--- zzzz-none-000/linux-4.4.271/drivers/mtd/mtdpart.c	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/drivers/mtd/mtdpart.c	2023-04-19 10:22:29.000000000 +0000
@@ -29,10 +29,15 @@
 #include <linux/kmod.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/magic.h>
+#include <linux/of.h>
 #include <linux/err.h>
 #include <linux/kconfig.h>
 
 #include "mtdcore.h"
+#include "mtdsplit/mtdsplit.h"
+
+#define MTD_ERASE_PARTIAL	0x8000 /* partition only covers parts of an erase block */
 
 /* Our partition linked list */
 static LIST_HEAD(mtd_partitions);
@@ -46,6 +51,8 @@
 	struct list_head list;
 };
 
+static void mtd_partition_split(struct mtd_info *master, struct mtd_part *part);
+
 /*
  * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
  * the pointer to that structure with this macro.
@@ -231,13 +238,61 @@
 	struct mtd_part *part = PART(mtd);
 	int ret;
 
+
+	instr->partial_start = false;
+	if (mtd->flags & MTD_ERASE_PARTIAL) {
+		size_t readlen = 0;
+		u64 mtd_ofs;
+
+		instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC);
+		if (!instr->erase_buf)
+			return -ENOMEM;
+
+		mtd_ofs = part->offset + instr->addr;
+		instr->erase_buf_ofs = do_div(mtd_ofs, part->master->erasesize);
+
+		if (instr->erase_buf_ofs > 0) {
+			instr->addr -= instr->erase_buf_ofs;
+			ret = mtd_read(part->master,
+				instr->addr + part->offset,
+				part->master->erasesize,
+				&readlen, instr->erase_buf);
+
+			instr->len += instr->erase_buf_ofs;
+			instr->partial_start = true;
+		} else {
+			mtd_ofs = part->offset + part->mtd.size;
+			instr->erase_buf_ofs = part->master->erasesize -
+				do_div(mtd_ofs, part->master->erasesize);
+
+			if (instr->erase_buf_ofs > 0) {
+				instr->len += instr->erase_buf_ofs;
+				ret = mtd_read(part->master,
+					part->offset + instr->addr +
+					instr->len - part->master->erasesize,
+					part->master->erasesize, &readlen,
+					instr->erase_buf);
+			} else {
+				ret = 0;
+			}
+		}
+		if (ret < 0) {
+			kfree(instr->erase_buf);
+			return ret;
+		}
+
+	}
+
 	instr->addr += part->offset;
 	ret = part->master->_erase(part->master, instr);
 	if (ret) {
 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 			instr->fail_addr -= part->offset;
 		instr->addr -= part->offset;
+		if (mtd->flags & MTD_ERASE_PARTIAL)
+			kfree(instr->erase_buf);
 	}
+
 	return ret;
 }
 
@@ -245,7 +300,25 @@
 {
 	if (instr->mtd->_erase == part_erase) {
 		struct mtd_part *part = PART(instr->mtd);
+		size_t wrlen = 0;
 
+		if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
+			if (instr->partial_start) {
+				part->master->_write(part->master,
+					instr->addr, instr->erase_buf_ofs,
+					&wrlen, instr->erase_buf);
+				instr->addr += instr->erase_buf_ofs;
+			} else {
+				instr->len -= instr->erase_buf_ofs;
+				part->master->_write(part->master,
+					instr->addr + instr->len,
+					instr->erase_buf_ofs, &wrlen,
+					instr->erase_buf +
+					part->master->erasesize -
+					instr->erase_buf_ofs);
+			}
+			kfree(instr->erase_buf);
+		}
 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 			instr->fail_addr -= part->offset;
 		instr->addr -= part->offset;
@@ -264,7 +337,14 @@
 static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 {
 	struct mtd_part *part = PART(mtd);
-	return part->master->_unlock(part->master, ofs + part->offset, len);
+
+	ofs += part->offset;
+	if (mtd->flags & MTD_ERASE_PARTIAL) {
+		/* round up len to next erasesize and round down offset to prev block */
+		len = (mtd_div_by_eb(len, part->master) + 1) * part->master->erasesize;
+		ofs &= ~(part->master->erasesize - 1);
+	}
+	return part->master->_unlock(part->master, ofs, len);
 }
 
 static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
@@ -449,14 +529,12 @@
 	if (slave->offset == MTDPART_OFS_APPEND)
 		slave->offset = cur_offset;
 	if (slave->offset == MTDPART_OFS_NXTBLK) {
-		slave->offset = cur_offset;
-		if (mtd_mod_by_eb(cur_offset, master) != 0) {
-			/* Round up to next erasesize */
-			slave->offset = (mtd_div_by_eb(cur_offset, master) + 1) * master->erasesize;
+		/* Round up to next erasesize */
+		slave->offset = mtd_roundup_to_eb(cur_offset, master);
+		if (slave->offset != cur_offset)
 			printk(KERN_NOTICE "Moving partition %d: "
 			       "0x%012llx -> 0x%012llx\n", partno,
 			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
-		}
 	}
 	if (slave->offset == MTDPART_OFS_RETAIN) {
 		slave->offset = cur_offset;
@@ -520,17 +598,20 @@
 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
 	    mtd_mod_by_eb(slave->offset, &slave->mtd)) {
 		/* Doesn't start on a boundary of major erase size */
-		/* FIXME: Let it be writable if it is on a boundary of
-		 * _minor_ erase size though */
-		slave->mtd.flags &= ~MTD_WRITEABLE;
-		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
-			part->name);
+		slave->mtd.flags |= MTD_ERASE_PARTIAL;
+		if (((u32) slave->mtd.size) > master->erasesize)
+			slave->mtd.flags &= ~MTD_WRITEABLE;
+		else
+			slave->mtd.erasesize = slave->mtd.size;
 	}
 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
-	    mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
-		slave->mtd.flags &= ~MTD_WRITEABLE;
-		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
-			part->name);
+	    mtd_mod_by_eb(slave->offset + slave->mtd.size, &slave->mtd)) {
+		slave->mtd.flags |= MTD_ERASE_PARTIAL;
+
+		if ((u32) slave->mtd.size > master->erasesize)
+			slave->mtd.flags &= ~MTD_WRITEABLE;
+		else
+			slave->mtd.erasesize = slave->mtd.size;
 	}
 
 	slave->mtd.ecclayout = master->ecclayout;
@@ -613,6 +694,7 @@
 	ret = add_mtd_device(&new->mtd);
 	if (ret)
 		goto err_remove_part;
+	mtd_partition_split(master, new);
 
 	mtd_add_partition_attrs(new);
 
@@ -654,6 +736,83 @@
 }
 EXPORT_SYMBOL_GPL(mtd_del_partition);
 
+static int
+run_parsers_by_type(struct mtd_part *slave, enum mtd_parser_type type)
+{
+	struct mtd_partition *parts;
+	int nr_parts;
+	int i;
+
+	nr_parts = parse_mtd_partitions_by_type(&slave->mtd, type, &parts,
+						NULL);
+	if (nr_parts <= 0)
+		return nr_parts;
+
+	if (WARN_ON(!parts))
+		return 0;
+
+	for (i = 0; i < nr_parts; i++) {
+		/* adjust partition offsets */
+		parts[i].offset += slave->offset;
+
+		mtd_add_partition(slave->master,
+				  parts[i].name,
+				  parts[i].offset,
+				  parts[i].size);
+	}
+
+	kfree(parts);
+
+	return nr_parts;
+}
+
+static inline unsigned long
+mtd_pad_erasesize(struct mtd_info *mtd, int offset, int len)
+{
+	unsigned long mask = mtd->erasesize - 1;
+
+	len += offset & mask;
+	len = (len + mask) & ~mask;
+	len -= offset & mask;
+	return len;
+}
+
+#ifdef CONFIG_MTD_SPLIT_FIRMWARE_NAME
+#define SPLIT_FIRMWARE_NAME	CONFIG_MTD_SPLIT_FIRMWARE_NAME
+#else
+#define SPLIT_FIRMWARE_NAME	"unused"
+#endif
+
+static void split_firmware(struct mtd_info *master, struct mtd_part *part)
+{
+	run_parsers_by_type(part, MTD_PARSER_TYPE_FIRMWARE);
+}
+
+void __weak arch_split_mtd_part(struct mtd_info *master, const char *name,
+                                int offset, int size)
+{
+}
+
+static void mtd_partition_split(struct mtd_info *master, struct mtd_part *part)
+{
+	static int rootfs_found = 0;
+
+	if (rootfs_found)
+		return;
+
+	if (!strcmp(part->mtd.name, "rootfs")) {
+		run_parsers_by_type(part, MTD_PARSER_TYPE_ROOTFS);
+
+		rootfs_found = 1;
+	}
+
+	if (!strcmp(part->mtd.name, SPLIT_FIRMWARE_NAME) &&
+	    config_enabled(CONFIG_MTD_SPLIT_FIRMWARE))
+		split_firmware(master, part);
+
+	arch_split_mtd_part(master, part->mtd.name, part->offset,
+			    part->mtd.size);
+}
 /*
  * This function, given a master MTD object and a partition table, creates
  * and registers slave MTD objects which are bound to the master according to
@@ -695,6 +854,7 @@
 		}
 
 		mtd_add_partition_attrs(slave);
+		mtd_partition_split(master, slave);
 
 		cur_offset = slave->offset + slave->mtd.size;
 	}
@@ -729,6 +889,30 @@
 
 #define put_partition_parser(p) do { module_put((p)->owner); } while (0)
 
+static struct mtd_part_parser *
+get_partition_parser_by_type(enum mtd_parser_type type,
+			     struct mtd_part_parser *start)
+{
+	struct mtd_part_parser *p, *ret = NULL;
+
+	spin_lock(&part_parser_lock);
+
+	p = list_prepare_entry(start, &part_parsers, list);
+	if (start)
+		put_partition_parser(start);
+
+	list_for_each_entry_continue(p, &part_parsers, list) {
+		if (p->type == type && try_module_get(p->owner)) {
+			ret = p;
+			break;
+		}
+	}
+
+	spin_unlock(&part_parser_lock);
+
+	return ret;
+}
+
 void register_mtd_parser(struct mtd_part_parser *p)
 {
 	spin_lock(&part_parser_lock);
@@ -746,11 +930,50 @@
 EXPORT_SYMBOL_GPL(deregister_mtd_parser);
 
 /*
+ * Parses the linux,part-probe device tree property.
+ * When a non null value is returned it has to be freed with kfree() by
+ * the caller.
+ */
+static const char * const *of_get_probes(struct device_node *dp)
+{
+	const char *cp;
+	int cplen;
+	unsigned int l;
+	unsigned int count;
+	const char **res;
+
+	cp = of_get_property(dp, "linux,part-probe", &cplen);
+	if (cp == NULL)
+		return NULL;
+
+	count = 0;
+	for (l = 0; l != cplen; l++)
+		if (cp[l] == 0)
+			count++;
+
+	res = kzalloc((count + 1) * sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return NULL;
+	count = 0;
+	while (cplen > 0) {
+		res[count] = cp;
+		l = strlen(cp) + 1;
+		cp += l;
+		cplen -= l;
+		count++;
+	}
+	return res;
+}
+
+/*
  * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
  * are changing this array!
  */
 static const char * const default_mtd_part_types[] = {
 	"cmdlinepart",
+#ifdef CONFIG_AVM_MTD_PARSER
+	"avmpart_of_nor_spi",
+#endif
 	"ofpart",
 	NULL
 };
@@ -781,6 +1004,13 @@
 {
 	struct mtd_part_parser *parser;
 	int ret, err = 0;
+	const char *const *types_of = NULL;
+
+	if (data && data->of_node) {
+		types_of = of_get_probes(data->of_node);
+		if (types_of != NULL)
+			types = types_of;
+	}
 
 	if (!types)
 		types = default_mtd_part_types;
@@ -810,9 +1040,42 @@
 		if (ret < 0 && !err)
 			err = ret;
 	}
+	kfree(types_of);
 	return err;
 }
 
+int parse_mtd_partitions_by_type(struct mtd_info *master,
+				 enum mtd_parser_type type,
+				 struct mtd_partition **pparts,
+				 struct mtd_part_parser_data *data)
+{
+	struct mtd_part_parser *prev = NULL;
+	int ret = 0;
+
+	while (1) {
+		struct mtd_part_parser *parser;
+
+		parser = get_partition_parser_by_type(type, prev);
+		if (!parser)
+			break;
+
+		ret = (*parser->parse_fn)(master, pparts, data);
+
+		if (ret > 0) {
+			put_partition_parser(parser);
+			printk(KERN_NOTICE
+			       "%d %s partitions found on MTD device %s\n",
+			       ret, parser->name, master->name);
+			break;
+		}
+
+		prev = parser;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(parse_mtd_partitions_by_type);
+
 int mtd_is_partition(const struct mtd_info *mtd)
 {
 	struct mtd_part *part;
@@ -830,6 +1093,24 @@
 }
 EXPORT_SYMBOL_GPL(mtd_is_partition);
 
+struct mtd_info *mtdpart_get_master(const struct mtd_info *mtd)
+{
+	if (!mtd_is_partition(mtd))
+		return (struct mtd_info *)mtd;
+
+	return PART(mtd)->master;
+}
+EXPORT_SYMBOL_GPL(mtdpart_get_master);
+
+uint64_t mtdpart_get_offset(const struct mtd_info *mtd)
+{
+	if (!mtd_is_partition(mtd))
+		return 0;
+
+	return PART(mtd)->offset;
+}
+EXPORT_SYMBOL_GPL(mtdpart_get_offset);
+
 /* Returns the size of the entire flash chip */
 uint64_t mtd_get_device_size(const struct mtd_info *mtd)
 {