【FAQ】全志D1芯片 如何移植 rtl8821cu wifi 驱动到 Linux-5.4内核？

[q1215200171]

问题背景
移植 Linux-4.9 或之前的内核版本下的 wifi 驱动到 Linux-5.4 内核版本时会出现编译和运行错误，
该 FAQ 主要用于帮助开发人员解决驱动移植出现的问题。

问题分析
移植到 Linux-5.4 内核版本时出现如下编译错误：

WARNING: module 8821cu uses symbol kernel_read from namespace VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver, but does not import it.

出现该 WANRING 的原因是内核版本升级后文件系统存在差异，驱动调用了 kernel_read（）和 kernel_write() 函数，需要进行 import VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver 处理。

移植到 Linux-5.4 内核版本时运行的错误：

出现该问题的原因是 Linux-5.3 及以后版本 cfg80211.h 里结构体 wiphy_vendor_command 新增了变量 policy 和 maxattr。

解决方案

出现编译错误时解决方案如下：

diff --git a/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c b/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
index c4b515763ac8..466a3b27f521 100644
--- a/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
+++ b/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
@@ -28,6 +28,8 @@ MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Realtek Wireless Lan Driver");
 MODULE_AUTHOR("Realtek Semiconductor Corp.");
 MODULE_VERSION(DRIVERVERSION);
+MODULE_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);

出现运行错误时解决方案为遍历驱动里所有使用 wiphy_vendor_command 结构体并修改如下：

diff --git a/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c b/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
index 6bac27d37766..09e24dcc9480 100644
--- a/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
+++ b/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
@@ -1756,6 +1756,11 @@ static const struct wiphy_vendor_command rtw_vendor_cmds[] = {
                },
                .flags = WIPHY_VENDOR_CMD_NEED_WDEV | WIPHY_VENDOR_CMD_NEED_NETDEV,
                .doit = rtw_cfgvendor_gscan_get_capabilities
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0))
+               ,
+               .policy = VENDOR_CMD_RAW_DATA,
+               .maxattr = 1
+#endif
        },

[szricky]

这个有用。

在 D1s 移植 RTL8189 上是有同样的问题。

[wyljkl]

你好，现在正在移植wifi驱动到F133,在加载内核时出现了：
module uses symbol (kernel_read) from namespace VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver, but does not import it.

，看上面说的：
出现该 WANRING 的原因是内核版本升级后文件系统存在差异，驱动调用了 kernel_read（）和 kernel_write() 函数，需要进行 import VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver 处理。
这个怎么操作？

[q1215200171]

@wyljkl 出现编译错误时解决方案如下：

diff --git a/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c b/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
index c4b515763ac8..466a3b27f521 100644
--- a/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
+++ b/drivers/net/wireless/rtl8821cu/os_dep/linux/os_intfs.c
@@ -28,6 +28,8 @@ MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Realtek Wireless Lan Driver");
 MODULE_AUTHOR("Realtek Semiconductor Corp.");
 MODULE_VERSION(DRIVERVERSION);
+MODULE_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);

出现运行错误时解决方案为遍历驱动里所有使用 wiphy_vendor_command 结构体并修改如下：

diff --git a/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c b/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
index 6bac27d37766..09e24dcc9480 100644
--- a/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
+++ b/drivers/net/wireless/rtl8821cu/os_dep/linux/rtw_cfgvendor.c
@@ -1756,6 +1756,11 @@ static const struct wiphy_vendor_command rtw_vendor_cmds[] = {
                },
                .flags = WIPHY_VENDOR_CMD_NEED_WDEV | WIPHY_VENDOR_CMD_NEED_NETDEV,
                .doit = rtw_cfgvendor_gscan_get_capabilities
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0))
+               ,
+               .policy = VENDOR_CMD_RAW_DATA,
+               .maxattr = 1
+#endif
        },

[wyljkl]

@q1215200171 收到，感谢，可以了

[casojie]

几乎是同类型的芯片 rtl8818FU，也是USB接口的WiFi芯片，但是移植编译加载后

[   65.256086] 8188fu: loading out-of-tree module taints kernel.
[   91.352280] RTW: module init start
[   91.352292] RTW: rtl8188fu v5.11.5.4-0-g65b8f0aad.20220413
[   91.352298] RTW: build time: Feb 28 2023 11:52:06
[   91.352307] RTW: rtw_drv_entry: power on failed!!(-22)
[   91.352312] RTW: module init ret=-1
[  117.393206] RTW: module init start
[  117.393217] RTW: rtl8188fu v5.11.5.4-0-g65b8f0aad.20220413
[  117.393223] RTW: build time: Feb 28 2023 11:52:06
[  117.393232] RTW: rtw_drv_entry: power on failed!!(-22)
[  117.393237] RTW: module init ret=-1

好像设备注册或者什么出了问题，导致有个变量没有初始化

还有你们没有遇到驱动原本的platform_ARM_SUNxl_usb.c不能使用吗，我很好奇你们你们这个文件中的函数是怎么写的

platform_wifi_power_on
platform_wifi_power_off

这是我的，大佬看看有问题吗

/******************************************************************************
 *
 * Copyright(c) 2013 - 2017 Realtek Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 *****************************************************************************/
/*
 * Description:
 *	This file can be applied to following platforms:
 *	CONFIG_PLATFORM_ARM_SUNXI Series platform
 *
 */

#include <drv_types.h>

extern int sunxi_usb_disable_hcd(__u32 usbc_no);
extern int sunxi_usb_enable_hcd(__u32 usbc_no);
extern int sunxi_wlan_get_bus_index(void);
extern void sunxi_wlan_set_power(int on);

int platform_wifi_power_on(void)
{
    int ret = 0;
    int wlan_bus_index = sunxi_wlan_get_bus_index();
    if (wlan_bus_index < 0)
        return wlan_bus_index;

    sunxi_wlan_set_power(1);
    mdelay(100);
    sunxi_usb_enable_hcd(wlan_bus_index);

    return ret;
}
void platform_wifi_power_off(void)
{
    int wlan_bus_index = sunxi_wlan_get_bus_index();
    if (wlan_bus_index < 0)
        return wlan_bus_index;
    sunxi_usb_disable_hcd(wlan_bus_index);
    sunxi_wlan_set_power(0);
}

就是platform_wifi_power_on报错才加载失败的，求指点