[ARM] tegra: Add support for reading fuses

The Tegra SOC contains fuses to identify the CPU type and
bin, and a unique id.  The CPU info is required to determine
the correct voltages for each cpu and core frequency.

Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/fuse.c b/arch/arm/mach-tegra/fuse.c
new file mode 100644
index 0000000..1fa26d9
--- /dev/null
+++ b/arch/arm/mach-tegra/fuse.c
@@ -0,0 +1,84 @@
+/*
+ * arch/arm/mach-tegra/fuse.c
+ *
+ * Copyright (C) 2010 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include <mach/iomap.h>
+
+#include "fuse.h"
+
+#define FUSE_UID_LOW		0x108
+#define FUSE_UID_HIGH		0x10c
+#define FUSE_SKU_INFO		0x110
+#define FUSE_SPARE_BIT		0x200
+
+static inline u32 fuse_readl(unsigned long offset)
+{
+	return readl(IO_TO_VIRT(TEGRA_FUSE_BASE + offset));
+}
+
+static inline void fuse_writel(u32 value, unsigned long offset)
+{
+	writel(value, IO_TO_VIRT(TEGRA_FUSE_BASE + offset));
+}
+
+void tegra_init_fuse(void)
+{
+	u32 reg = readl(IO_TO_VIRT(TEGRA_CLK_RESET_BASE + 0x48));
+	reg |= 1 << 28;
+	writel(reg, IO_TO_VIRT(TEGRA_CLK_RESET_BASE + 0x48));
+
+	pr_info("Tegra SKU: %d CPU Process: %d Core Process: %d\n",
+		tegra_sku_id(), tegra_cpu_process_id(),
+		tegra_core_process_id());
+}
+
+unsigned long long tegra_chip_uid(void)
+{
+	unsigned long long lo, hi;
+
+	lo = fuse_readl(FUSE_UID_LOW);
+	hi = fuse_readl(FUSE_UID_HIGH);
+	return (hi << 32ull) | lo;
+}
+
+int tegra_sku_id(void)
+{
+	int sku_id;
+	u32 reg = fuse_readl(FUSE_SKU_INFO);
+	sku_id = reg & 0xFF;
+	return sku_id;
+}
+
+int tegra_cpu_process_id(void)
+{
+	int cpu_process_id;
+	u32 reg = fuse_readl(FUSE_SPARE_BIT);
+	cpu_process_id = (reg >> 6) & 3;
+	return cpu_process_id;
+}
+
+int tegra_core_process_id(void)
+{
+	int core_process_id;
+	u32 reg = fuse_readl(FUSE_SPARE_BIT);
+	core_process_id = (reg >> 12) & 3;
+	return core_process_id;
+}