ARM: tegra: disable LP2 cpuidle state if PCIe is enabled

Tegra20 HW appears to have a bug such that PCIe device interrupts,
whether they are legacy IRQs or MSI, are lost when LP2 is enabled. To
work around this, simply disable LP2 if any PCIe devices with interrupts
are present. Detect this via the IRQ domain map operation. This is
slightly over-conservative; if a device with an interrupt is present but
the driver does not actually use them, LP2 will still be disabled.
However, this is a reasonable trade-off which enables a simpler
workaround.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/tegra-cpuidle.h b/include/linux/tegra-cpuidle.h
new file mode 100644
index 0000000..dda3647
--- /dev/null
+++ b/include/linux/tegra-cpuidle.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef __LINUX_TEGRA_CPUIDLE_H__
+#define __LINUX_TEGRA_CPUIDLE_H__
+
+void tegra_cpuidle_pcie_irqs_in_use(void);
+
+#endif