[PATCH 2/3] usb: dwc3: gadget: Ignore Update Transfer cmd params
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: 2021-11-30 02:53:18
Subsystem:
designware usb3 drd ip driver, the rest, usb subsystem · Maintainers:
Thinh Nguyen, Linus Torvalds, Greg Kroah-Hartman
The controller doesn't check for Update Transfer command parameters
DEPCMDPAR{0,1,2}. Writing to these registers is unnecessary. Ignoring
this improves performance slightly by removing the register write
delay.
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
drivers/usb/dwc3/gadget.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 00b3f19c4d3e..f66baaef8a40 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c@@ -331,9 +331,17 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd, } } - dwc3_writel(dep->regs, DWC3_DEPCMDPAR0, params->param0); - dwc3_writel(dep->regs, DWC3_DEPCMDPAR1, params->param1); - dwc3_writel(dep->regs, DWC3_DEPCMDPAR2, params->param2); + /* + * For some commands such as Update Transfer command, DEPCMDPARn + * registers are reserved. Since the driver often sends Update Transfer + * command, don't write to DEPCMDPARn to avoid register write delays and + * improve performance. + */ + if (DWC3_DEPCMD_CMD(cmd) != DWC3_DEPCMD_UPDATETRANSFER) { + dwc3_writel(dep->regs, DWC3_DEPCMDPAR0, params->param0); + dwc3_writel(dep->regs, DWC3_DEPCMDPAR1, params->param1); + dwc3_writel(dep->regs, DWC3_DEPCMDPAR2, params->param2); + } /* * Synopsys Databook 2.60a states in section 6.3.2.5.6 of that if we're
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2.28.0