[PATCH 10/30] staging: nvec: Introduce new internal API for msg alloc/free

[Julian Andres Klode]

Introduce two new functions nvec_msg_alloc() and nvec_msg_free()
that allocate and free message buffers from the internal pool
of messages.

Signed-off-by: Julian Andres Klode <jak at jak-linux.org>
---
 drivers/staging/nvec/nvec.c |   21 +++++++++++++++++++++
 drivers/staging/nvec/nvec.h |    6 ++++++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 43a83a9..8a97241 100644
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -17,6 +17,7 @@
 
 #include <asm/irq.h>
 
+#include <linux/atomic.h>
 #include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -91,6 +92,26 @@ static int nvec_status_notifier(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
+static struct nvec_msg *nvec_msg_alloc(struct nvec_chip *nvec)
+{
+	size_t i;
+	for (i = 0; i < NVEC_POOL_SIZE; i++)
+		if (atomic_xchg(&nvec->msg_pool[i].used, 1) == 0) {
+			dev_vdbg(nvec->dev, "INFO: Alloc %u\n", (uint) i);
+			return &nvec->msg_pool[i];
+		}
+
+	dev_err(nvec->dev, "could not allocate buffer\n");
+
+	return NULL;
+}
+
+static void nvec_msg_free(struct nvec_chip *nvec, struct nvec_msg *msg)
+{
+	dev_vdbg(nvec->dev, "INFO: Free %i\n", (int) (msg - nvec->msg_pool));
+	atomic_set(&msg->used, 0);
+}
+
 void nvec_write_async(struct nvec_chip *nvec, const unsigned char *data,
 			short size)
 {
diff --git a/drivers/staging/nvec/nvec.h b/drivers/staging/nvec/nvec.h
index fe11225..5440802 100644
--- a/drivers/staging/nvec/nvec.h
+++ b/drivers/staging/nvec/nvec.h
@@ -16,9 +16,13 @@
 #ifndef __LINUX_MFD_NVEC
 #define __LINUX_MFD_NVEC
 
+#include <linux/atomic.h>
 #include <linux/notifier.h>
 #include <linux/semaphore.h>
 
+/* NVEC_POOL_SIZE - Size of the pool in &struct nvec_msg */
+#define NVEC_POOL_SIZE	64
+
 typedef enum {
 	NVEC_2BYTES,
 	NVEC_3BYTES,
@@ -52,6 +56,7 @@ struct nvec_msg {
 	unsigned short size;
 	unsigned short pos;
 	struct list_head node;
+	atomic_t used;
 };
 
 struct nvec_subdev {
@@ -78,6 +83,7 @@ struct nvec_chip {
 	struct notifier_block nvec_status_notifier;
 	struct work_struct rx_work, tx_work;
 	struct nvec_msg *rx, *tx;
+	struct nvec_msg msg_pool[NVEC_POOL_SIZE];
 
 	/* sync write stuff */
 	struct semaphore sync_write_mutex;
-- 
1.7.5.4