dma.c

ARM9摄象头驱动程序

static int malloc_buffer()
{
	if ((csi_data_buf = (U32 *) __get_free_pages(GFP_KERNEL, 7)))	// 128 pages = 128x4K = 512K
	{
		dma_buf_phy_addr = virt_to_phys((void *) csi_data_buf);
		dprintcsi2c("Buffer start: 0x%08x, DMA addr: 0x%08x\n",
			    (int) csi_data_buf, (int) dma_buf_phy_addr);
	} else {
		printk
		    ("*** ERROR: cannot allocate buffer memory for driver ! ***\n");
		return -1;
	}
	return 0;
}

static void free_buffer()
{
	dprintcsi2c("free buffer\n");
	if (csi_data_buf)
		__free_pages((void *) csi_data_buf, 7);	// 512K
}

static void stopCMOScapture()
{
#if 0
	U32 flags;
	U8 allStopped;

	save_flags(flags);
	cli();
	stopCapture = 1;
	dmaStopped = 0;
	SOFintrStopped = 0;
	allStopped = 0;
	restore_flags(flags);

	do {
		save_flags(flags);
		cli();
		if ((dmaStopped) && (SOFintrStopped)) {
			allStopped = 1;
			restore_flags(flags);
		} else {
			interruptible_sleep_on(&stop_capture_wait);
			restore_flags(flags);
		}
	}
	while (!allStopped);
#endif
}


//------------------------------------
//
//      Capture image data with DMA
//
//      Unified function for all 
//      supported image size capture
//
//      Return TRUE if success
//      Return FALSE if FIFO is overrun
//
//------------------------------------
static U32 SFCM_capture_DMA(U32 nPixel)
{
	dma_data_size = nPixel;
	readSeqNum = capSeqNum = SOFseqNum = 0;
	stopCapture = 0;

	*(U32 *) CSI_STS_REG = 0x10000;	//clear last SOF irq
	*(U32 *) CSI_CTRL_REG1 |= 0x60;	//prepare for sync clear FIFOs
	*(U32 *) CSI_CTRL_REG1 |= 0x10000;	//enable SOF intr
	return TRUE;
}

static void dma_complete_handler()
{
	DMA_channel_disable(dma_channel);
	*((U32 *) DMA_ISR) = (1 << dma_channel);	// clear DMA complete interrupt flag

	wake_up_interruptible(&dma_wait);
	DMA_channel_enable(dma_channel);
	/*
	   if (*(U32 *) CSI_STS_REG & 1) {
	   printk("!!! Data in FIFO !!!\n");
	   return;
	   }
	 */
}

static void dma_error_handler(int error_type)
{
	printk("*** CSI DMA error, type = 0x%08x ! ***\n", error_type);
}

static void csi_intr_handler(int irq, void *dev_id, struct pt_regs *regs)
{
	if (*(U32 *) CSI_STS_REG & 0x10000)	// SOF intr ?
	{
		*(U32 *) CSI_STS_REG = 0x10000;	// clear SOF intr
		if (SOFseqNum == 0) {
			DMA_channel_enable(dma_channel);
			*(U32 *) CSI_CTRL_REG1 &= ~0x10000;	//disable SOF intr
			//printk("dma data size:%d\n", dma_data_size);
		} else {
			return;
		}
	}
	return;

}