[3.16.y-ckt stable] Patch "bus: mvebu-mbus: fix support of MBus window 13" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    bus: mvebu-mbus: fix support of MBus window 13

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From f1e612253c47a210cf94d2c9578c08bb322b75cd Mon Sep 17 00:00:00 2001
From: Andrew Lunn <andrew at lunn.ch>
Date: Sun, 18 Jan 2015 09:46:10 -0600
Subject: bus: mvebu-mbus: fix support of MBus window 13

commit 38bdf45f4aa5cb6186d50a29e6cbbd9d486a1519 upstream.

On Armada XP, 375 and 38x the MBus window 13 has the remap capability,
like windows 0 to 7. However, the mvebu-mbus driver isn't currently
taking into account this special case, which means that when window 13
is actually used, the remap registers are left to 0, making the device
using this MBus window unavailable.

As a minimal fix for stable, don't use window 13. A full fix will
follow later.

Fixes: fddddb52a6c ("bus: introduce an Marvell EBU MBus driver")
Reviewed-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Signed-off-by: Andrew Lunn <andrew at lunn.ch>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/bus/mvebu-mbus.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c
index 26c3779d871d..d29f5ffdb0f4 100644
--- a/drivers/bus/mvebu-mbus.c
+++ b/drivers/bus/mvebu-mbus.c
@@ -182,12 +182,25 @@ static void mvebu_mbus_disable_window(struct mvebu_mbus_state *mbus,
 }

 /* Checks whether the given window number is available */
+
+/* On Armada XP, 375 and 38x the MBus window 13 has the remap
+ * capability, like windows 0 to 7. However, the mvebu-mbus driver
+ * isn't currently taking into account this special case, which means
+ * that when window 13 is actually used, the remap registers are left
+ * to 0, making the device using this MBus window unavailable. The
+ * quick fix for stable is to not use window 13. A follow up patch
+ * will correctly handle this window.
+*/
 static int mvebu_mbus_window_is_free(struct mvebu_mbus_state *mbus,
 				     const int win)
 {
 	void __iomem *addr = mbus->mbuswins_base +
 		mbus->soc->win_cfg_offset(win);
 	u32 ctrl = readl(addr + WIN_CTRL_OFF);
+
+	if (win == 13)
+		return false;
+
 	return !(ctrl & WIN_CTRL_ENABLE);
 }

--
2.1.4