[RFC RESEND 06/10] fotg210: Make Xen notificaiton consistent with EHCI

From: Chris Rorvick
Date: Mon Sep 29 2014 - 00:51:18 EST

If CONFIG_XEN_DOM0 is enabled, the ehci-dbgp driver notifies Xen of
controller reset events via xen_dbgp_reset_prep() and
xen_dbgp_external_startup() (via calls to xen_dbgp_op().) Otherwise
<linux/usb/ehci_def.h> defines them as no-ops to disable this logic.

The fotg210 driver copies much of the dbgp code from ehci_def.h, but it
unconditionally defines the Xen hooks as no-ops, effectively disabling
these notifications when CONFIG_EARLY_PRINTK_DBGP is disabled. When
enabled, though, notifying Xen is dependent on CONFIG_XEN_DOM0 due to
fotg210 leveraging the ehci-dbgp driver.

The following table compares the implementations of xen_dbgp_reset_prep()
and xen_dbgp_external_startup() in the ehci-dbgp and fotg210 drivers
under the relevant configurations:

EARLY_PRINTK_DBGP? XEN_DOM0? ehci-dbgp fotg210
------------------ --------- ------------- -------------
n n no-op no-op
n y xen_dbgp_op() no-op
y n no-op no-op
y y xen_dbgp_op() xen_dbgp_op()

This suggests that fotg210 is, at best, indifferent to whether Xen is
notified of these events. Make fotg210 consistent with ehci-dbgp as a
step towards consolidating this code duplication.

Signed-off-by: Chris Rorvick <chris@xxxxxxxxxxx>
drivers/usb/host/fotg210.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/usb/host/fotg210.h b/drivers/usb/host/fotg210.h
index ac6cd1b..98c9670 100644
--- a/drivers/usb/host/fotg210.h
+++ b/drivers/usb/host/fotg210.h
@@ -326,6 +326,10 @@ extern struct console early_dbgp_console;

struct usb_hcd;

+extern int xen_dbgp_reset_prep(struct usb_hcd *);
+extern int xen_dbgp_external_startup(struct usb_hcd *);
static inline int xen_dbgp_reset_prep(struct usb_hcd *hcd)
return 1; /* Shouldn't this be 0? */
@@ -335,6 +339,7 @@ static inline int xen_dbgp_external_startup(struct usb_hcd *hcd)
return -1;

/* Call backs from fotg210 host driver to fotg210 debug driver */

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