Received-SPF: pass (google.com: domain of linux-wireless+bounces-3959-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
From: Johannes Berg <johannes@sipsolutions.net>
To: linux-wireless@vger.kernel.org
Cc: Siva Rebbagondla <siva8118@gmail.com>,
	Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH v2] wifi: rsi: fix endian conversions
Date: Fri, 23 Feb 2024 11:52:14 +0100
Message-ID: <20240223115214.682fb94159fa.I576bbf9fe7ca2948dbe3e00c0fa0f37594e85046@changeid>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: Johannes Berg <johannes.berg@intel.com>

This really seems like a bug, endian conversions now happen
twice in this code.

Note also that prior to the commit mentioned below, the code
was putting 16-bit values 0xBBAA as bytes "AA BB 00 00", and
the commit mentions making it work for 32-bit values and
makes no mention of fixing endian conversion; however, after
it, the bytes for 0xBBAA would now be "00 00 BB AA" on big
endian platforms.

Remove one conversion to make sparse no longer warn.

Not sure anyone can, has, or ever will use this on big endian
platforms though.

Fixes: 0a60014b76f5 ("rsi: miscallaneous changes for 9116 and common")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/rsi/rsi_91x_usb.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c b/drivers/net/wireless/rsi/rsi_91x_usb.c
index 10a465686439..0ce8c9aad1f1 100644
--- a/drivers/net/wireless/rsi/rsi_91x_usb.c
+++ b/drivers/net/wireless/rsi/rsi_91x_usb.c
@@ -222,7 +222,7 @@ static int rsi_usb_reg_write(struct usb_device *usbdev,
 			     u32 value,
 			     u16 len)
 {
-	u8 *usb_reg_buf;
+	__le32 *usb_reg_buf;
 	int status = -ENOMEM;
 
 	if (len > RSI_USB_CTRL_BUF_SIZE)
@@ -232,17 +232,14 @@ static int rsi_usb_reg_write(struct usb_device *usbdev,
 	if (!usb_reg_buf)
 		return status;
 
-	usb_reg_buf[0] = (cpu_to_le32(value) & 0x00ff);
-	usb_reg_buf[1] = (cpu_to_le32(value) & 0xff00) >> 8;
-	usb_reg_buf[2] = (cpu_to_le32(value) & 0x00ff0000) >> 16;
-	usb_reg_buf[3] = (cpu_to_le32(value) & 0xff000000) >> 24;
+	usb_reg_buf[0] = cpu_to_le32(value);
 
 	status = usb_control_msg(usbdev,
 				 usb_sndctrlpipe(usbdev, 0),
 				 USB_VENDOR_REGISTER_WRITE,
 				 RSI_USB_REQ_OUT,
-				 ((cpu_to_le32(reg) & 0xffff0000) >> 16),
-				 (cpu_to_le32(reg) & 0xffff),
+				 upper_16_bits(reg),
+				 lower_16_bits(reg),
 				 (void *)usb_reg_buf,
 				 len,
 				 USB_CTRL_SET_TIMEOUT);
-- 
2.43.2