Nouveau源代码分析(三)
向DRM注冊了Nouveau驱动之后,内核中的PCI模块就会扫描全部没有相应驱动的设备,然后和nouveau_drm_pci_table对比.
对于匹配的设备,PCI模块就调用相应的probe函数,也就是nouveau_drm_probe.
// /drivers/gpu/drm/nouveau/nouveau_drm.c
281 static int nouveau_drm_probe(struct pci_dev *pdev,
282 const struct pci_device_id *pent)
283 {
284 struct nouveau_device *device;
285 struct apertures_struct *aper;
286 bool boot = false;
287 int ret;
288
289 /* remove conflicting drivers (vesafb, efifb etc) */
290 aper = alloc_apertures(3);
291 if (!aper)
292 return -ENOMEM;
293
294 aper->ranges[0].base = pci_resource_start(pdev, 1);
295 aper->ranges[0].size = pci_resource_len(pdev, 1);
296 aper->count = 1;
297
298 if (pci_resource_len(pdev, 2)) {
299 aper->ranges[aper->count].base = pci_resource_start(pdev, 2);
300 aper->ranges[aper->count].size = pci_resource_len(pdev, 2);
301 aper->count++;
302 }
303
304 if (pci_resource_len(pdev, 3)) {
305 aper->ranges[aper->count].base = pci_resource_start(pdev, 3);
306 aper->ranges[aper->count].size = pci_resource_len(pdev, 3);
307 aper->count++;
308 }
309
310 #ifdef CONFIG_X86
311 boot = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
312 #endif
313 if (nouveau_modeset != 2)
314 remove_conflicting_framebuffers(aper, "nouveaufb", boot);
315 kfree(aper);
316
317 ret = nouveau_device_create(pdev, NOUVEAU_BUS_PCI,
318 nouveau_pci_name(pdev), pci_name(pdev),
319 nouveau_config, nouveau_debug, &device);
320 if (ret)
321 return ret;
322
323 pci_set_master(pdev);
324
325 ret = drm_get_pci_dev(pdev, pent, &driver);
326 if (ret) {
327 nouveau_object_ref(NULL, (struct nouveau_object **)&device);
328 return ret;
329 }
330
331 return 0;
332 }第290~315行,分配了一个aper,把资源位置写进去,调用了remove_conflicting_framebuffer,接着释放这个aper.
一行凝视和函数名已经说的非常明确,就是移除冲突的framebuffer.
第317行,创建一个NV设备的结构体,这个函数我们要细致看
// /drivers/gpu/drm/nouveau/core/include/engine/device.h
13 #define nouveau_device_create(p,t,n,s,c,d,u) \
14 nouveau_device_create_((void *)(p), (t), (n), (s), (c), (d), \
15 sizeof(**u), (void **)u)
16
17 int nouveau_device_create_(void *, enum nv_bus_type type, u64 name,
18 const char *sname, const char *cfg, const char *dbg,
19 int, void **);// /drivers/gpu/drm/nouveau/core/include/core/device.h
65 struct nouveau_device {
66 struct nouveau_engine base;
67 struct list_head head;
68
69 struct pci_dev *pdev;
70 struct platform_device *platformdev;
71 u64 handle;
72
73 struct nvkm_event event;
74
75 const char *cfgopt;
76 const char *dbgopt;
77 const char *name;
78 const char *cname;
79 u64 disable_mask;
80
81 enum {
82 NV_04 = 0x04,
83 NV_10 = 0x10,
84 NV_11 = 0x11,
85 NV_20 = 0x20,
86 NV_30 = 0x30,
87 NV_40 = 0x40,
88 NV_50 = 0x50,
89 NV_C0 = 0xc0,
90 NV_E0 = 0xe0,
91 GM100 = 0x110,
92 } card_type;
93 u32 chipset;
94 u32 crystal;
95
96 struct nouveau_oclass *oclass[NVDEV_SUBDEV_NR];
97 struct nouveau_object *subdev[NVDEV_SUBDEV_NR];
98
99 struct {
100 struct notifier_block nb;
101 } acpi;
102 };第67行,链接全部NV设备的链表.
第69行,相应的PCI设备.
第70行,相应的platform设备 (两者选一,要么是PCI设备,要么是platform设备,主要讨论前者).
第71行,算是一个标识符,在创建这个结构体的时候就比較它,有同样的就觉得已经被创建,返回-EEXIST.
第73行,一个事件,是和电源有关的,由AC Adapter在ACPI中发出,CLOCK中接受.
第75行,config设置.
第76行,debug设置.
第77行,PCI名称.
第78行,NV名称,比方GK110,GK20A.
第79行,表示禁用的subdev.
第92行,设备类别 [Family].
第93行,更精确的设备类别 [Chipset].
第94行,晶振频率.
第96行,每个subdev的oclass,oclass的含义參考上一节.
第97行,subdev列表.
第101行,是传给acpi用于触发上面那个event的一个东西.
然后来看nouveau_engine
// /drivers/gpu/drm/nouveau/core/include/core/engine.h
10 struct nouveau_engine {
11 struct nouveau_subdev base;
12 struct nouveau_oclass *cclass;
13 struct nouveau_oclass *sclass;
14
15 struct list_head contexts;
16 spinlock_t lock;
17
18 void (*tile_prog)(struct nouveau_engine *, int region);
19 int (*tlb_flush)(struct nouveau_engine *);
20 };
第12行,貌似是context oclass,构造context object的时候用的.
第13行,通过u32 oclass得到nouveau_oclass *oclass的一个东西.
第15行,context object链表.
第16行,自旋锁.
第18~19行,瓦片? 意义不明,仅仅在NV01~NV40 实用. [我准备讨论NVC0,由于我的显卡family就是NVC0,方便实验]
// /drivers/gpu/drm/nouveau/core/include/core/subdev.h
9 struct nouveau_subdev {
10 struct nouveau_object base;
11 struct mutex mutex;
12 const char *name;
13 void __iomem *mmio;
14 u32 debug;
15 u32 unit;
16
17 void (*intr)(struct nouveau_subdev *);
18 };第11行,锁.
第12行,名称,主要输出调试信息的时候用.
第13行,MMIO地址.
第14行,调试级别,用于推断是否输出调试信息.
第15行,subdev析构的使用用的,推測是禁用这个subdev.
第17行,中断处理函数指针.
最终到了object结构体------nouveau_object了.
// /drivers/gpu/drm/nouveau/core/include/core/object.h
17 struct nouveau_object {
18 struct nouveau_oclass *oclass;
19 struct nouveau_object *parent;
20 struct nouveau_object *engine;
21 atomic_t refcount;
22 atomic_t usecount;
23 #if CONFIG_NOUVEAU_DEBUG >= NV_DBG_PARANOIA
24 #define NOUVEAU_OBJECT_MAGIC 0x75ef0bad
25 struct list_head list;
26 u32 _magic;
27 #endif
28 };
第19行,parent,就是父结构体.
第20行,相应的engine.
第21行和第22行,两个计数器.
第23到第27行,调试用的魔数.
然后到了xxx_create_函数:
// /drivers/gpu/drm/nouveau/core/engine/device/base.c
662 int
663 nouveau_device_create_(void *dev, enum nv_bus_type type, u64 name,
664 const char *sname, const char *cfg, const char *dbg,
665 int length, void **pobject)
666 {
667 struct nouveau_device *device;
668 int ret = -EEXIST;
669
670 mutex_lock(&nv_devices_mutex);
671 list_for_each_entry(device, &nv_devices, head) {
672 if (device->handle == name)
673 goto done;
674 }
675
676 ret = nouveau_engine_create_(NULL, NULL, &nouveau_device_oclass, true,
677 "DEVICE", "device", length, pobject);
678 device = *pobject;
679 if (ret)
680 goto done;
681
682 switch (type) {
683 case NOUVEAU_BUS_PCI:
684 device->pdev = dev;
685 break;
686 case NOUVEAU_BUS_PLATFORM:
687 device->platformdev = dev;
688 break;
689 }
690 device->handle = name;
691 device->cfgopt = cfg;
692 device->dbgopt = dbg;
693 device->name = sname;
694
695 nv_subdev(device)->debug = nouveau_dbgopt(device->dbgopt, "DEVICE");
696 nv_engine(device)->sclass = nouveau_device_sclass;
697 list_add(&device->head, &nv_devices);
698
699 ret = nvkm_event_init(&nouveau_device_event_func, 1, 1,
700 &device->event);
701 done:
702 mutex_unlock(&nv_devices_mutex);
703 return ret;
704 }首先获取锁,然后遍历nv_devices链表,假设handle一样,那么说明这个设备已经被创建了,返回.
676行,初始化base结构体nouveau_engine. [照例等会再看.]
但这边有一个oclass,这个必需要看:
// /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 };1. nouveau_device的handle是用于标识设备,防止一个设备被注冊多次
2. nouveau_oclass的handle,这个比較复杂,最低两位能够表示subdev的type,然后还能表示class的type [就是engine,subdev,object之类的]
3. 另一个没接触到的nouveau_handle的handle,这个用于nouveau_namedb中搜索特定handle.
剩下的三个函数指针,运行到的时候再说吧.
然后初始化device的pdev,handle,cfgopt,dbgopt,name,这些字段上面都介绍过了,不再多说.
nv_subdev,nv_engine是什么呢? 事实上就是把指针强制转换为nouveau_subdev *,nouveau_engine *,当某个控制调试程度的宏大于某个值时,会添加检查语句.
由于各种base全都是结构体的第一个字段,所以能够强制转换而不出问题.
第695行,初始化(nouveau_subdev *)device的debug字段.
第696行,这个注意一下. nouveau_engine的sclass字段前面介绍过,就是控制u32 oclass到nouveau_oclass *oclass的转换,所以我们来看看:
// /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 };第699行,初始化device->event,然后解锁,返回.
好了,我们来看nouveau_engine_create_.
// /drivers/gpu/drm/nouveau/core/core/engine.c
29 int
30 nouveau_engine_create_(struct nouveau_object *parent,
31 struct nouveau_object *engobj,
32 struct nouveau_oclass *oclass, bool enable,
33 const char *iname, const char *fname,
34 int length, void **pobject)
35 {
36 struct nouveau_engine *engine;
37 int ret;
38
39 ret = nouveau_subdev_create_(parent, engobj, oclass, NV_ENGINE_CLASS,
40 iname, fname, length, pobject);
41 engine = *pobject;
42 if (ret)
43 return ret;
44
45 if (parent) {
46 struct nouveau_device *device = nv_device(parent);
47 int engidx = nv_engidx(nv_object(engine));
48
49 if (device->disable_mask & (1ULL << engidx)) {
50 if (!nouveau_boolopt(device->cfgopt, iname, false)) {
51 nv_debug(engine, "engine disabled by hw/fw\n");
52 return -ENODEV;
53 }
54
55 nv_warn(engine, "ignoring hw/fw engine disable\n");
56 }
57
58 if (!nouveau_boolopt(device->cfgopt, iname, enable)) {
59 if (!enable)
60 nv_warn(engine, "disabled, %s=1 to enable\n", iname);
61 return -ENODEV;
62 }
63 }
64
65 INIT_LIST_HEAD(&engine->contexts);
66 spin_lock_init(&engine->lock);
67 return 0;
68 }第45行,推断parent,紧接着把他转换成nouveau_device,注意这个不是直接的强制转换.
// /drivers/gpu/drm/nouveau/core/include/core/device.h
106 static inline struct nouveau_device *
107 nv_device(void *obj)
108 {
109 struct nouveau_object *object = nv_object(obj);
110 struct nouveau_object *device = object;
111
112 if (device->engine)
113 device = device->engine;
114 if (device->parent)
115 device = device->parent;
116
117 #if CONFIG_NOUVEAU_DEBUG >= NV_DBG_PARANOIA
118 if (unlikely(!nv_iclass(device, NV_SUBDEV_CLASS) ||
119 (nv_hclass(device) & 0xff) != NVDEV_ENGINE_DEVICE)) {
120 nv_assert("BAD CAST -> NvDevice, 0x%08x 0x%08x",
121 nv_hclass(object), nv_hclass(device));
122 }
123 #endif
124
125 return (void *)device;
126 }当然对于这个样例,device->engine和device->parent都为0,所以直接返回device.
回到刚才那个函数,第47行获取engidx,事实上就是subidx,再展开就是oclass::handle的最低两位.能够參考以下这个enum:
// /drivers/gpu/drm/nouveau/core/include/core/device.h
8 enum nv_subdev_type {
9 NVDEV_ENGINE_DEVICE,
10 NVDEV_SUBDEV_VBIOS,
11
12 /* All subdevs from DEVINIT to DEVINIT_LAST will be created before
13 * *any* of them are initialised. This subdev category is used
14 * for any subdevs that the VBIOS init table parsing may call out
15 * to during POST.
16 */
17 NVDEV_SUBDEV_DEVINIT,
18 NVDEV_SUBDEV_GPIO,
19 NVDEV_SUBDEV_I2C,
20 NVDEV_SUBDEV_DEVINIT_LAST = NVDEV_SUBDEV_I2C,
21
22 /* This grouping of subdevs are initialised right after they've
23 * been created, and are allowed to assume any subdevs in the
24 * list above them exist and have been initialised.
25 */
26 NVDEV_SUBDEV_MXM,
27 NVDEV_SUBDEV_MC,
28 NVDEV_SUBDEV_BUS,
29 NVDEV_SUBDEV_TIMER,
30 NVDEV_SUBDEV_FB,
31 NVDEV_SUBDEV_LTCG,
32 NVDEV_SUBDEV_IBUS,
33 NVDEV_SUBDEV_INSTMEM,
34 NVDEV_SUBDEV_VM,
35 NVDEV_SUBDEV_BAR,
36 NVDEV_SUBDEV_PWR,
37 NVDEV_SUBDEV_VOLT,
38 NVDEV_SUBDEV_THERM,
39 NVDEV_SUBDEV_CLOCK,
40
41 NVDEV_ENGINE_FIRST,
42 NVDEV_ENGINE_DMAOBJ = NVDEV_ENGINE_FIRST,
43 NVDEV_ENGINE_FIFO,
44 NVDEV_ENGINE_SW,
45 NVDEV_ENGINE_GR,
46 NVDEV_ENGINE_MPEG,
47 NVDEV_ENGINE_ME,
48 NVDEV_ENGINE_VP,
49 NVDEV_ENGINE_CRYPT,
50 NVDEV_ENGINE_BSP,
51 NVDEV_ENGINE_PPP,
52 NVDEV_ENGINE_COPY0,
53 NVDEV_ENGINE_COPY1,
54 NVDEV_ENGINE_COPY2,
55 NVDEV_ENGINE_VIC,
56 NVDEV_ENGINE_VENC,
57 NVDEV_ENGINE_DISP,
58 NVDEV_ENGINE_PERFMON,
59
60 NVDEV_SUBDEV_NR,
61 };接着第49行检查这个engine有没有被禁用,再依据cfgopt的值决定做法.
第58行,检查cfgopt和enable是否相应,出错就返回.
第65,66行,初始化链表和自旋锁,返回.
紧接着,来看nouveau_subdev_create_:
// /drivers/gpu/drm/nouveau/core/core/subdev.c
86 int
87 nouveau_subdev_create_(struct nouveau_object *parent,
88 struct nouveau_object *engine,
89 struct nouveau_oclass *oclass, u32 pclass,
90 const char *subname, const char *sysname,
91 int size, void **pobject)
92 {
93 struct nouveau_subdev *subdev;
94 int ret;
95
96 ret = nouveau_object_create_(parent, engine, oclass, pclass |
97 NV_SUBDEV_CLASS, size, pobject);
98 subdev = *pobject;
99 if (ret)
100 return ret;
101
102 __mutex_init(&subdev->mutex, subname, &oclass->lock_class_key);
103 subdev->name = subname;
104
105 if (parent) {
106 struct nouveau_device *device = nv_device(parent);
107 subdev->debug = nouveau_dbgopt(device->dbgopt, subname);
108 subdev->mmio = nv_subdev(device)->mmio;
109 }
110
111 return 0;
112 }接着初始化mutex,name字段
假设parent不为0,那么就把subdev的debug和mmio字段初始化为相应的这两个字段.
就这个样例来说,parent就是0,所以不会运行进去的.
最后nouveau_object_create_ :
// /drivers/gpu/drm/nouveau/core/core/object.c
33 int
34 nouveau_object_create_(struct nouveau_object *parent,
35 struct nouveau_object *engine,
36 struct nouveau_oclass *oclass, u32 pclass,
37 int size, void **pobject)
38 {
39 struct nouveau_object *object;
40
41 object = *pobject = kzalloc(size, GFP_KERNEL);
42 if (!object)
43 return -ENOMEM;
44
45 nouveau_object_ref(parent, &object->parent);
46 nouveau_object_ref(engine, &object->engine);
47 object->oclass = oclass;
48 object->oclass->handle |= pclass;
49 atomic_set(&object->refcount, 1);
50 atomic_set(&object->usecount, 0);
51
52 #ifdef NOUVEAU_OBJECT_MAGIC
53 object->_magic = NOUVEAU_OBJECT_MAGIC;
54 spin_lock(&_objlist_lock);
55 list_add(&object->list, &_objlist);
56 spin_unlock(&_objlist_lock);
57 #endif
58 return 0;
59 }由于parent,engine,object->parent,object->engine都为0,所以第45.46行代码事实上啥也没做.
初始化oclass字段,然后把oclass->handle或上plass标识符. [这个数究竟是多少能够向上翻,意义也非常easy理解.]
初始化refcount和usecount.
接下来的魔数忽略掉,调试查错用的.
然后58行,返回!
于是我们就这么回到了nouveau_drm_probe.
第323行,启用Bus-Mastering.
第325行,向DRM注冊PCI设备.
然后就是错误处理,假设失败还要把device处理一下,比方从链表中删除,释放空间等.
至于cfgopt,dbgopt,到头来各自是nouveau_config和nouveau_debug,是Nouveau的模块參数,有兴趣能够自己实验.
初始化远远没有结束,还有nouveau_drm_load,比这次这个函数不知道长多少倍.....