dma.c

嵌入式Linux系统下,ov965摄像头驱动.

static int malloc_buffer()
{
        printk("malloc buffer\n");
	if ((csi_data_buf = (U32 *) __get_free_pages(GFP_KERNEL, 8)))	// 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",
		printk("Buffer start: 0x%08x, DMA addr: 0x%08x\n",
			    (int) csi_data_buf, (int) dma_buf_phy_addr);
//			    (int) csi_data_buf, (int) dma_buf_phy_addr);
	} else {
		printk
		    ("*** ERROR: cannot allocate buffer memory for driver ! ***\n");
		return -1;
	}
	if ((csi_data_buf2 = (U32 *) __get_free_pages(GFP_KERNEL, 8)))	// 128 pages = 128x4K = 512K
	{
		dma_buf_phy_addr2 = virt_to_phys((void *) csi_data_buf2);
	}

	return 0;
	// 128 pages = 128x4K = 512K
}

static void free_buffer()
{
	if (csi_data_buf)
		__free_pages((void *) csi_data_buf, 8);	// 512K
	if (csi_data_buf2)
		__free_pages((void *) csi_data_buf2, 8);
}

//------------------------------------
//
//      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;

	PRP_enable();
	return TRUE;
}

void dma_complete_handler()
{
	disable_dma(dma_channel);
	_reg_DMA_DISR = (1 << dma_channel);	// clear DMA complete interrupt flag

	wake_up_interruptible(&dma_wait);
	enable_dma(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 (_reg_CSI_CSISTATR & 0x10000)	// SOF intr ?
	{
		_reg_CSI_CSISTATR = 0x10000;	// clear SOF intr
		if (SOFseqNum == 0) {
			_reg_CSI_CSICR1 &= ~0x10000;	//disable SOF intr
		} else {
			return;
		}
	}
	return;

}