soc/tegra: Add efuse driver for Tegra

Implement fuse driver for Tegra20, Tegra30, Tegra114 and Tegra124. This
replaces functionality previously provided in arch/arm/mach-tegra, which
is removed in this patch.

While at it, move the only user of the global tegra_revision variable
over to tegra_sku_info.revision and export tegra_fuse_readl() to allow
drivers to read calibration fuses.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 142 insertions, 0 deletions

diff --git a/drivers/soc/tegra/fuse/fuse-tegra20.c b/drivers/soc/tegra/fuse/fuse-tegra20.c
new file mode 100644
index 000000000000..7a9d0e045490
--- /dev/null
+++ b/drivers/soc/tegra/fuse/fuse-tegra20.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2013-2014, 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/>.
+ *
+ * Based on drivers/misc/eeprom/sunxi_sid.c
+ */
+
+#include <linux/device.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+
+#include <soc/tegra/fuse.h>
+
+#include "fuse.h"
+
+#define FUSE_BEGIN	0x100
+#define FUSE_SIZE	0x1f8
+#define FUSE_UID_LOW	0x08
+#define FUSE_UID_HIGH	0x0c
+
+static phys_addr_t fuse_phys;
+static struct clk *fuse_clk;
+static void __iomem __initdata *fuse_base;
+
+static u32 tegra20_fuse_readl(const unsigned int offset)
+{
+	int ret;
+	u32 val;
+
+	clk_prepare_enable(fuse_clk);
+
+	ret = tegra_apb_readl_using_dma(fuse_phys + FUSE_BEGIN + offset, &val);
+
+	clk_disable_unprepare(fuse_clk);
+
+	return (ret < 0) ? 0 : val;
+}
+
+static const struct of_device_id tegra20_fuse_of_match[] = {
+	{ .compatible = "nvidia,tegra20-efuse" },
+	{},
+};
+
+static int tegra20_fuse_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	fuse_clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(fuse_clk)) {
+		dev_err(&pdev->dev, "missing clock");
+		return PTR_ERR(fuse_clk);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+	fuse_phys = res->start;
+
+	if (tegra_fuse_create_sysfs(&pdev->dev, FUSE_SIZE, tegra20_fuse_readl))
+		return -ENODEV;
+
+	dev_dbg(&pdev->dev, "loaded\n");
+
+	return 0;
+}
+
+static struct platform_driver tegra20_fuse_driver = {
+	.probe = tegra20_fuse_probe,
+	.driver = {
+		.name = "tegra20_fuse",
+		.owner = THIS_MODULE,
+		.of_match_table = tegra20_fuse_of_match,
+	}
+};
+
+static int __init tegra20_fuse_init(void)
+{
+	return platform_driver_register(&tegra20_fuse_driver);
+}
+postcore_initcall(tegra20_fuse_init);
+
+/* Early boot code. This code is called before the devices are created */
+
+u32 __init tegra20_fuse_early(const unsigned int offset)
+{
+	return readl_relaxed(fuse_base + FUSE_BEGIN + offset);
+}
+
+bool __init tegra20_spare_fuse_early(int spare_bit)
+{
+	u32 offset = spare_bit * 4;
+	bool value;
+
+	value = tegra20_fuse_early(offset + 0x100);
+
+	return value;
+}
+
+static void __init tegra20_fuse_add_randomness(void)
+{
+	u32 randomness[7];
+
+	randomness[0] = tegra_sku_info.sku_id;
+	randomness[1] = tegra_read_straps();
+	randomness[2] = tegra_read_chipid();
+	randomness[3] = tegra_sku_info.cpu_process_id << 16;
+	randomness[3] |= tegra_sku_info.core_process_id;
+	randomness[4] = tegra_sku_info.cpu_speedo_id << 16;
+	randomness[4] |= tegra_sku_info.soc_speedo_id;
+	randomness[5] = tegra20_fuse_early(FUSE_UID_LOW);
+	randomness[6] = tegra20_fuse_early(FUSE_UID_HIGH);
+
+	add_device_randomness(randomness, sizeof(randomness));
+}
+
+void __init tegra20_init_fuse_early(void)
+{
+	fuse_base = ioremap(TEGRA_FUSE_BASE, TEGRA_FUSE_SIZE);
+
+	tegra_init_revision();
+	tegra20_init_speedo_data(&tegra_sku_info);
+	tegra20_fuse_add_randomness();
+
+	iounmap(fuse_base);
+}