soc: amlogic: add cpuinfo support

drivers/soc/amlogic/Kconfig

@@ -17,6 +17,15 @@ config MESON_CLK_MEASURE
 	  Say yes to support of Measuring a set of internal SoC clocks
 	  from the debugfs interface.
 
+config MESON_GX_CPUINFO
+	tristate "Amlogic Meson GX cpuinfo support"
+	depends on MESON_EFUSE && (ARM64 || ARM)
+	default MESON_EFUSE
+	help
+	  Say y here to enable Amlogic Meson GX cpuinfo support.
+	  Set system_serial from eFuse SN.
+	  Serial can read from /proc/cpuinfo.
+
 config MESON_GX_SOCINFO
 	bool "Amlogic Meson GX SoC Information driver"
 	depends on ARCH_MESON || COMPILE_TEST

drivers/soc/amlogic/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_MESON_CANVAS) += meson-canvas.o
 obj-$(CONFIG_MESON_CLK_MEASURE) += meson-clk-measure.o
+obj-$(CONFIG_MESON_GX_CPUINFO) += meson-gx-cpuinfo.o
 obj-$(CONFIG_MESON_GX_SOCINFO) += meson-gx-socinfo.o
 obj-$(CONFIG_MESON_GX_PM_DOMAINS) += meson-gx-pwrc-vpu.o
 obj-$(CONFIG_MESON_MX_SOCINFO) += meson-mx-socinfo.o

drivers/soc/amlogic/meson-gx-cpuinfo.c

@@ -0,0 +1,72 @@
+/*
+ * 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/of_platform.h>
+#include <linux/slab.h>
+#include <asm/system_info.h>
+
+static int meson_gx_cpuinfo_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct nvmem_cell *cell;
+	unsigned char *efuse_buf, buf[17];
+	size_t len;
+	int i;
+
+	cell = nvmem_cell_get(dev, "sn");
+	if (IS_ERR(cell)) {
+		dev_err(dev, "failed to get sn 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 sn len: %zu\n", len);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < 16; i++) {
+		buf[i] = efuse_buf[i];
+	}
+	buf[16] = 0;
+
+	kfree(efuse_buf);
+
+	system_serial = kasprintf(GFP_KERNEL, "%s", buf);
+
+	dev_info(dev, "Serial\t\t: %s\n", system_serial);
+
+	return 0;
+}
+
+static const struct of_device_id meson_gx_cpuinfo_of_match[] = {
+	{ .compatible = "amlogic,meson-gx-cpuinfo", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, meson_gx_cpuinfo_of_match);
+
+static struct platform_driver meson_gx_cpuinfo_driver = {
+	.probe = meson_gx_cpuinfo_probe,
+	.driver = {
+		.name = "meson-gx-cpuinfo",
+		.of_match_table = meson_gx_cpuinfo_of_match,
+	},
+};
+module_platform_driver(meson_gx_cpuinfo_driver);