Hi Xenia,
I get a checkpatch warning when I attempt to commit this change:
Applying: xhci: fix dma mask setup in xhci.c
WARNING: line over 80 characters
#23: FILE: drivers/usb/host/xhci.c:4686:
+ if (dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32)))
Can you fix that up by adding a newline after the comma and resubmit?
Thanks,
Sarah Sharp
On Sun, May 26, 2013 at 01:08:14PM +0300, Xenia Ragiadakou wrote:
> This patch adds a check on whether the host machine
> supports the xHC DMA address mask and sets the DMA
> mask for coherent DMA address allocation via an
> explicit call to dma_set_coherent_mask().
>
> According to DMA-API-HOWTO, if coherent DMA address
> mask has not been set explicitly via dma_set_coherent_mask(),
> and the driver calls dma_alloc_coherent() or
> dma_pool_create() to allocate consistent DMA memory
> blocks, the consistent DMA mapping interface will
> return by default DMA addresses which are 32-bit
> addressable.
>
> Hence, if 64-bit DMA mapping is supported, it
> is appropriate to call dma_set_coherent_mask()
> with DMA_BIT_MASK(64) to take advantage of it.
>
> Also, according to DMA-API-HOWTO, dma_set_coherent_mask()
> is guaranteed to set successfully the same or a smaller
> mask as dma_set_mask().
>
> Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
> ---
>
> After this change, (i have a 64-bit machine) the
> consistent_dma_mask_bits entry for xhci controller
> that appears under:
> /sys/devices/pci0000:00/0000:00:<device.function>/
> changed from 32 to 64.
> I did not find another way to test this change.
>
> drivers/usb/host/xhci.c | 32 ++++++++++++++++++++++++++------
> 1 file changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index b4aa79d..887db65 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4662,11 +4662,21 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
> */
> xhci = hcd_to_xhci(hcd);
> temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params);
> - if (HCC_64BIT_ADDR(temp)) {
> + /*
> + * Check if host machine supports 64 bit DMA address mask
> + * and enable it for both streaming and coherent DMA transfers.
> + * Otherwise, use 32bit DMA mask, if it is supported.
> + */
> + if (HCC_64BIT_ADDR(temp) &&
> + !dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64))) {
> xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
> - dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64));
> + dma_set_coherent_mask(hcd->self.controller,
> + DMA_BIT_MASK(64));
> } else {
> - dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32));
> + if (dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32)))
> + goto error;
> + dma_set_coherent_mask(hcd->self.controller,
> + DMA_BIT_MASK(32));
> }
> return 0;
> }
> @@ -4700,11 +4710,21 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
> xhci_dbg(xhci, "Reset complete\n");
>
> temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params);
> - if (HCC_64BIT_ADDR(temp)) {
> + /*
> + * Check if host machine supports 64 bit DMA address mask
> + * and enable it for both streaming and coherent DMA transfers.
> + * Otherwise, use 32bit DMA mask, if it is supported.
> + */
> + if (HCC_64BIT_ADDR(temp) &&
> + !dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64))) {
> xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
> - dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64));
> + dma_set_coherent_mask(hcd->self.controller,
> + DMA_BIT_MASK(64));
> } else {
> - dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32));
> + if (dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32)))
> + goto error;
> + dma_set_coherent_mask(hcd->self.controller,
> + DMA_BIT_MASK(32));
> }
>
> xhci_dbg(xhci, "Calling HCD init\n");
> --
> 1.7.10.4
>
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