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musb: support disconnect after HNP roleswitch

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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>
This commit is contained in:
David Brownell 2009-03-31 12:35:09 -07:00 committed by Greg Kroah-Hartman
parent 1de00dae80
commit ab983f2a1b
3 changed files with 35 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/usb/musb/musb_core.c
View File

@ -304,9 +304,11 @@ void musb_otg_timer_func(unsigned long data)
musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
musb->is_active = 0;
break;
case OTG_STATE_A_SUSPEND:
case OTG_STATE_A_WAIT_BCON:
DBG(1, "HNP: a_wait_bcon timeout; back to a_host\n");
musb_hnp_stop(musb);
DBG(1, "HNP: %s timeout\n", otg_state_string(musb));
musb_set_vbus(musb, 0);
musb->xceiv->state = OTG_STATE_A_WAIT_VFALL;
break;
default:
DBG(1, "HNP: Unhandled mode %s\n", otg_state_string(musb));
@ -324,15 +326,12 @@ void musb_hnp_stop(struct musb *musb)
void __iomem *mbase = musb->mregs;
u8 reg;
DBG(1, "HNP: stop from %s\n", otg_state_string(musb));
switch (musb->xceiv->state) {
case OTG_STATE_A_PERIPHERAL:
case OTG_STATE_A_WAIT_VFALL:
case OTG_STATE_A_WAIT_BCON:
DBG(1, "HNP: Switching back to A-host\n");
musb_g_disconnect(musb);
musb->xceiv->state = OTG_STATE_A_IDLE;
MUSB_HST_MODE(musb);
musb->is_active = 0;
DBG(1, "HNP: back to %s\n", otg_state_string(musb));
break;
case OTG_STATE_B_HOST:
DBG(1, "HNP: Disabling HR\n");
@ -775,7 +774,16 @@ static irqreturn_t musb_stage2_irq(struct musb *musb, u8 int_usb,
#endif /* HOST */
#ifdef CONFIG_USB_MUSB_OTG
case OTG_STATE_B_HOST:
musb_hnp_stop(musb);
/* REVISIT this behaves for "real disconnect"
* cases; make sure the other transitions from
* from B_HOST act right too. The B_HOST code
* in hnp_stop() is currently not used...
*/
musb_root_disconnect(musb);
musb_to_hcd(musb)->self.is_b_host = 0;
musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
MUSB_DEV_MODE(musb);
musb_g_disconnect(musb);
break;
case OTG_STATE_A_PERIPHERAL:
musb_hnp_stop(musb);
@ -807,10 +815,19 @@ static irqreturn_t musb_stage2_irq(struct musb *musb, u8 int_usb,
switch (musb->xceiv->state) {
#ifdef CONFIG_USB_MUSB_OTG
case OTG_STATE_A_PERIPHERAL:
/*
* We cannot stop HNP here, devctl BDEVICE might be
* still set.
/* We also come here if the cable is removed, since
* this silicon doesn't report ID-no-longer-grounded.
*
* We depend on T(a_wait_bcon) to shut us down, and
* hope users don't do anything dicey during this
* undesired detour through A_WAIT_BCON.
*/
musb_hnp_stop(musb);
usb_hcd_resume_root_hub(musb_to_hcd(musb));
musb_root_disconnect(musb);
musb_platform_try_idle(musb, jiffies
+ msecs_to_jiffies(musb->a_wait_bcon
? : OTG_TIME_A_WAIT_BCON));
break;
#endif
case OTG_STATE_B_PERIPHERAL:

2
drivers/usb/musb/musb_gadget.c
View File

@ -1962,9 +1962,11 @@ void musb_g_disconnect(struct musb *musb)
DBG(2, "Unhandled disconnect %s, setting a_idle\n",
otg_state_string(musb));
musb->xceiv->state = OTG_STATE_A_IDLE;
MUSB_HST_MODE(musb);
break;
case OTG_STATE_A_PERIPHERAL:
musb->xceiv->state = OTG_STATE_A_WAIT_BCON;
MUSB_HST_MODE(musb);
break;
case OTG_STATE_B_WAIT_ACON:
case OTG_STATE_B_HOST:

4
drivers/usb/musb/musb_virthub.c
View File

@ -83,6 +83,10 @@ static void musb_port_suspend(struct musb *musb, bool do_suspend)
musb->xceiv->state = OTG_STATE_A_SUSPEND;
musb->is_active = is_otg_enabled(musb)
&& musb->xceiv->host->b_hnp_enable;
if (musb->is_active)
mod_timer(&musb->otg_timer, jiffies
+ msecs_to_jiffies(
OTG_TIME_A_AIDL_BDIS));
musb_platform_try_idle(musb, 0);
break;
#ifdef CONFIG_USB_MUSB_OTG