Refactor the i8042 module to be thread-safe.

Any command/data coming from host will be placed in from_host queue, and
the interrupt handler returns immediately. The i8042_command_task() will
handle them later.

Data reply to the host will be protected by the mutex.

BUG=chrome-os-partner:10090
TEST=randomly play around on the link board.

Change-Id: Ic19d5abd1abf8dc261ddaad4224cd9305c2f36a4
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/24299
Commit-Ready: Yung-Chieh Lo <yjlou%chromium.org@gtempaccount.com>
Reviewed-by: Yung-Chieh Lo <yjlou%chromium.org@gtempaccount.com>
Tested-by: Yung-Chieh Lo <yjlou%chromium.org@gtempaccount.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/common/queue.c b/common/queue.c
new file mode 100644
index 0000000000..8018e4c0b0
--- /dev/null
+++ b/common/queue.c
@@ -0,0 +1,53 @@
+/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Queue data structure implementation.
+ */
+#include "queue.h"
+#include "util.h"
+
+void queue_reset(struct queue *queue)
+{
+	queue->head = queue->tail = 0;
+}
+
+int queue_is_empty(const struct queue *q)
+{
+	return q->head == q->tail;
+}
+
+int queue_has_space(const struct queue *q, int unit_count)
+{
+	return (q->tail + unit_count * q->unit_bytes) <=
+	       (q->head + q->buf_bytes - q->unit_bytes);
+}
+
+void queue_add_units(struct queue *q, const void *src, int unit_count)
+{
+	const uint8_t *s = (const uint8_t *)src;
+
+	if (!queue_has_space(q, unit_count))
+		return;
+
+	for (unit_count *= q->unit_bytes; unit_count; unit_count--) {
+		q->buf[q->tail++] = *(s++);
+		q->tail %= q->buf_bytes;
+	}
+}
+
+int queue_remove_unit(struct queue *q, void *dest)
+{
+	int count;
+	uint8_t *d = (uint8_t *)dest;
+
+	if (queue_is_empty(q))
+		return 0;
+
+	for (count = q->unit_bytes; count; count--) {
+		*(d++) = q->buf[q->head++];
+		q->head %= q->buf_bytes;
+	}
+
+	return 1;
+}