USB Mass Storage Gadget (or MSG) - Revision history

Lzenz: /* Apply Backing Storage */

2017-06-09T05:38:21Z

Apply Backing Storage

← Older revision		Revision as of 07:38, 9 June 2017
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	=== Apply Backing Storage ===		=== Apply Backing Storage ===
	On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:		On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:
	* <tt>am35x# echo /dev/mmcblk0p1 > >/sys/devices/platform/omap/musb-am35x/musb-hdrc/gadget/lun0/file</tt>		* <tt>am35x# echo /dev/mmcblk0p1 > /sys/devices/platform/omap/musb-am35x/musb-hdrc/gadget/lun0/file</tt>
	If you do not work the AM35x there are some differences in the path of the sysfs. (Easy to find when you go to <tt> cd /sys </tt> and type <tt> find . -name "lun*" </tt>)		If you do not work the AM35x there are some differences in the path of the sysfs. (Easy to find when you go to <tt> cd /sys </tt> and type <tt> find . -name "lun*" </tt>)

Lzenz at 13:27, 28 July 2015

2015-07-28T13:27:51Z

← Older revision		Revision as of 15:27, 28 July 2015
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	== General Information ==		== General Information ==

	For further information about details of the USB Mass Storage Gadget Driver and how to use it have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html]. It is possible to run the driver as loadable kernel module. The steps below descripe how to compile the ~~driver~~ statically into the kernel.		For further information about details of the USB Mass Storage Gadget Driver and how to use it have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] and [https://www.kernel.org/doc/Documentation/usb/mass-storage.txt www.kernel.org]. It is possible to run the driver as loadable kernel module. The steps below descripe how to compile the g_mass_storage module statically into the kernel image.

	== Configure the USB-OTG Port ==		== Configure the USB-OTG Port ==
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	On i.MX25 and AM35x to use USB Gadget features the USB-OTG Port has to be initialized in USB slave mode. Add <code>"otg_mode=device"</code> to the kernel commandline on the bootloader console.		On i.MX25 and AM35x to use USB Gadget features the USB-OTG Port has to be initialized in USB slave mode. Add <code>"otg_mode=device"</code> to the kernel commandline on the bootloader console.

	On DHCOM boards it is possible to use the u-boot environment variable <~~code~~>"linux_add_param"</~~code~~>:		On DHCOM boards it is possible to use the u-boot environment variable <tt>"linux_add_param"</tt>:
	# enter bootloader console with DEL/BS Key		# enter bootloader console with DEL/BS Key
	# <~~code~~>setenv linux_add_param otg_mode=device</~~code~~>		# <tt>setenv linux_add_param otg_mode=device</tt>
	# <~~code~~>saveenv</~~code~~>		# <tt>saveenv</tt>

	'''Remark:''' The DHCOM i.MX6 and AM335x have dual role usb controllers und drivers. It is not necessary to specify the otg_mode if you use this platforms.		'''Remark:''' The DHCOM i.MX6 and AM335x have dual role usb controllers und drivers. It is not necessary to specify the otg_mode if you use this platforms.
Line 23:		Line 23:

	Open a console window and go to the root directory of the kernel sources and start the kernel configuration dialog:		Open a console window and go to the root directory of the kernel sources and start the kernel configuration dialog:
	* <~~code~~> ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make menuconfig </~~code~~>		* <tt> ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make menuconfig </tt>

	Enable the following items:		Enable the following items:
Line 35:		Line 35:
	Rebuild the Linux kernel and install the kernel to your board. (See DHCOM Update for details.)		Rebuild the Linux kernel and install the kernel to your board. (See DHCOM Update for details.)

	== ~~Using USB Mass Storage Gadget~~ ==		== How to Use? ==

			=== Static Kernel Module ===
			If the '''g_mass_storage''' module has been statically built into the kernel image you have to provide the following parameters to the kernel module via kernel command line (bootargs in u-boot):
			* <tt> g_mass_storage.removable=1 </tt>
			* <tt> g_mass_storage.luns=1 </tt>

			=== Apply Backing Storage ===
	On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:		On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:
	* <~~code~~>am35x# echo /dev/mmcblk0p1 > >/sys/devices/platform/omap/musb-am35x/musb-hdrc/gadget/lun0/file</~~code~~>		* <tt>am35x# echo /dev/mmcblk0p1 > >/sys/devices/platform/omap/musb-am35x/musb-hdrc/gadget/lun0/file</tt>
	If you do not work the AM35x ~~maybe~~ there are some ~~tiny~~ differences in the path of the sysfs.		If you do not work the AM35x there are some differences in the path of the sysfs. (Easy to find when you go to <tt> cd /sys </tt> and type <tt> find . -name "lun*" </tt>)


	Now, if you connect the USB-OTG port to your host pc the specified device appears as a drive.		Now, if you connect the USB-OTG port to your host pc the specified device appears as a drive.


	'''Remark:'''		'''Remark:'''
	* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).		* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).
	* Do not use the rootfilesystem partition ~~of your microSD card~~. This will cause damage to the ~~used microSD-Card partition~~.		* Do not use the rootfilesystem partition. This will cause damage to the filesystem. Only one "Writer" on each Filesystem is allowed!


	'''AN IMPORTANT WARNING!'''		=== '''IMPORTANT WARNING!''' ===
	* While MSG is running and the gadget is connected to a USB host, that USB host will use the backing storage as a private disk drive. It will not expect to see any changes in the backing storage other than the ones it makes. Extraneous changes are liable to corrupt the filesystem and may even crash the host. Only one system (normally, the USB host) may write to the backing storage, and if one system is writing that data, no other should be reading it. The only safe way to share the backing storage between the host and the gadget's operating system at the same time is to make it read-only on both sides.		* While MSG is running and the gadget is connected to a USB host, that USB host will use the backing storage as a private disk drive. It will not expect to see any changes in the backing storage other than the ones it makes. Extraneous changes are liable to corrupt the filesystem and may even crash the host. Only one system (normally, the USB host) may write to the backing storage, and if one system is writing that data, no other should be reading it. The only safe way to share the backing storage between the host and the gadget's operating system at the same time is to make it read-only on both sides.

	Have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] to get a step by step guide how to work with „Backing Storage Files“.		Have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] to get a step by step guide how to work with „Backing Storage Files“.

Lzenz: /* Prepare the Kernel */

2015-07-28T13:11:03Z

Prepare the Kernel

@@ Line 32: / Line 32: @@
 ::: * DHCOM iMX25, iMX6: Freescale Highspeed USB DR Peripheral Controller
 * Device Drivers -->  USB Support -->  USB Gadget Support --> USB Gadget Drivers -->  Mass Storage Gadget
-Apply the following changes to the file <code>linux-2.6.38/drivers/usb/gadget/file_storage.c</code> in the lines 332 and 333:
+Rebuild the Linux kernel and install the kernel to your board. (See DHCOM Update for details.)
 == Using USB Mass Storage Gadget ==

Lzenz: /* Prepare the Kernel */

2015-07-28T13:08:19Z

Prepare the Kernel

← Older revision		Revision as of 15:08, 28 July 2015
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	* Device Drivers --> USB Support --> USB Gadget Support --> USB Peripheral Controller		* Device Drivers --> USB Support --> USB Gadget Support --> USB Peripheral Controller
	:: choose the matching device controller:		:: choose the matching device controller:
	::: * DHCOM AM35x: ~~OMAP~~ USB ~~Device Controller~~		::: * DHCOM AM35x, AM335x: Inventra HDRC USB Peripheral (TI, ADI, ...)
	::: * DHCOM iMX25, iMX6: Freescale Highspeed USB DR Peripheral Controller		::: * DHCOM iMX25, iMX6: Freescale Highspeed USB DR Peripheral Controller
	* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> Mass Storage Gadget		* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> Mass Storage Gadget

Lzenz: /* Prepare the Kernel */

2015-07-28T13:06:10Z

Prepare the Kernel

← Older revision		Revision as of 15:06, 28 July 2015
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	:: choose the matching device controller:		:: choose the matching device controller:
	::: * DHCOM AM35x: OMAP USB Device Controller		::: * DHCOM AM35x: OMAP USB Device Controller
	::: * DHCOM iMX25: Freescale Highspeed USB DR Peripheral Controller		::: * DHCOM iMX25, iMX6: Freescale Highspeed USB DR Peripheral Controller
	* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> Mass Storage Gadget		* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> Mass Storage Gadget
	<!--		<!--
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	Install the kernel on your board.		Install the kernel on your board.


	== Using USB Mass Storage Gadget ==		== Using USB Mass Storage Gadget ==

Lzenz: /* Configure the USB-OTG Port */

2015-07-28T13:03:19Z

Configure the USB-OTG Port

← Older revision		Revision as of 15:03, 28 July 2015
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	== Configure the USB-OTG Port ==		== Configure the USB-OTG Port ==

	To use USB Gadget features the USB-OTG Port has to be initialized in USB slave mode. Add <code>"otg_mode=device"</code> to the kernel commandline on the bootloader console.		On i.MX25 and AM35x to use USB Gadget features the USB-OTG Port has to be initialized in USB slave mode. Add <code>"otg_mode=device"</code> to the kernel commandline on the bootloader console.

	On DHCOM boards it is possible to use the u-boot environment variable <code>"linux_add_param"</code>:		On DHCOM boards it is possible to use the u-boot environment variable <code>"linux_add_param"</code>:
Line 15:		Line 15:
	# <code>setenv linux_add_param otg_mode=device</code>		# <code>setenv linux_add_param otg_mode=device</code>
	# <code>saveenv</code>		# <code>saveenv</code>

			'''Remark:''' The DHCOM i.MX6 and AM335x have dual role usb controllers und drivers. It is not necessary to specify the otg_mode if you use this platforms.

	== Prepare the Kernel ==		== Prepare the Kernel ==

Lzenz at 09:51, 27 January 2014

2014-01-27T09:51:48Z

← Older revision		Revision as of 11:51, 27 January 2014
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	The Mass Storage Gadget (MSG) provides support for the USB Mass Storage class. The System appears to the host as a SCSI disk drive. A file or a block device is used as a backing store for the drive.		The Mass Storage Gadget (MSG) provides support for the USB Mass Storage class. The System appears to the host (PC) as a SCSI disk drive if the USB-OTG port is used for the connection. A file or a block device is used as a backing store for the drive.

	__TOC__		__TOC__

Lzenz at 09:50, 27 January 2014

2014-01-27T09:50:01Z

← Older revision		Revision as of 11:50, 27 January 2014
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	The ~~USB~~ Gadget ~~File-backed Storage Driver implements~~ the USB Mass Storage class. The System appears to the host as a SCSI disk drive. A file or a block device is used as a backing store for the drive.		The Mass Storage Gadget (MSG) provides support for the USB Mass Storage class. The System appears to the host as a SCSI disk drive. A file or a block device is used as a backing store for the drive.

	__TOC__		__TOC__
Line 5:		Line 5:
	== General Information ==		== General Information ==

	For further information about details of the USB Gadget ~~File-backed Storage~~ Driver have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html]. It is possible to ~~work with~~ kernel~~-modules~~. The steps below descripe how to compile the driver statically into the kernel ~~because it is easier to handle~~.		For further information about details of the USB Mass Storage Gadget Driver and how to use it have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html]. It is possible to run the driver as loadable kernel module. The steps below descripe how to compile the driver statically into the kernel.

	== Configure the USB-OTG Port ==		== Configure the USB-OTG Port ==
Line 29:		Line 29:
	::: * DHCOM AM35x: OMAP USB Device Controller		::: * DHCOM AM35x: OMAP USB Device Controller
	::: * DHCOM iMX25: Freescale Highspeed USB DR Peripheral Controller		::: * DHCOM iMX25: Freescale Highspeed USB DR Peripheral Controller
	* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> ~~File~~-backed ~~Storage Gadget~~		* Device Drivers --> USB Support --> USB Gadget Support --> USB Gadget Drivers --> Mass Storage Gadget
			<!--
			Obsolete, does not apply to the MSG (file-backed gadget is obsolete)

	Apply the following changes to the file <code>linux-2.6.38/drivers/usb/gadget/file_storage.c</code> in the lines 332 and 333:		Apply the following changes to the file <code>linux-2.6.38/drivers/usb/gadget/file_storage.c</code> in the lines 332 and 333:
Line 37:		Line 39:
	<font color="#00FF10">+ .removable = 1, // old value = 0,		<font color="#00FF10">+ .removable = 1, // old value = 0,
	+ .can_stall = 0, // old value = 1, </font></code>		+ .can_stall = 0, // old value = 1, </font></code>
			-->


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	== Using USB Gadget ~~File-backed Storage~~ ==		== Using USB Mass Storage Gadget ==

	On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:		On the running device you can use the following line to add the FAT32 partition of the microSD-card to the usb gadget driver:
	* <code>~~i.mx25~~# echo /dev/mmcblk0p1 > /sys/devices/platform/~~fsl~~-~~usb2~~-~~udc~~/gadget/~~gadget-~~lun0/file</code>		* <code>am35x# echo /dev/mmcblk0p1 > >/sys/devices/platform/omap/musb-am35x/musb-hdrc/gadget/lun0/file</code>
	If you do not work the ~~i.mx25~~ maybe there are some tiny differences in the path of the sysfs.		If you do not work the AM35x maybe there are some tiny differences in the path of the sysfs.


Line 59:		Line 62:
	* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).		* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).
	* Do not use the rootfilesystem partition of your microSD card. This will cause damage to the used microSD-Card partition.		* Do not use the rootfilesystem partition of your microSD card. This will cause damage to the used microSD-Card partition.


			'''AN IMPORTANT WARNING!'''
			* While MSG is running and the gadget is connected to a USB host, that USB host will use the backing storage as a private disk drive. It will not expect to see any changes in the backing storage other than the ones it makes. Extraneous changes are liable to corrupt the filesystem and may even crash the host. Only one system (normally, the USB host) may write to the backing storage, and if one system is writing that data, no other should be reading it. The only safe way to share the backing storage between the host and the gadget's operating system at the same time is to make it read-only on both sides.

	Have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] to get a step by step guide how to work with „Backing Storage Files“.		Have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] to get a step by step guide how to work with „Backing Storage Files“.

Lzenz: moved USB Gadget File-backed Storage to USB Mass Storage Gadget (or MSG): File-backed Storage Gadget is obsolete and replaced by the Mass-Storage Gadget.

2014-01-27T09:25:10Z

moved USB Gadget File-backed Storage to USB Mass Storage Gadget (or MSG): File-backed Storage Gadget is obsolete and replaced by the Mass-Storage Gadget.

← Older revision	Revision as of 11:25, 27 January 2014
(No difference)

Lzenz at 13:42, 8 October 2012

2012-10-08T13:42:03Z

← Older revision		Revision as of 15:42, 8 October 2012
Line 1:		Line 1:
	The USB Gadget File-backed Storage Driver implements the USB ~~MAss~~ Storage class. The System appears to the host as a SCSI disk drive. A file or a block device is used as a backing store for the drive.		The USB Gadget File-backed Storage Driver implements the USB Mass Storage class. The System appears to the host as a SCSI disk drive. A file or a block device is used as a backing store for the drive.

	__TOC__		__TOC__
Line 51:		Line 51:
	* <code>i.mx25# echo /dev/mmcblk0p1 > /sys/devices/platform/fsl-usb2-udc/gadget/gadget-lun0/file</code>		* <code>i.mx25# echo /dev/mmcblk0p1 > /sys/devices/platform/fsl-usb2-udc/gadget/gadget-lun0/file</code>
	If you do not work the i.mx25 maybe there are some tiny differences in the path of the sysfs.		If you do not work the i.mx25 maybe there are some tiny differences in the path of the sysfs.


			Now, if you connect the USB-OTG port to your host pc the specified device appears as a drive.

	~~If you connect the USB-OTG port now the specified device appears as a drive on your host pc.~~
			'''Remark:'''
	Remark:
	* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).		* If you run windows then you can only use block devices with filesystems supported by windows (FAT32).
	* Do not use the rootfilesystem partition of your microSD card. This will cause damage to the used microSD-Card partition.		* Do not use the rootfilesystem partition of your microSD card. This will cause damage to the used microSD-Card partition.

	Have a look at [[http://www.linux-usb.org/gadget/file_storage.html \| www.linux-usb.org/gadget/file_storage.html]] to get a step by step guide how to work with „Backing Storage Files“.		Have a look at [http://www.linux-usb.org/gadget/file_storage.html www.linux-usb.org/gadget/file_storage.html] to get a step by step guide how to work with „Backing Storage Files“.