Hi all.
I'm using L138 EVM with PSP 3.22. For application we need board be able to connect Windows host pc with usb cable and transfer data to / commands from it.
I think gadget is what we need. from benchmarks I learned that ethernet RNDIS gadget reach ~ 20 Mbit/s, while Mass storage is ~ 80. Starting with basic kernel configuration I've add serial gadget, mass storage and g_acm_ms - composite gadget of mass storage and serial as modules. then I've successfully loaded and tested serial, ethernet and mass storage. the last one is really fast. now I'd like to have extra interface to send commands from pc.
loading g_acm_ms I get error:
root@arago:~# insmod /lib/modules/3.3.0/kernel/drivers/usb/gadget/g_acm_ms.ko file=/dev/shm/50M
gadget: Mass Storage Function, version: 2009/09/11
gadget: Number of LUNs=1
lun0: LUN: removable file: /dev/shm/50M
gadget: Composite Gadget (ACM + MS), version: 2011/10/10
gadget: g_acm_ms ready
g_acm_ms musb-hdrc: failed to start g_acm_ms: -22
insmod: error inserting '/lib/modules/3.3.0/kernel/drivers/usb/gadget/g_acm_ms.ko': -1
Invalid parameters
root@arago:~#
I believe parameter ffile=/dev/shm/50M is write and it is enough. here some info http://wiki.linpert.de/index.php?title=Kernel_USB_Gadget
what I'm doing wrong? does anybody tested this feature or multifunction gadget?
regards,.
Dmitriy.