memory: Add NVIDIA Tegra memory controller support

The memory controller on NVIDIA Tegra exposes various knobs that can be
used to tune the behaviour of the clients attached to it.

Currently this driver sets up the latency allowance registers to the HW
defaults. Eventually an API should be exported by this driver (via a
custom API or a generic subsystem) to allow clients to register latency
requirements.

This driver also registers an IOMMU (SMMU) that's implemented by the
memory controller. It is supported on Tegra30, Tegra114 and Tegra124
currently. Tegra20 has a GART instead.

The Tegra SMMU operates on memory clients and SWGROUPs. A memory client
is a unidirectional, special-purpose DMA master. A SWGROUP represents a
set of memory clients that form a logical functional unit corresponding
to a single device. Typically a device has two clients: one client for
read transactions and one client for write transactions, but there are
also devices that have only read clients, but many of them (such as the
display controllers).

Because there is no 1:1 relationship between memory clients and devices
the driver keeps a table of memory clients and the SWGROUPs that they
belong to per SoC. Note that this is an exception and due to the fact
that the SMMU is tightly integrated with the rest of the Tegra SoC. The
use of these tables is discouraged in drivers for generic IOMMU devices
such as the ARM SMMU because the same IOMMU could be used in any number
of SoCs and keeping such tables for each SoC would not scale.

Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/memory/tegra/mc.h b/drivers/memory/tegra/mc.h
new file mode 100644
index 0000000..d5d2114
--- /dev/null
+++ b/drivers/memory/tegra/mc.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2014 NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef MEMORY_TEGRA_MC_H
+#define MEMORY_TEGRA_MC_H
+
+#include <linux/io.h>
+#include <linux/types.h>
+
+#include <soc/tegra/mc.h>
+
+static inline u32 mc_readl(struct tegra_mc *mc, unsigned long offset)
+{
+	return readl(mc->regs + offset);
+}
+
+static inline void mc_writel(struct tegra_mc *mc, u32 value,
+			     unsigned long offset)
+{
+	writel(value, mc->regs + offset);
+}
+
+#ifdef CONFIG_ARCH_TEGRA_3x_SOC
+extern const struct tegra_mc_soc tegra30_mc_soc;
+#endif
+
+#ifdef CONFIG_ARCH_TEGRA_114_SOC
+extern const struct tegra_mc_soc tegra114_mc_soc;
+#endif
+
+#ifdef CONFIG_ARCH_TEGRA_124_SOC
+extern const struct tegra_mc_soc tegra124_mc_soc;
+#endif
+
+#endif /* MEMORY_TEGRA_MC_H */