* taken from: http://unixwiz.net/techtips/gnu-c-attributes.html)
*/
#ifndef __GNUC__
-# define __attribute__(x) /*NOTHING*/
+# define __attribute__(x) /* NOTHING */
#endif
/* Control shared library symbols visibility */
ret = libusb_bulk_transfer(dev->usb_device, 0x81, buffer, len, &transferred, 0);
if (ret != 0 || (unsigned int)transferred != len) {
- error(dev->ctx, "ret: %d\ttransferred: %d (expected %u)\n",
- ret, transferred, len);
+ error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
+ libusb_error_name(ret), transferred, len);
return ret;
}
ret = libusb_bulk_transfer(dev->usb_device, 0x1, buffer, len, &transferred, 0);
if (ret != 0 || (unsigned int)transferred != len) {
- error(dev->ctx, "ret: %d\ttransferred: %d (expected %u)\n",
- ret, transferred, len);
+ error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
+ libusb_error_name(ret), transferred, len);
return ret;
}
/* 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. */
+ * requires more dynamic allocations compared to 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",
return current;
}
+static int open_device(am7xxx_context *ctx,
+ unsigned int device_index,
+ libusb_device *usb_dev,
+ am7xxx_device **dev)
+{
+ int ret;
+ int current_configuration;
+
+ *dev = find_device(ctx, device_index);
+ if (*dev == NULL) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ /* the usb device has already been opened */
+ if ((*dev)->usb_device) {
+ debug(ctx, "(*dev)->usb_device already set\n");
+ ret = 1;
+ goto out;
+ }
+
+ ret = libusb_open(usb_dev, &((*dev)->usb_device));
+ if (ret < 0) {
+ debug(ctx, "libusb_open failed: %s\n", libusb_error_name(ret));
+ goto out;
+ }
+
+ /* XXX, the device is now open, if any of the calls below fail we need
+ * to close it again before bailing out.
+ */
+
+ current_configuration = -1;
+ ret = libusb_get_configuration((*dev)->usb_device,
+ ¤t_configuration);
+ if (ret < 0) {
+ debug(ctx, "libusb_get_configuration failed: %s\n",
+ libusb_error_name(ret));
+ goto out_libusb_close;
+ }
+
+ if (current_configuration != (*dev)->desc->configuration) {
+ /*
+ * In principle, before setting a new configuration, kernel
+ * drivers should be detached from _all_ interfaces; for
+ * example calling something like the following "invented"
+ * function _before_ setting the new configuration:
+ *
+ * libusb_detach_all_kernel_drivers((*dev)->usb_device);
+ *
+ * However, in practice, this is not necessary for most
+ * devices as they have only one configuration.
+ *
+ * When a device only has one configuration:
+ *
+ * - if there was a kernel driver bound to the device, it
+ * had already set the configuration and the call below
+ * will be skipped;
+ *
+ * - if no kernel driver was bound to the device, the call
+ * below will suceed.
+ */
+ ret = libusb_set_configuration((*dev)->usb_device,
+ (*dev)->desc->configuration);
+ if (ret < 0) {
+ debug(ctx, "libusb_set_configuration failed: %s\n",
+ libusb_error_name(ret));
+ debug(ctx, "Cannot set configuration %hhu\n",
+ (*dev)->desc->configuration);
+ goto out_libusb_close;
+ }
+ }
+
+ libusb_set_auto_detach_kernel_driver((*dev)->usb_device, 1);
+
+ ret = libusb_claim_interface((*dev)->usb_device,
+ (*dev)->desc->interface_number);
+ if (ret < 0) {
+ debug(ctx, "libusb_claim_interface failed: %s\n",
+ libusb_error_name(ret));
+ debug(ctx, "Cannot claim interface %hhu\n",
+ (*dev)->desc->interface_number);
+ goto out_libusb_close;
+ }
+
+ /* Checking that the configuration has not changed, as suggested in
+ * http://libusb.sourceforge.net/api-1.0/caveats.html
+ */
+ current_configuration = -1;
+ ret = libusb_get_configuration((*dev)->usb_device,
+ ¤t_configuration);
+ if (ret < 0) {
+ debug(ctx, "libusb_get_configuration after claim failed: %s\n",
+ libusb_error_name(ret));
+ goto out_libusb_release_interface;
+ }
+
+ if (current_configuration != (*dev)->desc->configuration) {
+ debug(ctx, "libusb configuration changed (expected: %hhu, current: %hhu\n",
+ (*dev)->desc->configuration, current_configuration);
+ ret = -EINVAL;
+ goto out_libusb_release_interface;
+ }
+out:
+ return ret;
+
+out_libusb_release_interface:
+ libusb_release_interface((*dev)->usb_device,
+ (*dev)->desc->interface_number);
+out_libusb_close:
+ libusb_close((*dev)->usb_device);
+ (*dev)->usb_device = NULL;
+ return ret;
+}
+
typedef enum {
SCAN_OP_BUILD_DEVLIST,
SCAN_OP_OPEN_DEVICE,
* This is where the central logic of multi-device support is.
*
* When 'op' == SCAN_OP_BUILD_DEVLIST the parameters 'open_device_index' and
- * 'dev' are ignored; the function returns 0 on success and a negative value
+ * 'dev' are ignored; the function returns 0 on success or a negative value
* on error.
*
* When 'op' == SCAN_OP_OPEN_DEVICE the function opens the supported USB
* device with index 'open_device_index' and returns the correspondent
- * am7xxx_device in the 'dev' parameter; the function returns 0 on success,
- * 1 if the device was already open and a negative value on error.
+ * am7xxx_device in the 'dev' parameter; the function returns the value from
+ * open_device(), which is 0 on success, 1 if the device was already open or
+ * a negative value on error.
*
* NOTES:
* if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
unsigned int open_device_index, am7xxx_device **dev)
{
ssize_t num_devices;
- libusb_device** list;
+ libusb_device **list;
unsigned int current_index;
int i;
int ret;
} else if (op == SCAN_OP_OPEN_DEVICE &&
current_index == open_device_index) {
- *dev = find_device(ctx, open_device_index);
- if (*dev == NULL) {
- ret = -ENODEV;
- goto out;
- }
-
- /* the usb device has already been opened */
- if ((*dev)->usb_device) {
- debug(ctx, "(*dev)->usb_device already set\n");
- ret = 1;
- goto out;
- }
-
- ret = libusb_open(list[i], &((*dev)->usb_device));
- if (ret < 0) {
- debug(ctx, "libusb_open failed\n");
- goto out;
- }
-
- /* XXX, the device is now open, if any
- * of the calls below fail we need to
- * close it again before bailing out.
- */
-
- ret = libusb_set_configuration((*dev)->usb_device,
- (*dev)->desc->configuration);
- if (ret < 0) {
- debug(ctx, "libusb_set_configuration failed\n");
- debug(ctx, "Cannot set configuration %hhu\n",
- (*dev)->desc->configuration);
- goto out_libusb_close;
- }
-
- ret = libusb_claim_interface((*dev)->usb_device,
- (*dev)->desc->interface_number);
- if (ret < 0) {
- debug(ctx, "libusb_claim_interface failed\n");
- debug(ctx, "Cannot claim interface %hhu\n",
- (*dev)->desc->interface_number);
-out_libusb_close:
- libusb_close((*dev)->usb_device);
- (*dev)->usb_device = NULL;
- goto out;
- }
+ ret = open_device(ctx,
+ open_device_index,
+ list[i],
+ dev);
+ if (ret < 0)
+ debug(ctx, "open_device failed\n");
+ /* exit the loop unconditionally after
+ * attempting to open the device
+ * requested by the user */
goto out;
}
current_index++;
}
}
- /* if we made it up to here we didn't find any device to open */
+ /* if we made it up to here when op == SCAN_OP_OPEN_DEVICE,
+ * no devices to open had been found. */
if (op == SCAN_OP_OPEN_DEVICE) {
error(ctx, "Cannot find any device to open\n");
ret = -ENODEV;
(*ctx)->log_level = AM7XXX_LOG_TRACE;
ret = libusb_init(&((*ctx)->usb_context));
- if (ret < 0)
+ if (ret < 0) {
+ error(*ctx, "libusb_init failed: %s\n", libusb_error_name(ret));
goto out_free_context;
+ }
libusb_set_debug((*ctx)->usb_context, LIBUSB_LOG_LEVEL_INFO);
projects / libam7xxx.git / blobdiff