[PATCH 1/4] Char: cyclades, remove bottom half processing

Jiri Slaby
2007-07-29T20:00:54Z

cyclades, remove bottom half processing

The work done in bottom half doesn't cost much cpu time (e.g. tty_hangup
itself schedules its own bottom half), it's possible to do the work in isr
directly and save hence some .text.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>

---
commit 3fc1c2f3f8414d72e12e8d6aed1c36ddb1f19567
tree 071c1c5998332b01ac34ad262b55c2334d6e2392
parent f0d76dfb19957f269687e89a62ba75ecd7339e03
author Jiri Slaby <jirislaby@gmail.com> Sat, 28 Jul 2007 10:32:14 +0200
committer Jiri Slaby <jirislaby@gmail.com> Sat, 28 Jul 2007 10:32:14 +0200

drivers/char/cyclades.c | 111 ++++++++--------------------------------------
include/linux/cyclades.h | 15 ------
2 files changed, 20 insertions(+), 106 deletions(-)

diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c
index d6d37c3..6aa91f2 100644
--- a/drivers/char/cyclades.c
+++ b/drivers/char/cyclades.c
@@ -897,71 +897,6 @@ static inline int serial_paranoia_check(struct cyclades_port *info,
return 0;
} /* serial_paranoia_check */

-/*
- * This routine is used by the interrupt handler to schedule
- * processing in the software interrupt portion of the driver
- * (also known as the "bottom half"). This can be called any
- * number of times for any channel without harm.
- */
-static inline void cy_sched_event(struct cyclades_port *info, int event)
-{
- info->event |= 1 << event; /* remember what kind of event and who */
- schedule_work(&info->tqueue);
-} /* cy_sched_event */
-
-/*
- * This routine is used to handle the "bottom half" processing for the
- * serial driver, known also the "software interrupt" processing.
- * This processing is done at the kernel interrupt level, after the
- * cy#/_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON. This
- * is where time-consuming activities which can not be done in the
- * interrupt driver proper are done; the interrupt driver schedules
- * them using cy_sched_event(), and they get done here.
- *
- * This is done through one level of indirection--the task queue.
- * When a hardware interrupt service routine wants service by the
- * driver's bottom half, it enqueues the appropriate tq_struct (one
- * per port) to the keventd work queue and sets a request flag
- * that the work queue be processed.
- *
- * Although this may seem unwieldy, it gives the system a way to
- * pass an argument (in this case the pointer to the cyclades_port
- * structure) to the bottom half of the driver. Previous kernels
- * had to poll every port to see if that port needed servicing.
- */
-static void
-do_softint(struct work_struct *work)
-{
- struct cyclades_port *info =
- container_of(work, struct cyclades_port, tqueue);
- struct tty_struct *tty;
-
- tty = info->tty;
- if (!tty)
- return;
-
- if (test_and_clear_bit(Cy_EVENT_HANGUP, &info->event)) {
- tty_hangup(info->tty);
- wake_up_interruptible(&info->open_wait);
- info->flags &= ~ASYNC_NORMAL_ACTIVE;
- }
- if (test_and_clear_bit(Cy_EVENT_OPEN_WAKEUP, &info->event))
- wake_up_interruptible(&info->open_wait);
-#ifdef CONFIG_CYZ_INTR
- if (test_and_clear_bit(Cy_EVENT_Z_RX_FULL, &info->event) &&
- !timer_pending(&cyz_rx_full_timer[info->line]))
- mod_timer(&cyz_rx_full_timer[info->line], jiffies + 1);
-#endif
- if (test_and_clear_bit(Cy_EVENT_DELTA_WAKEUP, &info->event))
- wake_up_interruptible(&info->delta_msr_wait);
- tty_wakeup(tty);
-#ifdef Z_WAKE
- if (test_and_clear_bit(Cy_EVENT_SHUTDOWN_WAKEUP, &info->event))
- complete(&info->shutdown_wait);
-#endif
-} /* do_softint */
-
-
/***********************************************************/
/********* Start of block of Cyclom-Y specific code ********/

@@ -1243,7 +1178,7 @@ static void cyy_intr_chip(struct cyclades_card *cinfo, int chip,
cy_writeb(base_addr + (CySRER << index),
readb(base_addr + (CySRER << index)) &
~CyTxRdy);
- goto txdone;
+ goto txend;
}

/* load the on-chip space for outbound data */
@@ -1334,9 +1269,7 @@ static void cyy_intr_chip(struct cyclades_card *cinfo, int chip,
}

txdone:
- if (info->xmit_cnt < WAKEUP_CHARS) {
- cy_sched_event(info, Cy_EVENT_WRITE_WAKEUP);
- }
+ tty_wakeup(info->tty);
txend:
/* end of service */
cy_writeb(base_addr + (CyTIR << index), (save_xir & 0x3f));
@@ -1369,17 +1302,16 @@ txend:
if (mdm_change & CyRI)
info->icount.rng++;

- cy_sched_event(info, Cy_EVENT_DELTA_WAKEUP);
+ wake_up_interruptible(&info->delta_msr_wait);
}

if ((mdm_change & CyDCD) &&
(info->flags & ASYNC_CHECK_CD)) {
- if (mdm_status & CyDCD) {
- cy_sched_event(info,
- Cy_EVENT_OPEN_WAKEUP);
- } else {
- cy_sched_event(info, Cy_EVENT_HANGUP);
+ if (!(mdm_status & CyDCD)) {
+ tty_hangup(info->tty);
+ info->flags &= ~ASYNC_NORMAL_ACTIVE;
}
+ wake_up_interruptible(&info->open_wait);
}
if ((mdm_change & CyCTS) &&
(info->flags & ASYNC_CTS_FLOW)) {
@@ -1394,8 +1326,7 @@ txend:
(CySRER <<
index))|
CyTxRdy);
- cy_sched_event(info,
- Cy_EVENT_WRITE_WAKEUP);
+ tty_wakeup(info->tty);
}
} else {
if (!(mdm_status & CyCTS)) {
@@ -1633,9 +1564,11 @@ cyz_handle_rx(struct cyclades_port *info, struct CH_CTRL __iomem *ch_ctrl,
char_count = rx_put - rx_get;
else
char_count = rx_put - rx_get + rx_bufsize;
- if (char_count >= (int)readl(&buf_ctrl->rx_threshold)) {
- cy_sched_event(info, Cy_EVENT_Z_RX_FULL);
- }
+ if (char_count >= (int)readl(&buf_ctrl->rx_threshold) &&
+ !timer_pending(&cyz_rx_full_timer[
+ info->line]))
+ mod_timer(&cyz_rx_full_timer[info->line],
+ jiffies + 1);
#endif
info->idle_stats.recv_idle = jiffies;
tty_schedule_flip(tty);
@@ -1717,9 +1650,7 @@ cyz_handle_tx(struct cyclades_port *info, struct CH_CTRL __iomem *ch_ctrl,
}
#endif
ztxdone:
- if (info->xmit_cnt < WAKEUP_CHARS) {
- cy_sched_event(info, Cy_EVENT_WRITE_WAKEUP);
- }
+ tty_wakeup(tty);
/* Update tx_put */
cy_writel(&buf_ctrl->tx_put, tx_put);
}
@@ -1781,10 +1712,11 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
if ((fw_ver > 241 ? ((u_long) param) :
readl(&ch_ctrl->rs_status)) &
C_RS_DCD) {
- cy_sched_event(info,
- Cy_EVENT_OPEN_WAKEUP);
+ wake_up_interruptible(&info->open_wait);
} else {
- cy_sched_event(info, Cy_EVENT_HANGUP);
+ tty_hangup(info->tty);
+ wake_up_interruptible(&info->open_wait);
+ info->flags &= ~ASYNC_NORMAL_ACTIVE;
}
}
break;
@@ -1802,7 +1734,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
break;
#ifdef Z_WAKE
case C_CM_IOCTLW:
- cy_sched_event(info, Cy_EVENT_SHUTDOWN_WAKEUP);
+ complete(&info->shutdown_wait);
break;
#endif
#ifdef CONFIG_CYZ_INTR
@@ -1834,7 +1766,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
break;
}
if (delta_count)
- cy_sched_event(info, Cy_EVENT_DELTA_WAKEUP);
+ wake_up_interruptible(&info->delta_msr_wait);
if (special_count)
tty_schedule_flip(tty);
}
@@ -2812,7 +2744,6 @@ static void cy_close(struct tty_struct *tty, struct file *filp)
spin_lock_irqsave(&card->card_lock, flags);

tty->closing = 0;
- info->event = 0;
info->tty = NULL;
if (info->blocked_open) {
spin_unlock_irqrestore(&card->card_lock, flags);
@@ -4444,7 +4375,6 @@ static void cy_hangup(struct tty_struct *tty)

cy_flush_buffer(tty);
shutdown(info);
- info->event = 0;
info->count = 0;
#ifdef CY_DEBUG_COUNT
printk(KERN_DEBUG "cyc:cy_hangup (%d): setting count to 0\n",
@@ -4502,7 +4432,6 @@ static int __devinit cy_init_card(struct cyclades_card *cinfo)
info->closing_wait = CLOSING_WAIT_DELAY;
info->close_delay = 5 * HZ / 10;

- INIT_WORK(&info->tqueue, do_softint);
init_waitqueue_head(&info->open_wait);
init_waitqueue_head(&info->close_wait);
init_completion(&info->shutdown_wait);
diff --git a/include/linux/cyclades.h b/include/linux/cyclades.h
index 72aa00c..06b2725 100644
--- a/include/linux/cyclades.h
+++ b/include/linux/cyclades.h
@@ -569,7 +569,6 @@ struct cyclades_port {
int x_char; /* to be pushed out ASAP */
int close_delay;
unsigned short closing_wait;
- unsigned long event;
int count; /* # of fd on device */
int breakon;
int breakoff;
@@ -584,7 +583,6 @@ struct cyclades_port {
struct cyclades_monitor mon;
struct cyclades_idle_stats idle_stats;
struct cyclades_icount icount;
- struct work_struct tqueue;
wait_queue_head_t open_wait;
wait_queue_head_t close_wait;
struct completion shutdown_wait;
@@ -592,19 +590,6 @@ struct cyclades_port {
int throttle;
};

-/*
- * Events are used to schedule things to happen at timer-interrupt
- * time, instead of at cy interrupt time.
- */
-#define Cy_EVENT_READ_PROCESS 0
-#define Cy_EVENT_WRITE_WAKEUP 1
-#define Cy_EVENT_HANGUP 2
-#define Cy_EVENT_BREAK 3
-#define Cy_EVENT_OPEN_WAKEUP 4
-#define Cy_EVENT_SHUTDOWN_WAKEUP 5
-#define Cy_EVENT_DELTA_WAKEUP 6
-#define Cy_EVENT_Z_RX_FULL 7
-
#define CLOSING_WAIT_DELAY 30*HZ
#define CY_CLOSING_WAIT_NONE 65535
#define CY_CLOSING_WAIT_INF 0