ARM: tegra: Trusted Foundations firmware support

Add support for the Trusted Foundations secure-mode firmware, as found
 on NVIDIA SHIELD. This allows Linux to run in non-secure mode on this
 board; all previous Tegra support has assumed the kernel is running in
 secure mode.
 
 This branch is based on v3.13-rc1, and shouldn't cause any merge
 conflicts.
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Merge tag 'tegra-for-3.14-trusted-foundations' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into next/drivers

From Stephen Warren:
ARM: tegra: Trusted Foundations firmware support

Add support for the Trusted Foundations secure-mode firmware, as found
on NVIDIA SHIELD. This allows Linux to run in non-secure mode on this
board; all previous Tegra support has assumed the kernel is running in
secure mode.

(The base TF support has been discussed back and forth a lot; for now
the most logical place for it seems to be under arch/arm, so we're adding
it here. We can move it out to a common location in the future if needed).

* tag 'tegra-for-3.14-trusted-foundations' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
  ARM: tegra: support Trusted Foundations by default
  ARM: tegra: set CPU reset handler using firmware
  ARM: tegra: split setting of CPU reset handler
  ARM: tegra: add support for Trusted Foundations
  of: add Trusted Foundations bindings documentation
  of: add vendor prefix for Trusted Logic Mobility
  ARM: add basic support for Trusted Foundations

Signed-off-by: Olof Johansson <olof@lixom.net>

Documentation/devicetree/bindings/arm/firmware/tlm,trusted-foundations.txt

@@ -0,0 +1,20 @@
+Trusted Foundations
+-------------------
+
+Boards that use the Trusted Foundations secure monitor can signal its
+presence by declaring a node compatible with "tlm,trusted-foundations"
+under the /firmware/ node
+
+Required properties:
+- compatible: "tlm,trusted-foundations"
+- tlm,version-major: major version number of Trusted Foundations firmware
+- tlm,version-minor: minor version number of Trusted Foundations firmware
+
+Example:
+	firmware {
+		trusted-foundations {
+			compatible = "tlm,trusted-foundations";
+			tlm,version-major = <2>;
+			tlm,version-minor = <8>;
+		};
+	};

Documentation/devicetree/bindings/arm/tegra.txt

@@ -32,3 +32,8 @@ board-specific compatible values:
   nvidia,whistler
   toradex,colibri_t20-512
   toradex,iris
+
+Trusted Foundations
+-------------------------------------------
+Tegra supports the Trusted Foundation secure monitor. See the
+"tlm,trusted-foundations" binding's documentation for more details.

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -71,6 +71,7 @@ st	STMicroelectronics
 ste	ST-Ericsson
 stericsson	ST-Ericsson
 ti	Texas Instruments
+tlm	Trusted Logic Mobility
 toshiba	Toshiba Corporation
 toumaz	Toumaz
 v3	V3 Semiconductor

arch/arm/Kconfig

@@ -1054,6 +1054,8 @@ config ARM_TIMER_SP804
 	select CLKSRC_MMIO
 	select CLKSRC_OF if OF
 
+source "arch/arm/firmware/Kconfig"
+
 source arch/arm/mm/Kconfig
 
 config ARM_NR_BANKS

arch/arm/Makefile

@@ -268,6 +268,7 @@ core-$(CONFIG_KVM_ARM_HOST) 	+= arch/arm/kvm/
 core-y				+= arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
 core-y				+= arch/arm/net/
 core-y				+= arch/arm/crypto/
+core-y				+= arch/arm/firmware/
 core-y				+= $(machdirs) $(platdirs)
 
 drivers-$(CONFIG_OPROFILE)      += arch/arm/oprofile/

arch/arm/configs/tegra_defconfig

@@ -33,6 +33,7 @@ CONFIG_PCI=y
 CONFIG_PCI_MSI=y
 CONFIG_PCI_TEGRA=y
 CONFIG_PCIEPORTBUS=y
+CONFIG_TRUSTED_FOUNDATIONS=y
 CONFIG_SMP=y
 CONFIG_PREEMPT=y
 CONFIG_AEABI=y

arch/arm/firmware/Kconfig

@@ -0,0 +1,28 @@
+config ARCH_SUPPORTS_FIRMWARE
+	bool
+
+config ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
+	bool
+	select ARCH_SUPPORTS_FIRMWARE
+
+menu "Firmware options"
+	depends on ARCH_SUPPORTS_FIRMWARE
+
+config TRUSTED_FOUNDATIONS
+	bool "Trusted Foundations secure monitor support"
+	depends on ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
+	help
+	  Some devices (including most Tegra-based consumer devices on the
+	  market) are booted with the Trusted Foundations secure monitor
+	  active, requiring some core operations to be performed by the secure
+	  monitor instead of the kernel.
+
+	  This option allows the kernel to invoke the secure monitor whenever
+	  required on devices using Trusted Foundations. See
+	  arch/arm/include/asm/trusted_foundations.h or the
+	  tl,trusted-foundations device tree binding documentation for details
+	  on how to use it.
+
+	  Say n if you don't know what this is about.
+
+endmenu

arch/arm/firmware/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_TRUSTED_FOUNDATIONS)	+= trusted_foundations.o

arch/arm/firmware/trusted_foundations.c

@@ -0,0 +1,81 @@
+/*
+ * Trusted Foundations support for ARM CPUs
+ *
+ * Copyright (c) 2013, NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <asm/firmware.h>
+#include <asm/trusted_foundations.h>
+
+#define TF_SET_CPU_BOOT_ADDR_SMC 0xfffff200
+
+static void __naked tf_generic_smc(u32 type, u32 arg1, u32 arg2)
+{
+	asm volatile(
+		".arch_extension	sec\n\t"
+		"stmfd	sp!, {r4 - r11, lr}\n\t"
+		__asmeq("%0", "r0")
+		__asmeq("%1", "r1")
+		__asmeq("%2", "r2")
+		"mov	r3, #0\n\t"
+		"mov	r4, #0\n\t"
+		"smc	#0\n\t"
+		"ldmfd	sp!, {r4 - r11, pc}"
+		:
+		: "r" (type), "r" (arg1), "r" (arg2)
+		: "memory");
+}
+
+static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
+{
+	tf_generic_smc(TF_SET_CPU_BOOT_ADDR_SMC, boot_addr, 0);
+
+	return 0;
+}
+
+static const struct firmware_ops trusted_foundations_ops = {
+	.set_cpu_boot_addr = tf_set_cpu_boot_addr,
+};
+
+void register_trusted_foundations(struct trusted_foundations_platform_data *pd)
+{
+	/*
+	 * we are not using version information for now since currently
+	 * supported SMCs are compatible with all TF releases
+	 */
+	register_firmware_ops(&trusted_foundations_ops);
+}
+
+void of_register_trusted_foundations(void)
+{
+	struct device_node *node;
+	struct trusted_foundations_platform_data pdata;
+	int err;
+
+	node = of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations");
+	if (!node)
+		return;
+
+	err = of_property_read_u32(node, "tlm,version-major",
+				   &pdata.version_major);
+	if (err != 0)
+		panic("Trusted Foundation: missing version-major property\n");
+	err = of_property_read_u32(node, "tlm,version-minor",
+				   &pdata.version_minor);
+	if (err != 0)
+		panic("Trusted Foundation: missing version-minor property\n");
+	register_trusted_foundations(&pdata);
+}

arch/arm/include/asm/trusted_foundations.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2013, NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+/*
+ * Support for the Trusted Foundations secure monitor.
+ *
+ * Trusted Foundation comes active on some ARM consumer devices (most
+ * Tegra-based devices sold on the market are concerned). Such devices can only
+ * perform some basic operations, like setting the CPU reset vector, through
+ * SMC calls to the secure monitor. The calls are completely specific to
+ * Trusted Foundations, and do *not* follow the SMC calling convention or the
+ * PSCI standard.
+ */
+
+#ifndef __ASM_ARM_TRUSTED_FOUNDATIONS_H
+#define __ASM_ARM_TRUSTED_FOUNDATIONS_H
+
+#include <linux/kconfig.h>
+#include <linux/printk.h>
+#include <linux/bug.h>
+#include <linux/of.h>
+
+struct trusted_foundations_platform_data {
+	unsigned int version_major;
+	unsigned int version_minor;
+};
+
+#if IS_ENABLED(CONFIG_TRUSTED_FOUNDATIONS)
+
+void register_trusted_foundations(struct trusted_foundations_platform_data *pd);
+void of_register_trusted_foundations(void);
+
+#else /* CONFIG_TRUSTED_FOUNDATIONS */
+
+static inline void register_trusted_foundations(
+				   struct trusted_foundations_platform_data *pd)
+{
+	/*
+	 * If we try to register TF, this means the system needs it to continue.
+	 * Its absence if thus a fatal error.
+	 */
+	panic("No support for Trusted Foundations, stopping...\n");
+}
+
+static inline void of_register_trusted_foundations(void)
+{
+	/*
+	 * If we find the target should enable TF but does not support it,
+	 * fail as the system won't be able to do much anyway
+	 */
+	if (of_find_compatible_node(NULL, NULL, "tl,trusted-foundations"))
+		register_trusted_foundations(NULL);
+}
+#endif /* CONFIG_TRUSTED_FOUNDATIONS */
+
+#endif

arch/arm/mach-tegra/Kconfig

@@ -2,6 +2,7 @@ config ARCH_TEGRA
 	bool "NVIDIA Tegra" if ARCH_MULTI_V7
 	select ARCH_HAS_CPUFREQ
 	select ARCH_REQUIRE_GPIOLIB
+	select ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
 	select ARM_GIC
 	select CLKSRC_MMIO
 	select CLKSRC_OF

arch/arm/mach-tegra/reset.c

@@ -21,6 +21,7 @@
 
 #include <asm/cacheflush.h>
 #include <asm/hardware/cache-l2x0.h>
+#include <asm/firmware.h>
 
 #include "iomap.h"
 #include "irammap.h"
@@ -33,26 +34,18 @@
 
 static bool is_enabled;
 
-static void __init tegra_cpu_reset_handler_enable(void)
+static void __init tegra_cpu_reset_handler_set(const u32 reset_address)
 {
-	void __iomem *iram_base = IO_ADDRESS(TEGRA_IRAM_RESET_BASE);
 	void __iomem *evp_cpu_reset =
 		IO_ADDRESS(TEGRA_EXCEPTION_VECTORS_BASE + 0x100);
 	void __iomem *sb_ctrl = IO_ADDRESS(TEGRA_SB_BASE);
 	u32 reg;
 
-	BUG_ON(is_enabled);
-	BUG_ON(tegra_cpu_reset_handler_size > TEGRA_IRAM_RESET_HANDLER_SIZE);
-
-	memcpy(iram_base, (void *)__tegra_cpu_reset_handler_start,
-			tegra_cpu_reset_handler_size);
-
 	/*
 	 * NOTE: This must be the one and only write to the EVP CPU reset
 	 *       vector in the entire system.
 	 */
-	writel(TEGRA_IRAM_RESET_BASE + tegra_cpu_reset_handler_offset,
-			evp_cpu_reset);
+	writel(reset_address, evp_cpu_reset);
 	wmb();
 	reg = readl(evp_cpu_reset);
 
@@ -66,8 +59,33 @@ static void __init tegra_cpu_reset_handler_enable(void)
 		writel(reg, sb_ctrl);
 		wmb();
 	}
+}
 
-	is_enabled = true;
+static void __init tegra_cpu_reset_handler_enable(void)
+{
+	void __iomem *iram_base = IO_ADDRESS(TEGRA_IRAM_RESET_BASE);
+	const u32 reset_address = TEGRA_IRAM_RESET_BASE +
+						tegra_cpu_reset_handler_offset;
+	int err;
+
+	BUG_ON(is_enabled);
+	BUG_ON(tegra_cpu_reset_handler_size > TEGRA_IRAM_RESET_HANDLER_SIZE);
+
+	memcpy(iram_base, (void *)__tegra_cpu_reset_handler_start,
+			tegra_cpu_reset_handler_size);
+
+	err = call_firmware_op(set_cpu_boot_addr, 0, reset_address);
+	switch (err) {
+	case -ENOSYS:
+		tegra_cpu_reset_handler_set(reset_address);
+		/* pass-through */
+	case 0:
+		is_enabled = true;
+		break;
+	default:
+		pr_crit("Cannot set CPU reset handler: %d\n", err);
+		BUG();
+	}
 }
 
 void __init tegra_cpu_reset_handler_init(void)

arch/arm/mach-tegra/tegra.c

@@ -40,6 +40,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
 #include <asm/setup.h>
+#include <asm/trusted_foundations.h>
 
 #include "apbio.h"
 #include "board.h"
@@ -90,6 +91,7 @@ static void __init tegra_init_cache(void)
 
 static void __init tegra_init_early(void)
 {
+	of_register_trusted_foundations();
 	tegra_apb_io_init();
 	tegra_init_fuse();
 	tegra_cpu_reset_handler_init();