VDK中的器件驱动

VDK带有器件驱动，一般如在DM642中使用的微驱动之类的东西，就是省却了工程师对底层部件的控制源代码的书写，换言之，要熟悉使用这些API函数，还要熟悉21369的底层接口和部件，不能简单 的调用一下函数了事，况且，ADI没有像TI那样提供足够的技术资料，很多API的调用都是要靠自己去翻源码出来阅读，而且要不断的猜测函数的作用，不是很方便，在C6713的BIOS当中，我是不使用其硬件驱动的，只是直接在初始化的时候把全部的部件都初始化完了，然后在OS中开启中断，再在中断里面发消息。这样也能达到程序设计的目的，感觉没有必要太劳累去迁就公司提供的API函数。

 

 

2011-11-14

今天看资料发现原来sharc是没有器件的驱动库函数了，跟bf系列不大一样，其实要不要驱动库都无所谓，因为作为音频专用的芯片，本来就没有多少外设需要做设置的，

都很简单，随便做个寄存器配置就行了，

同时，有文章可以从侧面证明，在ISR中直接使用VDK_C_ISR_PostSemaphore();不需要开启器件驱动。

Calling C_ISR_PostSemaphore from a thread

I have a function that does a post on a semaphore and at times this same function might be called by a thread, to make this code easier I was just calling the C_ISR_PostSemaphore, so it is ISR safe.  Does this cause any issues calling C_ISR_PostSemaphore via a thread instead of PostSemaphore?

 

Also, one caveat is only one type of calling function is enabled at anyone time... ie a thread calls the function no ISR is configured... the user does something... then disables the thread and enables the ISR... etc...

 

For example

 

commonFoo()

{

...

VDK::C_ISR_PostSemaphore(semaphore)

}

 

 

void ISR()

{

commonFoo();

}

 

 

workerThread()

{

 

.... code

commonFoo()

}

 

 

 

The ISR functions are not designed to be called from kernel or thread levels. In theory there should not be a problem doing but it is not something that we recommend. Instead, I would suggest calling the right API from the commonFoo function like this

Blackfin

inline int IS_USER_ISR_LEVEL (){
        return (*pIPEND  & ~( (1<<EVT_IRPTEN_P) | (1<< EVT_IVG15_P) | (1 <<  EVT_IVG14_P))) ;
}

SHARC

#ifdef __2116x__
inline int IS_USER_ISR_LEVEL (){
        return (sysreg_read(sysreg_IMASKP) & (~(SFT2I|LPISUMI)) );
}

 

#else
inline int IS_USER_ISR_LEVEL (){
        return (sysreg_read(sysreg_IMASKP) & ~SFT2I ) ;
}

 

#endif

 

So you could have  something like

commonFoo()

{

if (IS_USER_ISR_LEVEL())  {

       VDK_C_ISR_PostSemaphore();

} else {

       VDK_PostSemaphore();

}

}

Of  course you can change this and make it suit your needs. We are assuming that the  reserved bits in IPEND are 0.