基于全志A20 android4.2平台如何支持三个SD卡

 

         做过android平台的同仁大多都知道android原生态只支持了一个sd卡，默认的挂载点也就是/mnt/sdcard，所以在应用中使用getExternalStorageDirectory（）得到的都是/mnt/sdcard,通常会symlink 到/sdcard目录。做过全志平台的童鞋也知道全志android SDK支持2个sd卡，通常是一个内置的，一个外置的，内置的一般是从nand上或者emmc上的用户数据区，因为现在的nand、emmc容量都比较大，存放android程序、cache、backup、download等之外，还有大量的空间剩余，因此这部分大多都会做成一个sd卡来使用，通常挂载到/mnt/sdcard上；外置的是挂载在/mnt/extsd节点上。但是，如何在全志平台上使用三个sd卡呢？即再增加一个外置的SD卡支持。

      为了多支持一个SD卡，我们有以下基本需要做：

      1、          在系统配置文件里，打开对应的SD卡驱动支持，设置好检测方式，如果是gpio方式的要配置好gpio引脚；笔者测试过，如果两个外置的SD卡，都使用gpio polling的方式，系统只识别一个SD卡，笔者把两个SD卡一个配置成gpio polling，另外一个配置成了GPIO IRQ中断模式；

[mmc0_para]
sdc_used            = 1
sdc_detmode         = 2
sdc_buswidth        = 4
sdc_clk             = port:PF02<2><1><2><default>
sdc_cmd             = port:PF03<2><1><2><default>
sdc_d0              = port:PF01<2><1><2><default>
sdc_d1              = port:PF00<2><1><2><default>
sdc_d2              = port:PF05<2><1><2><default>
sdc_d3              = port:PF04<2><1><2><default>
sdc_det             = port:PH3<6><1><default><default>
sdc_use_wp          = 0
sdc_wp              =
sdc_isio            = 0
sdc_regulator       = "none"

[mmc1_para]
sdc_used            = 1
sdc_detmode         = 1
sdc_buswidth        = 4
sdc_clk             = port:PH23<5><1><2><default>
sdc_cmd             = port:PH22<5><1><2><default>
sdc_d0                   = port:PH24<5><1><2><default>
sdc_d1                   = port:PH25<5><1><2><default>
sdc_d2                   = port:PH26<5><1><2><default>
sdc_d3                   = port:PH27<5><1><2><default>
sdc_det                  = port:PH2<0><1><default><default>
sdc_use_wp          = 0
sdc_wp              =
sdc_isio            = 0
sdc_regulator       = "none"

[mmc0_para]
sdc_used            = 1
sdc_detmode         = 2
sdc_buswidth        = 4
sdc_clk             = port:PF02<2><1><2><default>
sdc_cmd             = port:PF03<2><1><2><default>
sdc_d0              = port:PF01<2><1><2><default>
sdc_d1              = port:PF00<2><1><2><default>
sdc_d2              = port:PF05<2><1><2><default>
sdc_d3              = port:PF04<2><1><2><default>
sdc_det             = port:PH3<6><1><default><default>
sdc_use_wp          = 0
sdc_wp              =
sdc_isio            = 0
sdc_regulator       = "none"

[mmc1_para]
sdc_used            = 1
sdc_detmode         = 1
sdc_buswidth        = 4
sdc_clk             = port:PH23<5><1><2><default>
sdc_cmd             = port:PH22<5><1><2><default>
sdc_d0                   = port:PH24<5><1><2><default>
sdc_d1                   = port:PH25<5><1><2><default>
sdc_d2                   = port:PH26<5><1><2><default>
sdc_d3                   = port:PH27<5><1><2><default>
sdc_det                  = port:PH2<0><1><default><default>
sdc_use_wp          = 0
sdc_wp              =
sdc_isio            = 0
sdc_regulator       = "none"

     2、          在vold.fstab里，需要修改一下，如下：

## Vold 2.0 fstab for HTC Passion
#
## - San Mehat ([email protected])
##
#######################
## Regular device mount
##
## Format: dev_mount <label> <mount_point> <part> <sysfs_path1...>
## label        - Label for the volume
## mount_point  - Where the volume will be mounted
## part         - Partition # (1 based), or 'auto' for first usable partition.
## <sysfs_path> - List of sysfs paths to source devices
######################

# Mounts the first usable partition of the specified device
#/devices/platform/awsmc.3/mmc_host for sdio
dev_mount   sdcard  /mnt/sdcard auto    /devices/virtual/block/nandk    /devices/platform/sunxi-mmc.2/mmc_host
dev_mount   extsd   /mnt/extsd  auto    /devices/platform/sunxi-mmc.1/mmc_host
dev_mount   extsd2  /mnt/extsd2 auto    /devices/platform/sunxi-mmc.0/mmc_host
dev_mount   usbhost1    /mnt/usbhost1   auto    /devices/platform/sw-ehci.1 /devices/platform/sw_hcd_host0  /devices/platform/sw-ohci.1

## Vold 2.0 fstab for HTC Passion
#
## - San Mehat ([email protected])
## 
#######################
## Regular device mount
##
## Format: dev_mount <label> <mount_point> <part> <sysfs_path1...> 
## label        - Label for the volume
## mount_point  - Where the volume will be mounted
## part         - Partition # (1 based), or 'auto' for first usable partition.
## <sysfs_path> - List of sysfs paths to source devices
######################

# Mounts the first usable partition of the specified device
#/devices/platform/awsmc.3/mmc_host for sdio
dev_mount	sdcard	/mnt/sdcard	auto	/devices/virtual/block/nandk	/devices/platform/sunxi-mmc.2/mmc_host
dev_mount	extsd	/mnt/extsd	auto	/devices/platform/sunxi-mmc.1/mmc_host
dev_mount	extsd2	/mnt/extsd2	auto	/devices/platform/sunxi-mmc.0/mmc_host
dev_mount	usbhost1	/mnt/usbhost1	auto	/devices/platform/sw-ehci.1	/devices/platform/sw_hcd_host0	/devices/platform/sw-ohci.1

这三个SD卡挂载点都是可以随便交换的；

3、          如果完成了上面两步，extsd2对应的SD卡热插拔是可以自动挂载，如果是开机启动前就在sd卡槽里面的话，就不会自动识别，因此我们得明确告诉系统storage配置，配置在storage_list.xml文件中，如下：

         <storage android:mountPoint="/mnt/extsd"

             android:storageDescription="extsd"

             android:primary="false"

             android:removable="true"

             android:emulated="false"

             android:mtpReserve="0"

             android:allowMassStorage="true"

             android:maxFileSize="0"/>

         <storage android:mountPoint="/mnt/extsd"

             android:storageDescription="extsd"

             android:primary="false"

             android:removable="true"

             android:emulated="false"  

             android:mtpReserve="0" 

             android:allowMassStorage="true"

             android:maxFileSize="0"/>
 

4、          在system/vold下面做一些处理，类似extsd处理，加上即可，如下：

diff --git a/DirectVolume.cpp b/DirectVolume.cpp
index 16ac2d8..43ce612 100755
--- a/DirectVolume.cpp
+++ b/DirectVolume.cpp
@@ -346,7 +346,7 @@ void DirectVolume::handlePartitionRemoved(const char *devpath, NetlinkEvent *evt
          * Yikes, our mounted partition is going away!
          */

-        if(!strstr(getLabel(),"usb")&&!strstr(getLabel(),"extsd")){
+        if(!strstr(getLabel(),"usb")&&!strstr(getLabel(),"extsd")&&!strstr(getLabel(),"extsd2")){
         snprintf(msg, sizeof(msg), "Volume %s %s bad removal (%d:%d)",
                  getLabel(), getMountpoint(), major, minor);
         mVm->getBroadcaster()->sendBroadcast(ResponseCode::VolumeBadRemoval,
diff --git a/Volume.cpp b/Volume.cpp
old mode 100644
new mode 100755
index 23556ea..a1f059a
--- a/Volume.cpp
+++ b/Volume.cpp
@@ -864,7 +864,7 @@ int Volume::unmountVol(bool force, bool revert) {
     setState(Volume::State_Unmounting);
     usleep(1000 * 1000); // Give the framework some time to react

-    if(getMountpoint()!=NULL&&!strstr(getMountpoint(),"usb")&&!strstr(getMountpoint(),"extsd")){
+    if(getMountpoint()!=NULL&&!strstr(getMountpoint(),"usb")&&!strstr(getMountpoint(),"extsd")&&!strstr(getMountpoint(),"extsd2")){
         /*
          * Remove the bindmount we were using to keep a reference to
          * the previously obscured directory.

diff --git a/DirectVolume.cpp b/DirectVolume.cpp
index 16ac2d8..43ce612 100755
--- a/DirectVolume.cpp
+++ b/DirectVolume.cpp
@@ -346,7 +346,7 @@ void DirectVolume::handlePartitionRemoved(const char *devpath, NetlinkEvent *evt
          * Yikes, our mounted partition is going away!
          */
 
-        if(!strstr(getLabel(),"usb")&&!strstr(getLabel(),"extsd")){
+        if(!strstr(getLabel(),"usb")&&!strstr(getLabel(),"extsd")&&!strstr(getLabel(),"extsd2")){
         snprintf(msg, sizeof(msg), "Volume %s %s bad removal (%d:%d)",
                  getLabel(), getMountpoint(), major, minor);
         mVm->getBroadcaster()->sendBroadcast(ResponseCode::VolumeBadRemoval,
diff --git a/Volume.cpp b/Volume.cpp
old mode 100644
new mode 100755
index 23556ea..a1f059a
--- a/Volume.cpp
+++ b/Volume.cpp
@@ -864,7 +864,7 @@ int Volume::unmountVol(bool force, bool revert) {
     setState(Volume::State_Unmounting);
     usleep(1000 * 1000); // Give the framework some time to react
 
-    if(getMountpoint()!=NULL&&!strstr(getMountpoint(),"usb")&&!strstr(getMountpoint(),"extsd")){
+    if(getMountpoint()!=NULL&&!strstr(getMountpoint(),"usb")&&!strstr(getMountpoint(),"extsd")&&!strstr(getMountpoint(),"extsd2")){
         /*
          * Remove the bindmount we were using to keep a reference to
          * the previously obscured directory.

 

     完成了以上几步，三个SD卡已经可以自动识别挂载了，mount的信息如下：

root@android:/ # mount

rootfs / rootfs rw 0 0
tmpfs /dev tmpfs rw,nosuid,relatime,mode=755 0 0
devpts /dev/pts devpts rw,relatime,mode=600 0 0
proc /proc proc rw,relatime 0 0
sysfs /sys sysfs rw,relatime 0 0
debugfs /sys/kernel/debug debugfs rw,relatime 0 0
none /acct cgroup rw,relatime,cpuacct 0 0
tmpfs /mnt/secure tmpfs rw,relatime,mode=700 0 0
tmpfs /mnt/asec tmpfs rw,relatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,relatime,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,relatime,cpu 0 0
/dev/block/nandd /system ext4 rw,nodev,noatime,nobarrier,data=ordered 0 0
/dev/block/nande /data ext4 rw,nosuid,nodev,noatime,journal_checksum,nobarrier,noauto_da_alloc,data=ordered 0 0
/dev/block/nandh /cache ext4 rw,nosuid,nodev,noatime,journal_checksum,nobarrier,noauto_da_alloc,data=ordered 0 0
/dev/block/vold/179:16 /mnt/extsd vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1023,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:0 /mnt/extsd2 vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1023,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/93:80 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/93:80 /mnt/secure/asec vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /mnt/sdcard/.android_secure tmpfs ro,relatime,size=0k,mode=000 0 0
root@android:/ #