* [DBG SRC] Re: DMA Problem
2005-04-20 17:37 DMA Problem Sanjay Bajaj
@ 2005-04-21 20:42 ` Roger Larsson
0 siblings, 0 replies; 2+ messages in thread
From: Roger Larsson @ 2005-04-21 20:42 UTC (permalink / raw)
To: linuxppc-embedded
On Wednesday 20 April 2005 19.37, Sanjay Bajaj wrote:
> I am having a setup issue with the DMA channel 0 with the DMA Controller
> on PPC440GX. The code I wrote is:
>
> #if defined(CONFIG_PPC4xx_DMA)
> /* Setup the DMA */
> DPRINTK("PPC4xx pwidth: %d\n", ppc4xx_get_peripheral_width(DMA_CH0));
> ppc4xx_set_dma_mode(DMA_CH0, DMA_MODE_READ);
> ppc4xx_set_src_addr(DMA_CH0, (phys_addr_t)(pdev->x2mem_phys_addr +
> src_addr));
> ppc4xx_set_dst_addr(DMA_CH0, (phys_addr_t)dst_addr);
> ppc4xx_set_dma_count(DMA_CH0, count);
> ppc4xx_enable_dma(DMA_CH0);
> DPRINTK("PPC4xx DMA Status: %d\n", ppc4xx_get_dma_status());
> #endif
>
> The DMA never completes and leaves a residue of 'count'. What am I missing?
>
Request irq and dma?
if ((ret = request_irq(dma_irq, dma_irq_handler, SA_SHIRQ, "NAME")))
- - -
/* reserve a DMA channel */
if (DBG_DMA(request_dma(DMA_CH0, const char *device_id))
BTW you should check return values, try this:
int fgrabber_report_dma_error(const char *call, int ret)
{
switch (ret)
{
case DMA_STATUS_GOOD:
// printk(KERN_DEBUG "dma: %s STATUS_GOOD\n", call);
break;
case DMA_STATUS_BAD_CHANNEL:
printk(KERN_DEBUG "dma: %s STATUS_BAD_CHANNEL\n", call);
break;
case DMA_STATUS_BAD_HANDLE:
printk(KERN_DEBUG "dma: %s STATUS_BAD_HANDLE", call);
break;
case DMA_STATUS_BAD_MODE:
printk(KERN_DEBUG "dma: %s STATUS_BAD_MODE", call);
break;
case DMA_STATUS_NULL_POINTER:
printk(KERN_DEBUG "dma: %s STATUS_NULL_POINTER", call);
break;
case DMA_STATUS_OUT_OF_MEMORY:
printk(KERN_DEBUG "dma: %s STATUS_OUT_OF_MEMORY", call);
break;
case DMA_STATUS_SGL_LIST_EMPTY:
printk(KERN_DEBUG "dma: %s STATUS_SGL_LIST_EMPTY", call);
break;
case DMA_STATUS_GENERAL_ERROR:
printk(KERN_DEBUG "dma: %s STATUS_GENERAL_ERROR", call);
break;
case DMA_STATUS_CHANNEL_NOTFREE:
printk(KERN_DEBUG "dma: %s STATUS_CHANNEL_NOTFREE", call);
break;
default:
printk(KERN_DEBUG "dma: %s STATUS(0x%x)", call, ret);
break;
}
return ret;
}
#ifdef DEBUG_DMA
#define DBG_DMA(call) fgrabber_report_dma_error(#call, call)
#else
#define DBG_DMA(call) call
#endif
/RogerL
^ permalink raw reply [flat|nested] 2+ messages in thread