contrib: add AppStream metadata
[libam7xxx.git] / src / am7xxx.c
index f4203e3..8573a59 100644 (file)
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 
-/* If we're not using GNU C, elide __attribute__
+/*
+ * If we're not using GNU C, elide __attribute__
  * taken from: http://unixwiz.net/techtips/gnu-c-attributes.html)
  */
 #ifndef __GNUC__
-#  define  __attribute__(x)  /* NOTHING */
+       #define  __attribute__(x)  /* NOTHING */
+#endif
+
+/*
+ * Fix printf format when compiling for Windows with MinGW, see:
+ * https://sourceforge.net/p/mingw-w64/wiki2/gnu%20printf/
+ */
+#ifdef __MINGW_PRINTF_FORMAT
+       #define AM7XXX_PRINTF_FORMAT __MINGW_PRINTF_FORMAT
+#else
+       #define AM7XXX_PRINTF_FORMAT printf
 #endif
 
 /* Control shared library symbols visibility */
 
 static void log_message(am7xxx_context *ctx,
                        int level,
-                       const char *function,
+                       const char *function_name,
                        int line,
                        const char *fmt,
-                       ...) __attribute__ ((format (printf, 5, 6)));
+                       ...) __attribute__ ((format (AM7XXX_PRINTF_FORMAT, 5, 6)));
 
 #define fatal(...)        log_message(NULL, AM7XXX_LOG_FATAL,   __func__, __LINE__, __VA_ARGS__)
 #define error(ctx, ...)   log_message(ctx,  AM7XXX_LOG_ERROR,   __func__, __LINE__, __VA_ARGS__)
@@ -341,7 +352,7 @@ static inline unsigned int in_80chars(unsigned int i)
 {
        /* The 3 below is the length of "xx " where xx is the hex string
         * representation of a byte */
-       return ((i+1) % (80/3));
+       return ((i + 1) % (80 / 3));
 }
 
 static void trace_dump_buffer(am7xxx_context *ctx, const char *message,
@@ -381,8 +392,9 @@ static void trace_dump_buffer(am7xxx_context *ctx, const char *message,
 static int read_data(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
 {
        int ret;
-       int transferred = 0;
+       int transferred;
 
+       transferred = 0;
        ret = libusb_bulk_transfer(dev->usb_device, 0x81, buffer, len, &transferred, 0);
        if (ret != 0 || (unsigned int)transferred != len) {
                error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
@@ -398,10 +410,11 @@ 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 = 0;
+       int transferred;
 
        trace_dump_buffer(dev->ctx, "sending -->", buffer, len);
 
+       transferred = 0;
        ret = libusb_bulk_transfer(dev->usb_device, 0x1, buffer, len, &transferred, 0);
        if (ret != 0 || (unsigned int)transferred != len) {
                error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
@@ -412,7 +425,7 @@ 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)
+static void LIBUSB_CALL send_data_async_complete_cb(struct libusb_transfer *transfer)
 {
        am7xxx_device *dev = (am7xxx_device *)(transfer->user_data);
        int *completed = &(dev->transfer_completed);
@@ -489,8 +502,8 @@ static int send_data_async(am7xxx_device *dev, uint8_t *buffer, unsigned int len
 
        /* 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",
@@ -626,7 +639,7 @@ static int send_command(am7xxx_device *dev, am7xxx_packet_type type)
  * set up */
 static void log_message(am7xxx_context *ctx,
                        int level,
-                       const char *function,
+                       const char *function_name,
                        int line,
                        const char *fmt,
                        ...)
@@ -634,8 +647,8 @@ static void log_message(am7xxx_context *ctx,
        va_list ap;
 
        if (level == AM7XXX_LOG_FATAL || (ctx && level <= ctx->log_level)) {
-               if (function) {
-                       fprintf(stderr, "%s", function);
+               if (function_name) {
+                       fprintf(stderr, "%s", function_name);
                        if (line)
                                fprintf(stderr, "[%d]", line);
                        fprintf(stderr, ": ");
@@ -662,7 +675,7 @@ static am7xxx_device *add_new_device(am7xxx_context *ctx,
 
        new_device = malloc(sizeof(*new_device));
        if (new_device == NULL) {
-               fatal("cannot allocate a new device (%s)\n", strerror(errno));
+               debug(ctx, "cannot allocate a new device (%s)\n", strerror(errno));
                return NULL;
        }
        memset(new_device, 0, sizeof(*new_device));
@@ -718,7 +731,6 @@ static int open_device(am7xxx_context *ctx,
 
        /* the usb device has already been opened */
        if ((*dev)->usb_device) {
-               debug(ctx, "(*dev)->usb_device already set\n");
                ret = 1;
                goto out;
        }
@@ -734,8 +746,35 @@ static int open_device(am7xxx_context *ctx,
         */
 
        current_configuration = -1;
-       libusb_get_configuration((*dev)->usb_device, &current_configuration);
+       ret = libusb_get_configuration((*dev)->usb_device,
+                                      &current_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) {
@@ -763,16 +802,26 @@ static int open_device(am7xxx_context *ctx,
         * http://libusb.sourceforge.net/api-1.0/caveats.html
         */
        current_configuration = -1;
-       libusb_get_configuration((*dev)->usb_device, &current_configuration);
+       ret = libusb_get_configuration((*dev)->usb_device,
+                                      &current_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\n");
-               debug(ctx, "Cannot claim interface %hhu\n",
-                     (*dev)->desc->interface_number);
-               goto out_libusb_close;
+               debug(ctx, "libusb configuration changed (expected: %hhu, current: %d)\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;
@@ -1055,8 +1104,7 @@ AM7XXX_PUBLIC int am7xxx_init(am7xxx_context **ctx)
        *ctx = malloc(sizeof(**ctx));
        if (*ctx == NULL) {
                fatal("cannot allocate the context (%s)\n", strerror(errno));
-               ret = -ENOMEM;
-               goto out;
+               return -ENOMEM;
        }
        memset(*ctx, 0, sizeof(**ctx));
 
@@ -1064,8 +1112,10 @@ AM7XXX_PUBLIC int am7xxx_init(am7xxx_context **ctx)
        (*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);
 
@@ -1140,14 +1190,14 @@ AM7XXX_PUBLIC int am7xxx_open_device(am7xxx_context *ctx, am7xxx_device **dev,
         * is the first one to be sent to the device in order for it to
         * successfully return the correct device information.
         *
-        * So, if there is not a cached version of it (from a previous open),
-        * we ask for device info at open time,
+        * NOTE: am7xxx_get_device_info() will fetch the actual device info
+        * from the device only the very first time it's called for a given
+        * device, otherwise, it'll return a cached version of the device info
+        * (from a previous call to am7xxx_open_device(), for instance).
         */
-       if ((*dev)->device_info == NULL) {
-               ret = am7xxx_get_device_info(*dev, NULL);
-               if (ret < 0)
-                       error(ctx, "cannot get device info\n");
-       }
+       ret = am7xxx_get_device_info(*dev, NULL);
+       if (ret < 0)
+               error(ctx, "cannot get device info\n");
 
 out:
        return ret;
@@ -1174,10 +1224,9 @@ AM7XXX_PUBLIC int am7xxx_get_device_info(am7xxx_device *dev,
        int ret;
        struct am7xxx_header h;
 
-       if (dev->device_info) {
-               memcpy(device_info, dev->device_info, sizeof(*device_info));
-               return 0;
-       }
+       /* if there is a cached copy of the device info, just return that */
+       if (dev->device_info)
+               goto return_value;
 
        ret = send_command(dev, AM7XXX_PACKET_TYPE_DEVINFO);
        if (ret < 0)
@@ -1191,8 +1240,8 @@ AM7XXX_PUBLIC int am7xxx_get_device_info(am7xxx_device *dev,
        if (h.packet_type != AM7XXX_PACKET_TYPE_DEVINFO) {
                error(dev->ctx, "expected packet type: %d, got %d instead!\n",
                      AM7XXX_PACKET_TYPE_DEVINFO, h.packet_type);
-               errno = ENOTSUP;
-               return -ENOTSUP;
+               errno = EINVAL;
+               return -EINVAL;
        }
 
        dev->device_info = malloc(sizeof(*dev->device_info));
@@ -1211,6 +1260,9 @@ AM7XXX_PUBLIC int am7xxx_get_device_info(am7xxx_device *dev,
        dev->device_info->unknown1 = h.header_data.devinfo.unknown1;
 #endif
 
+return_value:
+       if (device_info)
+               memcpy(device_info, dev->device_info, sizeof(*device_info));
        return 0;
 }
 
@@ -1221,7 +1273,6 @@ AM7XXX_PUBLIC int am7xxx_calc_scaled_image_dimensions(am7xxx_device *dev,
                                        unsigned int *scaled_width,
                                        unsigned int *scaled_height)
 {
-
        am7xxx_device_info device_info;
        float width_ratio;
        float height_ratio;