usb: dwc3: ep0: add dwc3_ep0_prepare_one_trb()

For now this is just a cleanup patch, no functional
changes. We will be using the new function to fix a
bug introduced long ago by commit 0416e494ce7d
("usb: dwc3: ep0: correct cache sync issue in case
of ep0_bounced") and further worsened by commit
c0bd5456a470 ("usb: dwc3: ep0: handle non maxpacket
aligned transfers > 512")

Cc: <stable@vger.kernel.org>
Reported-by: Janusz Dziedzic <januszx.dziedzic@linux.intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 4878d187c7d4a4b3b3851c29624ff04bb32df020..06febd07ec4ed9d2400d301e9a414a209f2f4005 100644 (file)
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -39,18 +39,13 @@ static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep);
 static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
                struct dwc3_ep *dep, struct dwc3_request *req);
 
-static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
-               u32 len, u32 type, bool chain)
+static void dwc3_ep0_prepare_one_trb(struct dwc3 *dwc, u8 epnum,
+               dma_addr_t buf_dma, u32 len, u32 type, bool chain)
 {
-       struct dwc3_gadget_ep_cmd_params params;
        struct dwc3_trb                 *trb;
        struct dwc3_ep                  *dep;
 
-       int                             ret;
-
        dep = dwc->eps[epnum];
-       if (dep->flags & DWC3_EP_BUSY)
-               return 0;
 
        trb = &dwc->ep0_trb[dep->trb_enqueue];
 
@@ -71,15 +66,26 @@ static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
                trb->ctrl |= (DWC3_TRB_CTRL_IOC
                                | DWC3_TRB_CTRL_LST);
 
-       if (chain)
+       trace_dwc3_prepare_trb(dep, trb);
+}
+
+static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
+               u32 len, u32 type, bool chain)
+{
+       struct dwc3_gadget_ep_cmd_params params;
+       struct dwc3_ep                  *dep;
+       int                             ret;
+
+       dep = dwc->eps[epnum];
+       if (dep->flags & DWC3_EP_BUSY)
                return 0;
 
+       dwc3_ep0_prepare_one_trb(dwc, epnum, buf_dma, len, type, chain);
+
        memset(&params, 0, sizeof(params));
        params.param0 = upper_32_bits(dwc->ep0_trb_addr);
        params.param1 = lower_32_bits(dwc->ep0_trb_addr);
 
-       trace_dwc3_prepare_trb(dep, trb);
-
        ret = dwc3_send_gadget_ep_cmd(dep, DWC3_DEPCMD_STARTTRANSFER, &params);
        if (ret < 0)
                return ret;