usb:hsotg:samsung: NAK management for EP0 (Setup stage of control transfers)

For SETUP stage of USB control transmission, the NAK shall NOT be
CLEAR.

The SNAK/CNAK control is crucial for this type of driver,
since data arrives to earlier defined requests.

Tested with:
- DFU gadget (various size of the sent data - also packet = MPS)
- Ethernet gadget (CDC and RNDIS)
- Multi Function Gadget (g_multi)

HW:
- Samsung's C210 Universal rev.0

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index e1a54d21ecaf..7b46af3e014f 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -147,6 +147,7 @@ struct s3c_hsotg_ep {
  * @ep0_buff: Buffer for EP0 reply data, if needed.
  * @ctrl_buff: Buffer for EP0 control requests.
  * @ctrl_req: Request for EP0 control packets.
+ * @setup: NAK management for EP0 SETUP
  * @eps: The endpoints being supplied to the gadget framework
  */
 struct s3c_hsotg {
@@ -173,6 +174,7 @@ struct s3c_hsotg {
         u8                      ctrl_buff[8];
 
         struct usb_gadget       gadget;
+        unsigned int            setup;
         struct s3c_hsotg_ep     eps[];
 };
 
@@ -696,7 +698,8 @@ static void s3c_hsotg_start_req(struct s3c_hsotg *hsotg,
         }
 
         length = ureq->length - ureq->actual;
-
+        dev_dbg(hsotg->dev, "ureq->length:%d ureq->actual:%d\n",
+                ureq->length, ureq->actual);
         if (0)
                 dev_dbg(hsotg->dev,
                         "REQ buf %p len %d dma 0x%08x noi=%d zp=%d snok=%d\n",
@@ -762,7 +765,15 @@ static void s3c_hsotg_start_req(struct s3c_hsotg *hsotg,
 
         ctrl |= S3C_DxEPCTL_EPEna;      /* ensure ep enabled */
         ctrl |= S3C_DxEPCTL_USBActEp;
-        ctrl |= S3C_DxEPCTL_CNAK;       /* clear NAK set by core */
+
+        dev_dbg(hsotg->dev, "setup req:%d\n", hsotg->setup);
+
+        /* For Setup request do not clear NAK */
+        if (hsotg->setup && index == 0)
+                hsotg->setup = 0;
+        else
+                ctrl |= S3C_DxEPCTL_CNAK;       /* clear NAK set by core */
+
 
         dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x\n", __func__, ctrl);
         writel(ctrl, hsotg->regs + epctrl_reg);
@@ -1527,6 +1538,12 @@ static void s3c_hsotg_handle_outdone(struct s3c_hsotg *hsotg,
         if (req->actual < req->length && size_left == 0) {
                 s3c_hsotg_start_req(hsotg, hs_ep, hs_req, true);
                 return;
+        } else if (epnum == 0) {
+                /*
+                 * After was_setup = 1 =>
+                 * set CNAK for non Setup requests
+                 */
+                hsotg->setup = was_setup ? 0 : 1;
         }
 
         if (req->actual < req->length && req->short_not_ok) {