[PATCH 33/39] input: Split i8042 interrupt handling into an IRQ handler and a tasklet [excluded later]

Vojtech Pavlik
2004-06-07T12:10:14Z

ChangeSet@1.1587.27.13, 2004-05-10 01:39:35-05:00, dtor_core@ameritech.net
Input: split i8042 interrupt handling into an IRQ handler and a tasklet

i8042.c | 141 +++++++++++++++++++++++++++++++++++++++++-----------------------
1 files changed, 92 insertions(+), 49 deletions(-)

===================================================================

diff -Nru a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
--- a/drivers/input/serio/i8042.c 2004-06-07 13:10:49 +02:00
+++ b/drivers/input/serio/i8042.c 2004-06-07 13:10:49 +02:00
@@ -2,6 +2,7 @@
* i8042 keyboard and mouse controller driver for Linux
*
* Copyright (c) 1999-2002 Vojtech Pavlik
+ * Copyright (c) 2004 Dmitry Torokhov
*/

/*
@@ -74,6 +75,14 @@
unsigned char *phys;
};

+#define I8042_QUEUE_LEN 64
+struct {
+ unsigned char str[I8042_QUEUE_LEN];
+ unsigned char data[I8042_QUEUE_LEN];
+ unsigned int read_pos;
+ unsigned int write_pos;
+} i8042_buf;
+
static struct serio i8042_kbd_port;
static struct serio i8042_aux_port;
static unsigned char i8042_initial_ctr;
@@ -82,7 +91,7 @@
static unsigned char i8042_mux_present;
static unsigned char i8042_sysdev_initialized;
static struct pm_dev *i8042_pm_dev;
-struct timer_list i8042_timer;
+static struct timer_list i8042_timer;

/*
* Shared IRQ's require a device pointer, but this driver doesn't support
@@ -374,77 +383,109 @@
static char i8042_mux_phys[4][32];

/*
- * i8042_interrupt() is the most important function in this driver -
- * it handles the interrupts from the i8042, and sends incoming bytes
- * to the upper layers.
+ * i8042_handle_data() is the most important function in this driver -
+ * it processes data received by i8042_interrupt and sends it to the
+ * upper layers.
*/

-static irqreturn_t i8042_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static void i8042_handle_data(unsigned long notused)
{
- unsigned long flags;
unsigned char str, data = 0;
unsigned int dfl;
- int ret;

- mod_timer(&i8042_timer, jiffies + I8042_POLL_PERIOD);
+ /*
+ * No locking it required on i8042_buf as the tasklet is guaranteed
+ * to be serialized and if write_pos changes while comparing it with
+ * read_pos another run will be scheduled by i8042_interrupt.
+ */
+ while (i8042_buf.read_pos != i8042_buf.write_pos) {

- spin_lock_irqsave(&i8042_lock, flags);
- str = i8042_read_status();
- if (str & I8042_STR_OBF)
- data = i8042_read_data();
- spin_unlock_irqrestore(&i8042_lock, flags);
+ str = i8042_buf.str[i8042_buf.read_pos];
+ data = i8042_buf.data[i8042_buf.read_pos];

- if (~str & I8042_STR_OBF) {
- if (irq) dbg("Interrupt %d, without any data", irq);
- ret = 0;
- goto out;
+ i8042_buf.read_pos++;
+ i8042_buf.read_pos %= I8042_QUEUE_LEN;
+
+ dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) |
+ ((str & I8042_STR_TIMEOUT) ? SERIO_TIMEOUT : 0);
+
+ if (i8042_mux_values[0].exists && (str & I8042_STR_AUXDATA)) {
+
+ if (str & I8042_STR_MUXERR) {
+ switch (data) {
+ case 0xfd:
+ case 0xfe: dfl = SERIO_TIMEOUT; break;
+ case 0xff: dfl = SERIO_PARITY; break;
+ }
+ data = 0xfe;
+ } else dfl = 0;
+
+ dbg("%02x <- i8042 (interrupt, aux%d, %d%s%s)",
+ data, (str >> 6), irq,
+ dfl & SERIO_PARITY ? ", bad parity" : "",
+ dfl & SERIO_TIMEOUT ? ", timeout" : "");
+
+ serio_interrupt(i8042_mux_port + ((str >> 6) & 3), data, dfl, NULL);
+ } else {
+
+ dbg("%02x <- i8042 (interrupt, %s, %d%s%s)",
+ data, (str & I8042_STR_AUXDATA) ? "aux" : "kbd", irq,
+ dfl & SERIO_PARITY ? ", bad parity" : "",
+ dfl & SERIO_TIMEOUT ? ", timeout" : "");
+
+ if (i8042_aux_values.exists && (str & I8042_STR_AUXDATA))
+ serio_interrupt(&i8042_aux_port, data, dfl, NULL);
+ else if (i8042_kbd_values.exists)
+ serio_interrupt(&i8042_kbd_port, data, dfl, NULL);
+ }
}
+}
+
+DECLARE_TASKLET(i8042_tasklet, i8042_handle_data, 0);
+
+/*
+ * i8042_interrupt() handles the interrupts from i8042 and schedules
+ * i8042_handle_data to process and pass received bytes to the upper
+ * layers.
+ */

- dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) |
- ((str & I8042_STR_TIMEOUT) ? SERIO_TIMEOUT : 0);
+static irqreturn_t i8042_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ unsigned long flags;
+ unsigned char str;
+ unsigned int n_bytes = 0;

- if (i8042_mux_values[0].exists && (str & I8042_STR_AUXDATA)) {
+ mod_timer(&i8042_timer, jiffies + I8042_POLL_PERIOD);

- if (str & I8042_STR_MUXERR) {
- switch (data) {
- case 0xfd:
- case 0xfe: dfl = SERIO_TIMEOUT; break;
- case 0xff: dfl = SERIO_PARITY; break;
- }
- data = 0xfe;
- } else dfl = 0;
+ spin_lock_irqsave(&i8042_lock, flags);

- dbg("%02x <- i8042 (interrupt, aux%d, %d%s%s)",
- data, (str >> 6), irq,
- dfl & SERIO_PARITY ? ", bad parity" : "",
- dfl & SERIO_TIMEOUT ? ", timeout" : "");
+ while ((str = i8042_read_status()) & I8042_STR_OBF) {

- serio_interrupt(i8042_mux_port + ((str >> 6) & 3), data, dfl, regs);
+ n_bytes++;

- goto irq_ret;
- }
+ i8042_buf.str[i8042_buf.write_pos] = str;
+ i8042_buf.data[i8042_buf.write_pos] = i8042_read_data();

- dbg("%02x <- i8042 (interrupt, %s, %d%s%s)",
- data, (str & I8042_STR_AUXDATA) ? "aux" : "kbd", irq,
- dfl & SERIO_PARITY ? ", bad parity" : "",
- dfl & SERIO_TIMEOUT ? ", timeout" : "");
+ i8042_buf.write_pos++;
+ i8042_buf.write_pos %= I8042_QUEUE_LEN;

- if (i8042_aux_values.exists && (str & I8042_STR_AUXDATA)) {
- serio_interrupt(&i8042_aux_port, data, dfl, regs);
- goto irq_ret;
+ if (unlikely(i8042_buf.write_pos == i8042_buf.read_pos))
+ printk(KERN_WARNING "i8042.c: ring buffer full\n");
}

- if (!i8042_kbd_values.exists)
- goto irq_ret;
+ spin_unlock_irqrestore(&i8042_lock, flags);

- serio_interrupt(&i8042_kbd_port, data, dfl, regs);
+ if (unlikely(n_bytes == 0)) {
+ if (irq) dbg("Interrupt %d, without any data", irq);
+ return IRQ_NONE;
+ }

-irq_ret:
- ret = 1;
-out:
- return IRQ_RETVAL(ret);
+ tasklet_schedule(&i8042_tasklet);
+
+ return IRQ_HANDLED;
}

+
/*
* i8042_enable_mux_mode checks whether the controller has an active
* multiplexor and puts the chip into Multiplexed (as opposed to
@@ -1019,6 +1060,8 @@
for (i = 0; i < 4; i++)
if (i8042_mux_values[i].exists)
serio_unregister_port(i8042_mux_port + i);
+
+ tasklet_kill(&i8042_tasklet);

i8042_platform_exit();
}