am7xxx: add multi-device support

Allow operating on more than one am7xxx device at the same time.

diff --git a/src/am7xxx.c b/src/am7xxx.c
index 272a249..114027e 100644 (file)
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -55,6 +55,12 @@ static struct am7xxx_usb_device_descriptor supported_devices[] = {
 struct _am7xxx_device {
        libusb_device_handle *usb_device;
        uint8_t buffer[AM7XXX_HEADER_WIRE_SIZE];
+       am7xxx_device *next;
+};
+
+struct _am7xxx_context {
+       libusb_context *usb_context;
+       am7xxx_device *devices_list;
 };
 
 typedef enum {
@@ -315,55 +321,245 @@ static int send_header(am7xxx_device *dev, struct am7xxx_header *h)
        return ret;
 }
 
-am7xxx_device *am7xxx_init(void)
+static am7xxx_device *add_new_device(am7xxx_device **devices_list)
 {
-       unsigned int i;
+       am7xxx_device *new_device;
 
-       am7xxx_device *dev = malloc(sizeof(*dev));
-       if (dev == NULL) {
+       new_device = malloc(sizeof(*new_device));
+       if (new_device == NULL) {
                perror("malloc");
+               return NULL;
+       }
+       memset(new_device, 0, sizeof(*new_device));
+
+       if (*devices_list == NULL) {
+               *devices_list = new_device;
+       } else {
+               am7xxx_device *prev = *devices_list;
+               while (prev->next)
+                       prev = prev->next;
+               prev->next = new_device;
+       }
+       return new_device;
+}
+
+static am7xxx_device *find_device(am7xxx_device *devices_list,
+                                 unsigned int device_index)
+{
+       unsigned int i = 0;
+       am7xxx_device *current = devices_list;
+
+       while (current && i++ < device_index)
+               current = current->next;
+
+       return current;
+}
+
+typedef enum {
+       SCAN_OP_BUILD_DEVLIST,
+       SCAN_OP_OPEN_DEVICE,
+} scan_op;
+
+/**
+ * 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
+ * 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.
+ * 
+ * NOTES:
+ * if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
+ * the caller might want to call am7xxx_shutdown() in order to remove
+ * devices possibly added before the failure.
+ */
+static int scan_devices(am7xxx_context *ctx, scan_op op,
+                       unsigned int open_device_index, am7xxx_device **dev)
+{
+       int num_devices;
+       libusb_device** list;
+       unsigned int current_index;
+       int i;
+       int ret;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+       if (op == SCAN_OP_BUILD_DEVLIST && ctx->devices_list != NULL) {
+               fprintf(stderr, "%s: device scan done already? Abort!\n", __func__);
+               return -EINVAL;
+       }
+
+       num_devices = libusb_get_device_list(ctx->usb_context, &list);
+       if (num_devices < 0) {
+               ret = -ENODEV;
                goto out;
        }
-       memset(dev, 0, sizeof(*dev));
-
-       libusb_init(NULL);
-       libusb_set_debug(NULL, 3);
-
-       for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {
-               dev->usb_device = libusb_open_device_with_vid_pid(NULL,
-                                                     supported_devices[i].vendor_id,
-                                                     supported_devices[i].product_id);
-               if (dev->usb_device) {
-                       printf("%s: device found: %s\n", __func__, supported_devices[i].name);
-                       break;
+
+       current_index = 0;
+       for (i = 0; i < num_devices; i++) {
+               struct libusb_device_descriptor desc;
+               unsigned int j;
+
+               ret = libusb_get_device_descriptor(list[i], &desc);
+               if (ret < 0)
+                       continue;
+
+               for (j = 0; j < ARRAY_SIZE(supported_devices); j++) {
+                       if (desc.idVendor == supported_devices[j].vendor_id
+                           && desc.idProduct == supported_devices[j].product_id) {
+
+                               if (op == SCAN_OP_BUILD_DEVLIST) {
+                                       am7xxx_device *new_device;
+                                       /* debug */
+                                       printf("am7xxx device found, index: %d, name: %s\n",
+                                              current_index,
+                                              supported_devices[j].name);
+                                       new_device = add_new_device(&(ctx->devices_list));
+                                       if (new_device == NULL) {
+                                               /* XXX, the caller may want
+                                                * to call am7xxx_shutdown() if
+                                                * we fail here, as we may have
+                                                * added some devices already
+                                                */
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+                               } else if (op == SCAN_OP_OPEN_DEVICE &&
+                                          current_index == open_device_index) {
+
+                                       *dev = find_device(ctx->devices_list, open_device_index);
+                                       if (*dev == NULL) {
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+
+                                       /* the usb device has already been opened */
+                                       if ((*dev)->usb_device) {
+                                               ret = 1;
+                                               goto out;
+                                       }
+
+                                       ret = libusb_open(list[i], &((*dev)->usb_device));
+                                       if (ret < 0)
+                                               goto out;
+
+                                       libusb_set_configuration((*dev)->usb_device, 1);
+                                       libusb_claim_interface((*dev)->usb_device, 0);
+                                       goto out;
+                               }
+                               current_index++;
+                       }
                }
        }
-       if (dev->usb_device == NULL) {
-               errno = ENODEV;
-               perror("libusb_open_device_with_vid_pid");
-               goto out_libusb_exit;
+
+       /* if we made it up to here we didn't find any device to open */
+       if (op == SCAN_OP_OPEN_DEVICE) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+out:
+       libusb_free_device_list(list, 1);
+       return ret;
+}
+
+int am7xxx_init(am7xxx_context **ctx)
+{
+       int ret = 0;
+
+       *ctx = malloc(sizeof(**ctx));
+       if (*ctx == NULL) {
+               perror("malloc");
+               ret = -ENOMEM;
+               goto out;
        }
+       memset(*ctx, 0, sizeof(**ctx));
 
-       libusb_set_configuration(dev->usb_device, 1);
-       libusb_claim_interface(dev->usb_device, 0);
+       ret = libusb_init(&((*ctx)->usb_context));
+       if (ret < 0)
+               goto out_free_context;
+
+       libusb_set_debug((*ctx)->usb_context, 3);
+
+       ret = scan_devices(*ctx, SCAN_OP_BUILD_DEVLIST , 0, NULL);
+       if (ret < 0) {
+               fprintf(stderr, "%s: scan_devices failed\n", __func__);
+               am7xxx_shutdown(*ctx);
+               goto out;
+       }
 
-       return dev;
+       return 0;
 
-out_libusb_exit:
-       libusb_exit(NULL);
-       free(dev);
+out_free_context:
+       free(*ctx);
+       *ctx = NULL;
 out:
-       return NULL;
+       return ret;
+}
+
+void am7xxx_shutdown(am7xxx_context *ctx)
+{
+       am7xxx_device *current;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return;
+       }
+
+       current = ctx->devices_list;
+       while (current) {
+               am7xxx_device *next = current->next;
+               am7xxx_close_device(current);
+               free(current);
+               current = next;
+       }
+
+       libusb_exit(ctx->usb_context);
+       free(ctx);
+       ctx = NULL;
+}
+
+int am7xxx_open_device(am7xxx_context *ctx, am7xxx_device **dev,
+                      unsigned int device_index)
+{
+       int ret;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+
+       ret = scan_devices(ctx, SCAN_OP_OPEN_DEVICE, device_index, dev);
+       if (ret < 0) {
+               errno = ENODEV;
+       } else if (ret > 0) {
+               /* warning */
+               fprintf(stderr, "%s: device %d already open\n", __func__, device_index);
+               errno = EBUSY;
+               ret = -EBUSY;
+       }
+
+       return ret;
 }
 
-void am7xxx_shutdown(am7xxx_device *dev)
+int am7xxx_close_device(am7xxx_device *dev)
 {
-       if (dev) {
+       if (dev == NULL) {
+               fprintf(stderr, "%s: dev must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+       if (dev->usb_device) {
+               libusb_release_interface(dev->usb_device, 0);
                libusb_close(dev->usb_device);
-               libusb_exit(NULL);
-               free(dev);
-               dev = NULL;
+               dev->usb_device = NULL;
        }
+       return 0;
 }
 
 int am7xxx_get_device_info(am7xxx_device *dev,

diff --git a/src/am7xxx.h b/src/am7xxx.h
index 5367145..b6a2a9a 100644 (file)
--- a/src/am7xxx.h
+++ b/src/am7xxx.h
@@ -23,6 +23,10 @@
 extern "C" {
 #endif
 
+
+struct _am7xxx_context;
+typedef struct _am7xxx_context am7xxx_context;
+
 struct _am7xxx_device;
 typedef struct _am7xxx_device am7xxx_device;
 
@@ -39,9 +43,15 @@ typedef enum {
        AM7XXX_POWER_TURBO  = 4,
 } am7xxx_power_mode;
 
-am7xxx_device *am7xxx_init(void);
+int am7xxx_init(am7xxx_context **ctx);
+
+void am7xxx_shutdown(am7xxx_context *ctx);
+
+int am7xxx_open_device(am7xxx_context *ctx,
+                      am7xxx_device **dev,
+                      unsigned int device_index);
 
-void am7xxx_shutdown(am7xxx_device *dev);
+int am7xxx_close_device(am7xxx_device *dev);
 
 int am7xxx_get_device_info(am7xxx_device *dev,
                           unsigned int *native_width,

diff --git a/src/picoproj.c b/src/picoproj.c
index cc31714..db27573 100644 (file)
--- a/src/picoproj.c
+++ b/src/picoproj.c
@@ -50,6 +50,7 @@ int main(int argc, char *argv[])
        char filename[FILENAME_MAX] = {0};
        int image_fd;
        struct stat st;
+       am7xxx_context *ctx;
        am7xxx_device *dev;
        int format = AM7XXX_IMAGE_FORMAT_JPEG;
        int width = 800;
@@ -130,13 +131,35 @@ int main(int argc, char *argv[])
                goto out_close_image_fd;
        }
 
-       dev = am7xxx_init();
-       if (dev == NULL) {
+       ret = am7xxx_init(&ctx);
+       if (ret < 0) {
                perror("am7xxx_init");
                exit_code = EXIT_FAILURE;
                goto out_munmap;
        }
 
+       ret = am7xxx_open_device(ctx, &dev, 0);
+       if (ret < 0) {
+               perror("am7xxx_open_device");
+               exit_code = EXIT_FAILURE;
+               goto cleanup;
+       }
+
+
+       ret = am7xxx_close_device(dev);
+       if (ret < 0) {
+               perror("am7xxx_close_device");
+               exit_code = EXIT_FAILURE;
+               goto cleanup;
+       }
+
+       ret = am7xxx_open_device(ctx, &dev, 0);
+       if (ret < 0) {
+               perror("am7xxx_open_device");
+               exit_code = EXIT_FAILURE;
+               goto cleanup;
+       }
+
        ret = am7xxx_get_device_info(dev, &native_width, &native_height, &unknown0, &unknown1);
        if (ret < 0) {
                perror("am7xxx_get_info");
@@ -164,7 +187,7 @@ int main(int argc, char *argv[])
        exit_code = EXIT_SUCCESS;
 
 cleanup:
-       am7xxx_shutdown(dev);
+       am7xxx_shutdown(ctx);
 
 out_munmap:
        ret = munmap(image, size);