openwrt/target/linux/generic/pending-4.14/411-mtd-partial_eraseblock_write.patch
Rafał Miłecki 2a598bbaa3 kernel: backport mtd support for subpartitions in DT
This is a new & warm feature that allows nesting partiitons in DT and
mixing their types (e.g. static vs. dynamic). It's very useful for
boards that have most partitions static but some of them require extra
parsing (e.g. a "firmware" partition).

It's required to successfully backport support for new devices using
that new syntax in their DT files.

Since brcm63xx has a custom alternative patch the upstream one is being
reverted for it. The plan is to make brcm63xx use the upstream
implementation.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
2018-07-27 22:16:24 +02:00

155 lines
4.5 KiB
Diff

From: Felix Fietkau <nbd@nbd.name>
Subject: mtd: implement write support for partitions covering only a part of an eraseblock (buffer data that would otherwise be erased)
lede-commit: 87a8e8ac1067f58ba831c4aae443f3655c31cd80
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
drivers/mtd/mtdpart.c | 90 ++++++++++++++++++++++++++++++++++++++++++++-----
include/linux/mtd/mtd.h | 4 +++
2 files changed, 85 insertions(+), 9 deletions(-)
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -37,6 +37,8 @@
#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);
static DEFINE_MUTEX(mtd_partitions_mutex);
@@ -242,13 +244,61 @@ static int part_erase(struct mtd_info *m
struct mtd_part *part = mtd_to_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->parent->erasesize, GFP_ATOMIC);
+ if (!instr->erase_buf)
+ return -ENOMEM;
+
+ mtd_ofs = part->offset + instr->addr;
+ instr->erase_buf_ofs = do_div(mtd_ofs, part->parent->erasesize);
+
+ if (instr->erase_buf_ofs > 0) {
+ instr->addr -= instr->erase_buf_ofs;
+ ret = mtd_read(part->parent,
+ instr->addr + part->offset,
+ part->parent->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->parent->erasesize -
+ do_div(mtd_ofs, part->parent->erasesize);
+
+ if (instr->erase_buf_ofs > 0) {
+ instr->len += instr->erase_buf_ofs;
+ ret = mtd_read(part->parent,
+ part->offset + instr->addr +
+ instr->len - part->parent->erasesize,
+ part->parent->erasesize, &readlen,
+ instr->erase_buf);
+ } else {
+ ret = 0;
+ }
+ }
+ if (ret < 0) {
+ kfree(instr->erase_buf);
+ return ret;
+ }
+
+ }
+
instr->addr += part->offset;
ret = part->parent->_erase(part->parent, 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;
}
@@ -256,6 +306,25 @@ void mtd_erase_callback(struct erase_inf
{
if (instr->mtd->_erase == part_erase) {
struct mtd_part *part = mtd_to_part(instr->mtd);
+ size_t wrlen = 0;
+
+ if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
+ if (instr->partial_start) {
+ part->parent->_write(part->parent,
+ instr->addr, instr->erase_buf_ofs,
+ &wrlen, instr->erase_buf);
+ instr->addr += instr->erase_buf_ofs;
+ } else {
+ instr->len -= instr->erase_buf_ofs;
+ part->parent->_write(part->parent,
+ instr->addr + instr->len,
+ instr->erase_buf_ofs, &wrlen,
+ instr->erase_buf +
+ part->parent->erasesize -
+ instr->erase_buf_ofs);
+ }
+ kfree(instr->erase_buf);
+ }
if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
instr->fail_addr -= part->offset;
@@ -570,19 +639,22 @@ static struct mtd_part *allocate_partiti
remainder = do_div(tmp, wr_alignment);
if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
/* 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/write block boundary -- force read-only\n",
- part->name);
+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
+ if (((u32)slave->mtd.size) > parent->erasesize)
+ slave->mtd.flags &= ~MTD_WRITEABLE;
+ else
+ slave->mtd.erasesize = slave->mtd.size;
}
- tmp = slave->mtd.size;
+ tmp = slave->offset + slave->mtd.size;
remainder = do_div(tmp, wr_alignment);
if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
- slave->mtd.flags &= ~MTD_WRITEABLE;
- printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
- part->name);
+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
+
+ if ((u32)slave->mtd.size > parent->erasesize)
+ slave->mtd.flags &= ~MTD_WRITEABLE;
+ else
+ slave->mtd.erasesize = slave->mtd.size;
}
mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -56,6 +56,10 @@ struct erase_info {
u_long priv;
u_char state;
struct erase_info *next;
+
+ u8 *erase_buf;
+ u32 erase_buf_ofs;
+ bool partial_start;
};
struct mtd_erase_region_info {