1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/i2c-slave/i2c_slave_ring_buffer.c b/drivers/i2c-slave/i2c_slave_ring_buffer.c
new file mode 100644
index 000000000000..4a55e099235f
--- /dev/null
+++ b/drivers/i2c-slave/i2c_slave_ring_buffer.c
@@ -0,0 +1,185 @@
+/*
+ * Copyright 2007-2008 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+#include <linux/slab.h>
+#include <linux/hardirq.h>
+#include "i2c_slave_ring_buffer.h"
+
+i2c_slave_ring_buffer_t *i2c_slave_rb_alloc(int size)
+{
+	i2c_slave_ring_buffer_t *ring_buf;
+
+	ring_buf =
+	    (i2c_slave_ring_buffer_t *) kzalloc(sizeof(i2c_slave_ring_buffer_t),
+						GFP_KERNEL);
+	if (!ring_buf) {
+		pr_debug("%s: alloc ring_buf error\n", __func__);
+		goto error;
+	}
+
+	ring_buf->buffer = kmalloc(size, GFP_KERNEL);
+	if (!ring_buf->buffer) {
+		pr_debug("%s: alloc buffer error\n", __func__);
+		goto error1;
+	}
+
+	ring_buf->total = size;
+
+	ring_buf->lock = __SPIN_LOCK_UNLOCKED(ring_buf->lock);
+	return ring_buf;
+
+      error1:
+	kfree(ring_buf);
+      error:
+	return NULL;
+}
+
+void i2c_slave_rb_release(i2c_slave_ring_buffer_t *ring)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(ring->lock, flags);
+	kfree(ring->buffer);
+	spin_unlock_irqrestore(ring->lock, flags);
+	kfree(ring);
+}
+
+int i2c_slave_rb_produce(i2c_slave_ring_buffer_t *ring, int num, char *data)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(ring->lock, flags);
+
+	if (ring->start < ring->end) {
+		if ((ring->start + num) < ring->end) {	/*have enough space */
+			memcpy(&ring->buffer[ring->start], data, num);
+			ring->start += num;
+			ret = num;
+		} else {	/*space not enough, just copy part of it. */
+			ret = ring->end - ring->start;
+			memcpy(&ring->buffer[ring->start], data, ret);
+			ring->start += ret;
+			ring->full = 1;
+		}
+	} else if (ring->start >= ring->end && !ring->full) {
+		if (ring->start + num <= ring->total) {	/*space enough */
+			ret = num;
+			memcpy(&ring->buffer[ring->start], data, ret);
+			ring->start += ret;
+		} else {	/*turn ring->start around */
+			ret = ring->total - ring->start;
+			memcpy(&ring->buffer[ring->start], data, ret);
+			ring->start = 0;
+			num -= ret;
+			data += ret;
+			if (num < ring->end) {	/*space enough */
+				ret += num;
+				memcpy(&ring->buffer[ring->start], data, num);
+			} else {	/*space not enough, just copy part of it. */
+				ret += ring->end;
+				memcpy(&ring->buffer[ring->start], data,
+				       ring->end);
+				ring->start = ring->end;
+				ring->full = 1;
+			}
+		}
+	} else {		/*(ring->data == ring->end) && ring->full ) : full */
+		ret = 0;
+	}
+
+	spin_unlock_irqrestore(ring->lock, flags);
+	return ret;
+}
+
+int i2c_slave_rb_consume(i2c_slave_ring_buffer_t *ring, int num, char *data)
+{
+	int ret;
+	unsigned long flags;
+	spin_lock_irqsave(ring->lock, flags);
+	if (num <= 0) {
+		ret = 0;
+		goto out;
+	}
+
+	if (ring->start > ring->end) {
+		if (num <= ring->start - ring->end) {	/*enough */
+			ret = num;
+			memcpy(data, &ring->buffer[ring->end], ret);
+			ring->end += ret;
+		} else {	/*not enough */
+			ret = ring->start - ring->end;
+			memcpy(data, &ring->buffer[ring->end], ret);
+			ring->end += ret;
+		}
+	} else if (ring->start < ring->end || ring->full) {
+		if (num <= ring->total - ring->end) {
+			ret = ring->total - ring->end;
+			memcpy(data, &ring->buffer[ring->end], ret);
+			ring->end += ret;
+		} else if (num <= ring->total - ring->end + ring->start) {
+			ret = ring->total - ring->end;
+			memcpy(data, &ring->buffer[ring->end], ret);
+			ring->end = 0;
+			data += ret;
+			num -= ret;
+			memcpy(data, &ring->buffer[ring->end], num);
+			ring->end = num;
+			ret += num;
+		} else {
+			ret = ring->total - ring->end;
+			memcpy(data, &ring->buffer[ring->end], ret);
+			ring->end = 0;
+			data += ret;
+			num -= ret;
+			memcpy(data, &ring->buffer[ring->end], ring->start);
+			ring->end = ring->start;
+			ret += ring->start;
+		}
+		ring->full = 0;
+	} else {		/*empty */
+		ret = 0;
+	}
+
+      out:
+	spin_unlock_irqrestore(ring->lock, flags);
+
+	return ret;
+}
+
+int i2c_slave_rb_num(i2c_slave_ring_buffer_t *ring)
+{
+	int ret;
+	unsigned long flags;
+	spin_lock_irqsave(ring->lock, flags);
+	if (ring->start > ring->end) {
+		ret = ring->start - ring->end;
+	} else if (ring->start < ring->end) {
+		ret = ring->total - ring->end + ring->start;
+	} else if (ring->full) {
+		ret = ring->total;
+	} else {
+		ret = 0;
+	}
+	spin_unlock_irqrestore(ring->lock, flags);
+	return ret;
+}
+
+void i2c_slave_rb_clear(i2c_slave_ring_buffer_t *ring)
+{
+	unsigned long flags;
+	spin_lock_irqsave(ring->lock, flags);
+
+	ring->start = ring->end = 0;
+	ring->full = 0;
+	spin_unlock_irqrestore(ring->lock, flags);
+}