am7xxx: initialize the 'transferred' variable before USB transfers

[libam7xxx.git] / src / am7xxx.c

diff --git a/src/am7xxx.c b/src/am7xxx.c
index cdcbf3f..c02b539 100644 (file)
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -26,6 +26,71 @@
 #define AM7XXX_VENDOR_ID  0x1de1
 #define AM7XXX_PRODUCT_ID 0xc101
 
+typedef enum {
+       AM7XXX_PACKET_TYPE_DEVINFO = 0x01,
+       AM7XXX_PACKET_TYPE_IMAGE   = 0x02,
+       AM7XXX_PACKET_TYPE_POWER   = 0x04,
+       AM7XXX_PACKET_TYPE_UNKNOWN = 0x05,
+} am7xxx_packet_type;
+
+struct am7xxx_generic_header {
+       uint32_t field0;
+       uint32_t field1;
+       uint32_t field2;
+       uint32_t field3;
+};
+
+struct am7xxx_devinfo_header {
+       uint32_t native_width;
+       uint32_t native_height;
+       uint32_t unknown0;
+       uint32_t unknown1;
+};
+
+struct am7xxx_image_header {
+       uint32_t format;
+       uint32_t width;
+       uint32_t height;
+       uint32_t image_size;
+};
+
+struct am7xxx_power_header {
+       uint32_t bit2;
+       uint32_t bit1;
+       uint32_t bit0;
+};
+
+/*
+ * Examples of packet headers:
+ *
+ * Image header:
+ * 02 00 00 00 00 10 3e 10 01 00 00 00 20 03 00 00 e0 01 00 00 53 E8 00 00
+ *
+ * Power header:
+ * 04 00 00 00 00 0c ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ */
+
+/* The header size on the wire is known to be always 24 bytes, regardless of
+ * the memory configuration enforced by different architechtures or compilers
+ * for struct am7xxx_header
+ */
+#define AM7XXX_HEADER_WIRE_SIZE 24
+
+struct am7xxx_header {
+       uint32_t packet_type;
+       uint8_t unknown0;
+       uint8_t header_data_len;
+       uint8_t unknown2;
+       uint8_t unknown3;
+       union {
+               struct am7xxx_generic_header data;
+               struct am7xxx_devinfo_header devinfo;
+               struct am7xxx_image_header image;
+               struct am7xxx_power_header power;
+       } header_data;
+};
+
+
 static void dump_devinfo_header(struct am7xxx_devinfo_header *d)
 {
        if (d == NULL)
@@ -116,7 +181,7 @@ static void dump_buffer(uint8_t *buffer, unsigned int len)
 static int read_data(am7xxx_device dev, uint8_t *buffer, unsigned int len)
 {
        int ret;
-       int transferred;
+       int transferred = 0;
 
        ret = libusb_bulk_transfer(dev, 0x81, buffer, len, &transferred, 0);
        if (ret != 0 || (unsigned int)transferred != len) {
@@ -137,7 +202,7 @@ static int read_data(am7xxx_device dev, uint8_t *buffer, unsigned int len)
 static int send_data(am7xxx_device dev, uint8_t *buffer, unsigned int len)
 {
        int ret;
-       int transferred;
+       int transferred = 0;
 
 #if DEBUG
        printf("\nsending -->\n");