(&vdev->dev, NULL);
if (port->tty) {
port->removed = true;
vcc_put(port, true);