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Nouveau源码分析(五):NVIDIA设备初始化之nouveau_drm_load (2)

Nouveau源码分析(五)

接着上一篇来,先把nouveau_drm_load再贴出一遍来吧:

// /drivers/gpu/drm/nouveau/nouveau_drm.c
364 static int
365 nouveau_drm_load(struct drm_device *dev, unsigned long flags)
366 {
367         struct pci_dev *pdev = dev->pdev;
368         struct nouveau_drm *drm;
369         int ret;
370 
371         ret = nouveau_cli_create(nouveau_name(dev), "DRM", sizeof(*drm),
372                                  (void **)&drm);
373         if (ret)
374                 return ret;
375 
376         dev->dev_private = drm;
377         drm->dev = dev;
378         nvkm_client(&drm->client.base)->debug =
379                 nouveau_dbgopt(nouveau_debug, "DRM");
380 
381         INIT_LIST_HEAD(&drm->clients);
382         spin_lock_init(&drm->tile.lock);
383 
384         nouveau_get_hdmi_dev(drm);
385 
386         /* make sure AGP controller is in a consistent state before we
387          * (possibly) execute vbios init tables (see nouveau_agp.h)
388          */
389         if (pdev && drm_pci_device_is_agp(dev) && dev->agp) {
390                 const u64 enables = NV_DEVICE_V0_DISABLE_IDENTIFY |
391                                     NV_DEVICE_V0_DISABLE_MMIO;
392                 /* dummy device object, doesn't init anything, but allows
393                  * agp code access to registers
394                  */
395                 ret = nvif_device_init(&drm->client.base.base, NULL,
396                                        NVDRM_DEVICE, NV_DEVICE,
397                                        &(struct nv_device_v0) {
398                                                 .device = ~0,
399                                                 .disable = ~enables,
400                                                 .debug0 = ~0,
401                                        }, sizeof(struct nv_device_v0),
402                                        &drm->device);
403                 if (ret)
404                         goto fail_device;
405 
406                 nouveau_agp_reset(drm);
407                 nvif_device_fini(&drm->device);
408         }
409 
410         ret = nvif_device_init(&drm->client.base.base, NULL, NVDRM_DEVICE,
411                                NV_DEVICE,
412                                &(struct nv_device_v0) {
413                                         .device = ~0,
414                                         .disable = 0,
415                                         .debug0 = 0,
416                                }, sizeof(struct nv_device_v0),
417                                &drm->device);
418         if (ret)
419                 goto fail_device;
420 
421         dev->irq_enabled = true;
422 
423         /* workaround an odd issue on nvc1 by disabling the device's
424          * nosnoop capability.  hopefully won't cause issues until a
425          * better fix is found - assuming there is one...
426          */
427         if (drm->device.info.chipset == 0xc1)
428                 nvif_mask(&drm->device, 0x00088080, 0x00000800, 0x00000000);
429 
430         nouveau_vga_init(drm);
431         nouveau_agp_init(drm);
432 
433         if (drm->device.info.family >= NV_DEVICE_INFO_V0_TESLA) {
434                 ret = nouveau_vm_new(nvkm_device(&drm->device), 0, (1ULL << 40),
435                                      0x1000, &drm->client.vm);
436                 if (ret)
437                         goto fail_device;
438 
439                 nvkm_client(&drm->client.base)->vm = drm->client.vm;
440         }
441 
442         ret = nouveau_ttm_init(drm);
443         if (ret)
444                 goto fail_ttm;
445 
446         ret = nouveau_bios_init(dev);
447         if (ret)
448                 goto fail_bios;
449 
450         ret = nouveau_display_create(dev);
451         if (ret)
452                 goto fail_dispctor;
453 
454         if (dev->mode_config.num_crtc) {
455                 ret = nouveau_display_init(dev);
456                 if (ret)
457                         goto fail_dispinit;
458         }
459 
460         nouveau_sysfs_init(dev);
461         nouveau_hwmon_init(dev);
462         nouveau_accel_init(drm);
463         nouveau_fbcon_init(dev);
464 
465         if (nouveau_runtime_pm != 0) {
466                 pm_runtime_use_autosuspend(dev->dev);
467                 pm_runtime_set_autosuspend_delay(dev->dev, 5000);
468                 pm_runtime_set_active(dev->dev);
469                 pm_runtime_allow(dev->dev);
470                 pm_runtime_mark_last_busy(dev->dev);
471                 pm_runtime_put(dev->dev);
472         }
473         return 0;
474 
475 fail_dispinit:
476         nouveau_display_destroy(dev);
477 fail_dispctor:
478         nouveau_bios_takedown(dev);
479 fail_bios:
480         nouveau_ttm_fini(drm);
481 fail_ttm:
482         nouveau_agp_fini(drm);
483         nouveau_vga_fini(drm);
484 fail_device:
485         nvif_device_fini(&drm->device);
486         nouveau_cli_destroy(&drm->client);
487         return ret;
488 }

第386行到第408行,注释说的很清楚,重置AGP. 好了来看nvif_device_init:

// /drivers/gpu/drm/nouveau/nvif/device.c
 33 int
 34 nvif_device_init(struct nvif_object *parent, void (*dtor)(struct nvif_device *),
 35                  u32 handle, u32 oclass, void *data, u32 size,
 36                  struct nvif_device *device)
 37 {
 38         int ret = nvif_object_init(parent, (void *)dtor, handle, oclass,
 39                                    data, size, &device->base);
 40         if (ret == 0) {
 41                 device->object = &device->base;
 42                 device->info.version = 0;
 43                 ret = nvif_object_mthd(&device->base, NV_DEVICE_V0_INFO,
 44                                        &device->info, sizeof(device->info));
 45         }
 46         return ret;
 47 }
首先第38行,nvif_object_init,还记得在上一篇中被忽略掉的那部分代码吗? 这里展开说:

// /drivers/gpu/drm/nouveau/nvif/object.c
217 int
218 nvif_object_init(struct nvif_object *parent, void (*dtor)(struct nvif_object *),
219                  u32 handle, u32 oclass, void *data, u32 size,
220                  struct nvif_object *object)
221 {
222         struct ctor *ctor;
223         int ret = 0;
224 
225         object->parent = NULL;
226         object->object = object;
227         nvif_object_ref(parent, &object->parent);
228         kref_init(&object->refcount);
229         object->handle = handle;
230         object->oclass = oclass;
231         object->data = http://www.mamicode.com/NULL;>第238行,分配一个ctor.

第244行,把传进来的数据复制进去,数据就是:"&(struct nv_device_v0) { .device = ~0, .disable = ~enables, .debug0 = ~0, }"

下面的几个字段简单说一下:

ctor->ioctl.version 貌似是用来校验版本的东西,目前只可能是0.

ctor->ioctl.type 表示ioctl的命令.

ctor->new.version 貌似和上面那个version一样.

ctor->new.route 表示这是nvif. 除了nvif另一种是usif,用户空间用的.

ctor->new.token 此处是储存对应的nvif_object.

ctor->new.handle 此处是储存要创建的nouveau_object的handle.

ctor->new.oclass 此处是储存要创建的nouveau_object的oclass.

第254行,正式调用nvif_object_ioctl函数.

// /drivers/gpu/drm/nouveau/nvif/object.c
 30 int
 31 nvif_object_ioctl(struct nvif_object *object, void *data, u32 size, void **hack)
 32 {
 33         struct nvif_client *client = nvif_client(object);
 34         union {
 35                 struct nvif_ioctl_v0 v0;
 36         } *args = data;
 37 
 38         if (size >= sizeof(*args) && args->v0.version == 0) {
 39                 args->v0.owner = NVIF_IOCTL_V0_OWNER_ANY;
 40                 args->v0.path_nr = 0;
 41                 while (args->v0.path_nr < ARRAY_SIZE(args->v0.path)) {
 42                         args->v0.path[args->v0.path_nr++] = object->handle;
 43                         if (object->parent == object)
 44                                 break;
 45                         object = object->parent;
 46                 }
 47         } else
 48                 return -ENOSYS;
 49 
 50         return client->driver->ioctl(client->base.priv, client->super, data, size, hack);
 51 }

第38行,首先检查version和大小是否正确

第39行,设置一下owner,这个是表示是对nvif还是usif还是any进行ioctl的. 可以防止用户态程序ioctl的时候ioctl到nvif [只能对usif进行ioctl.].

之后第41行一个whlie循环,逐级object = object->parent,然后把handle储存到path里.

第50行,交给client的driver进行处理.

// /drivers/gpu/drm/nouveau/nouveau_nvif.c
 54 static int
 55 nvkm_client_ioctl(void *priv, bool super, void *data, u32 size, void **hack)
 56 {
 57         return nvkm_ioctl(priv, super, data, size, hack);
 58 }
再交给nvkm_ioctl处理.

// /drivers/gpu/drm/nouveau/core/core/ioctl.c
502 int
503 nvkm_ioctl(struct nouveau_client *client, bool supervisor,
504            void *data, u32 size, void **hack)
505 {
506         union {
507                 struct nvif_ioctl_v0 v0;
508         } *args = data;
509         int ret;
510 
511         client->super = supervisor;
512         nv_ioctl(client, "size %d\n", size);
513 
514         if (nvif_unpack(args->v0, 0, 0, true)) {
515                 nv_ioctl(client, "vers %d type %02x path %d owner %02x\n",
516                          args->v0.version, args->v0.type, args->v0.path_nr,
517                          args->v0.owner);
518                 ret = nvkm_ioctl_path(client->root, args->v0.type,
519                                       args->v0.path_nr, args->v0.path,
520                                       data, size, args->v0.owner,
521                                      &args->v0.route, &args->v0.token);
522         }
523 
524         nv_ioctl(client, "return %d\n", ret);
525         if (hack) {
526                 *hack = client->data;
527                 client->data = http://www.mamicode.com/NULL;>client->super意义不明,忽略之.

然后第514行,看看nvif_unpack:

// /drivers/gpu/drm/nouveau/nvif/unpack.h
  9 #define nvif_unpack(d,vl,vh,m) ({                                               10         if ((vl) == 0 || ret == -ENOSYS) {                                      11                 int _size = sizeof(d);                                          12                 if (_size <= size && (d).version >= (vl) &&                     13                                      (d).version <= (vh)) {                     14                         data = http://www.mamicode.com/(u8 *)data + _size;                              15                         size = size - _size;                                    16                         ret = ((m) || !size) ? 0 : -E2BIG;                      17                 } else {                                                        18                         ret = -ENOSYS;                                          19                 }                                                               20         }                                                                       21         (ret == 0);                                                             22 })

大体上来说就是检查版本是否对应,大小是否正常,然后把data加上header的size,把size减去header的size.

第518行,调用nvkm_ioctl_path.

第526行,把data存到*hack里.

重点看nvkm_ioctl_path:

// /drivers/gpu/drm/nouveau/core/core/ioctl.c
459 static int
460 nvkm_ioctl_path(struct nouveau_handle *parent, u32 type, u32 nr,
461                   u32 *path, void *data, u32 size,
462                   u8 owner, u8 *route, u64 *token)
463 {
464         struct nouveau_handle *handle = parent;
465         struct nouveau_namedb *namedb;
466         struct nouveau_object *object;
467         int ret;
468 
469         while ((object = parent->object), nr--) {
470                 nv_ioctl(object, "path 0x%08x\n", path[nr]);
471                 if (!nv_iclass(object, NV_PARENT_CLASS)) {
472                         nv_debug(object, "cannot have children (path)\n");
473                         return -EINVAL;
474                 }
475 
476                 if (!(namedb = (void *)nv_pclass(object, NV_NAMEDB_CLASS)) ||
477                     !(handle = nouveau_namedb_get(namedb, path[nr]))) {
478                         nv_debug(object, "handle 0x%08x not found\n", path[nr]);
479                         return -ENOENT;
480                 }
481                 nouveau_namedb_put(handle);
482                 parent = handle;
483         }
484 
485         if (owner != NVIF_IOCTL_V0_OWNER_ANY &&
486             owner != handle->route) {
487                 nv_ioctl(object, "object route != owner\n");
488                 return -EACCES;
489         }
490         *route = handle->route;
491         *token = handle->token;
492 
493         if (ret = -EINVAL, type < ARRAY_SIZE(nvkm_ioctl_v0)) {
494                 if (nvkm_ioctl_v0[type].version == 0) {
495                         ret = nvkm_ioctl_v0[type].func(handle, data, size);
496                 }
497         }
498 
499         return ret;
500 }
参数parent是client->root,它对应的object就是它自己client.

第469行的while语句,逐个把path[--nr]取出来,从后往前,也就是从parent到children,在namedb中查找.

这样一来,最后的handle就是path[0]所对应的nouveau_handle. 也就是当初调用nvif_object_init第一个参数nvif_object *object对应的nouveau_object *object对应的nouveau_handle *handle! 对于这个例子就是nouveau_client *client的root字段.

接下来第485行,检查owner和handle->route是否匹配,作用前面提到了.

第490行.把handle->route和handle->token储存到*route和*token中,再调用真正的ioctl函数.

// /drivers/gpu/drm/nouveau/core/core/ioctl.c
439 static struct {
440         int version;
441         int (*func)(struct nouveau_handle *, void *, u32);
442 }
443 nvkm_ioctl_v0[] = {
444         { 0x00, nvkm_ioctl_nop },
445         { 0x00, nvkm_ioctl_sclass },
446         { 0x00, nvkm_ioctl_new },
447         { 0x00, nvkm_ioctl_del },
448         { 0x00, nvkm_ioctl_mthd },
449         { 0x00, nvkm_ioctl_rd },
450         { 0x00, nvkm_ioctl_wr },
451         { 0x00, nvkm_ioctl_map },
452         { 0x00, nvkm_ioctl_unmap },
453         { 0x00, nvkm_ioctl_ntfy_new },
454         { 0x00, nvkm_ioctl_ntfy_del },
455         { 0x00, nvkm_ioctl_ntfy_get },
456         { 0x00, nvkm_ioctl_ntfy_put },
457 };
本例当然是nvkm_ioctl_new,来看一下这个函数:

 87 static int
 88 nvkm_ioctl_new(struct nouveau_handle *parent, void *data, u32 size)
 89 {
 90         union {
 91                 struct nvif_ioctl_new_v0 v0;
 92         } *args = data;
 93         struct nouveau_client *client = nouveau_client(parent->object);
 94         struct nouveau_object *engctx = NULL;
 95         struct nouveau_object *object = NULL;
 96         struct nouveau_object *engine;
 97         struct nouveau_oclass *oclass;
 98         struct nouveau_handle *handle;
 99         u32 _handle, _oclass;
100         int ret;
101 
102         nv_ioctl(client, "new size %d\n", size);
103         if (nvif_unpack(args->v0, 0, 0, true)) {
104                 _handle = args->v0.handle;
105                 _oclass = args->v0.oclass;
106         } else
107                 return ret;
108 
109         nv_ioctl(client, "new vers %d handle %08x class %08x "
110                          "route %02x token %llx\n",
111                 args->v0.version, _handle, _oclass,
112                 args->v0.route, args->v0.token);
113 
114         if (!nv_iclass(parent->object, NV_PARENT_CLASS)) {
115                 nv_debug(parent->object, "cannot have children (ctor)\n");
116                 ret = -ENODEV;
117                 goto fail_class;
118         }
119 
120         /* check that parent supports the requested subclass */
121         ret = nouveau_parent_sclass(parent->object, _oclass, &engine, &oclass);
122         if (ret) {
123                 nv_debug(parent->object, "illegal class 0x%04x\n", _oclass);
124                 goto fail_class;
125         }
126 
127         /* make sure engine init has been completed *before* any objects
128          * it controls are created - the constructors may depend on
129          * state calculated at init (ie. default context construction)
130          */
131         if (engine) {
132                 ret = nouveau_object_inc(engine);
133                 if (ret)
134                         goto fail_class;
135         }
136 
137         /* if engine requires it, create a context object to insert
138          * between the parent and its children (eg. PGRAPH context)
139          */
140         if (engine && nv_engine(engine)->cclass) {
141                 ret = nouveau_object_ctor(parent->object, engine,
142                                           nv_engine(engine)->cclass,
143                                           data, size, &engctx);
144                 if (ret)
145                         goto fail_engctx;
146         } else {
147                 nouveau_object_ref(parent->object, &engctx);
148         }
149 
150         /* finally, create new object and bind it to its handle */
151         ret = nouveau_object_ctor(engctx, engine, oclass, data, size, &object);
152         client->data = http://www.mamicode.com/object;>第103行,再次使用nvif_unpack检查参数的正确性.

第121行,这就是u32 oclass到nouveau_oclass *oclass的转换了.

// /drivers/gpu/drm/nouveau/core/core/parent.c
 29 int
 30 nouveau_parent_sclass(struct nouveau_object *parent, u16 handle,
 31                       struct nouveau_object **pengine,
 32                       struct nouveau_oclass **poclass)
 33 {
 34         struct nouveau_sclass *sclass;
 35         struct nouveau_engine *engine;
 36         struct nouveau_oclass *oclass;
 37         u64 mask;
 38 
 39         sclass = nv_parent(parent)->sclass;
 40         while (sclass) {
 41                 if ((sclass->oclass->handle & 0xffff) == handle) {
 42                         *pengine = parent->engine;
 43                         *poclass = sclass->oclass;
 44                         return 0;
 45                 }
 46 
 47                 sclass = sclass->sclass;
 48         }
 49 
 50         mask = nv_parent(parent)->engine;
 51         while (mask) {
 52                 int i = __ffs64(mask);
 53 
 54                 if (nv_iclass(parent, NV_CLIENT_CLASS))
 55                         engine = nv_engine(nv_client(parent)->device);
 56                 else
 57                         engine = nouveau_engine(parent, i);
 58 
 59                 if (engine) {
 60                         oclass = engine->sclass;
 61                         while (oclass->ofuncs) {
 62                                 if ((oclass->handle & 0xffff) == handle) {
 63                                         *pengine = nv_object(engine);
 64                                         *poclass = oclass;
 65                                         return 0;
 66                                 }
 67                                 oclass++;
 68                         }
 69                 }
 70 
 71                 mask &= ~(1ULL << i);
 72         }
 73 
 74         return -EINVAL;
 75 }
首先第40行的while语句,直接在parent->sclass中寻找,这个东西可以看作是一个单向链表. 对于这个例子,parent->sclass为0,故不存在这种可能性.

然后第52行,从((nouveau_parent *)parent)->engine指示的subdev中寻找. __ffs64返回的是二进制中第一个为1的位是第几位. 比如0b1返回0 ,0b1000返回3.

如果parent不是一个nouveau_client对象,那么就先向上获取一个nouveau_device对象,然后返回device->subdev[i] .

如果parent是一个nouveau_client对象,那么直接使用client->device.

对于本例当然是后者,也就是直接使用我们在第三篇中用nouveau_device_create创建的那个nouveau_device *device. (此处需要注意nouveau_parent::sclass是个单向链表,但nouveau_device::sclass是个数组.)

还记得当初传递进去的sclass是什么吗?

// /drivers/gpu/drm/nouveau/core/engine/device/base.c
501 static struct nouveau_oclass
502 nouveau_device_sclass[] = {
503         { 0x0080, &nouveau_devobj_ofuncs },
504         {}
505 };
看看我们现在的这个oclass是什么:

// /drivers/gpu/drm/nouveau/core/include/nvif/class.h
  9 #define NV_DEVICE                                                    0x00000080

匹配成功! 于是对pengine和poclass进行赋值操作,返回.

第132行,对engine执行nouveau_object_inc函数:

// /drivers/gpu/drm/nouveau/core/core/object.c
164 int
165 nouveau_object_inc(struct nouveau_object *object)
166 {
167         int ref = atomic_add_return(1, &object->usecount);
168         int ret;
169 
170         nv_trace(object, "use(+1) == %d\n", atomic_read(&object->usecount));
171         if (ref != 1)
172                 return 0;
173 
174         nv_trace(object, "initialising...\n");
175         if (object->parent) {
176                 ret = nouveau_object_inc(object->parent);
177                 if (ret) {
178                         nv_error(object, "parent failed, %d\n", ret);
179                         goto fail_parent;
180                 }
181         }
182 
183         if (object->engine) {
184                 mutex_lock(&nv_subdev(object->engine)->mutex);
185                 ret = nouveau_object_inc(object->engine);
186                 mutex_unlock(&nv_subdev(object->engine)->mutex);
187                 if (ret) {
188                         nv_error(object, "engine failed, %d\n", ret);
189                         goto fail_engine;
190                 }
191         }
192 
193         ret = nv_ofuncs(object)->init(object);
194         atomic_set(&object->usecount, 1);
195         if (ret) {
196                 nv_error(object, "init failed, %d\n", ret);
197                 goto fail_self;
198         }
199 
200         nv_trace(object, "initialised\n");
201         return 0;
202 
203 fail_self:
204         if (object->engine) {
205                 mutex_lock(&nv_subdev(object->engine)->mutex);
206                 nouveau_object_dec(object->engine, false);
207                 mutex_unlock(&nv_subdev(object->engine)->mutex);
208         }
209 fail_engine:
210         if (object->parent)
211                  nouveau_object_dec(object->parent, false);
212 fail_parent:
213         atomic_dec(&object->usecount);
214         return ret;
215 }
因此这是第一次执行nouveau_object_inc函数,所以第171行并没有返回.

然后第176行,对parent执行inc操作,第185行,对engine执行inc操作. 此处对由于parent和engine都为0,所以并没有执行进这两个if语句.

第193行,执行oclass里的init函数:

// /drivers/gpu/drm/nouveau/core/engine/device/base.c
652 static struct nouveau_oclass
653 nouveau_device_oclass = {
654         .handle = NV_ENGINE(DEVICE, 0x00),
655         .ofuncs = &(struct nouveau_ofuncs) {
656                 .dtor = nouveau_device_dtor,
657                 .init = nouveau_device_init,
658                 .fini = nouveau_device_fini,
659         },
660 };
// /drivers/gpu/drm/nouveau/core/engine/device/base.c
557 static int
558 nouveau_device_init(struct nouveau_object *object)
559 {
560         struct nouveau_device *device = (void *)object;
561         struct nouveau_object *subdev;
562         int ret, i = 0;
563 
564         ret = nvkm_acpi_init(device);
565         if (ret)
566                 goto fail;
567 
568         for (i = 0; i < NVDEV_SUBDEV_NR; i++) {
569                 if ((subdev = device->subdev[i])) {
570                         if (!nv_iclass(subdev, NV_ENGINE_CLASS)) {
571                                 ret = nouveau_object_inc(subdev);
572                                 if (ret)
573                                         goto fail;
574                         } else {
575                                 nouveau_subdev_reset(subdev);
576                         }
577                 }
578         }
579 
580         ret = 0;
581 fail:
582         for (--i; ret && i >= 0; i--) {
583                 if ((subdev = device->subdev[i])) {
584                         if (!nv_iclass(subdev, NV_ENGINE_CLASS))
585                                 nouveau_object_dec(subdev, false);
586                 }
587         }
588 
589         if (ret)
590                 nvkm_acpi_fini(device, false);
591         return ret;
592 }
首先第564行执行nvkm_acpi_init,这个函数对ACPI模块注册了一个回调函数,当AC Adapter发出事件时就触发device->event,然后这个事件会在clock中被受理. 暂时不展开说了.

接下来第568行的for语句,遍历一下device->subdev,执行nouveau_object_inc或者nouveau_subdev_reset.

然后第582行的for语句,再遍历一遍执行nouveau_object_dec. 前面执行一次inc,这里再执行一次dec,也就相当于reset了. 所以这段代码的作用就是reset所有subdev..

但现在subdev还没有被初始化,因此所有if语句都不会进入,所以啥也没做直接返回.

回到nvkm_ioctl_new,第141行,检查engine有没有cclass,有的话创建一个context object,对于这个例子没有.

第151行,创建一个nvif_object对应的nouveau_object:

// /drivers/gpu/drm/nouveau/core/core/object.c
105 int
106 nouveau_object_ctor(struct nouveau_object *parent,
107                     struct nouveau_object *engine,
108                     struct nouveau_oclass *oclass, void *data, u32 size,
109                     struct nouveau_object **pobject)
110 {
111         struct nouveau_ofuncs *ofuncs = oclass->ofuncs;
112         struct nouveau_object *object = NULL;
113         int ret;
114 
115         ret = ofuncs->ctor(parent, engine, oclass, data, size, &object);
116         *pobject = object;
117         if (ret < 0) {
118                 if (ret != -ENODEV) {
119                         nv_error(parent, "failed to create 0x%08x, %d\n",
120                                  oclass->handle, ret);
121                 }
122 
123                 if (object) {
124                         ofuncs->dtor(object);
125                         *pobject = NULL;
126                 }
127 
128                 return ret;
129         }
130 
131         if (ret == 0) {
132                 nv_trace(object, "created\n");
133                 atomic_set(&object->refcount, 1);
134         }
135 
136         return 0;
137 }
这个函数就是调用了一下oclass里的ctor函数,然后进行错误检查,出错就销毁一下. 第133行,再初始化一下refcount,返回.

对于这个例子,对应的是"nouveau_devobj_init",这又是一个超级长的函数,所以决定下一篇单独描述这个函数,现在只需要知道它对设备的类型进行了检测,然后初始化了各个subdev就可以了.

再看nvkm_ioctl_new的第156行,对新创建的nouveau_object执行nouveau_object_inc操作,将会调用它的oclass里对应的init函数,对于这个例子是个空函数,无视.

第160行,创建一个nouveau_handle,它将会被自动加入到对应的namedb中,下一次我们就能从namedb中找到这个nouveau_object了.

第165行,执行一个nouveau_handle_init函数,这个函数首先执行nouveau_object_inc(handle->object); 然后对handle->tree链表里储存的所有children进行nouveau_handle_init操作.

然后第166行,把route和token储存到handle里.

最后第171行到第181行,进行一些清理操作,返回. [这些清理操作绝对不会执行任何对象的析构函数,或者导致内存释放. 因为这些对象均已经在其他地方被引用. (除非是出错之后用goto跳过来的,那种情况另说.)]

于是我们一路回到了nvif_device_init, 第43行,发送一个mthd ioctl,作用是获取设备信息储存到device->info里,这个同样留到下一篇在说.

然后我们回到了nouveau_drm_load的第395行,这一篇就先写到这里了.

Nouveau源码分析(五):NVIDIA设备初始化之nouveau_drm_load (2)