USB: ehci-dbgp,ehci: Allow early or late use of the dbgp device

If the EHCI debug port is initialized and in use, the EHCI host
controller driver must follow two rules.

1) If the EHCI host driver issues a controller reset, the debug
   controller driver re-initialization must get called after the reset
   is completed.

2) The EHCI host driver should ignore any requests to the physical
   EHCI debug port when the EHCI debug port is in use.

The code to check for the debug port was moved from ehci_pci_reinit()
to ehci_pci_setup because it must get called prior to ehci_reset()
which will clear the debug port registers.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: dbrownell@users.sourceforge.net
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/usb/early/ehci-dbgp.c b/drivers/usb/early/ehci-dbgp.c
index 06e05ea17871..b88cb65b64e0 100644
--- a/drivers/usb/early/ehci-dbgp.c
+++ b/drivers/usb/early/ehci-dbgp.c
@@ -933,3 +933,26 @@ struct console early_dbgp_console = {
         .flags =        CON_PRINTBUFFER,
         .index =        -1,
 };
+
+int dbgp_reset_prep(void)
+{
+        u32 ctrl;
+
+        dbgp_not_safe = 1;
+        if (!ehci_debug)
+                return 0;
+
+        if (early_dbgp_console.index != -1 &&
+                !(early_dbgp_console.flags & CON_BOOT))
+                return 1;
+        /* This means the console is not initialized, or should get
+         * shutdown so as to allow for reuse of the usb device, which
+         * means it is time to shutdown the usb debug port. */
+        ctrl = readl(&ehci_debug->control);
+        if (ctrl & DBGP_ENABLED) {
+                ctrl &= ~(DBGP_CLAIM);
+                writel(ctrl, &ehci_debug->control);
+        }
+        return 0;
+}
+EXPORT_SYMBOL_GPL(dbgp_reset_prep);