diff options
| author | Felipe Balbi <felipe.balbi@linux.intel.com> | 2016-04-05 12:42:15 +0300 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2016-04-18 15:23:49 +0300 |
| commit | c28f82595dde97dda0b769f78f0faea78acd993b (patch) | |
| tree | 05f7efc2fc0731cb1f5dc382a9439aa2aa2696fd | |
| parent | 5ef68c56e169a9249b94645a9ea9ca8d14672d26 (diff) | |
| download | linux-c28f82595dde97dda0b769f78f0faea78acd993b.tar.xz | |
usb: dwc3: switch trb enqueue/dequeue and first_trb_index to u8
We *know* that we have 1 PAGE (4096 bytes) for our
TRB poll. We also know the size of each TRB and know
that we can fit 256 of them in one PAGE. By using a
u8 type we can make sure that:
enqueue++ % 256;
gets optimized to an increment only.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
| -rw-r--r-- | drivers/usb/dwc3/core.h | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index c0049c811cca..2f19573e08d9 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -470,8 +470,6 @@ struct dwc3_ep { struct dwc3_trb *trb_pool; dma_addr_t trb_pool_dma; - u32 trb_enqueue; - u32 trb_dequeue; const struct usb_ss_ep_comp_descriptor *comp_desc; struct dwc3 *dwc; @@ -487,6 +485,18 @@ struct dwc3_ep { /* This last one is specific to EP0 */ #define DWC3_EP0_DIR_IN (1 << 31) + /* + * IMPORTANT: we *know* we have 256 TRBs in our @trb_pool, so we will + * use a u8 type here. If anybody decides to increase number of TRBs to + * anything larger than 256 - I can't see why people would want to do + * this though - then this type needs to be changed. + * + * By using u8 types we ensure that our % operator when incrementing + * enqueue and dequeue get optimized away by the compiler. + */ + u8 trb_enqueue; + u8 trb_dequeue; + u8 number; u8 type; u8 resource_index; @@ -641,8 +651,8 @@ struct dwc3_request { struct usb_request request; struct list_head list; struct dwc3_ep *dep; - u32 first_trb_index; + u8 first_trb_index; u8 epnum; struct dwc3_trb *trb; dma_addr_t trb_dma; |