On Tuesday 19 September 2006 18:40, Larry Finger wrote:
> The patch below implements a quick-and-dirty approach to solving the problem
> of
> DMA with more than 1 GB memory. Unfortunately, I don't have the hardware to
> test
> it. The patch is intended for the wireless-2.6 tree. It will not work with
> 2.6.18-rcX. Please report your results, and the log messages.
Q: Does this help > 1GB memory problem?
A: No ;)
Please lookup old SVN archives, where I implemented such a
dirty workaround like this.
1) We also need to have descriptor buffers under 1G
2) I think it's clear to you, that this is based on pure
luck, as retrying 10 times can easily fail as well
as only trying once.
If you want >1G, get a device which supports this.
> Thanks,
>
> Larry
>
>
> Index: wireless-2.6/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
> ===================================================================
> --- wireless-2.6.orig/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
> +++ wireless-2.6/drivers/net/wireless/bcm43xx/bcm43xx_dma.c
> @@ -215,15 +215,36 @@ void free_descriptor_buffer(struct bcm43
> static int alloc_ringmemory(struct bcm43xx_dmaring *ring)
> {
> struct device *dev = &(ring->bcm->pci_dev->dev);
> + int i, j;
> + struct {
> + dma_addr_t dmabase;
> + void *descbase;
> + } dma_trial[10];
>
> - ring->descbase = dma_alloc_coherent(dev, BCM43xx_DMA_RINGMEMSIZE,
> + for (i=0; i<10; i++) {
> + ring->descbase = dma_alloc_coherent(dev,
> BCM43xx_DMA_RINGMEMSIZE,
> &(ring->dmabase), GFP_KERNEL);
> - if (!ring->descbase) {
> - printk(KERN_ERR PFX "DMA ringmemory allocation failed\n");
> - return -ENOMEM;
> + if (!ring->descbase) {
> + printk(KERN_ERR PFX "DMA ringmemory allocation
> failed\n");
> + return -ENOMEM;
> + }
> + if (ring->dmabase + BCM43xx_DMA_RINGMEMSIZE < 0x3fffffff)
> + goto low_mem_ok;
> + dma_trial[i].descbase = ring->descbase;
> + dma_trial[i].dmabase = ring->dmabase;
> + printk(KERN_INFO PFX "Trial %d: dmabase = 0x%.8x\n", i+1,
> ring->dmabase);
> }
> + printk(KERN_INFO PFX "Unable to get DMA memory below 1 GB boundary.\n");
> +
> +low_mem_ok:
> memset(ring->descbase, 0, BCM43xx_DMA_RINGMEMSIZE);
>
> + if (i != 0) {
> + for (j=0; j<i; j++) /* get rid of any trials that failed */
> + dma_free_coherent(dev, BCM43xx_DMA_RINGMEMSIZE,
> + dma_trial[j].descbase,
> dma_trial[j].dmabase);
> + }
> +
> return 0;
> }
>
>
>
> _______________________________________________
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> Bcm43xx-dev@lists.berlios.de
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>
--
Greetings Michael.
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