From 860428c1b8ee26b327ec3c9fb8943fd17a49d755 Mon Sep 17 00:00:00 2001
From: Antonio Ospite <ospite@studenti.unina.it>
Date: Sun, 21 Jul 2013 00:10:28 +0200
Subject: [PATCH] am7xxx: implement am7xxx_send_image_async()
Implement am7xxx_send_image_async() the non-blocking version of
am7xxx_send_image().
This way user programs can more easily overlap encoding and
communication and achieve higher framerates.
---
src/am7xxx.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/am7xxx.h | 26 ++++++++++
2 files changed, 177 insertions(+)
diff --git a/src/am7xxx.c b/src/am7xxx.c
index f37ad70..3e6b461 100644
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -130,6 +130,8 @@ static const struct am7xxx_usb_device_descriptor supported_devices[] = {
struct _am7xxx_device {
libusb_device_handle *usb_device;
+ struct libusb_transfer *transfer;
+ int transfer_completed;
uint8_t buffer[AM7XXX_HEADER_WIRE_SIZE];
am7xxx_device_info *device_info;
am7xxx_context *ctx;
@@ -372,6 +374,117 @@ static int send_data(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
return 0;
}
+static void send_data_async_complete_cb(struct libusb_transfer *transfer)
+{
+ am7xxx_device *dev = (am7xxx_device *)(transfer->user_data);
+ int *completed = &(dev->transfer_completed);
+ int transferred = transfer->actual_length;
+ int ret;
+
+ if (transferred != transfer->length) {
+ error(dev->ctx, "transferred: %d (expected %u)\n",
+ transferred, transfer->length);
+ }
+
+ switch (transfer->status) {
+ case LIBUSB_TRANSFER_COMPLETED:
+ ret = 0;
+ break;
+ case LIBUSB_TRANSFER_TIMED_OUT:
+ ret = LIBUSB_ERROR_TIMEOUT;
+ break;
+ case LIBUSB_TRANSFER_STALL:
+ ret = LIBUSB_ERROR_PIPE;
+ break;
+ case LIBUSB_TRANSFER_OVERFLOW:
+ ret = LIBUSB_ERROR_OVERFLOW;
+ break;
+ case LIBUSB_TRANSFER_NO_DEVICE:
+ ret = LIBUSB_ERROR_NO_DEVICE;
+ break;
+ case LIBUSB_TRANSFER_ERROR:
+ case LIBUSB_TRANSFER_CANCELLED:
+ ret = LIBUSB_ERROR_IO;
+ break;
+ default:
+ error(dev->ctx, "unrecognised status code %d", transfer->status);
+ ret = LIBUSB_ERROR_OTHER;
+ }
+
+ if (ret < 0)
+ error(dev->ctx, "libusb transfer failed: %s",
+ libusb_error_name(ret));
+
+ libusb_free_transfer(transfer);
+ transfer = NULL;
+
+ *completed = 1;
+}
+
+static inline void wait_for_trasfer_completed(am7xxx_device *dev)
+{
+ while (!dev->transfer_completed) {
+ int ret = libusb_handle_events_completed(dev->ctx->usb_context,
+ &(dev->transfer_completed));
+ if (ret < 0) {
+ if (ret == LIBUSB_ERROR_INTERRUPTED)
+ continue;
+ error(dev->ctx, "libusb_handle_events failed: %s, cancelling transfer and retrying",
+ libusb_error_name(ret));
+ libusb_cancel_transfer(dev->transfer);
+ continue;
+ }
+ }
+}
+
+static int send_data_async(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
+{
+ int ret;
+ uint8_t *transfer_buffer;
+
+ dev->transfer = libusb_alloc_transfer(0);
+ if (dev->transfer == NULL) {
+ error(dev->ctx, "cannot allocate transfer (%s)\n",
+ strerror(errno));
+ return -ENOMEM;
+ }
+
+ /* Make a copy of the buffer so the caller can safely reuse it just
+ * after libusb_submit_transfer() has returned. This technique
+ * requires more allocations than a proper double-buffering approach
+ * but it takes a lot less code. */
+ transfer_buffer = malloc(len);
+ if (transfer_buffer == NULL) {
+ error(dev->ctx, "cannot allocate transfer buffer (%s)\n",
+ strerror(errno));
+ ret = -ENOMEM;
+ goto err;
+ }
+ memcpy(transfer_buffer, buffer, len);
+
+ dev->transfer->flags |= LIBUSB_TRANSFER_FREE_BUFFER;
+ libusb_fill_bulk_transfer(dev->transfer, dev->usb_device, 0x1,
+ transfer_buffer, len,
+ send_data_async_complete_cb, dev, 0);
+
+ /* wait for the previous transfer to complete */
+ wait_for_trasfer_completed(dev);
+
+ trace_dump_buffer(dev->ctx, "sending -->", buffer, len);
+
+ dev->transfer_completed = 0;
+ ret = libusb_submit_transfer(dev->transfer);
+ if (ret < 0)
+ goto err;
+
+ return 0;
+
+err:
+ libusb_free_transfer(dev->transfer);
+ dev->transfer = NULL;
+ return ret;
+}
+
static void serialize_header(struct am7xxx_header *h, uint8_t *buffer)
{
uint8_t **buffer_iterator = &buffer;
@@ -496,6 +609,7 @@ static am7xxx_device *add_new_device(am7xxx_context *ctx,
new_device->ctx = ctx;
new_device->desc = desc;
+ new_device->transfer_completed = 1;
devices_list = &(ctx->devices_list);
@@ -786,6 +900,7 @@ AM7XXX_PUBLIC int am7xxx_close_device(am7xxx_device *dev)
return -EINVAL;
}
if (dev->usb_device) {
+ wait_for_trasfer_completed(dev);
libusb_release_interface(dev->usb_device, dev->desc->interface_number);
libusb_close(dev->usb_device);
dev->usb_device = NULL;
@@ -950,6 +1065,42 @@ AM7XXX_PUBLIC int am7xxx_send_image(am7xxx_device *dev,
return send_data(dev, image, image_size);
}
+AM7XXX_PUBLIC int am7xxx_send_image_async(am7xxx_device *dev,
+ am7xxx_image_format format,
+ unsigned int width,
+ unsigned int height,
+ uint8_t *image,
+ unsigned int image_size)
+{
+ int ret;
+ struct am7xxx_header h = {
+ .packet_type = AM7XXX_PACKET_TYPE_IMAGE,
+ .direction = AM7XXX_DIRECTION_OUT,
+ .header_data_len = sizeof(struct am7xxx_image_header),
+ .unknown2 = 0x3e,
+ .unknown3 = 0x10,
+ .header_data = {
+ .image = {
+ .format = format,
+ .width = width,
+ .height = height,
+ .image_size = image_size,
+ },
+ },
+ };
+
+ ret = send_header(dev, &h);
+ if (ret < 0)
+ return ret;
+
+ if (image == NULL || image_size == 0) {
+ warning(dev->ctx, "Not sending any data, check the 'image' or 'image_size' parameters\n");
+ return 0;
+ }
+
+ return send_data_async(dev, image, image_size);
+}
+
AM7XXX_PUBLIC int am7xxx_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power)
{
int ret;
diff --git a/src/am7xxx.h b/src/am7xxx.h
index 1c353ab..ec9869d 100644
--- a/src/am7xxx.h
+++ b/src/am7xxx.h
@@ -242,6 +242,32 @@ int am7xxx_send_image(am7xxx_device *dev,
unsigned int image_size);
/**
+ * Queue transfer of an image for display on an am7xxx device and return immediately.
+ *
+ * This is the function that actually makes the device display something.
+ * Static pictures can be sent just once and the device will keep showing them
+ * until another image get sent or some command resets or turns off the display.
+ *
+ * @note This _async() variant makes a copy of the image buffer, so the caller
+ * is free to reuse the buffer just after the function returns.
+ *
+ * @param[in] dev A pointer to the structure representing the device to get info of
+ * @param[in] format The format the image is in (see @link am7xxx_image_format @endlink enum)
+ * @param[in] width The width of the image
+ * @param[in] height The height of the image
+ * @param[in] image A buffer holding data in the format specified by the format parameter
+ * @param[in] image_size The size in bytes of the image buffer
+ *
+ * @return 0 on success, a negative value on error
+ */
+int am7xxx_send_image_async(am7xxx_device *dev,
+ am7xxx_image_format format,
+ unsigned int width,
+ unsigned int height,
+ unsigned char *image,
+ unsigned int image_size);
+
+/**
* Set the power mode of an am7xxx device.
*
* @note When setting the mode to AM7XXX_POWER_OFF the display can't be turned
--
2.1.4