[PATCH v4 18/18] staging: r8188eu: Shorten calls chain of rtw_write8/16/32/N()

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

Shorten the calls chain of rtw_write8/16/32() down to the actual writes.
For this purpose unify the four usb_write8/16/32/N() into the new
usb_write(); make the latter parameterizable with 'size'; embed most of
the code of usbctrl_vendorreq() into usb_write() and use in it the new
usb_control_msg_send() API of USB Core.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---

v3->v4:
        Make some changes according to a first review of Greg
        Kroah-Hartman; remove unnecessary 'while' loop and a couple of
        'if' test; handle the errors returned by usb_control_msg_send().

v2->v3: Fix the version number of the patch.
 
v1->v2: Replace parameter REALTEK_USB_VENQT_READ with REALTEK_USB_VENQT_WRITE
	in usb_control_msg_send(). More in-depth explanation at
	https://lore.kernel.org/lkml/2791328.7pjKATJfGa@localhost.localdomain/T/#m1fc1ab2f7c1f463049ad88d5df5bb1b107b37260

 drivers/staging/r8188eu/hal/usb_ops_linux.c | 111 +++++++-------------
 1 file changed, 39 insertions(+), 72 deletions(-)

diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/staging/r8188eu/hal/usb_ops_linux.c
index 75475b0083db..cf27c84c3c90 100644
--- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
+++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
@@ -8,88 +8,57 @@
 #include "../include/recv_osdep.h"
 #include "../include/rtl8188e_hal.h"
 
-static int usbctrl_vendorreq(struct intf_hdl *intfhdl, u16 value, void *data, u16 len, u8 requesttype)
+static int usb_read(struct intf_hdl *intfhdl, u16 addr, void *data, u8 size)
 {
-	int status = 0;
-	u8 *io_buf;
-	unsigned int pipe;
-	int vendorreq_times = 0;
+	int status;
+	u8 *io_buf; /* pointer to I/O buffer */
 	struct adapter *adapt = intfhdl->padapter;
 	struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
 	struct usb_device *udev = dvobjpriv->pusbdev;
 
-	if ((adapt->bSurpriseRemoved) || (adapt->pwrctrlpriv.pnp_bstop_trx)) {
+	if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx) {
 		status = -EPERM;
 		goto exit;
 	}
 
-	if (len > MAX_VENDOR_REQ_CMD_SIZE) {
-		DBG_88E("[%s] Buffer len error ,vendor request failed\n", __func__);
-		status = -EINVAL;
-		goto exit;
-	}
-
 	mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
 
-	/*  Acquire IO memory for vendorreq */
 	io_buf = dvobjpriv->usb_vendor_req_buf;
 
-	if (requesttype == REALTEK_USB_VENQT_READ)
-		/* read in */
-		pipe = usb_rcvctrlpipe(udev, 0);
-	else
-		/* write out */
-		pipe = usb_sndctrlpipe(udev, 0);
-
-	while (++vendorreq_times <= MAX_USBCTRL_VENDORREQ_TIMES) {
-		if (requesttype == REALTEK_USB_VENQT_READ)
-			memset(io_buf, 0, len);
-		else
-			memcpy(io_buf, data, len);
-
-		status = usb_control_msg(udev, pipe, REALTEK_USB_VENQT_CMD_REQ,
-					 requesttype, value, REALTEK_USB_VENQT_CMD_IDX,
-					 io_buf, len, RTW_USB_CONTROL_MSG_TIMEOUT);
-
-		if (status == len) {
-			/*  success */
-			rtw_reset_continual_urb_error(dvobjpriv);
-			if (requesttype == REALTEK_USB_VENQT_READ)
-				memcpy(data, io_buf,  len);
-		} else {
-			/* errors */
-			if (status < 0) {
-				if (status == (-ESHUTDOWN || -ENODEV)) {
-					adapt->bSurpriseRemoved = true;
-				} else {
-					struct hal_data_8188e *haldata = GET_HAL_DATA(adapt);
-					haldata->srestpriv.wifi_error_status = USB_VEN_REQ_CMD_FAIL;
-				}
-			} else {
-				/*  status != len && status >= 0 */
-				if (status > 0) {
-					if (requesttype == REALTEK_USB_VENQT_READ)
-						memcpy(data, io_buf,  len);
-				}
-			}
-
-			if (rtw_inc_and_chk_continual_urb_error(dvobjpriv)) {
-				adapt->bSurpriseRemoved = true;
-				break;
-			}
-
-		}
-		/*  firmware download is checksummed, don't retry */
-		if ((value >= FW_8188E_START_ADDRESS && value <= FW_8188E_END_ADDRESS) || status == len)
-			break;
+	status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
+				      REALTEK_USB_VENQT_READ, addr,
+				      REALTEK_USB_VENQT_CMD_IDX, io_buf,
+				      size, RTW_USB_CONTROL_MSG_TIMEOUT,
+				      GFP_KERNEL);
+	if (!status) {
+		/*  Success this control transfer. */
+		rtw_reset_continual_urb_error(dvobjpriv);
+		memcpy(data, io_buf, size);
+		goto mutex_unlock;
 	}
-
+	/*  error cases */
+	if (status == (-ESHUTDOWN || -ENODEV || -ENOENT)) {
+		/*
+		 * device or controller has been disabled due to
+		 * some problem that could not be worked around,
+		 * device or bus doesn’t exist, endpoint does not
+		 * exist or is not enabled.
+		 */
+		adapt->bSurpriseRemoved = true;
+			goto mutex_unlock;
+	}
+	GET_HAL_DATA(adapt)->srestpriv.wifi_error_status = USB_VEN_REQ_CMD_FAIL;
+	if (rtw_inc_and_chk_continual_urb_error(dvobjpriv)) {
+		adapt->bSurpriseRemoved = true;
+		goto mutex_unlock;
+	}
+mutex_unlock:
 	mutex_unlock(&dvobjpriv->usb_vendor_req_mutex);
 exit:
 	return status;
 }
 
-static int usb_read(struct intf_hdl *intfhdl, u16 addr, void *data, u8 size)
+static int usb_write(struct intf_hdl *intfhdl, u16 addr, void *data, u8 size)
 {
 	int status;
 	u8 *io_buf; /* pointer to I/O buffer */
@@ -105,16 +74,16 @@ static int usb_read(struct intf_hdl *intfhdl, u16 addr, void *data, u8 size)
 	mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
 
 	io_buf = dvobjpriv->usb_vendor_req_buf;
+	memcpy(io_buf, data, size);
 
-	status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
-				      REALTEK_USB_VENQT_READ, addr,
+	status = usb_control_msg_send(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
+				      REALTEK_USB_VENQT_WRITE, addr,
 				      REALTEK_USB_VENQT_CMD_IDX, io_buf,
 				      size, RTW_USB_CONTROL_MSG_TIMEOUT,
 				      GFP_KERNEL);
 	if (!status) {
 		/*  Success this control transfer. */
 		rtw_reset_continual_urb_error(dvobjpriv);
-		memcpy(data, io_buf, size);
 		goto mutex_unlock;
 	}
 	/*  error cases */
@@ -182,7 +151,7 @@ int rtw_write8(struct adapter *adapter, u32 addr, u8 val)
 	struct io_priv *io_priv = &adapter->iopriv;
 	struct intf_hdl *intfhdl = &io_priv->intf;
 
-	ret = usbctrl_vendorreq(intfhdl, address, &val, 1, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, address, &val, 1);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -195,7 +164,7 @@ int rtw_write16(struct adapter *adapter, u32 addr, u16 val)
 	struct io_priv *io_priv = &adapter->iopriv;
 	struct intf_hdl *intfhdl = &io_priv->intf;
 
-	ret = usbctrl_vendorreq(intfhdl, address, &data, 2, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, address, &data, 2);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -208,7 +177,7 @@ int rtw_write32(struct adapter *adapter, u32 addr, u32 val)
 	struct io_priv *io_priv = &adapter->iopriv;
 	struct intf_hdl *intfhdl = &io_priv->intf;
 
-	ret = usbctrl_vendorreq(intfhdl, address, &data, 4, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, address, &data, 4);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -218,15 +187,13 @@ int rtw_writeN(struct adapter *adapter, u32 addr, u32 len, u8 *data)
 	int ret;
 	u16 address = (u16)(addr & 0xffff);
 	u16 length = (u16)(len & 0xffff);
-	u8 buf[VENDOR_CMD_MAX_DATA_LEN] = {0};
 	struct io_priv *io_priv = &adapter->iopriv;
 	struct intf_hdl *intfhdl = &io_priv->intf;
 
 	if (length > VENDOR_CMD_MAX_DATA_LEN)
 		return _FAIL;
 
-	memcpy(buf, data, length);
-	ret = usbctrl_vendorreq(intfhdl, address, buf, length, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, address, data, length);
 
 	return RTW_STATUS_CODE(ret);
 }
-- 
2.33.0