musb: support disconnect after HNP roleswitch
Adjust HNP state machines in MUSB driver so that they handle the
case where the cable is disconnected. The A-side machine was
very wrong (unrecoverable); the B-Side was much less so.
- A_PERIPHERAL ... as usual, the non-observability of the ID
pin through Mentor's registers makes trouble. We can't go
directly to A_WAIT_VFALL to end the session and start the
disconnect processing. We can however sense link suspending,
go to A_WAIT_BCON, and from there use OTG timeouts to finally
trigger that A_WAIT_VFALL transition. (Hoping that nobody
reconnects quickly to that port and notices the wrong state.)
- B_HOST ... actually clear the Host Request (HR) bit as the
messages say, disconnect the peripheral from the root hub,
and don't detour through a suspend state. (In some cases
this would eventually have cleaned up.)
Also adjust the A_SUSPEND transition to respect the A_AIDL_BDIS
timeout, so if HNP doesn't trigger quickly enough the A_WAIT_VFALL
transition happens as it should.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
3 files changed