RTOS/EVMK2G: USB Driver Enumeration issue

Krishna Mohan

Part Number: EVMK2G

Tool/software: TI-RTOS

Hi,

I am having one K2G-EVM and using TI RTOS (Processor SDK) on it. The PSDK have USB driver and it implements mass storage class.

I am trying to enumerate an iPhone. I am not concerned about any USB class now. I am just trying to get the device descriptor.

With iPhone models like iPhone 6, iPhone SE and iPhone X, I am able to get the device descriptor with the existing PSDK USB driver without any modification.

But for iPhone 5c, I am unable to do the same. Unlike other iPhones, iPhone 5c is not even getting charged when I connect it to the K2G board.

I am debugging the code and I have found the following:

In working scenario, once I get event interrupt in USBSTS register, I go ahead and read DWC_USB_PORTSC1 register where I get value 0x206E1. The 0th bit (Current Connect Status bit) transitions to 1 indicating that a device is connected. The Port Link State bits(bit 8:5) is 7 which means Link is in Polling State.
In case of iPhone 5c, I get the event interrupt in USBSTS register but when I read DWC_USB_PORTSC1 register, I get value 0x202a0. The 0th bit (Current Connect Status bit) is still 0 and the value of Port Link State bit is 5 which means Link is in RxDetect Sate.

Would you please suggest me where should I look to fix the issue?

Regards,

Krishna

over 6 years ago

0 Cvetolin Shulev-XID over 6 years ago

TI__Guru 65405 points

The team is notified. They will post their feedback directly here.

BR
Tsvetolin Shulev

0 lding over 6 years ago in reply to Cvetolin Shulev-XID

TI__Guru* 95265 points

Hi,

Can you clarify if you used the latest Processor SDK RTOS 4.2 for K2G and USB_HostMsc_evmK2G_armExampleProject to do iphone enumeration?

Regards, Eric

0 Krishna Mohan over 6 years ago in reply to lding

Intellectual 485 points

Hi Eric,

I was using Processor SDK RTOS 4.01.00.06. But I have verified the same behavior on the latest Processor SDK RTOS 4.02.00.09 as well.

In the lastest Processor SDK RTOS 4.02.00.09, iPhone 6 is not getting charged whereas in Processor SDK RTOS 4.01.00.06 it was getting charged.

I have checked the enumeration in case of android device (Nokia 6), it works fine with both the Processor SDKs and the phone gets charged as well.

Regards,
Krishna

0 lding over 6 years ago in reply to Krishna Mohan

TI__Guru* 95265 points

Hi,

We tested the USB host example with a few USB thumb drives, there may be some incompatibility issue with all kinds of storage devices, but we can't test them all. Can you let us know what is your usage case letting K2G USB to enumerate an iphone?

Regards, Eric

0 Thanh H Tran over 6 years ago

TI__Intellectual 760 points

Hi Krishna

Thanks for the detail description of the problem. I'm not entirely sure why it behaves that way with the Iphone 5c. On K2G I noticed that the xHCI could send more events than what we expected. Because of this, if you let the code run on its own, how many TRB events do you receive (or how many interrupts do you see) before the PortSC settles at the state you saw?

Thanks

Thanh

0 lding over 5 years ago in reply to Thanh H Tran

TI__Guru* 95265 points

Any update?

Regards, Eric

0 Krishna Mohan over 5 years ago in reply to lding

Intellectual 485 points

Hi,

I was able to fix my issue by checking for Connect Status Change flag of PORTSC register in xhci_handle_psc_event(). I just added a condition that if the flag is set, then I change state of the port state machine maintained in the code to USB_HOST_DEV_CONNECTED or USB_HOST_DEV_DETACHED.

Regards,

Krishna Mohan

0 lding over 5 years ago in reply to Krishna Mohan

TI__Guru* 95265 points

Hi,

Thanks! That is a good news! Would you mind to upload the file you changed (I believe it is usb_xhci_hcd.c) we can review? If it is a bug, we will fix it.

Regards, Eric

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RTOS/EVMK2G: USB Driver Enumeration issue