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From 4288b7df4ae6629a4fb14aca2c489da01d4d19c3 Mon Sep 17 00:00:00 2001
From: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Date: Tue, 31 Mar 2009 12:35:09 -0700
Subject: [PATCH] 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-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
---
drivers/usb/musb/musb_core.c | 41 +++++++++++++++++++++++++++-----------
drivers/usb/musb/musb_gadget.c | 2 +
drivers/usb/musb/musb_virthub.c | 4 +++
3 files changed, 35 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 9dc995a..5770ccb 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -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:
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 7dd3d59..8b3c4e2 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -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:
diff --git a/drivers/usb/musb/musb_virthub.c b/drivers/usb/musb/musb_virthub.c
index 14f7cf3..e8ef925 100644
--- a/drivers/usb/musb/musb_virthub.c
+++ b/drivers/usb/musb/musb_virthub.c
@@ -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
--
1.6.0.4
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