leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

usb: dwc3: gadget: make use of No Response Update Transfer

Browse Source 
No Response Update Transfer is a special type of
Update Transfer command which can be used whenever
we're not relying on XferNotReady to prepare
transfers. With this, we don't need to wait for
CMDACT to be cleared and issue further commands to
the endpoint straight away.

Let's start using this version to skip the long-ish
wait.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Felipe Balbi 2016-09-22 10:56:08 +03:00
parent 5999914f22
commit 8897a761c3
1 changed files with 23 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/usb/dwc3/gadget.c
View File

@ -233,6 +233,7 @@ static int __dwc3_gadget_wakeup(struct dwc3 *dwc);
int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
struct dwc3_gadget_ep_cmd_params *params)
{
const struct usb_endpoint_descriptor *desc = dep->endpoint.desc;
struct dwc3 *dwc = dep->dwc;
u32 timeout = 500;
u32 reg;
@ -276,7 +277,28 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
dwc3_writel(dep->regs, DWC3_DEPCMDPAR1, params->param1);
dwc3_writel(dep->regs, DWC3_DEPCMDPAR2, params->param2);
dwc3_writel(dep->regs, DWC3_DEPCMD, cmd | DWC3_DEPCMD_CMDACT);
/*
* Synopsys Databook 2.60a states in section 6.3.2.5.6 of that if we're
* not relying on XferNotReady, we can make use of a special "No
* Response Update Transfer" command where we should clear both CmdAct
* and CmdIOC bits.
*
* With this, we don't need to wait for command completion and can
* straight away issue further commands to the endpoint.
*
* NOTICE: We're making an assumption that control endpoints will never
* make use of Update Transfer command. This is a safe assumption
* because we can never have more than one request at a time with
* Control Endpoints. If anybody changes that assumption, this chunk
* needs to be updated accordingly.
*/
if (DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_UPDATETRANSFER &&
!usb_endpoint_xfer_isoc(desc))
cmd &= ~(DWC3_DEPCMD_CMDIOC | DWC3_DEPCMD_CMDACT);
else
cmd |= DWC3_DEPCMD_CMDACT;
dwc3_writel(dep->regs, DWC3_DEPCMD, cmd);
do {
reg = dwc3_readl(dep->regs, DWC3_DEPCMD);
if (!(reg & DWC3_DEPCMD_CMDACT)) {