laforge has submitted this change. ( 
https://gerrit.osmocom.org/c/libosmocore/+/16928 )

Change subject: usb: Add osmo_libusb_find_open_claim() all-in-one API
......................................................................

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
---
M include/osmocom/usb/libusb.h
M src/usb/osmo_libusb.c
2 files changed, 126 insertions(+), 0 deletions(-)

Approvals:
  laforge: Looks good to me, approved
  pespin: Looks good to me, but someone else must approve
  Jenkins Builder: Verified



diff --git a/include/osmocom/usb/libusb.h b/include/osmocom/usb/libusb.h
index 2220e03..9ad3f71 100644
--- a/include/osmocom/usb/libusb.h
+++ b/include/osmocom/usb/libusb.h
@@ -55,6 +55,31 @@
        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 @@
 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);

diff --git a/src/usb/osmo_libusb.c b/src/usb/osmo_libusb.c
index 3c8a22a..bb86206 100644
--- a/src/usb/osmo_libusb.c
+++ b/src/usb/osmo_libusb.c
@@ -590,6 +590,102 @@
        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

--
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I748ded6cc7b73a73625588bd7a34a017a905b6bf
Gerrit-Change-Number: 16928
Gerrit-PatchSet: 5
Gerrit-Owner: laforge <lafo...@osmocom.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <lafo...@osmocom.org>
Gerrit-Reviewer: pespin <pes...@sysmocom.de>
Gerrit-CC: fixeria <axilira...@gmail.com>
Gerrit-MessageType: merged

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