media: allegro: add field for number of buffers

When pushing the buffers for the intermediate and reference frames to
the MCU, the driver relied on the message size to calculate the number
of buffers. As it is not necessary anymore to keep the messages binary
compatible to the firmware, we can just explicitly write the number of
buffers into the message.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/allegro-dvt/allegro-core.c

@@ -1115,6 +1115,7 @@ static int allegro_mcu_push_buffer_internal(struct allegro_channel *channel,
 	msg->header.length = size - sizeof(msg->header);
 	msg->header.type = type;
 	msg->channel_id = channel->mcu_channel_id;
+	msg->num_buffers = num_buffers;
 
 	buffer = msg->buffer;
 	list_for_each_entry(al_buffer, list, head) {

drivers/staging/media/allegro-dvt/allegro-mail.c

@@ -156,7 +156,7 @@ allegro_enc_push_buffers(u32 *dst, struct mcu_msg_push_buffers_internal *msg)
 {
 	unsigned int i = 0;
 	struct mcu_msg_push_buffers_internal_buffer *buffer;
-	unsigned int num_buffers = (msg->header.length - 4) / sizeof(*buffer);
+	unsigned int num_buffers = msg->num_buffers;
 	unsigned int j;
 
 	dst[i++] = msg->channel_id;

drivers/staging/media/allegro-dvt/allegro-mail.h

@@ -169,6 +169,7 @@ struct mcu_msg_push_buffers_internal_buffer {
 struct mcu_msg_push_buffers_internal {
 	struct mcu_msg_header header;
 	u32 channel_id;
+	size_t num_buffers;
 	struct mcu_msg_push_buffers_internal_buffer buffer[];
 } __attribute__ ((__packed__));