renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 05:34:00 +08:00
Code

usb: dwc3: gadget: offset Start Transfer latency for bulk EPs

Browse Source 
We can offset the latency of a full Start Transfer
command - where we _must_ poll for its completion -
to usb_ep_enable() time. This means that once
requests start showing up from the gadget driver, we
can rely on No Response Update Transfer command -
where we don't need to poll for completion.

This patch, starts implementing this method for Bulk
endpoints, even though, technically, we could extend
it to all other endpoints in future commits.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Felipe Balbi 2016-09-29 16:28:56 +03:00
parent fa8d965d73
commit a97ea99460
1 changed files with 29 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/usb/dwc3/gadget.c
View File

@ -617,6 +617,35 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
trb_link->ctrl |= DWC3_TRB_CTRL_HWO;
}
/*
* Issue StartTransfer here with no-op TRB so we can always rely on No
* Response Update Transfer command.
*/
if (usb_endpoint_xfer_bulk(desc)) {
struct dwc3_gadget_ep_cmd_params params;
struct dwc3_trb *trb;
dma_addr_t trb_dma;
u32 cmd;
memset(&params, 0, sizeof(params));
trb = &dep->trb_pool[0];
trb_dma = dwc3_trb_dma_offset(dep, trb);
params.param0 = upper_32_bits(trb_dma);
params.param1 = lower_32_bits(trb_dma);
cmd = DWC3_DEPCMD_STARTTRANSFER;
ret = dwc3_send_gadget_ep_cmd(dep, cmd, &params);
if (ret < 0)
return ret;
dep->flags |= DWC3_EP_BUSY;
dep->resource_index = dwc3_gadget_ep_get_transfer_index(dep);
WARN_ON_ONCE(!dep->resource_index);
}
return 0;
}