ARM: tegra30: cpuidle: add powered-down state for secondary CPUs

This supports power-gated idle on secondary CPUs for Tegra30. The
secondary CPUs can go into powered-down state independently. When
CPU goes into this state, it saves it's contexts and puts itself
to flow controlled WFI state. After that, it will been power gated.

Be aware of that, you may see the legacy power state "LP2" in the
code which is exactly the same meaning of "CPU power down".

Based on the work by:
Scott Williams <scwilliams@nvidia.com>

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
new file mode 100644
index 000000000000..f88595abc471
--- /dev/null
+++ b/arch/arm/mach-tegra/pm.c
@@ -0,0 +1,74 @@
+/*
+ * CPU complex suspend & resume functions for Tegra SoCs
+ *
+ * Copyright (c) 2009-2012, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/cpumask.h>
+
+#include "iomap.h"
+#include "reset.h"
+
+#ifdef CONFIG_PM_SLEEP
+static unsigned int g_diag_reg;
+static DEFINE_SPINLOCK(tegra_lp2_lock);
+
+void save_cpu_arch_register(void)
+{
+	/* read diagnostic register */
+	asm("mrc p15, 0, %0, c15, c0, 1" : "=r"(g_diag_reg) : : "cc");
+	return;
+}
+
+void restore_cpu_arch_register(void)
+{
+	/* write diagnostic register */
+	asm("mcr p15, 0, %0, c15, c0, 1" : : "r"(g_diag_reg) : "cc");
+	return;
+}
+
+void __cpuinit tegra_clear_cpu_in_lp2(int phy_cpu_id)
+{
+	u32 *cpu_in_lp2 = tegra_cpu_lp2_mask;
+
+	spin_lock(&tegra_lp2_lock);
+
+	BUG_ON(!(*cpu_in_lp2 & BIT(phy_cpu_id)));
+	*cpu_in_lp2 &= ~BIT(phy_cpu_id);
+
+	spin_unlock(&tegra_lp2_lock);
+}
+
+bool __cpuinit tegra_set_cpu_in_lp2(int phy_cpu_id)
+{
+	bool last_cpu = false;
+	cpumask_t *cpu_lp2_mask = tegra_cpu_lp2_mask;
+	u32 *cpu_in_lp2 = tegra_cpu_lp2_mask;
+
+	spin_lock(&tegra_lp2_lock);
+
+	BUG_ON((*cpu_in_lp2 & BIT(phy_cpu_id)));
+	*cpu_in_lp2 |= BIT(phy_cpu_id);
+
+	if ((phy_cpu_id == 0) && cpumask_equal(cpu_lp2_mask, cpu_online_mask))
+		last_cpu = true;
+
+	spin_unlock(&tegra_lp2_lock);
+	return last_cpu;
+}
+#endif