xf86-video-intel源码分析6 —— intel_device.c和intel_driver.h（1）
intel_driver.h
intel_driver.h位于src目录下，内容为：
#ifndef INTEL_DRIVER_H
#define INTEL_DRIVER_H
struct xf86_platform_device;
#define INTEL_VERSION 4000
#define INTEL_NAME "intel"
#define INTEL_DRIVER_NAME "intel"
#define INTEL_VERSION_MAJOR PACKAGE_VERSION_MAJOR
#define INTEL_VERSION_MINOR PACKAGE_VERSION_MINOR
#define INTEL_VERSION_PATCH PACKAGE_VERSION_PATCHLEVEL
#define PCI_CHIP_I810 0x7121
#define PCI_CHIP_I810_DC100 0x7123
#define PCI_CHIP_I810_E 0x7125
#define PCI_CHIP_I815 0x1132
#define PCI_CHIP_I830_M 0x3577
#define PCI_CHIP_845_G 0x2562
#define PCI_CHIP_I854 0x358E
#define PCI_CHIP_I855_GM 0x3582
#define PCI_CHIP_I865_G 0x2572
#define PCI_CHIP_I915_G 0x2582
#define PCI_CHIP_I915_GM 0x2592
#define PCI_CHIP_E7221_G 0x258A
#define PCI_CHIP_I945_G 0x2772
#define PCI_CHIP_I945_GM 0x27A2
#define PCI_CHIP_I945_GME 0x27AE
#define PCI_CHIP_PINEVIEW_M 0xA011
#define PCI_CHIP_PINEVIEW_G 0xA001
#define PCI_CHIP_Q35_G 0x29B2
#define PCI_CHIP_G33_G 0x29C2
#define PCI_CHIP_Q33_G 0x29D2
#define PCI_CHIP_G35_G 0x2982
#define PCI_CHIP_I965_Q 0x2992
#define PCI_CHIP_I965_G 0x29A2
#define PCI_CHIP_I946_GZ 0x2972
#define PCI_CHIP_I965_GM 0x2A02
#define PCI_CHIP_I965_GME 0x2A12
#define PCI_CHIP_GM45_GM 0x2A42
#define PCI_CHIP_G45_E_G 0x2E02
#define PCI_CHIP_G45_G 0x2E22
#define PCI_CHIP_Q45_G 0x2E12
#define PCI_CHIP_G41_G 0x2E32
#define PCI_CHIP_B43_G 0x2E42
#define PCI_CHIP_B43_G1 0x2E92
#define PCI_CHIP_IRONLAKE_D_G 0x0042
#define PCI_CHIP_IRONLAKE_M_G 0x0046
#define PCI_CHIP_SANDYBRIDGE_GT1 0x0102
#define PCI_CHIP_SANDYBRIDGE_GT2 0x0112
#define PCI_CHIP_SANDYBRIDGE_GT2_PLUS 0x0122
#define PCI_CHIP_SANDYBRIDGE_M_GT1 0x0106
#define PCI_CHIP_SANDYBRIDGE_M_GT2 0x0116
#define PCI_CHIP_SANDYBRIDGE_M_GT2_PLUS 0x0126
#define PCI_CHIP_SANDYBRIDGE_S_GT 0x010A
#define PCI_CHIP_IVYBRIDGE_M_GT1 0x0156
#define PCI_CHIP_IVYBRIDGE_M_GT2 0x0166
#define PCI_CHIP_IVYBRIDGE_D_GT1 0x0152
#define PCI_CHIP_IVYBRIDGE_D_GT2 0x0162
#define PCI_CHIP_IVYBRIDGE_S_GT1 0x015a
#define PCI_CHIP_IVYBRIDGE_S_GT2 0x016a
#define PCI_CHIP_HASWELL_D_GT1 0x0402
#define PCI_CHIP_HASWELL_D_GT2 0x0412
#define PCI_CHIP_HASWELL_D_GT3 0x0422
#define PCI_CHIP_HASWELL_M_GT1 0x0406
#define PCI_CHIP_HASWELL_M_GT2 0x0416
#define PCI_CHIP_HASWELL_M_GT3 0x0426
#define PCI_CHIP_HASWELL_S_GT1 0x040A
#define PCI_CHIP_HASWELL_S_GT2 0x041A
#define PCI_CHIP_HASWELL_S_GT3 0x042A
#define PCI_CHIP_HASWELL_B_GT1 0x040B
#define PCI_CHIP_HASWELL_B_GT2 0x041B
#define PCI_CHIP_HASWELL_B_GT3 0x042B
#define PCI_CHIP_HASWELL_E_GT1 0x040E
#define PCI_CHIP_HASWELL_E_GT2 0x041E
#define PCI_CHIP_HASWELL_E_GT3 0x042E
#define PCI_CHIP_HASWELL_ULT_D_GT1 0x0A02
#define PCI_CHIP_HASWELL_ULT_D_GT2 0x0A12
#define PCI_CHIP_HASWELL_ULT_D_GT3 0x0A22
#define PCI_CHIP_HASWELL_ULT_M_GT1 0x0A06
#define PCI_CHIP_HASWELL_ULT_M_GT2 0x0A16
#define PCI_CHIP_HASWELL_ULT_M_GT3 0x0A26
#define PCI_CHIP_HASWELL_ULT_S_GT1 0x0A0A
#define PCI_CHIP_HASWELL_ULT_S_GT2 0x0A1A
#define PCI_CHIP_HASWELL_ULT_S_GT3 0x0A2A
#define PCI_CHIP_HASWELL_ULT_B_GT1 0x0A0B
#define PCI_CHIP_HASWELL_ULT_B_GT2 0x0A1B
#define PCI_CHIP_HASWELL_ULT_B_GT3 0x0A2B
#define PCI_CHIP_HASWELL_ULT_E_GT1 0x0A0E
#define PCI_CHIP_HASWELL_ULT_E_GT2 0x0A1E
#define PCI_CHIP_HASWELL_ULT_E_GT3 0x0A2E
#define PCI_CHIP_HASWELL_CRW_D_GT1 0x0D02
#define PCI_CHIP_HASWELL_CRW_D_GT2 0x0D12
#define PCI_CHIP_HASWELL_CRW_D_GT3 0x0D22
#define PCI_CHIP_HASWELL_CRW_M_GT1 0x0D06
#define PCI_CHIP_HASWELL_CRW_M_GT2 0x0D16
#define PCI_CHIP_HASWELL_CRW_M_GT3 0x0D26
#define PCI_CHIP_HASWELL_CRW_S_GT1 0x0D0A
#define PCI_CHIP_HASWELL_CRW_S_GT2 0x0D1A
#define PCI_CHIP_HASWELL_CRW_S_GT3 0x0D2A
#define PCI_CHIP_HASWELL_CRW_B_GT1 0x0D0B
#define PCI_CHIP_HASWELL_CRW_B_GT2 0x0D1B
#define PCI_CHIP_HASWELL_CRW_B_GT3 0x0D2B
#define PCI_CHIP_HASWELL_CRW_E_GT1 0x0D0E
#define PCI_CHIP_HASWELL_CRW_E_GT2 0x0D1E
#define PCI_CHIP_HASWELL_CRW_E_GT3 0x0D2E
struct intel_device_info {
int gen;
};
struct intel_device;
int intel_entity_get_devid(int index);
int intel_open_device(int entity_num,
const struct pci_device *pci,
struct xf86_platform_device *dev);
void intel_close_device(int entity_num);
int __intel_peek_fd(ScrnInfoPtr scrn);
struct intel_device *intel_get_device(ScrnInfoPtr scrn, int *fd);
int intel_has_render_node(struct intel_device *dev);
const char *intel_get_master_name(struct intel_device *dev);
const char *intel_get_client_name(struct intel_device *dev);
int intel_get_client_fd(struct intel_device *dev);
int intel_get_device_id(struct intel_device *dev);
int intel_get_master(struct intel_device *dev);
int intel_put_master(struct intel_device *dev);
void intel_put_device(struct intel_device *dev);
void intel_detect_chipset(ScrnInfoPtr scrn, struct intel_device *dev);
#define IS_DEFAULT_ACCEL_METHOD(x) ({ \
enum { NOACCEL, SNA, UXA } default_accel_method__ = DEFAULT_ACCEL_METHOD; \
default_accel_method__ == x; \
})
#define hosted() (0)
#endif /* INTEL_DRIVER_H */
intel_driver.h中声明了intel_device.c中实现的函数，虽然名字一个叫driver、一个叫device。其中内容在下边分析inter_device.c的时候再做讲解。
intel_device.c
intel_device.c位于src目录下，文件内容较长（将近850行），因此在此不全部列出，而是一个函数一个函数来分析。
- intel_open_device
int intel_open_device(int entity_num,
const struct pci_device *pci,
struct xf86_platform_device *platform)
{
struct intel_device *dev;
char *path;
int fd, master_count;
if (intel_device_key == -1)
intel_device_key = xf86AllocateEntityPrivateIndex();
if (intel_device_key == -1)
return -1;
dev = xf86GetEntityPrivate(entity_num, intel_device_key)->ptr;
if (dev)
return dev->fd;
path = get_path(platform);
master_count = 1; /* DRM_MASTER is managed by Xserver */
fd = get_fd(platform);
if (fd == -1) {
fd = __intel_open_device(pci, path);
if (fd == -1)
goto err_path;
master_count = 0;
}
if (path == NULL) {
path = find_master_node(fd);
if (path == NULL)
goto err_close;
}
if (!__intel_check_device(fd))
goto err_close;
dev = malloc(sizeof(*dev));
if (dev == NULL)
goto err_close;
/* If hosted under a system compositor, just pretend to be master */
if (hosted())
master_count++;
/* Non-root user holding MASTER, don't let go */
if (geteuid() && is_master(fd))
master_count++;
if (pci)
dev->device_id = pci->device_id;
else
dev->device_id = __intel_get_device_id(fd);
dev->idx = entity_num;
dev->fd = fd;
dev->open_count = master_count;
dev->master_count = master_count;
dev->master_node = path;
dev->render_node = find_render_node(fd);
if (dev->render_node == NULL)
dev->render_node = dev->master_node;
xf86GetEntityPrivate(entity_num, intel_device_key)->ptr = dev;
return fd;
err_close:
if (master_count == 0) /* Don't close server-fds */
close(fd);
err_path:
free(path);
return -1;
}这个函数本身也不短，分块来分析。先看第1段：
if (intel_device_key == -1)
intel_device_key = xf86AllocateEntityPrivateIndex();
if (intel_device_key == -1)
return -1;intel_device_key在同文件中定义，为静态全局变量：
static int intel_device_key = -1;初始时intel_device_key的值为-1，必定会调用xf86AllocateEntityPrivateIndex()。xf86AllocateEntityPrivateIndex函数在xorg-server源码的hw/xfree86/common/xf86Bus.c中，代码如下：
/*
* Allocate a private in the entities.
*/
int
xf86AllocateEntityPrivateIndex(void)
{
int idx, i;
EntityPtr pEnt;
DevUnion *nprivs;
idx = xf86EntityPrivateCount++;
for (i = 0; i < xf86NumEntities; i++) {
pEnt = xf86Entities[i];
nprivs = xnfreallocarray(pEnt->entityPrivates,
xf86EntityPrivateCount, sizeof(DevUnion));
/* Zero the new private */
memset(&nprivs[idx], 0, sizeof(DevUnion));
pEnt->entityPrivates = nprivs;
}
return idx;
}
再来看第2段：
dev = xf86GetEntityPrivate(entity_num, intel_device_key)->ptr;
if (dev)
return dev->fd;xf86GetEntityPrivate函数同在xorg-server源码的hw/xfree86/common/xf86Bus.c中，就在xf86AllocateEntityPrivateIndex函数实现的下边，代码如下：
DevUnion *
xf86GetEntityPrivate(int entityIndex, int privIndex)
{
if (entityIndex >= xf86NumEntities || privIndex >= xf86EntityPrivateCount)
return NULL;
return &(xf86Entities[entityIndex]->entityPrivates[privIndex]);
}接下来看第3段：
path = get_path(platform);path是函数内部定义的局部变量：char *path;。
这段代码的意思是根据intel_open_device函数的入参struct xf86_platform_device *platform即平台设备指针获得相应的路径。
get_path函数在同文件中实现，代码如下：
#if defined(ODEV_ATTRIB_PATH)
static char *get_path(struct xf86_platform_device *dev)
{
const char *path;
if (dev == NULL)
return NULL;
path = xf86_get_platform_device_attrib(dev, ODEV_ATTRIB_PATH);
if (path == NULL)
return NULL;
return strdup(path);
}
#else
static char *get_path(struct xf86_platform_device *dev)
{
return NULL;
}
#endif接下来看第4段：
master_count = 1; /* DRM_MASTER is managed by Xserver */
fd = get_fd(platform);
if (fd == -1) {
fd = __intel_open_device(pci, path);
if (fd == -1)
goto err_path;
master_count = 0;
}这段代码的意思是根据intel_open_device函数的入参struct xf86_platform_device *platform即平台设备指针获得相应的文件描述符。如果获取不到，则调用__intel_open_device函数根据intel_open_device函数的入参pci打开设备。
get_path函数在同文件中实现，代码如下：
#if defined(ODEV_ATTRIB_FD)
static int get_fd(struct xf86_platform_device *dev)
{
if (dev == NULL)
return -1;
return xf86_get_platform_device_int_attrib(dev, ODEV_ATTRIB_FD, -1);
}
#else
static int get_fd(struct xf86_platform_device *dev)
{
return -1;
}
#endif__intel_open_device函数在同文件中实现，代码如下：
static int __intel_open_device(const struct pci_device *pci, const char *path)
{
int fd;
if (path == NULL) {
if (pci == NULL)
return -1;
fd = __intel_open_device__pci(pci);
if (fd == -1)
fd = __intel_open_device__legacy(pci);
} else
fd = open_cloexec(path);
return fd;
}__intel_open_device函数中包含的2个函数都比较大，我们在下一篇文章中进行分析。