soc/tegra: fuse: Unify Tegra20 and Tegra30 drivers

Unifying the drivers makes it easier to restrict the legacy probing
paths to 32-bit ARM. This in turn will come in handy as support for
new 64-bit ARM SoCs is added.

Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/mach-tegra/iomap.h

@@ -82,9 +82,6 @@
 #define TEGRA_EMC_BASE			0x7000F400
 #define TEGRA_EMC_SIZE			SZ_1K
 
-#define TEGRA_FUSE_BASE			0x7000F800
-#define TEGRA_FUSE_SIZE			SZ_1K
-
 #define TEGRA_EMC0_BASE			0x7001A000
 #define TEGRA_EMC0_SIZE			SZ_2K
 

drivers/soc/tegra/fuse/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= speedo-tegra20.o
 obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= speedo-tegra30.o
 obj-$(CONFIG_ARCH_TEGRA_114_SOC)	+= speedo-tegra114.o
 obj-$(CONFIG_ARCH_TEGRA_124_SOC)	+= speedo-tegra124.o
+obj-$(CONFIG_ARCH_TEGRA_132_SOC)	+= speedo-tegra124.o

drivers/soc/tegra/fuse/fuse-tegra.c

@@ -15,9 +15,10 @@
  *
  */
 
+#include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/kobject.h>
-#include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -28,8 +29,6 @@
 
 #include "fuse.h"
 
-static u32 (*fuse_readl)(const unsigned int offset);
-static int fuse_size;
 struct tegra_sku_info tegra_sku_info;
 EXPORT_SYMBOL(tegra_sku_info);
 
@@ -42,31 +41,33 @@ static const char *tegra_revision_name[TEGRA_REVISION_MAX] = {
 	[TEGRA_REVISION_A04]     = "A04",
 };
 
-static u8 fuse_readb(const unsigned int offset)
+static u8 fuse_readb(struct tegra_fuse *fuse, unsigned int offset)
 {
 	u32 val;
 
-	val = fuse_readl(round_down(offset, 4));
+	val = fuse->read(fuse, round_down(offset, 4));
 	val >>= (offset % 4) * 8;
 	val &= 0xff;
 
 	return val;
 }
 
 static ssize_t fuse_read(struct file *fd, struct kobject *kobj,
-			struct bin_attribute *attr, char *buf,
-			loff_t pos, size_t size)
+			 struct bin_attribute *attr, char *buf,
+			 loff_t pos, size_t size)
 {
+	struct device *dev = kobj_to_dev(kobj);
+	struct tegra_fuse *fuse = dev_get_drvdata(dev);
 	int i;
 
-	if (pos < 0 || pos >= fuse_size)
+	if (pos < 0 || pos >= attr->size)
 		return 0;
 
-	if (size > fuse_size - pos)
-		size = fuse_size - pos;
+	if (size > attr->size - pos)
+		size = attr->size - pos;
 
 	for (i = 0; i < size; i++)
-		buf[i] = fuse_readb(pos + i);
+		buf[i] = fuse_readb(fuse, pos + i);
 
 	return i;
 }
@@ -76,6 +77,14 @@ static struct bin_attribute fuse_bin_attr = {
 	.read = fuse_read,
 };
 
+static int tegra_fuse_create_sysfs(struct device *dev, unsigned int size,
+				   const struct tegra_fuse_info *info)
+{
+	fuse_bin_attr.size = size;
+
+	return device_create_bin_file(dev, &fuse_bin_attr);
+}
+
 static const struct of_device_id car_match[] __initconst = {
 	{ .compatible = "nvidia,tegra20-car", },
 	{ .compatible = "nvidia,tegra30-car", },
@@ -85,73 +94,211 @@ static const struct of_device_id car_match[] __initconst = {
 	{},
 };
 
-static void tegra_enable_fuse_clk(void __iomem *base)
+static struct tegra_fuse *fuse = &(struct tegra_fuse) {
+	.base = NULL,
+	.soc = NULL,
+};
+
+static const struct of_device_id tegra_fuse_match[] = {
+#ifdef CONFIG_ARCH_TEGRA_132_SOC
+	{ .compatible = "nvidia,tegra132-efuse", .data = &tegra124_fuse_soc },
+#endif
+#ifdef CONFIG_ARCH_TEGRA_124_SOC
+	{ .compatible = "nvidia,tegra124-efuse", .data = &tegra124_fuse_soc },
+#endif
+#ifdef CONFIG_ARCH_TEGRA_114_SOC
+	{ .compatible = "nvidia,tegra114-efuse", .data = &tegra114_fuse_soc },
+#endif
+#ifdef CONFIG_ARCH_TEGRA_3x_SOC
+	{ .compatible = "nvidia,tegra30-efuse", .data = &tegra30_fuse_soc },
+#endif
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+	{ .compatible = "nvidia,tegra20-efuse", .data = &tegra20_fuse_soc },
+#endif
+	{ /* sentinel */ }
+};
+
+static int tegra_fuse_probe(struct platform_device *pdev)
 {
-	u32 reg;
+	void __iomem *base = fuse->base;
+	struct resource *res;
+	int err;
+
+	/* take over the memory region from the early initialization */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	fuse->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(fuse->base))
+		return PTR_ERR(fuse->base);
+
+	fuse->clk = devm_clk_get(&pdev->dev, "fuse");
+	if (IS_ERR(fuse->clk)) {
+		dev_err(&pdev->dev, "failed to get FUSE clock: %ld",
+			PTR_ERR(fuse->clk));
+		return PTR_ERR(fuse->clk);
+	}
 
-	reg = readl_relaxed(base + 0x48);
-	reg |= 1 << 28;
-	writel(reg, base + 0x48);
+	platform_set_drvdata(pdev, fuse);
+	fuse->dev = &pdev->dev;
 
-	/*
-	 * Enable FUSE clock. This needs to be hardcoded because the clock
-	 * subsystem is not active during early boot.
-	 */
-	reg = readl(base + 0x14);
-	reg |= 1 << 7;
-	writel(reg, base + 0x14);
+	if (fuse->soc->probe) {
+		err = fuse->soc->probe(fuse);
+		if (err < 0)
+			return err;
+	}
+
+	if (tegra_fuse_create_sysfs(&pdev->dev, fuse->soc->info->size,
+				    fuse->soc->info))
+		return -ENODEV;
+
+	/* release the early I/O memory mapping */
+	iounmap(base);
+
+	return 0;
+}
+
+static struct platform_driver tegra_fuse_driver = {
+	.driver = {
+		.name = "tegra-fuse",
+		.of_match_table = tegra_fuse_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = tegra_fuse_probe,
+};
+module_platform_driver(tegra_fuse_driver);
+
+bool __init tegra_fuse_read_spare(unsigned int spare)
+{
+	unsigned int offset = fuse->soc->info->spare + spare * 4;
+
+	return fuse->read_early(fuse, offset) & 1;
+}
+
+u32 __init tegra_fuse_read_early(unsigned int offset)
+{
+	return fuse->read_early(fuse, offset);
 }
 
 int tegra_fuse_readl(unsigned long offset, u32 *value)
 {
-	if (!fuse_readl)
+	if (!fuse->read)
 		return -EPROBE_DEFER;
 
-	*value = fuse_readl(offset);
+	*value = fuse->read(fuse, offset);
 
 	return 0;
 }
 EXPORT_SYMBOL(tegra_fuse_readl);
 
-int tegra_fuse_create_sysfs(struct device *dev, int size,
-		     u32 (*readl)(const unsigned int offset))
+static void tegra_enable_fuse_clk(void __iomem *base)
 {
-	if (fuse_size)
-		return -ENODEV;
-
-	fuse_bin_attr.size = size;
-	fuse_bin_attr.read = fuse_read;
+	u32 reg;
 
-	fuse_size = size;
-	fuse_readl = readl;
+	reg = readl_relaxed(base + 0x48);
+	reg |= 1 << 28;
+	writel(reg, base + 0x48);
 
-	return device_create_bin_file(dev, &fuse_bin_attr);
+	/*
+	 * Enable FUSE clock. This needs to be hardcoded because the clock
+	 * subsystem is not active during early boot.
+	 */
+	reg = readl(base + 0x14);
+	reg |= 1 << 7;
+	writel(reg, base + 0x14);
 }
 
 static int __init tegra_init_fuse(void)
 {
+	const struct of_device_id *match;
 	struct device_node *np;
-	void __iomem *car_base;
-
-	if (!soc_is_tegra())
-		return 0;
+	struct resource regs;
 
 	tegra_init_apbmisc();
 
-	np = of_find_matching_node(NULL, car_match);
-	car_base = of_iomap(np, 0);
-	if (car_base) {
-		tegra_enable_fuse_clk(car_base);
-		iounmap(car_base);
+	np = of_find_matching_node_and_match(NULL, tegra_fuse_match, &match);
+	if (!np) {
+		/*
+		 * Fall back to legacy initialization for 32-bit ARM only. All
+		 * 64-bit ARM device tree files for Tegra are required to have
+		 * a FUSE node.
+		 *
+		 * This is for backwards-compatibility with old device trees
+		 * that didn't contain a FUSE node.
+		 */
+		if (IS_ENABLED(CONFIG_ARM) && soc_is_tegra()) {
+			u8 chip = tegra_get_chip_id();
+
+			regs.start = 0x7000f800;
+			regs.end = 0x7000fbff;
+			regs.flags = IORESOURCE_MEM;
+
+			switch (chip) {
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+			case TEGRA20:
+				fuse->soc = &tegra20_fuse_soc;
+				break;
+#endif
+
+#ifdef CONFIG_ARCH_TEGRA_3x_SOC
+			case TEGRA30:
+				fuse->soc = &tegra30_fuse_soc;
+				break;
+#endif
+
+#ifdef CONFIG_ARCH_TEGRA_114_SOC
+			case TEGRA114:
+				fuse->soc = &tegra114_fuse_soc;
+				break;
+#endif
+
+#ifdef CONFIG_ARCH_TEGRA_124_SOC
+			case TEGRA124:
+				fuse->soc = &tegra124_fuse_soc;
+				break;
+#endif
+
+			default:
+				pr_warn("Unsupported SoC: %02x\n", chip);
+				break;
+			}
+		} else {
+			/*
+			 * At this point we're not running on Tegra, so play
+			 * nice with multi-platform kernels.
+			 */
+			return 0;
+		}
 	} else {
-		pr_err("Could not enable fuse clk. ioremap tegra car failed.\n");
+		/*
+		 * Extract information from the device tree if we've found a
+		 * matching node.
+		 */
+		if (of_address_to_resource(np, 0, &regs) < 0) {
+			pr_err("failed to get FUSE register\n");
+			return -ENXIO;
+		}
+
+		fuse->soc = match->data;
+	}
+
+	np = of_find_matching_node(NULL, car_match);
+	if (np) {
+		void __iomem *base = of_iomap(np, 0);
+		if (base) {
+			tegra_enable_fuse_clk(base);
+			iounmap(base);
+		} else {
+			pr_err("failed to map clock registers\n");
+			return -ENXIO;
+		}
+	}
+
+	fuse->base = ioremap_nocache(regs.start, resource_size(&regs));
+	if (!fuse->base) {
+		pr_err("failed to map FUSE registers\n");
 		return -ENXIO;
 	}
 
-	if (tegra_get_chip_id() == TEGRA20)
-		tegra20_init_fuse_early();
-	else
-		tegra30_init_fuse_early();
+	fuse->soc->init(fuse);
 
 	pr_info("Tegra Revision: %s SKU: %d CPU Process: %d Core Process: %d\n",
 		tegra_revision_name[tegra_sku_info.revision],