研究导向：
open camera过程中有些初始化设置参数需要从vendor层获取，而vendor与hal隶属于不同进程，通过ION机制设置共享内存来实现不同进程间数据共享，下面简要介绍流程：
在初始化过程中hal层会通过socket将消息发送至vendor层-通知vendor map共享内存。
ION初始化过程：
vim hardware/qcom/camera/QCamera2/HAL/QCamera2HWI.cpp
int QCamera2HardwareInterface::openCamera()
{
……
if (NULL == gCamCapability[mCameraId]) {
if(NO_ERROR != initCapabilities(mCameraId,mCameraHandle)) { //会初始化ION
......
}
}
mCameraHandle->ops->register_event_notify(mCameraHandle->camera_handle,
camEvtHandle,
(void *) this);
……
pthread_mutex_lock(&m_parm_lock);
//初始化m_pCapability-从vendor层拿到的camera相关初始化数据
mParameters.init(gCamCapability[mCameraId], mCameraHandle, this, this);
pthread_mutex_unlock(&m_parm_lock);
mParameters.m_parm_lock_ptr = &m_parm_lock;
ALOGI("openCamera: m_parm_lock_ptr = 0x%x", mParameters.m_parm_lock_ptr);
mCameraOpened = true;
gCameraOpened = true;
#ifdef USE_ARCSOFT_FEATURE
if ((NULL != mArcSoft_Feature)&&(mCameraId == 0))
mArcSoft_Feature->imx214_module_source = gCamCapability[0]->fih_imx214_module_source;//MM-YW-Get module source for HAL-00
#endif
return NO_ERROR;
}
int QCamera2HardwareInterface::initCapabilities(uint32_t cameraId,
mm_camera_vtbl_t *cameraHandle)
{
ATRACE_CALL();
int rc = NO_ERROR;
QCameraHeapMemory *capabilityHeap = NULL;
capabilityHeap = new QCameraHeapMemory(QCAMERA_ION_USE_CACHE);
rc = capabilityHeap->allocate(1, sizeof(cam_capability_t)); //1、设置ION共享内存
......
memset(DATA_PTR(capabilityHeap,0), 0, sizeof(cam_capability_t));
//2、通过socket通知vendor映射共享内存用于进程间通信
rc = cameraHandle->ops->map_buf(cameraHandle->camera_handle,
CAM_MAPPING_BUF_TYPE_CAPABILITY,
capabilityHeap->getFd(0),
sizeof(cam_capability_t));
if(rc < 0) {
ALOGE("%s: failed to map capability buffer", __func__);
goto map_failed;
}
rc = cameraHandle->ops->query_capability(cameraHandle->camera_handle);
if(rc < 0) {
ALOGE("%s: failed to query capability",__func__);
goto query_failed;
}
gCamCapability[cameraId] = (cam_capability_t *)malloc(sizeof(cam_capability_t));
if (!gCamCapability[cameraId]) {
ALOGE("%s: out of memory", __func__);
goto query_failed;
}
memcpy(gCamCapability[cameraId], DATA_PTR(capabilityHeap,0),
sizeof(cam_capability_t));
//copy the preview sizes and video sizes lists because they
//might be changed later
copyList(gCamCapability[cameraId]->preview_sizes_tbl, savedSizes[cameraId].all_preview_sizes,
gCamCapability[cameraId]->preview_sizes_tbl_cnt);
savedSizes[cameraId].all_preview_sizes_cnt = gCamCapability[cameraId]->preview_sizes_tbl_cnt;
copyList(gCamCapability[cameraId]->video_sizes_tbl, savedSizes[cameraId].all_video_sizes,
gCamCapability[cameraId]->video_sizes_tbl_cnt);
savedSizes[cameraId].all_video_sizes_cnt = gCamCapability[cameraId]->video_sizes_tbl_cnt;
rc = NO_ERROR;
query_failed:
cameraHandle->ops->unmap_buf(cameraHandle->camera_handle,
CAM_MAPPING_BUF_TYPE_CAPABILITY);
……
}
1、设置ION共享内存：
vim hardware/qcom/camera/QCamera2/HAL/QCameraMem.cpp
int QCameraHeapMemory::allocate(uint8_t count, size_t size)
{
traceLogAllocStart(size, count, "HeapMemsize");
unsigned int heap_mask = 0x1 << ION_IOMMU_HEAP_ID;
int rc = alloc(count, size, heap_mask); //主要填充mMemInfo
if (rc < 0)
return rc;
for (int i = 0; i < count; i ++) {
void *vaddr = mmap(NULL, //映射共享内存
mMemInfo[i].size,
PROT_READ | PROT_WRITE,
MAP_SHARED,
mMemInfo[i].fd, 0);
if (vaddr == MAP_FAILED) {
for (int j = i-1; j >= 0; j --) {
munmap(mPtr[j], mMemInfo[j].size);
mPtr[j] = NULL;
deallocOneBuffer(mMemInfo[j]);
}
return NO_MEMORY;
} else
mPtr[i] = vaddr;
}
if (rc == 0)
mBufferCount = count;
traceLogAllocEnd((size * count));
return OK;
}
int QCameraMemory::alloc(int count, size_t size, unsigned int heap_id)
{
……s
int new_bufCnt = mBufferCount + count;
traceLogAllocStart(size, count, "Memsize");
……
for (int i = mBufferCount; i < new_bufCnt; i ++) {
if ( NULL == mMemoryPool ) {
CDBG_HIGH("%s : No memory pool available and So allocate new buffer", __func__);
rc = allocOneBuffer(mMemInfo[i], heap_id, size, m_bCached);
if (rc < 0) {
ALOGE("%s: AllocateIonMemory failed", __func__);
for (int j = i-1; j >= 0; j--)
deallocOneBuffer(mMemInfo[j]);
break;
}
} else {
rc = mMemoryPool->allocateBuffer(mMemInfo[i],
heap_id,
size,
m_bCached,
mStreamType);
if (rc < 0) {
ALOGE("%s: Memory pool allocation failed", __func__);
for (int j = i-1; j >= 0; j--)
mMemoryPool->releaseBuffer(mMemInfo[j],
mStreamType);
break;
}
}
}
traceLogAllocEnd (size * (size_t)count);
return rc;
}
int QCameraMemory::allocOneBuffer(QCameraMemInfo &memInfo,
unsigned int heap_id, size_t size, bool cached)
{
int rc = OK;
struct ion_handle_data handle_data;
struct ion_allocation_data alloc;
struct ion_fd_data ion_info_fd;
int main_ion_fd = 0;
main_ion_fd = open("/dev/ion", O_RDONLY);
if (main_ion_fd < 0) {
ALOGE("Ion dev open failed: %s\n", strerror(errno));
goto ION_OPEN_FAILED;
}
memset(&alloc, 0, sizeof(alloc));
memset(&ion_info_fd, 0, sizeof(ion_info_fd));
alloc.len = size;
alloc.len = (alloc.len + 4095U) & (~4095U);
alloc.align = 4096;
if (cached) {
alloc.flags = ION_FLAG_CACHED;
}
alloc.heap_id_mask = heap_id;
rc = ioctl(main_ion_fd, ION_IOC_ALLOC, &alloc);
if (rc < 0) {
ALOGE("ION allocation failed: %s\n", strerror(errno));
goto ION_ALLOC_FAILED;
}
//memset(&ion_info_fd, 0, sizeof(ion_info_fd));
ion_info_fd.handle = alloc.handle;
rc = ioctl(main_ion_fd, ION_IOC_SHARE, &ion_info_fd);
if (rc < 0) {
ALOGE("ION map failed %s\n", strerror(errno));
goto ION_MAP_FAILED;
}
memInfo.main_ion_fd = main_ion_fd;
memInfo.fd = ion_info_fd.fd;
memInfo.handle = ion_info_fd.handle;
memInfo.size = alloc.len;
memInfo.cached = cached;
memInfo.heap_id = heap_id;
CDBG_HIGH("%s : ION buffer %lx with size %d allocated",
__func__, (unsigned long)memInfo.handle, memInfo.size);
return OK;
ION_MAP_FAILED:
memset(&handle_data, 0, sizeof(handle_data));
handle_data.handle = ion_info_fd.handle;
ioctl(main_ion_fd, ION_IOC_FREE, &handle_data);
ION_ALLOC_FAILED:
close(main_ion_fd);
ION_OPEN_FAILED:
return NO_MEMORY;
}
2、通过socket通知vendor映射相应共享内存用于进程间通信：
vim hardware/qcom/camera/QCamera2/stack/mm-camera-interface/src/mm_camera_interface.c
static int32_t mm_camera_intf_map_buf(uint32_t camera_handle,
uint8_t buf_type,
int fd,
size_t size)
{
int32_t rc = -1;
mm_camera_obj_t * my_obj = NULL;
pthread_mutex_lock(&g_intf_lock);
my_obj = mm_camera_util_get_camera_by_handler(camera_handle);
if(my_obj) {
pthread_mutex_lock(&my_obj->cam_lock);
pthread_mutex_unlock(&g_intf_lock);
rc = mm_camera_map_buf(my_obj, buf_type, fd, size);
} else {
pthread_mutex_unlock(&g_intf_lock);
}
return rc;
}
vim hardware/qcom/camera/QCamera2/stack/mm-camera-interface/src/mm_camera.c
int32_t mm_camera_map_buf(mm_camera_obj_t *my_obj,
uint8_t buf_type,
int fd,
size_t size)
{
int32_t rc = 0;
cam_sock_packet_t packet;
memset(&packet, 0, sizeof(cam_sock_packet_t));
packet.msg_type = CAM_MAPPING_TYPE_FD_MAPPING;
packet.payload.buf_map.type = buf_type;
packet.payload.buf_map.fd = fd;
packet.payload.buf_map.size = size;
rc = mm_camera_util_sendmsg(my_obj,
&packet,
sizeof(cam_sock_packet_t),
fd);
pthread_mutex_unlock(&my_obj->cam_lock);
return rc;
}
int32_t mm_camera_util_sendmsg(mm_camera_obj_t *my_obj,
void *msg,
size_t buf_size,
int sendfd)
{
int32_t rc = -1;
uint32_t status;
pthread_mutex_lock(&my_obj->msg_lock);
if(mm_camera_socket_sendmsg(my_obj->ds_fd, msg, buf_size, sendfd) > 0) {
mm_camera_util_wait_for_event(my_obj, CAM_EVENT_TYPE_MAP_UNMAP_DONE, &status);
if (MSM_CAMERA_STATUS_SUCCESS == status) {
rc = 0;
}
}
pthread_mutex_unlock(&my_obj->msg_lock);
return rc;
}
vim hardware/qcom/camera/QCamera2/stack/mm-camera-interface/src/mm_camera_sock.c
int mm_camera_socket_sendmsg(
int fd, //socket fd
void *msg,
size_t buf_size,
int sendfd)
{
struct msghdr msgh;
struct iovec iov[1];
struct cmsghdr * cmsghp = NULL;
char control[CMSG_SPACE(sizeof(int))];
if (msg == NULL) {
CDBG("%s: msg is NULL", __func__);
return -1;
}
memset(&msgh, 0, sizeof(msgh));
msgh.msg_name = NULL;
msgh.msg_namelen = 0;
iov[0].iov_base = msg;
iov[0].iov_len = buf_size;
msgh.msg_iov = iov;
msgh.msg_iovlen = 1;
CDBG("%s: iov_len=%llu", __func__,
(unsigned long long int)iov[0].iov_len);
msgh.msg_control = NULL;
msgh.msg_controllen = 0;
if( sendfd > 0) {
msgh.msg_control = control;
msgh.msg_controllen = sizeof(control);
cmsghp = CMSG_FIRSTHDR(&msgh);
if (cmsghp != NULL) {
CDBG("%s: Got ctrl msg pointer", __func__);
cmsghp->cmsg_level = SOL_SOCKET;
cmsghp->cmsg_type = SCM_RIGHTS;
cmsghp->cmsg_len = CMSG_LEN(sizeof(int));
*((int *)CMSG_DATA(cmsghp)) = sendfd;
CDBG("%s: cmsg data=%d", __func__, *((int *) CMSG_DATA(cmsghp)));
} else {
CDBG("%s: ctrl msg NULL", __func__);
return -1;
}
}
return sendmsg(fd, &(msgh), 0); //socket发送数据到vendor通知映射共享内存
}
refer: ION机制介绍
http://blog.csdn.net/cosmoslhf/article/details/41209925
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