WLAN overview

本文介绍了WLAN框架的组成方式，配置方法以及使用方法。

Purpose

无线局域网（WLAN）是一种无线计算机网络，它使用无线通信链接两个或多个设备以在有限的区域内形成局域网（LAN），例如家庭，学校，计算机实验室，校园，办公楼等。这使用户能够在该区域内四处移动，但仍可以连接到网络。通过网关，WLAN还可以提供与更广泛的Internet的连接。
Linux^® 无线子系统包含两个主要模块：cfg80211和mac80211，它们帮助WiFi驱动程序与内核的其余部分和用户空间建立接口。
特别是，cfg80211在内核中提供配置管理服务。它还通过nl80211在内核和用户空间之间提供管理接口。
软MAC（soft MAC）设备和完整MAC设备都需要与cfg80211一起使用。 Mac80211是仅支持软件MAC设备的驱动程序API

WLAN可以在许多不同的用例中使用，如How to use WLAN部分所述：

如何在客户端模式下配置无线接口： How to configure a wlan interface on client mode
如何在热点模式下配置无线接口：如何将无线网卡配置为热点模式

System overview

WLAN Overview

Description of the components

从用户空间到硬件

应用 (用户空间)

有许多使用WLAN的应用程序：例如Internet浏览器，流应用程序，FTP应用程序。

WLAN工具 (用户空间)

有一组实用程序可以管理WLAN网络： Network tools

CFG80211 API (内核空间)

cfg80211^[1] 是Linux中的IEEE 802.11^[2] 设备的配置API。
- 它桥接了用户空间和驱动程序，并提供了与IEEE 802.11相关的某些实用程序功能。
-Linux中的所有现代无线驱动程序都必须通过mac80211直接或间接地使用它，以便它们通过nl80211提供一致的API^[3].
- 它与 Netlink^[4] socket 连接。

MAC80211框架 (内核空间)

MAC80211是Linux内核的一个子系统，它实现了软MAC/半MAC无线共享代码^[5]

WLAN配套驱动程序 (内核空间)

WLAN配套驱动程序注册和控制WLAN设备。

MMC框架：MMC核心 (内核空间)

MMC内核”'确保与MultiMediaCard（MMC）嵌入式^[6] / ^[7] / 安全数字规范安全数字输入/输出（SDIO )^[8].
MP1和WLAN设备之间的通信链接是SDIO总线。

SDMMC驱动程序 (内核空间)

有关更多信息，请参阅 MMC overview

STM32: SDMMC (硬件)

有关更多信息，请参阅 MMC overview

外部设备 (硬件)

WLAN配套芯片

APIs description

MAC80211是新的无线驱动程序API，它为soft-MAC / half-MAC无线设备实现共享代码^[9]

cfg80211^[10] 是IEEE 802.11的新驱动程序配置API^[11] 在Linux中

Configuration

默认情况下，在ST传送中不会激活WLAN API。要激活它，可以使用Linux Menuconfig工具： Menuconfig or how to configure kernel 然后选择：

对于网络功能：

[*] Networking support  --->  
    [*] Networking options  --->
        [*] Packet socket 
        [*] TCP/IP networking
          [*] IP: kernel level autoconfiguration
            [*] IP: DHCP support
            [*] IP: BOOTP support
            [*] IP: RARP support
        [*] INET: socket monitoring interface
        [*] The IPv6 protocol
        [*] DNS Resolver support
    [*]   Wireless  --->
        [*]   cfg80211 - wireless configuration API
                [*]   cfg80211 wireless extensions compatibility
        [*]   Generic IEEE 802.11 Networking Stack (mac80211)

例如，如果配套芯片是Murata芯片1DX^[12]

[*] Device Drivers  --->
    [*]   Network device support  --->
        [*]   Wireless LAN  --->
             [*]   Broadcom devices
                [*]   Broadcom FullMAC WLAN driver

对于STM32 SDMMC：请参阅 SDMMC configuration

Device tree

DT绑定文档处理所有必需的或可选的 device tree 属性。

STM32外设的详细DT配置： WLAN device tree configuration.

How to use WLAN

How to use the WLAN user space interface

Please see examples based on the following use cases:

How to setup wifi connection: 如何设置WiFi连接
How to configure a wlan interface on client mode: How to configure a wlan interface on client mode
How to configure a wlan interface on hotspot mode: 如何将无线网卡配置为热点模式

How to trace and debug the framework

How to monitor

Please give instruction to help the developer/user to get information about this framework in the Linux file system

How to watch link quality

Proc filesystem provides information about Quality link:

Board $> cat /proc/net/wireless 
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
wlan0: 0000    0     0     0        0      0      0      0      0        0

Example of stat:

Board $> watch -d -n 3 "iw dev wlan0 station dump; iwconfig wlan0; cat /proc/net/wireless"

Every 3.0s: iw dev wlan0 station dump; iwconfig wlan0; cat /proc/net/wir...  stm32mp1: Sun Nov  4 16:32:52 2018

Station 00:16:b6:2c:47:36 (on wlan0)
       inactive time:  0 ms   
       rx bytes:       11001
       rx packets:     37
       tx bytes:       13077
       tx packets:     83
       tx failed:      0
       signal:         -72 [-72] dBm
       tx bitrate:     12.0 MBit/s
       rx bitrate:     1.0 MBit/s 
       authorized:     yes
       authenticated:  yes
       associated:     yes
       WMM/WME:        no
       TDLS peer:      yes
       DTIM period:    1
       beacon interval:100
       short preamble: yes
       short slot time:yes
       connected time: 55 seconds
wlan0     IEEE 802.11  ESSID:"NETWORK1"
         Mode:Managed  Frequency:2.462 GHz  Access Point: 00:16:B6:2C:47:36
         Bit Rate=12 Mb/s   Tx-Power=31 dBm
         Retry short limit:7   RTS thr:off   Fragment thr:off
         Encryption key:off
         Power Management:on
         Link Quality=38/70  Signal level=-72 dBm
         Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
         Tx excessive retries:0  Invalid misc:0   Missed beacon:0

Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
wlan0: 0000   38.  -72.  -256        0      0      0      0      0        0

How to trace

This part is as example in case the companion chip is Murata chip

How to verify than the WLAN driver is well probed

In dmesg log, check "brcmfmac" logs :

[   67.306154] brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Aug  6 2017 23:19:25 version 7.45.98.30 (r666241 CY) FWID 01-f0b000
[   67.326146] brcmfmac: brcmf_c_preinit_dcmds: CLM version = API: 12.2 Data: 7.11.15 Compiler: 1.24.2 ClmImport: 1.24.1 Creation: 2014-05 
[   67.676323] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)

How to debug the WLAN driver

Add dynamic debug firmware traces

Need to activate in the kernel config: CONFIG_DYNAMIC_DEBUG, more info on the dynamic debug How_to_use_the_kernel_dynamic_debug

# cd /sys/kernel/debug/dynamic_debug/

Check all functions used to manage firmware:

# cat control | grep firmware
drivers/base/firmware_class.c:339 [firmware_class]__fw_free_buf =_ "%s: fw-%s buf=%p data=%p size=%u\012"
drivers/base/firmware_class.c:462 [firmware_class]fw_set_page_data =_ "%s: fw-%s buf=%p data=%p size=%u\012"
drivers/base/firmware_class.c:1102 [firmware_class]_request_firmware_prepare =_ "using built-in %s\012"
drivers/base/firmware_class.c:290 [firmware_class]__allocate_fw_buf =_ "%s: fw-%s buf=%p\012"
drivers/base/firmware_class.c:1194 [firmware_class]_request_firmware =_ "firmware: %s loading timed out\012"
drivers/base/firmware_class.c:423 [firmware_class]fw_get_filesystem_firmware =_ "loading %s failed with error %d\012"
drivers/base/firmware_class.c:429 [firmware_class]fw_get_filesystem_firmware =_ "direct-loading %s\012"

Add print info "+p" in all firmware functions (p: causes a printk() message to be emitted to dmesg)

# echo "file drivers/base/firmware_class.c +p" > control

Now "p" option is added in all firmware functions.

# cat control | grep firmware
drivers/base/firmware_class.c:339 [firmware_class]__fw_free_buf =p "%s: fw-%s buf=%p data=%p size=%u\012"
drivers/base/firmware_class.c:462 [firmware_class]fw_set_page_data =p "%s: fw-%s buf=%p data=%p size=%u\012"
drivers/base/firmware_class.c:1102 [firmware_class]_request_firmware_prepare =p "using built-in %s\012"
drivers/base/firmware_class.c:290 [firmware_class]__allocate_fw_buf =p "%s: fw-%s buf=%p\012"
drivers/base/firmware_class.c:1194 [firmware_class]_request_firmware =p "firmware: %s loading timed out\012"
drivers/base/firmware_class.c:423 [firmware_class]fw_get_filesystem_firmware =p "loading %s failed with error %d\012"
drivers/base/firmware_class.c:429 [firmware_class]fw_get_filesystem_firmware =p "direct-loading %s\012"

FMAC debug

Enable debug features in the defconfig file

Enable CPTCFG_BRCMDBG and CONFIG_DEBUG_FS
Rebuild your kernel

Enable brcmfmac debug log

Message levels are listed in drivers/net/wireless/broadcom/brcm80211/brcmfmac/debug.h

/* message levels */
#define BRCMF_TRACE_VAL 0x00000002
#define BRCMF_INFO_VAL 0x00000004
#define BRCMF_DATA_VAL 0x00000008
#define BRCMF_CTL_VAL 0x00000010
#define BRCMF_TIMER_VAL 0x00000020
#define BRCMF_HDRS_VAL 0x00000040
#define BRCMF_BYTES_VAL 0x00000080
#define BRCMF_INTR_VAL 0x00000100
#define BRCMF_GLOM_VAL 0x00000200
#define BRCMF_EVENT_VAL 0x00000400
#define BRCMF_BTA_VAL 0x00000800
#define BRCMF_FIL_VAL 0x00001000
#define BRCMF_USB_VAL 0x00002000
#define BRCMF_SCAN_VAL 0x00004000
#define BRCMF_CONN_VAL 0x00008000
#define BRCMF_BCDC_VAL 0x00010000
#define BRCMF_SDIO_VAL 0x00020000
#define BRCMF_MSGBUF_VAL 0x00040000
#define BRCMF_PCIE_VAL 0x00080000
#define BRCMF_FWCON_VAL 0x00100000

$ modprobe brcmfmac debug=${BRCMF_Message_Level}
$ dmesg -n 8

Examples

Add TRACE and INFO

$ modprobe brcmfmac debug=0x6

Add TRACE, INFO and SDIO

$ modprobe brcmfmac debug=0x20006

Add TRACE, INFO and WIFI_FW_LOG

$ modprobe brcmfmac debug=0x00100006

How to check wlreg_on status and voltage setting

$ cat /sys/kernel/debug/regulator/regulator_summary

Source code location

The source files are located inside the Linux kernel.

Broadcom wlan driver: of.c^[13]

References

↑ [1], cfg80211
↑ [2], IEEE_802.11
↑ [3], nl80211
↑ [4], Netlink
↑ [5], mac80211
↑ MultiMediaCard, MultiMediaCard规范安全数字（SD）
↑ Secure Digital,
↑ Secure Digital Input Output, 安全数字输入输出规范
↑ [6], mac80211
↑ [7], cfg80211
↑ [8], IEEE_802.11
↑ [9], 1DX
↑ [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c ],of.c

[1] [1], cfg80211

[2] [2], IEEE_802.11

[3] [3], nl80211

[4] [4], Netlink

[5] [5], mac80211

[6] MultiMediaCard, MultiMediaCard规范安全数字（SD）

[7] Secure Digital,

[8] Secure Digital Input Output, 安全数字输入输出规范

[9] [6], mac80211

[10] [7], cfg80211

[11] [8], IEEE_802.11

[12] [9], 1DX

[13] [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c ],of.c

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

匿名

搜索

WLAN overview

名字空间

更多

页面选项

目录

Purpose

System overview

Description of the components

APIs description

Configuration

Device tree

How to use WLAN

How to use the WLAN user space interface

How to trace and debug the framework

How to monitor

How to watch link quality

How to trace

How to verify than the WLAN driver is well probed

How to debug the WLAN driver

Add dynamic debug firmware traces

FMAC debug

Enable debug features in the defconfig file

Enable brcmfmac debug log

Examples

How to check wlreg_on status and voltage setting

Source code location

References

导航

导航

所有产品

Wiki工具

Wiki工具

匿名

搜索

WLAN overview

目录

Purpose

System overview

Description of the components

APIs description

Configuration

Device tree

How to use WLAN

How to use the WLAN user space interface

How to trace and debug the framework

How to monitor

How to watch link quality

How to trace

How to verify than the WLAN driver is well probed

How to debug the WLAN driver

Add dynamic debug firmware traces

FMAC debug

Enable debug features in the defconfig file

Enable brcmfmac debug log

Examples

How to check wlreg_on status and voltage setting

Source code location

References

导航

Wiki工具

页面工具