[PATCH v8 17/19] staging: r8188eu: call the new usb_write() from rtw_write{8,16,32,N}()

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

Create and call new usb_write() instead of usbctrl_vendorreq() from
inside rtw_write{8,16,32,N}().

In old code, rtw_write{8,16,32,N}() called usbctrl_vendorreq() which in
turn uses usb_control_msg() from within a "while" loop to build a control
URB, send it off and wait for completion. usbctrl_vendorreq() was used
for both receiving and sending messages, depending on the "requesttype"
argument which is passed by callers.

Compared to usbctrl_vendorreq(), which manages both reads and writes
from and to the USB endpoint, the new usb_write() manages only writes.
For this purpose it uses the newer USB Core usb_control_msg_send() API.
The latter is preferred according both to suggestions by Greg Kroah-Hartman
and also to its actual design.

A noteworthy feature of usb_control_msg_send() is that the data pointer
can be made to a reference on the stack because it does not have the
restriction that usb_control_msg() has where the data pointer must be to
dynamically allocated memory.

usbctrl_vendorreq() used a "while" loop that we considered unnecessary
so that it is not in the new usb_write(). Furthermore, the latter has no
redundant checking, less obvious comments, no debug prints, and it manages
errors before success case. All in all, usb_write() is simpler than
usbctrl_vendorreq() and uses less lines of code.

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>
---
 drivers/staging/r8188eu/hal/usb_ops_linux.c | 117 +++++++-------------
 1 file changed, 42 insertions(+), 75 deletions(-)

diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/staging/r8188eu/hal/usb_ops_linux.c
index 53704b7c1059..2552450ab152 100644
--- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
+++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
@@ -8,93 +8,60 @@
 #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 value, void *data, u8 size)
 {
 	struct adapter *adapt = intfhdl->padapter;
 	struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
 	struct usb_device *udev = dvobjpriv->pusbdev;
-	int vendorreq_times = 0;
-	unsigned int pipe;
-	int status = 0;
-	u8 *io_buf;
-
-	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;
-	}
+	int status;
+	u8 *io_buf; /* Pointer to I/O buffer */
 
 	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);
+	if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx)
+		return -EPERM;
 
-	while (++vendorreq_times <= MAX_USBCTRL_VENDORREQ_TIMES) {
-		if (requesttype == REALTEK_USB_VENQT_READ)
-			memset(io_buf, 0, len);
-		else
-			memcpy(io_buf, data, len);
+	io_buf = dvobjpriv->usb_vendor_req_buf;
 
-		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);
+	status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
+				      REALTEK_USB_VENQT_READ, value,
+				      REALTEK_USB_VENQT_CMD_IDX, io_buf,
+				      size, RTW_USB_CONTROL_MSG_TIMEOUT,
+				      GFP_KERNEL);
 
-		if (status == len) {
-			/*  success */
-			rtw_reset_continual_urb_error(dvobjpriv);
-			if (requesttype == REALTEK_USB_VENQT_READ)
-				memcpy(data, io_buf,  len);
-		} else {
-			/* error cases */
-			DBG_88E("reg 0x%x, usb %s %u fail, status:%d value=0x%x, vendorreq_times:%d\n",
-				value, (requesttype == REALTEK_USB_VENQT_READ) ? "read" : "write",
-				len, status, *(u32 *)data, vendorreq_times);
-
-			if (status < 0) {
-				if (status == -ESHUTDOWN || status == -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 (status == -ESHUTDOWN ||
+	    status == -ENODEV ||
+	    status == -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;
+	}
 
-			if (rtw_inc_and_chk_continual_urb_error(dvobjpriv)) {
-				adapt->bSurpriseRemoved = true;
-				break;
-			}
+	if (status < 0) {
+		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;
 
-		/*  firmware download is checksummed, don't retry */
-		if ((value >= FW_8188E_START_ADDRESS && value <= FW_8188E_END_ADDRESS) || status == len)
-			break;
+		goto mutex_unlock;
 	}
 
+	rtw_reset_continual_urb_error(dvobjpriv);
+	memcpy(data, io_buf, size);
+
+mutex_unlock:
 	mutex_unlock(&dvobjpriv->usb_vendor_req_mutex);
-exit:
+
 	return status;
 }
 
-static int usb_read(struct intf_hdl *intfhdl, u16 value, void *data, u8 size)
+static int usb_write(struct intf_hdl *intfhdl, u16 value, void *data, u8 size)
 {
 	struct adapter *adapt = intfhdl->padapter;
 	struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
@@ -109,8 +76,9 @@ static int usb_read(struct intf_hdl *intfhdl, u16 value, void *data, u8 size)
 
 	io_buf = dvobjpriv->usb_vendor_req_buf;
 
-	status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
-				      REALTEK_USB_VENQT_READ, value,
+	memcpy(io_buf, data, size);
+	status = usb_control_msg_send(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
+				      REALTEK_USB_VENQT_WRITE, value,
 				      REALTEK_USB_VENQT_CMD_IDX, io_buf,
 				      size, RTW_USB_CONTROL_MSG_TIMEOUT,
 				      GFP_KERNEL);
@@ -139,7 +107,6 @@ static int usb_read(struct intf_hdl *intfhdl, u16 value, void *data, u8 size)
 	}
 
 	rtw_reset_continual_urb_error(dvobjpriv);
-	memcpy(data, io_buf, size);
 
 mutex_unlock:
 	mutex_unlock(&dvobjpriv->usb_vendor_req_mutex);
@@ -190,7 +157,7 @@ int rtw_write8(struct adapter *adapter, u32 addr, u8 val)
 	u16 value = addr & 0xffff;
 	int ret;
 
-	ret = usbctrl_vendorreq(intfhdl, value, &val, 1, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, value, &val, 1);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -203,7 +170,7 @@ int rtw_write16(struct adapter *adapter, u32 addr, u16 val)
 	__le16 data = cpu_to_le16(val);
 	int ret;
 
-	ret = usbctrl_vendorreq(intfhdl, value, &data, 2, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, value, &data, 2);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -216,7 +183,7 @@ int rtw_write32(struct adapter *adapter, u32 addr, u32 val)
 	__le32 data = cpu_to_le32(val);
 	int ret;
 
-	ret = usbctrl_vendorreq(intfhdl, value, &data, 4, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, value, &data, 4);
 
 	return RTW_STATUS_CODE(ret);
 }
@@ -231,7 +198,7 @@ int rtw_writeN(struct adapter *adapter, u32 addr, u32 length, u8 *data)
 	if (length > VENDOR_CMD_MAX_DATA_LEN)
 		return _FAIL;
 
-	ret = usbctrl_vendorreq(intfhdl, value, data, length, REALTEK_USB_VENQT_WRITE);
+	ret = usb_write(intfhdl, value, data, length);
 
 	return RTW_STATUS_CODE(ret);
 }
-- 
2.33.0