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usb: Add osmo_libusb_find_open_claim() all-in-one API 

This function offers the highest level of API among all libosmousb
helper functions. It is intended as a one-stop shop for everything
related to grabbing an interface.

Change-Id: I748ded6cc7b73a73625588bd7a34a017a905b6bf
This commit is contained in:
Harald Welte 2020-01-12 23:45:42 +01:00 committed by laforge
parent 508fad90e4
commit 3edd70c1f1
2 changed files with 126 additions and 0 deletions
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30
include/osmocom/usb/libusb.h
View File

@ -55,6 +55,31 @@ struct usb_interface_match {
uint8_t string_idx;
};
/*! Description of the USB device+interface we're looking for */
struct osmo_usb_matchspec {
/*! specify the USB device */
struct {
int vendor_id; /*!< typically -1 for compile time defaults */
int product_id; /*!< typically -1 for compile time defaults */
char *path; /*!< used for disambiguation when multiple matches; can be NULL */
} dev;
/*! specify the USB configuration */
int config_id; /*!< typically -1 unless user selects specific configuration */
/*! specify the USB interface */
struct {
/* typically those three are set to application defaults */
int class; /*!< -1 or a user-specified class */
int subclass; /*!< -1 or a user-specified subclass */
int proto; /*!< -1 or a user-specified protocol */
/* typically those two are -1; but user can override them */
int num;
int altsetting;
} intf;
};
char *osmo_libusb_dev_get_path_buf(char *buf, size_t bufsize, libusb_device *dev);
char *osmo_libusb_dev_get_path_c(void *ctx, libusb_device *dev);
@ -81,6 +106,11 @@ int osmo_libusb_find_matching_interfaces(libusb_context *luctx, const struct dev
libusb_device_handle *osmo_libusb_open_claim_interface(void *ctx, libusb_context *luctx,
const struct usb_interface_match *ifm);
void osmo_libusb_match_init(struct osmo_usb_matchspec *cfg, int if_class, int if_subclass, int if_proto);
libusb_device_handle *osmo_libusb_find_open_claim(const struct osmo_usb_matchspec *cfg,
const struct dev_id *default_dev_ids);
int osmo_libusb_get_ep_addrs(libusb_device_handle *devh, unsigned int if_num,
uint8_t *out, uint8_t *in, uint8_t *irq);

96
src/usb/osmo_libusb.c
View File

@ -590,6 +590,102 @@ libusb_device_handle *osmo_libusb_open_claim_interface(void *ctx, libusb_context
return usb_devh;
}
void osmo_libusb_match_init(struct osmo_usb_matchspec *cfg, int if_class, int if_subclass, int if_proto)
{
cfg->dev.vendor_id = -1;
cfg->dev.product_id = -1;
cfg->dev.path = NULL;
cfg->config_id = -1;
cfg->intf.class = if_class;
cfg->intf.subclass = if_subclass;
cfg->intf.proto = if_proto;
cfg->intf.num = cfg->intf.altsetting = -1;
}
/*! high-level all-in-one function for USB device, config + interface matching + opening.
* This function offers the highest level of API among all libosmousb helper functions. It
* is intended as a one-stop shop for everything related to grabbing an interface.
*
* 1) looks for a device matching either the VID/PID from 'cfg' or 'default_dev_ids',
* if more than one is found, the user is expected to fill in cfg->dev.path to disambiguate.
* 2) find any interfaces on the device that match the specification in 'cfg'. The match
* could be done based on any of (class, subclass, proto, interface number). If there
* are multiple matches, the caller must disambiguate by specifying the interface number.
* 3) open the USB device; set the configuration (if needed); claim the interface and set
* the altsetting
*
* \param[in] cfg user-supplied match configuration (from command line or config file)
* \param[in] default_dev_ids Default list of supported VendorId/ProductIds
* \returns libusb_device_handle on success, NULL on error
*/
libusb_device_handle *osmo_libusb_find_open_claim(const struct osmo_usb_matchspec *cfg,
const struct dev_id *default_dev_ids)
{
struct usb_interface_match if_matches[16];
struct usb_interface_match *ifm = NULL;
libusb_device_handle *usb_devh = NULL;
struct dev_id user_dev_ids[2] = {
{ cfg->dev.vendor_id, cfg->dev.product_id },
{ 0, 0 }
};
const struct dev_id *dev_ids = default_dev_ids;
libusb_device *dev;
int rc, i;
/* Stage 1: Find a device matching either the user-specified VID/PID or
* the list of IDs in default_dev_ids plus optionally the user-specified path */
if (cfg->dev.vendor_id != -1 || cfg->dev.product_id != -1)
dev_ids = user_dev_ids;
dev = osmo_libusb_find_matching_dev_path(NULL, dev_ids, cfg->dev.path);
if (!dev)
goto close_exit;
/* Stage 2: Find any interfaces matching the class/subclass/proto as specified */
rc = osmo_libusb_dev_find_matching_interfaces(dev, cfg->intf.class, cfg->intf.subclass,
cfg->intf.proto, if_matches, sizeof(if_matches));
if (rc < 1) {
LOGP(DLUSB, LOGL_NOTICE, "can't find matching USB interface at device\n");
goto close_exit;
} else if (rc == 1) {
ifm = if_matches;
} else if (rc > 1) {
if (cfg->intf.num == -1) {
LOGP(DLUSB, LOGL_ERROR, "Found %d matching USB interfaces, you "
"have to specify the interface number\n", rc);
goto close_exit;
}
for (i = 0; i < rc; i++) {
if (if_matches[i].interface == cfg->intf.num) {
ifm = &if_matches[i];
break;
}
/* FIXME: match altsetting */
}
}
if (!ifm) {
LOGP(DLUSB, LOGL_NOTICE, "Couldn't find matching interface\n");
goto close_exit;
}
/* Stage 3: Open device; set config (if required); claim interface; set altsetting */
usb_devh = osmo_libusb_open_claim_interface(NULL, NULL, ifm);
if (!usb_devh) {
LOGP(DLUSB, LOGL_ERROR, "can't open USB device (permissions issue?)\n");
goto close_exit;
}
return usb_devh;
close_exit:
/* release if_matches */
if (usb_devh)
libusb_close(usb_devh);
return NULL;
}
/*! obtain the endpoint addresses for a given USB interface.
* \param[in] devh USB device handle on which to operate
* \param[in] if_num USB Interface number on which to operate