Linux内核移植 part3:usb host驱动

初期教育应是一种娱乐,这样才更容易发现一个人天生的爱好。 —— 柏拉图

深深赞同柏拉图的这个观点,人是有天性的,教育无非就是如何引导天性朝有利的方向发展。

继续Linux内核移植系列,今天介绍如何移植Exynos4412 usb驱动,采用的平台依旧是itop Exynos4412精英板。协议的知识就不介绍了,直接来移植一个可以使用的usb host驱动。

一 硬件配置

1.1 外部管脚

首先usb host必须有vbus,通过vbus给端口上的设备供电,所以the very first应该是去检查vbus的供电电路。通过查看原理图,发现vbus是通过gpio(ETC6)控制的。由于ETC6和其他gpio管脚的映射方式不太一样,这里就不通过gpio驱动来控制了,直接在usb驱动中添加以下语句使能vbus。

    //exynos_setup_vbus_gpio(&pdev->dev);

    void __iomem *etc6_addr = ioremap(0x11000228, 2);
    unsigned int etc6pud, etc6drv;
    if (!etc6_addr)
        pr_info("Can't Map ETC6.\n");
    else {
        etc6pud = readl(etc6_addr);
        etc6drv = readl(etc6_addr+4);
        pr_info("ETC6PUD = 0x%x\tETC6DRV = 0x%x.\n", etc6pud, etc6drv);
        writel(etc6pud | (0x3<<12), etc6_addr);
        writel(etc6drv | (0x1<<12), etc6_addr+4);
        pr_info("Configed ETC6PUD = 0x%x, ETC6DRV = 0x%x.\n", readl(etc6_addr), readl(etc6_addr+4));
    }

内核起来后,就可以测量到vbus的5V电压了。

其次是去检查时钟管脚,这里用的现成的就可以,设备树中默认已经配置好了。

1.2 hub

这里用的是usb3503芯片,也去查看原理图,找到reset/connect/int脚,都配置到设备树中。

二 设备树和内核配置

2.1 设备树配置

配置控制器,phy和hub,代码如下:

exynos-usbphy@125B0000 {
        status = "okay";    
    };

    ehci: ehci@12580000 {
        //samsung,vbus-gpio = <&gpx3 5 1>;
        status = "okay";    
        port@0 {
            status = "okay";
        };
        port@1 {
            status = "okay";
        };
        port@2 {
            status = "okay";    
        };
    };

    usb3503 {
        compatible = "smsc,usb3503";    
        reg = <0x08 0x4>;
        connect-gpios = <&gpm3 3 GPIO_ACTIVE_LOW>;
        intn-gpios = <&gpx2 3 GPIO_ACTIVE_LOW>;
        reset-gpios = <&gpm2 4 GPIO_ACTIVE_LOW>;
        initial-mode = <1>;
    };

2.2 内核配置

  • usb3503驱动配置

Linux内核移植 part3:usb host驱动_第1张图片

  • usb控制器驱动配置

Linux内核移植 part3:usb host驱动_第2张图片

开启usb storage驱动,后面我们用u盘进行测试。

如果要生成设备文件节点的话,还需要添加scsi支持。

Linux内核移植 part3:usb host驱动_第3张图片

三 测试

启动log如下:

[    1.201505] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    1.207715] ehci-exynos: EHCI EXYNOS driver
[    1.211970] ETC6PUD = 0xc000 ETC6DRV = 0x0.
[    1.216040] Configed ETC6PUD = 0xf000, ETC6DRV = 0x1000.
[    1.221339] usb phy_number = 0.
[    1.224474] usb phy_number = 1.
[    1.227585] usb phy_number = 2.
[    1.231196] exynos-ehci 12580000.ehci: EHCI Host Controller
[    1.236287] exynos-ehci 12580000.ehci: new USB bus registered, assigned bus number 1
[    1.244271] exynos-ehci 12580000.ehci: irq 45, io mem 0x12580000
[    1.257078] exynos-ehci 12580000.ehci: USB 2.0 started, EHCI 1.00
[    1.262439] hub 1-0:1.0: USB hub found
[    1.265482] hub 1-0:1.0: 3 ports detected
[    1.270181] usbcore: registered new interface driver usb-storage
[    1.285771] usb3503 8.usb3503: switched to HUB mode
[    1.289186] usb3503 8.usb3503: usb3503_probe: probed in hub mode

插上读卡器试试:

[root@osee ]#[ 1205.437072] usb 1-3.3: new high-speed USB device number 7 using exynos-ehci
[ 1205.551613] usb-storage 1-3.3:1.0: USB Mass Storage device detected
[ 1205.556746] scsi host0: usb-storage 1-3.3:1.0
[ 1206.558784] scsi 0:0:0:0: Direct-Access     TS-RDF5  SD  Transcend    TS37 PQ: 0 ANSI: 6
[ 1206.566175] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 1206.923615] sd 0:0:0:0: [sda] 30881792 512-byte logical blocks: (15.8 GB/14.7 GiB)
[ 1206.930982] sd 0:0:0:0: [sda] Write Protect is off
[ 1206.935733] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 1206.950255]  sda: sda1
[ 1206.955367] sd 0:0:0:0: [sda] Attached SCSI removable disk

挂载访问(如果没有发现设备文件,执行mdev -s看看):

[root@osee ]#mdev -s
[root@osee ]#ls /dev/sda
sda   sda1
[root@osee ]#ls /dev/sda1 
/dev/sda1
[root@osee ]#ls home/
[root@osee ]#mkdir home/usb
[root@osee ]#
[root@osee ]#mount /dev/sda1 home/usb/
[root@osee ]#ls home/usb/
DCIM  FFDB
[root@osee ]#ls home/usb/DCIM/
100_FUJI
[root@osee ]#df -h
Filesystem                Size      Used Available Use% Mounted on
tmpfs                   504.9M         0    504.9M   0% /dev/shm
/dev/sda1                14.7G     83.6M     14.6G   1% /home/usb

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