ARM: tegra: Add external memory controller driver

The frequency memory bus on Tegra can be adjusted without
disabling accesses to memory by updating the memory
configuration registers from a per-board table, and then
changing the clock frequency.  The clock controller and
memory controller have an interlock that prevents the
new memory registers from taking effect until the
clock frequency change.

Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/tegra2_emc.h b/arch/arm/mach-tegra/tegra2_emc.h
new file mode 100644
index 000000000000..19f08cb31603
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra2_emc.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ */
+
+#define TEGRA_EMC_NUM_REGS 46
+
+struct tegra_emc_table {
+	unsigned long rate;
+	u32 regs[TEGRA_EMC_NUM_REGS];
+};
+
+int tegra_emc_set_rate(unsigned long rate);
+long tegra_emc_round_rate(unsigned long rate);
+void tegra_init_emc(const struct tegra_emc_table *table, int table_size);