Hi,
Peter Chen <hzpeterchen@xxxxxxxxx> writes:
>> > According to xHCI ch4.20 Scratchpad Buffers
>> > A Scratchpad Buffer is a PAGESIZE block of system memory
>> > located on a PAGESIZE boundary
>> > ...
>> > Software clears the Scratchpad Buffer to ‘0’
>> >
>> > So, we need to use dma pool for PAGESIZE boundary buffer, and zeroed
>> > its region using dma_pool_zalloc.
>>
>> you're doing two separate things here...
>>
>> > Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
>> > ---
>> > drivers/usb/host/xhci-mem.c | 21 +++++++++++++++------
>> > drivers/usb/host/xhci.h | 1 +
>> > 2 files changed, 16 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
>> > index 22a03b7..56aa0a6 100644
>> > --- a/drivers/usb/host/xhci-mem.c
>> > +++ b/drivers/usb/host/xhci-mem.c
>> > @@ -1710,12 +1710,18 @@ static int scratchpad_alloc(struct xhci_hcd *xhci, gfp_t flags)
>> > goto fail_sp3;
>> >
>> > xhci->dcbaa->dev_context_ptrs[0] = cpu_to_le64(xhci->scratchpad->sp_dma);
>> > +
>> > + xhci->scratchpad_pool = dma_pool_create("xhci scratchpad buffer pool",
>> > + dev, xhci->page_size,
>> > + xhci->page_size, xhci->page_size);
>>
>> adding a DMA pool here, and ...
>>
>> > + if (!xhci->scratchpad_pool)
>> > + goto fail_sp4;
>> > +
>> > for (i = 0; i < num_sp; i++) {
>> > dma_addr_t dma;
>> > - void *buf = dma_alloc_coherent(dev, xhci->page_size, &dma,
>> > - flags);
>> > + void *buf = dma_pool_zalloc(xhci->scratchpad_pool, flags, &dma);
>>
>> ... fixing a possible bug here.
>>
>
> I know it is two things, but after the dma pool is introduced, we need a
> new API to allocate memory, do you want to me use dma_pool_alloc first,
> then, change it to use dma_pool_zalloc at another patch? I am ok to do
> that.
the other way around. First you patch dma_alloc_coherent() to
dma_zalloc_coherent() and that could go in during the -rc and possibly
get a stable tag, since spec requires kernel to zero the memory area.
--
balbi
Attachment:
signature.asc
Description: PGP signature
