soc: rockchip: add cpuinfo support

Set system_serial_low/high from eFuse ID.
Serial can read from /proc/cpuinfo.

Change-Id: If412fc5a89a5e5092b510452fc5a126fdd374ac2
Signed-off-by: Huang, Tao <huangtao@rock-chips.com>

Documentation/devicetree/bindings/soc/rockchip/rockchip-cpuinfo.txt

@@ -0,0 +1,16 @@
+Rockchip cpuinfo device tree bindings
+----------------------------------
+
+Required properties:
+- compatible: Should be one of the following.
+ - "rockchip,cpuinfo"
+- nvmem-cells: A phandle to the ID data provided by a nvmem device.
+- nvmem-cell-names: Should be "id"
+
+Example:
+
+cpuinfo {
+	compatible = "rockchip,cpuinfo";
+	nvmem-cells = <&efuse_id>;
+	nvmem-cell-names = "id";
+};

drivers/soc/rockchip/Kconfig

@@ -3,6 +3,16 @@ if ARCH_ROCKCHIP || COMPILE_TEST
 #
 # Rockchip Soc drivers
 #
+config ROCKCHIP_CPUINFO
+	tristate "Rockchip cpuinfo support"
+	depends on ROCKCHIP_EFUSE && (ARM64 || ARM)
+	help
+	  Say y here to enable Rockchip cpuinfo support.
+	  Set system_serial_low/high from eFuse ID.
+	  Serial can read from /proc/cpuinfo.
+
+	  If unsure, say N.
+
 config ROCKCHIP_PM_TEST
 	bool "Rockchip pm_test support"
 	default n

drivers/soc/rockchip/Makefile

@@ -1,6 +1,7 @@
 #
 # Rockchip Soc drivers
 #
+obj-$(CONFIG_ROCKCHIP_CPUINFO)	+= rockchip-cpuinfo.o
 obj-$(CONFIG_ROCKCHIP_PM_TEST)	+= pm_test.o
 obj-$(CONFIG_ROCKCHIP_PM_DOMAINS) += pm_domains.o
 obj-$(CONFIG_FIQ_DEBUGGER) += rk_fiq_debugger.o

drivers/soc/rockchip/rockchip-cpuinfo.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 Rockchip Electronics Co. Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * 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/crc32.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <asm/system_info.h>
+
+static int rockchip_cpuinfo_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct nvmem_cell *cell;
+	unsigned char *efuse_buf, buf[16];
+	size_t len;
+	int i;
+
+	cell = nvmem_cell_get(dev, "id");
+	if (IS_ERR(cell)) {
+		dev_err(dev, "failed to get id cell: %ld\n", PTR_ERR(cell));
+		if (PTR_ERR(cell) == -EPROBE_DEFER)
+			return PTR_ERR(cell);
+		return PTR_ERR(cell);
+	}
+	efuse_buf = nvmem_cell_read(cell, &len);
+	nvmem_cell_put(cell);
+
+	if (len != 16) {
+		kfree(efuse_buf);
+		dev_err(dev, "invalid id len: %zu\n", len);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < 8; i++) {
+		buf[i] = efuse_buf[1 + (i << 1)];
+		buf[i + 8] = efuse_buf[i << 1];
+	}
+
+	kfree(efuse_buf);
+
+	system_serial_low = crc32(0, buf, 8);
+	system_serial_high = crc32(system_serial_low, buf + 8, 8);
+
+	dev_info(dev, "Serial\t\t: %08x%08x\n",
+		 system_serial_high, system_serial_low);
+
+	return 0;
+}
+
+static const struct of_device_id rockchip_cpuinfo_of_match[] = {
+	{ .compatible = "rockchip,cpuinfo", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rockchip_cpuinfo_of_match);
+
+static struct platform_driver rockchip_cpuinfo_driver = {
+	.probe = rockchip_cpuinfo_probe,
+	.driver = {
+		.name = "rockchip-cpuinfo",
+		.of_match_table = rockchip_cpuinfo_of_match,
+	},
+};
+module_platform_driver(rockchip_cpuinfo_driver);