From 85ae140ba9b2750b78ef4efff001a70833217653 Mon Sep 17 00:00:00 2001
From: Marc Schink <jaylink-dev@marcschink.de>
Date: Thu, 25 Sep 2014 05:19:06 -0400
Subject: [PATCH] device: Add function to retrieve free memory size.

---
 libjaylink/device.c     | 56 +++++++++++++++++++++++++++++++++++++++++++++++++
 libjaylink/libjaylink.h |  4 ++++
 2 files changed, 60 insertions(+)

diff --git a/libjaylink/device.c b/libjaylink/device.c
index 31d6a91..18de63f 100644
--- a/libjaylink/device.c
+++ b/libjaylink/device.c
@@ -25,6 +25,7 @@
 
 #define CMD_GET_VERSION		0x01
 #define CMD_GET_HW_STATUS	0x07
+#define CMD_GET_FREE_MEMORY	0xd4
 #define CMD_GET_CAPS		0xe8
 #define CMD_GET_EXT_CAPS	0xed
 
@@ -443,3 +444,58 @@ int jaylink_get_extended_caps(struct jaylink_device_handle *devh, uint8_t *caps)
 
 	return JAYLINK_OK;
 }
+
+/**
+ * Retrieve the size of free memory of a device.
+ *
+ * @note This function must only be used if the device has the
+ * 	 #JAYLINK_DEV_CAP_GET_FREE_MEMORY capability.
+ *
+ * @param[in,out] devh Device handle.
+ * @param[out] size Size of free memory in bytes on success, and undefined on
+ * 		    failure.
+ *
+ * @retval JAYLINK_OK Success.
+ * @retval JAYLINK_ERR_ARG Invalid arguments.
+ * @retval JAYLINK_ERR_TIMEOUT A timeout occurred.
+ * @retval JAYLINK_ERR Other error conditions.
+ *
+ * @see jaylink_get_caps() to retrieve device capabilities.
+ */
+int jaylink_get_free_memory(struct jaylink_device_handle *devh, uint32_t *size)
+{
+	int ret;
+	struct jaylink_context *ctx;
+	uint8_t buf[4];
+
+	if (!devh || !size)
+		return JAYLINK_ERR_ARG;
+
+	ctx = devh->dev->ctx;
+	ret = transport_start_write_read(devh, 1, 4, 1);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_start_write_read() failed: %i.", ret);
+		return ret;
+	}
+
+	buf[0] = CMD_GET_FREE_MEMORY;
+
+	ret = transport_write(devh, buf, 1);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_write() failed: %i.", ret);
+		return ret;
+	}
+
+	ret = transport_read(devh, buf, 4);
+
+	if (ret != JAYLINK_OK) {
+		log_err(ctx, "transport_read() failed: %i.", ret);
+		return ret;
+	}
+
+	*size = buffer_get_u32(buf, 0);
+
+	return JAYLINK_OK;
+}
diff --git a/libjaylink/libjaylink.h b/libjaylink/libjaylink.h
index bbfc3f6..bbf7add 100644
--- a/libjaylink/libjaylink.h
+++ b/libjaylink/libjaylink.h
@@ -41,6 +41,8 @@ enum jaylink_log_level {
 
 /** Device capabilities. */
 enum jaylink_device_capability {
+	/** Device supports retrieval of free memory size. */
+	JAYLINK_DEV_CAP_GET_FREE_MEMORY = 11,
 	/** Device supports retrieval of extended capabilities. */
 	JAYLINK_DEV_CAP_GET_EXT_CAPS = 31
 };
@@ -107,4 +109,6 @@ int jaylink_get_caps(struct jaylink_device_handle *devh, uint8_t *caps);
 int jaylink_get_extended_caps(struct jaylink_device_handle *devh,
 		uint8_t *caps);
 
+int jaylink_get_free_memory(struct jaylink_device_handle *devh, uint32_t *size);
+
 #endif /* LIBJAYLINK_LIBJAYLINK_H */
-- 
2.11.4.GIT