nvmem: sunxi: Move the SID driver to the nvmem framework

Now that we have the nvmem framework, we can consolidate the common
driver code. Move the driver to the framework, and hopefully, it will
fix the sysfs file creation race.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[srinivas.kandagatla: Moved to regmap based EEPROM framework]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-driver-sunxi-sid

-What:		/sys/devices/*/<our-device>/eeprom
-Date:		August 2013
-Contact:	Oliver Schinagl <oliver@schinagl.nl>
-Description:	read-only access to the SID (Security-ID) on current
-		A-series SoC's from Allwinner. Currently supports A10, A10s, A13
-		and A20 CPU's. The earlier A1x series of SoCs exports 16 bytes,
-		whereas the newer A20 SoC exposes 512 bytes split into sections.
-		Besides the 16 bytes of SID, there's also an SJTAG area,
-		HDMI-HDCP key and some custom keys. Below a quick overview, for
-		details see the user manual:
-		0x000  128 bit root-key (sun[457]i)
-		0x010  128 bit boot-key (sun7i)
-		0x020   64 bit security-jtag-key (sun7i)
-		0x028   16 bit key configuration (sun7i)
-		0x02b   16 bit custom-vendor-key (sun7i)
-		0x02c  320 bit low general key (sun7i)
-		0x040   32 bit read-control access (sun7i)
-		0x064  224 bit low general key (sun7i)
-		0x080 2304 bit HDCP-key (sun7i)
-		0x1a0  768 bit high general key (sun7i)
-Users:		any user space application which wants to read the SID on
-		Allwinner's A-series of CPU's.

Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt → Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt

@@ -4,6 +4,10 @@ Required properties:
 - compatible: "allwinner,sun4i-a10-sid" or "allwinner,sun7i-a20-sid"
 - reg: Should contain registers location and length
 
+= Data cells =
+Are child nodes of qfprom, bindings of which as described in
+bindings/nvmem/nvmem.txt
+
 Example for sun4i:
 	sid@01c23800 {
 		compatible = "allwinner,sun4i-a10-sid";

drivers/misc/eeprom/Kconfig

@@ -96,17 +96,4 @@ config EEPROM_DIGSY_MTC_CFG
 
 	  If unsure, say N.
 
-config EEPROM_SUNXI_SID
-	tristate "Allwinner sunxi security ID support"
-	depends on ARCH_SUNXI && SYSFS
-	help
-	  This is a driver for the 'security ID' available on various Allwinner
-	  devices.
-
-	  Due to the potential risks involved with changing e-fuses,
-	  this driver is read-only.
-
-	  This driver can also be built as a module. If so, the module
-	  will be called sunxi_sid.
-
 endmenu

drivers/misc/eeprom/Makefile

@@ -4,5 +4,4 @@ obj-$(CONFIG_EEPROM_LEGACY)	+= eeprom.o
 obj-$(CONFIG_EEPROM_MAX6875)	+= max6875.o
 obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
 obj-$(CONFIG_EEPROM_93XX46)	+= eeprom_93xx46.o
-obj-$(CONFIG_EEPROM_SUNXI_SID)	+= sunxi_sid.o
 obj-$(CONFIG_EEPROM_DIGSY_MTC_CFG) += digsy_mtc_eeprom.o

drivers/nvmem/Kconfig

@@ -25,4 +25,15 @@ config QCOM_QFPROM
 	  This driver can also be built as a module. If so, the module
 	  will be called nvmem_qfprom.
 
+config NVMEM_SUNXI_SID
+	tristate "Allwinner SoCs SID support"
+	depends on ARCH_SUNXI
+	select REGMAP_MMIO
+	help
+	  This is a driver for the 'security ID' available on various Allwinner
+	  devices.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem_sunxi_sid.
+
 endif

drivers/nvmem/Makefile

@@ -8,3 +8,5 @@ nvmem_core-y			:= core.o
 # Devices
 obj-$(CONFIG_QCOM_QFPROM)	+= nvmem_qfprom.o
 nvmem_qfprom-y			:= qfprom.o
+obj-$(CONFIG_NVMEM_SUNXI_SID)	+= nvmem_sunxi_sid.o
+nvmem_sunxi_sid-y		:= sunxi_sid.o

drivers/misc/eeprom/sunxi_sid.c → drivers/nvmem/sunxi_sid.c

 /*
+ * Allwinner sunXi SoCs Security ID support.
+ *
  * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
- * http://www.linux-sunxi.org
+ * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
  *
  * 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
@@ -12,32 +14,28 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * This driver exposes the Allwinner security ID, efuses exported in byte-
- * sized chunks.
  */
 
-#include <linux/compiler.h>
+
 #include <linux/device.h>
-#include <linux/err.h>
-#include <linux/export.h>
-#include <linux/fs.h>
 #include <linux/io.h>
-#include <linux/kernel.h>
-#include <linux/kobject.h>
 #include <linux/module.h>
-#include <linux/of_device.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
-#include <linux/random.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
-#include <linux/stat.h>
-#include <linux/sysfs.h>
-#include <linux/types.h>
+#include <linux/random.h>
 
-#define DRV_NAME "sunxi-sid"
 
-struct sunxi_sid_data {
-	void __iomem *reg_base;
-	unsigned int keysize;
+static struct nvmem_config econfig = {
+	.name = "sunxi-sid",
+	.read_only = true,
+	.owner = THIS_MODULE,
+};
+
+struct sunxi_sid {
+	void __iomem		*base;
 };
 
 /* We read the entire key, due to a 32 bit read alignment requirement. Since we
@@ -45,107 +43,124 @@ struct sunxi_sid_data {
  * uses 4 times more reads as needed but keeps code simpler. Since the SID is
  * only very rarely probed, this is not really an issue.
  */
-static u8 sunxi_sid_read_byte(const struct sunxi_sid_data *sid_data,
+static u8 sunxi_sid_read_byte(const struct sunxi_sid *sid,
 			      const unsigned int offset)
 {
 	u32 sid_key;
 
-	if (offset >= sid_data->keysize)
-		return 0;
-
-	sid_key = ioread32be(sid_data->reg_base + round_down(offset, 4));
+	sid_key = ioread32be(sid->base + round_down(offset, 4));
 	sid_key >>= (offset % 4) * 8;
 
 	return sid_key; /* Only return the last byte */
 }
 
-static ssize_t sid_read(struct file *fd, struct kobject *kobj,
-			struct bin_attribute *attr, char *buf,
-			loff_t pos, size_t size)
+static int sunxi_sid_read(void *context,
+			    const void *reg, size_t reg_size,
+			    void *val, size_t val_size)
 {
-	struct platform_device *pdev;
-	struct sunxi_sid_data *sid_data;
-	int i;
-
-	pdev = to_platform_device(kobj_to_dev(kobj));
-	sid_data = platform_get_drvdata(pdev);
+	struct sunxi_sid *sid = context;
+	unsigned int offset = *(u32 *)reg;
+	u8 *buf = val;
 
-	if (pos < 0 || pos >= sid_data->keysize)
-		return 0;
-	if (size > sid_data->keysize - pos)
-		size = sid_data->keysize - pos;
+	while (val_size) {
+		*buf++ = sunxi_sid_read_byte(sid, offset);
+		val_size--;
+		offset++;
+	}
 
-	for (i = 0; i < size; i++)
-		buf[i] = sunxi_sid_read_byte(sid_data, pos + i);
+	return 0;
+}
 
-	return i;
+static int sunxi_sid_write(void *context, const void *data, size_t count)
+{
+	/* Unimplemented, dummy to keep regmap core happy */
+	return 0;
 }
 
-static struct bin_attribute sid_bin_attr = {
-	.attr = { .name = "eeprom", .mode = S_IRUGO, },
-	.read = sid_read,
+static struct regmap_bus sunxi_sid_bus = {
+	.read = sunxi_sid_read,
+	.write = sunxi_sid_write,
+	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 };
 
-static int sunxi_sid_remove(struct platform_device *pdev)
+static bool sunxi_sid_writeable_reg(struct device *dev, unsigned int reg)
 {
-	device_remove_bin_file(&pdev->dev, &sid_bin_attr);
-	dev_dbg(&pdev->dev, "driver unloaded\n");
-
-	return 0;
+	return false;
 }
 
-static const struct of_device_id sunxi_sid_of_match[] = {
-	{ .compatible = "allwinner,sun4i-a10-sid", .data = (void *)16},
-	{ .compatible = "allwinner,sun7i-a20-sid", .data = (void *)512},
-	{/* sentinel */},
+static struct regmap_config sunxi_sid_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 8,
+	.reg_stride = 1,
+	.writeable_reg = sunxi_sid_writeable_reg,
 };
-MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
 
 static int sunxi_sid_probe(struct platform_device *pdev)
 {
-	struct sunxi_sid_data *sid_data;
+	struct device *dev = &pdev->dev;
 	struct resource *res;
-	const struct of_device_id *of_dev_id;
-	u8 *entropy;
-	unsigned int i;
-
-	sid_data = devm_kzalloc(&pdev->dev, sizeof(struct sunxi_sid_data),
-				GFP_KERNEL);
-	if (!sid_data)
+	struct nvmem_device *nvmem;
+	struct regmap *regmap;
+	struct sunxi_sid *sid;
+	int i, size;
+	char *randomness;
+
+	sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
+	if (!sid)
 		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	sid_data->reg_base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(sid_data->reg_base))
-		return PTR_ERR(sid_data->reg_base);
-
-	of_dev_id = of_match_device(sunxi_sid_of_match, &pdev->dev);
-	if (!of_dev_id)
-		return -ENODEV;
-	sid_data->keysize = (int)of_dev_id->data;
+	sid->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(sid->base))
+		return PTR_ERR(sid->base);
+
+	size = resource_size(res) - 1;
+	sunxi_sid_regmap_config.max_register = size;
+
+	regmap = devm_regmap_init(dev, &sunxi_sid_bus, sid,
+				  &sunxi_sid_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "regmap init failed\n");
+		return PTR_ERR(regmap);
+	}
+
+	econfig.dev = dev;
+	nvmem = nvmem_register(&econfig);
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	randomness = kzalloc(sizeof(u8) * size, GFP_KERNEL);
+	for (i = 0; i < size; i++)
+		randomness[i] = sunxi_sid_read_byte(sid, i);
 
-	platform_set_drvdata(pdev, sid_data);
+	add_device_randomness(randomness, size);
+	kfree(randomness);
 
-	sid_bin_attr.size = sid_data->keysize;
-	if (device_create_bin_file(&pdev->dev, &sid_bin_attr))
-		return -ENODEV;
+	platform_set_drvdata(pdev, nvmem);
 
-	entropy = kzalloc(sizeof(u8) * sid_data->keysize, GFP_KERNEL);
-	for (i = 0; i < sid_data->keysize; i++)
-		entropy[i] = sunxi_sid_read_byte(sid_data, i);
-	add_device_randomness(entropy, sid_data->keysize);
-	kfree(entropy);
+	return 0;
+}
 
-	dev_dbg(&pdev->dev, "loaded\n");
+static int sunxi_sid_remove(struct platform_device *pdev)
+{
+	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 
-	return 0;
+	return nvmem_unregister(nvmem);
 }
 
+static const struct of_device_id sunxi_sid_of_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-sid" },
+	{ .compatible = "allwinner,sun7i-a20-sid" },
+	{/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
+
 static struct platform_driver sunxi_sid_driver = {
 	.probe = sunxi_sid_probe,
 	.remove = sunxi_sid_remove,
 	.driver = {
-		.name = DRV_NAME,
+		.name = "eeprom-sunxi-sid",
 		.of_match_table = sunxi_sid_of_match,
 	},
 };