init module for rootfs partition unlocking and reading serial number from otp area

src/drivers/elphel/Kconfig

@@ -13,6 +13,11 @@ config ELPHEL393
 config ELPHELDRVONMICROZED
         tristate "Provide only Elphel features which are compatible with Microzed"
         help
-          Say Y here if you debug Elpel camera code on Microzed board.
+          Say Y here if you debug Elphel camera code on Microzed board.
 
+config ELPHEL393_INIT
+		bool
+		default y
+		help
+			If unsure, say Y.
 endmenu  

src/drivers/elphel/Makefile

@@ -2,6 +2,7 @@
 # Makefile for Elphel specific devices.                                                                                              
 #                                                                                                                                    
                                                                                                                                      
-obj-$(CONFIG_ELPHEL393)         += elphel393-pwr.o  
-obj-$(CONFIG_ELPHEL393)         += elphel393-mem.o  
-obj-$(CONFIG_ELPHELDRVONMICROZED)          += elphel393-mem.o  
+obj-$(CONFIG_ELPHEL393)           += elphel393-pwr.o  
+obj-$(CONFIG_ELPHEL393)           += elphel393-mem.o  
+obj-$(CONFIG_ELPHELDRVONMICROZED) += elphel393-mem.o
+obj-$(CONFIG_ELPHEL393_INIT)      += elphel393-init.o   

src/drivers/elphel/elphel393-init.c

+/*!***************************************************************************
+ *! FILE NAME  : elphel393-init.c
+ *! DESCRIPTION: * Unlock rootfs NAND flash partition
+ *!              * Read MAC and other useful info from NAND flash OTP area
+ *!                and put to sysfs
+ *!
+ *! E-mail: oleg@elphel.com, support-list@elphel.com
+ *!
+ *! Copyright (C) 2016 Elphel, Inc.
+ *! -----------------------------------------------------------------------------**
+ *!
+ *!  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
+ *!  the Free Software Foundation, either version 3 of the License, or
+ *!  (at your option) any later version.
+ *!
+ *!  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.
+ *!
+ *!  You should have received a copy of the GNU General Public License
+ *!  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *!****************************************************************************/
+#define pr_fmt(fmt) "elphel393-init: " fmt
+
+#include <asm/page.h>
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+#include <elphel/elphel393-init.h>
+
+/* from elphel393-mem.c */
+#define SYSFS_PERMISSIONS         0644 /* default permissions for sysfs files */
+#define SYSFS_READONLY            0444
+#define SYSFS_WRITEONLY           0222
+
+/*
+ * Read and parse bootargs parameter in the device tree
+ * This driver is run in the last place - at least after NAND driver is probed
+ */
+static char *bootargs;
+static struct mtd_info *mtd;
+
+static int __init elphel393_init_init (void)
+{
+	struct device_node *node;
+	int len=0;
+
+	node = of_find_node_by_name(NULL, "chosen");
+	//just throw an error
+	if (!node)
+	{
+		pr_err("Device tree node 'chosen' not found.");
+		return -ENODEV;
+	}
+	of_property_read_string(node, "bootargs", &bootargs);
+	if (bootargs!=NULL) {
+		pr_debug("bootargs line from device tree is %s",bootargs);
+	}
+
+	return 0;
+}
+
+static void __exit elphel393_init_exit(void)
+{
+    printk("Exit\n");
+}
+
+// SYSFS
+
+static ssize_t get_bootargs(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf,"%s\n",bootargs);
+}
+static ssize_t get_boardinfo(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf,"%s\n",bootargs);
+}
+static ssize_t get_revision(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf,"%s\n",bootargs);
+}
+static ssize_t get_serial(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf,"%s\n",bootargs);
+}
+
+static DEVICE_ATTR(bootargs  ,  SYSFS_PERMISSIONS & SYSFS_READONLY,    get_bootargs ,   NULL);
+static DEVICE_ATTR(board_info,  SYSFS_PERMISSIONS & SYSFS_READONLY,    get_boardinfo,   NULL);
+static DEVICE_ATTR(revision  ,  SYSFS_PERMISSIONS & SYSFS_READONLY,    get_revision ,   NULL);
+static DEVICE_ATTR(serial    ,  SYSFS_PERMISSIONS & SYSFS_READONLY,    get_serial ,     NULL);
+
+static struct attribute *root_dev_attrs[] = {
+        &dev_attr_bootargs.attr,
+        &dev_attr_board_info.attr,
+        &dev_attr_revision.attr,
+        &dev_attr_serial.attr,
+        NULL
+};
+
+static const struct attribute_group dev_attr_root_group = {
+	.attrs = root_dev_attrs,
+	.name  = NULL,
+};
+
+static int elphel393_init_sysfs_register(struct platform_device *pdev)
+{
+	int retval=0;
+	struct device *dev = &pdev->dev;
+	if (&dev->kobj) {
+		if (((retval = sysfs_create_group(&dev->kobj, &dev_attr_root_group)))<0) return retval;
+	}
+	return retval;
+}
+
+static int elphel393_init_probe(struct platform_device *pdev)
+{
+	char *bootargs_copy;
+
+	char *token;
+	char *token_copy;
+
+	char *param;
+	char *value;
+
+	//mtd device number to unlock
+	u8 devnum=-1;
+	u8 unlock= 0;
+
+	pr_debug("Probing");
+	//copy bootargs string
+	bootargs_copy = kstrdup(bootargs,GFP_KERNEL);
+	//find out which partition to unlock if any
+	//parse bootargs
+	do {
+		token = strsep(&bootargs_copy," ");
+		if (token) {
+			//if '=' is found - split by '='
+			token_copy = token;
+			if (strchr(token_copy,'=')){
+				if (!strcmp(token_copy,"rootfstype=ubifs")){
+					unlock=1;
+				}
+				param = strsep(&token_copy,"=");
+	            //if "ubi.mtd" then get the partition number and unlock /dev/mtdN - if not found then don't care
+				if (!strcmp(param,"ubi.mtd")){
+					value = strsep(&token_copy,",");
+					if (kstrtou8(value,10,&devnum)){
+						pr_err("Partition number str to u8 conversion.");
+					}
+				}
+			}
+		}
+	} while (token);
+
+	kfree(bootargs_copy);
+
+	//unlock /dev/mtdN partition
+	if (unlock&&(devnum>=0)){
+		mtd = get_mtd_device(NULL,devnum);
+		mtd_unlock(mtd,0,mtd->size);
+		pr_info("/dev/mtd%d: unlocked",devnum);
+	}
+
+	//
+
+    //look in the nand drivers how to do this:
+    //read the factory info string from NAND flash otp area - look in the 1st page?
+    //parse the string:
+    //string start 1st occurence of <board>
+    //string end 1st occurence of </board>
+    //parse all of the entries
+    //<revision>
+    //<serial>
+	//mtd_read_user_prot_reg(mtd,(loff_t)0x0,);
+	//struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, uint8_t *buf
+        
+	elphel393_init_sysfs_register(pdev);
+
+	return 0;
+}
+
+static int elphel393_init_remove(struct platform_device *pdev)
+{
+	pr_info("Remove");
+	return 0;
+}
+
+static struct of_device_id elphel393_init_of_match[] = {
+	{ .compatible = "elphel,elphel393-init-1.00", },
+	{ /* end of table */}
+};
+MODULE_DEVICE_TABLE(of, elphel393_init_of_match);
+
+static struct platform_driver elphel393_initialize = {
+	.probe   = elphel393_init_probe,
+	.remove  = elphel393_init_remove,
+	.driver  = {
+		.name  = "elphel393-init",
+		.owner = THIS_MODULE,
+		.of_match_table = elphel393_init_of_match,
+		.pm = NULL, /* power management */
+	},
+};
+
+module_platform_driver(elphel393_initialize);
+module_init(elphel393_init_init);
+module_exit(elphel393_init_exit);
+MODULE_LICENSE("GPL");

src/include/elphel/elphel393-init.h

+