Hi,
On Mon, May 7, 2018 at 8:07 PM, William Wu <william.wu@xxxxxxxxxxxxxx> wrote:
> +static int dwc2_alloc_split_dma_aligned_buf(struct dwc2_hsotg *hsotg,
> + struct dwc2_qh *qh,
> + struct dwc2_host_chan *chan)
> +{
> + if (!hsotg->unaligned_cache)
> + return -ENOMEM;
> +
> + if (!qh->dw_align_buf) {
> + qh->dw_align_buf = kmem_cache_alloc(hsotg->unaligned_cache,
> + GFP_ATOMIC | GFP_DMA);
> + if (!qh->dw_align_buf)
> + return -ENOMEM;
> +
> + qh->dw_align_buf_size = min_t(u32, chan->max_packet,
> + DWC2_KMEM_UNALIGNED_BUF_SIZE);
Rather than using min_t, wouldn't it be better to return -ENOMEM if
"max_packet" > DWC2_KMEM_UNALIGNED_BUF_SIZE? As it is, you might
allocate less space than you need, right? That seems like it would be
bad (even though this is probably impossible).
> @@ -2797,6 +2837,32 @@ static int dwc2_assign_and_init_hc(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
> /* Set the transfer attributes */
> dwc2_hc_init_xfer(hsotg, chan, qtd);
>
> + /* For non-dword aligned buffers */
> + if (hsotg->params.host_dma && qh->do_split &&
> + chan->ep_is_in && (chan->xfer_dma & 0x3)) {
> + dev_vdbg(hsotg->dev, "Non-aligned buffer\n");
> + if (dwc2_alloc_split_dma_aligned_buf(hsotg, qh, chan)) {
> + dev_err(hsotg->dev,
> + "Failed to allocate memory to handle non-aligned buffer\n");
> + /* Add channel back to free list */
> + chan->align_buf = 0;
> + chan->multi_count = 0;
> + list_add_tail(&chan->hc_list_entry,
> + &hsotg->free_hc_list);
> + qtd->in_process = 0;
> + qh->channel = NULL;
> + return -ENOMEM;
> + }
> + } else {
> + /*
> + * We assume that DMA is always aligned in non-split
> + * case or split out case. Warn if not.
> + */
> + WARN_ON_ONCE(hsotg->params.host_dma &&
> + (chan->xfer_dma & 0x3));
> + chan->align_buf = 0;
> + }
> +
> if (chan->ep_type == USB_ENDPOINT_XFER_INT ||
> chan->ep_type == USB_ENDPOINT_XFER_ISOC)
> /*
> @@ -5241,6 +5307,17 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
> hsotg->params.dma_desc_enable = false;
> hsotg->params.dma_desc_fs_enable = false;
> }
> + } else if (hsotg->params.host_dma) {
Are you sure this is "else if"? Can't you have descriptor DMA enabled
in the controller and still need to do a normal DMA transfer if you
plug in a hub? Seems like this should be just "if".
> + /*
> + * Create kmem caches to handle non-aligned buffer
> + * in Buffer DMA mode.
> + */
> + hsotg->unaligned_cache = kmem_cache_create("dwc2-unaligned-dma",
> + DWC2_KMEM_UNALIGNED_BUF_SIZE, 4,
Worth using "DWC2_USB_DMA_ALIGN" rather than 4?
> + SLAB_CACHE_DMA, NULL);
> + if (!hsotg->unaligned_cache)
> + dev_err(hsotg->dev,
> + "unable to create dwc2 unaligned cache\n");
> }
>
> hsotg->otg_port = 1;
> @@ -5279,6 +5356,7 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
> error4:
> kmem_cache_destroy(hsotg->desc_gen_cache);
> kmem_cache_destroy(hsotg->desc_hsisoc_cache);
> + kmem_cache_destroy(hsotg->unaligned_cache);
nitty nit: freeing order should be opposite of allocation, so the new
line should be above the other two.
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