On 30.03.2017 04:48, Peter Chen wrote:
On Wed, Mar 29, 2017 at 11:06:53AM +0300, Felipe Balbi wrote:
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
In fact, it fixes two things at spec, the other thing is the scratchpad
buffer needs to be page_size boundary. I will send these two fixes
first.
If I remember correctly dma_alloc_coherent() takes care of proper alignment
and won't cross the boundary
-Mathias
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
