X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/45e0326f3c336070c59b7e501a2c720dd0a203aa..14b6a47d284966d034259b433028e25c5adcd9bd:/src/am7xxx.c diff --git a/src/am7xxx.c b/src/am7xxx.c index 272a249..114027e 100644 --- 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,