Few changes...
- add a lot of comments - only lookup symbols as needed to keep the paths thru the function as small as possible - add comments about the problems we have and give some idea about what needs fixing and what then needs removal from this file - show the hooks pointer being passed to detect NULL pointers more quickly git-svn-id: file:///srv/svn/repos/haiku/trunk/current@272 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
David Reid
parent
fa10e022b1
commit
d2c1ff9a7d
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@ -71,7 +71,7 @@ image_id dev_load_dev_module(const char *name, const char *dirpath)
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{
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image_id id;
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char path[SYS_MAX_PATH_LEN];
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// uint32 * api_version;
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uint32 *api_version;
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status_t (*init_hardware)(void);
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status_t (*init_driver)(void);
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status_t (*uninit_driver)(void);
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@ -82,15 +82,23 @@ image_id dev_load_dev_module(const char *name, const char *dirpath)
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sprintf(path, "%s/%s", dirpath, name);
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/* Load the module, return error if unable */
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id = elf_load_kspace(path, "");
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if(id < 0)
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return id;
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// get device driver API symbols
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// api_version = (uint32 *) elf_lookup_symbol(id, "api_version");
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init_hardware = (void *) elf_lookup_symbol(id, "init_hardware");
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init_driver = (void *) elf_lookup_symbol(id, "init_driver");
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uninit_driver = (void *) elf_lookup_symbol(id, "uninit_driver");
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/* Don't get all the symbols we will require initially. Just get the
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* ones we need to check we have a valid module.
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* elf_find_symbol is an extra call and so we don't make it more often
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* than we have to.
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*/
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/* For a valid device driver we MUST have the publish_devices and
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* find_device functions available
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*/
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/* XXX - very few drivers have the api_version symbol defined yet.
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* Add api_version to the rest of the drivers!
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*/
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api_version = (uint32 *) elf_lookup_symbol(id, "api_version");
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publish_devices = (void *) elf_lookup_symbol(id, "publish_devices");
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find_device = (void *) elf_lookup_symbol(id, "find_device");
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@ -100,44 +108,81 @@ image_id dev_load_dev_module(const char *name, const char *dirpath)
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goto error;
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}
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/* Next, do we have an init_hardware function? If we do run it and
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* if it fails simply fall through to the exit...
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*/
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init_hardware = (void *) elf_lookup_symbol(id, "init_hardware");
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if (init_hardware && init_hardware() != 0) {
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dprintf("DEV: %s: init_hardware failed :(\n", name);
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id = ENXIO;
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goto error;
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}
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/* OK, so we now have what appears to be a valid module that has
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* completed init_hardware and thus thinks it should be used.
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* XXX - this is bogus!
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* XXX - the driver init routines should be called by devfs and
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* only when the driver is first needed. However, that level
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* level of support is not yet in devfs, so we have a hack
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* here that calls the init_driver function at this point.
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* As a result we will check to see if we actually manage to
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* publish the device, and if we do we will keep the module
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* loaded.
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* XXX - remove this when devfs is fixed!
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*/
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init_driver = (void *) elf_lookup_symbol(id, "init_driver");
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if (init_driver && init_driver() != 0) {
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dprintf("DEV: %s: init_driver failed :(\n", name);
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id = ENXIO;
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goto error;
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}
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// dprintf("DEV: Well alright - %s init'd OK!\n", name);
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}
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/* Should really cycle through these... */
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devfs_paths = publish_devices();
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/* Start of with the keep_loaded as false. If we have a successful
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* call to devfs_publish_device we will set this to true.
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*/
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keep_loaded = false;
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devfs_paths = publish_devices();
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for (; *devfs_paths; devfs_paths++) {
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device_hooks * hooks;
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hooks = find_device(*devfs_paths);
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dprintf("DEV: %s: publishing %s\n", name, *devfs_paths);
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device_hooks *hooks = find_device(*devfs_paths);
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if (hooks) {
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dprintf("DEV: %s: publishing %s with hooks %p\n",
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name, *devfs_paths, hooks);
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if (devfs_publish_device(*devfs_paths, NULL, hooks) == 0)
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keep_loaded = true;
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}
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}
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/* If we've managed to publish at least one of the device entry
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* points that the driver wished us to then we MUST keep the driver in
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* memory or the pointer that devfs has will become invalid.
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* XXX - This is bogus, see above
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*/
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if (keep_loaded)
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// okay, keep this driver image in memory, as he publish *something*
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return id;
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// no need to keep this driver image loaded...
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/* If the fucntion gets here then the following has happenned...
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* - the driver has been loaded
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* - it has appeared valid
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* - init_hardware has returned saying it should be used
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* - init_driver has been run OK
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* - devfs_publish_devices has for some reason failed.
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* The error value we're about to return is 0, which probably
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* means we're loosing error information here :(
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* XXX - what error code should we be returning
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*
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* However, before we unload ourselves we will try to find and run
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* the uninit routine.
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*/
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uninit_driver = (void *) elf_lookup_symbol(id, "uninit_driver");
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if (uninit_driver)
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uninit_driver();
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id = 0;
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error:
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/* If we've gotten here then the driver will be unloaded and an
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* error code returned.
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*/
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elf_unload_kspace(path);
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return id;
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}
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