sparc64: vcc: Add RX & TX timer for delayed LDC operation
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>hifive-unleashed-5.1
Jag Raman
David S. Miller
parent
8868e44a56
commit
f8c553354e
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@ -1480,6 +1480,7 @@ int ldc_rx_reset(struct ldc_channel *lp)
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{
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return __set_rx_head(lp, lp->rx_tail);
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}
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EXPORT_SYMBOL(ldc_rx_reset);
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void __ldc_print(struct ldc_channel *lp, const char *caller)
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{
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@ -9,6 +9,7 @@
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <asm/vio.h>
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#include <asm/ldc.h>
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@ -52,6 +53,7 @@ struct vcc_port {
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#define VCC_MAX_PORTS 1024
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#define VCC_MINOR_START 0 /* must be zero */
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#define VCC_BUFF_LEN VIO_VCC_MTU_SIZE
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#define VCC_CTL_BREAK -1
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#define VCC_CTL_HUP -2
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@ -256,6 +258,185 @@ static struct vcc_port *vcc_get_ne(unsigned long index)
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return port;
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}
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static void vcc_kick_rx(struct vcc_port *port)
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{
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struct vio_driver_state *vio = &port->vio;
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assert_spin_locked(&port->lock);
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if (!timer_pending(&port->rx_timer) && !port->removed) {
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disable_irq_nosync(vio->vdev->rx_irq);
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port->rx_timer.expires = (jiffies + 1);
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add_timer(&port->rx_timer);
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}
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}
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static void vcc_kick_tx(struct vcc_port *port)
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{
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assert_spin_locked(&port->lock);
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if (!timer_pending(&port->tx_timer) && !port->removed) {
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port->tx_timer.expires = (jiffies + 1);
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add_timer(&port->tx_timer);
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}
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}
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static int vcc_rx_check(struct tty_struct *tty, int size)
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{
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if (WARN_ON(!tty || !tty->port))
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return 1;
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/* tty_buffer_request_room won't sleep because it uses
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* GFP_ATOMIC flag to allocate buffer
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*/
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if (test_bit(TTY_THROTTLED, &tty->flags) ||
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(tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
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return 0;
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return 1;
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}
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static int vcc_rx(struct tty_struct *tty, char *buf, int size)
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{
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int len = 0;
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if (WARN_ON(!tty || !tty->port))
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return len;
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len = tty_insert_flip_string(tty->port, buf, size);
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if (len)
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tty_flip_buffer_push(tty->port);
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return len;
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}
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static int vcc_ldc_read(struct vcc_port *port)
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{
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struct vio_driver_state *vio = &port->vio;
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struct tty_struct *tty;
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struct vio_vcc pkt;
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int rv = 0;
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tty = port->tty;
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if (!tty) {
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rv = ldc_rx_reset(vio->lp);
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vccdbg("VCC: reset rx q: rv=%d\n", rv);
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goto done;
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}
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/* Read as long as LDC has incoming data. */
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while (1) {
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if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
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vcc_kick_rx(port);
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break;
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}
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vccdbgl(vio->lp);
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rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
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if (rv <= 0)
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break;
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vccdbg("VCC: ldc_read()=%d\n", rv);
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vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
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pkt.tag.type, pkt.tag.stype,
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pkt.tag.stype_env, pkt.tag.sid);
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if (pkt.tag.type == VIO_TYPE_DATA) {
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vccdbgp(pkt);
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/* vcc_rx_check ensures memory availability */
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vcc_rx(tty, pkt.data, pkt.tag.stype);
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} else {
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pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
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pkt.tag.type, pkt.tag.stype,
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pkt.tag.stype_env, pkt.tag.sid);
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rv = -ECONNRESET;
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break;
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}
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WARN_ON(rv != LDC_PACKET_SIZE);
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}
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done:
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return rv;
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}
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static void vcc_rx_timer(unsigned long index)
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{
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struct vio_driver_state *vio;
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struct vcc_port *port;
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unsigned long flags;
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int rv;
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port = vcc_get_ne(index);
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if (!port)
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return;
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spin_lock_irqsave(&port->lock, flags);
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port->rx_timer.expires = 0;
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vio = &port->vio;
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enable_irq(vio->vdev->rx_irq);
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if (!port->tty || port->removed)
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goto done;
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rv = vcc_ldc_read(port);
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if (rv == -ECONNRESET)
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vio_conn_reset(vio);
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done:
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spin_unlock_irqrestore(&port->lock, flags);
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vcc_put(port, false);
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}
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static void vcc_tx_timer(unsigned long index)
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{
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struct vcc_port *port;
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struct vio_vcc *pkt;
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unsigned long flags;
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int tosend = 0;
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int rv;
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port = vcc_get_ne(index);
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if (!port)
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return;
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spin_lock_irqsave(&port->lock, flags);
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port->tx_timer.expires = 0;
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if (!port->tty || port->removed)
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goto done;
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tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
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if (!tosend)
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goto done;
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pkt = &port->buffer;
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pkt->tag.type = VIO_TYPE_DATA;
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pkt->tag.stype = tosend;
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vccdbgl(port->vio.lp);
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rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
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WARN_ON(!rv);
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if (rv < 0) {
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vccdbg("VCC: ldc_write()=%d\n", rv);
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vcc_kick_tx(port);
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} else {
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struct tty_struct *tty = port->tty;
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port->chars_in_buffer = 0;
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if (tty)
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tty_wakeup(tty);
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}
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done:
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spin_unlock_irqrestore(&port->lock, flags);
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vcc_put(port, false);
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}
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static void vcc_event(void *arg, int event)
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{
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}
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@ -322,7 +503,7 @@ static ssize_t vcc_sysfs_break_store(struct device *dev,
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if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
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rv = -EINVAL;
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else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
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pr_err("VCC: unable to send CTL_BREAK\n");
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vcc_kick_tx(port);
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spin_unlock_irqrestore(&port->lock, flags);
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@ -428,6 +609,14 @@ static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
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if (rv)
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goto free_domain;
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init_timer(&port->rx_timer);
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port->rx_timer.function = vcc_rx_timer;
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port->rx_timer.data = port->index;
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init_timer(&port->tx_timer);
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port->tx_timer.function = vcc_tx_timer;
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port->tx_timer.data = port->index;
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dev_set_drvdata(&vdev->dev, port);
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/* It's possible to receive IRQs in the middle of vio_port_up. Disable
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@ -470,6 +659,9 @@ static int vcc_remove(struct vio_dev *vdev)
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if (!port)
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return -ENODEV;
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del_timer_sync(&port->rx_timer);
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del_timer_sync(&port->tx_timer);
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/* If there's a process with the device open, do a synchronous
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* hangup of the TTY. This *may* cause the process to call close
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* asynchronously, but it's not guaranteed.
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@ -491,7 +683,6 @@ static int vcc_remove(struct vio_dev *vdev)
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vio_ldc_free(&port->vio);
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sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
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dev_set_drvdata(&vdev->dev, NULL);
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if (port->tty) {
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port->removed = true;
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vcc_put(port, true);
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