Re: USB PM suspend/resume problems with Marvell Orion SoC

["Rafael J. Wysocki" <rjw@sisk.pl>]

Added some relevant CCs.

On Sunday, 6 of January 2008, Tawfik Bayyouk wrote:
> Hi,
> 
> I am working with Linux version 2.6.24-rc4 for adding the power
> management capabilities to the USB ehci driver for Orion SoC 
> device of Marvell.
> 
> I need help in 2 issues:
> 
> 1- The SoC device supports 2 levels of power management and I'd 
> like to reflect this at the driver level. 
> The first is "standby" where only clocks are halted while 
> preserving the registers values. The second is "mem" where the 
> whole SoC (including the USB HC) are powered off.
> What is the correct way to distinguish between the 2 modes in 
> the .suspend and .resume routines of the platform_driver?
> I believe that the parameter I am looking for is the PM target 
> state which is usually passed in the .set_target of the 
> platform_suspend_ops routine.

That is correct.

Note, however, that (most probably) .set_target() is going to be
changed to .open() and a complementary callback .close() is to be added.

> 2- After resuming from "mem" suspend, the USB can no longer 
> detect plugging in and out of USB devices.
> I have investigate the problem and found that 4 registers where 
> not configured correctly. Saving the values of these registers 
> in the .suspend routine and loading them back in the .resume 
> routine resolves the problem. 
> The following are the 4 problematic registers:
>     USBCMD (0x140)
>     USBINTR (0x148)
>     PORTSC1 (0x184)
>     USBMODE (0x1A8)
> 
> I would be very thankful for any clue in either of the 2 problems.

Greetings,
Rafael