[PATCH 4.4 062/101] usb: dwc3: ep0: add dwc3_ep0_prepare_one_trb()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Felipe Balbi <felipe.ba...@linux.intel.com>

commit 7931ec86c1b738e4e90e58c6d95e5f720d45ee56 upstream.

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")

Reported-by: Janusz Dziedzic <januszx.dzied...@linux.intel.com>
Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>


---
 drivers/usb/dwc3/ep0.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -55,20 +55,13 @@ static const char *dwc3_ep0_state_string
        }
 }
 
-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) {
-               dwc3_trace(trace_dwc3_ep0, "%s still busy", dep->name);
-               return 0;
-       }
 
        trb = &dwc->ep0_trb[dep->free_slot];
 
@@ -89,15 +82,28 @@ static int dwc3_ep0_start_trans(struct d
                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) {
+               dwc3_trace(trace_dwc3_ep0, "%s still busy", dep->name);
                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(dwc, dep->number,
                        DWC3_DEPCMD_STARTTRANSFER, &params);
        if (ret < 0) {