kernel: backport 2 mtd partitioning fixes

This improves handling of subpartitions.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

2 files changed, 113 insertions, 0 deletions

diff --git a/target/linux/generic/backport-4.14/047-v4.21-mtd-keep-original-flags-for-every-struct-mtd_info.patch b/target/linux/generic/backport-4.14/047-v4.21-mtd-keep-original-flags-for-every-struct-mtd_info.patch
new file mode 100644
index 0000000000..7f90cf946a
--- /dev/null
+++ b/target/linux/generic/backport-4.14/047-v4.21-mtd-keep-original-flags-for-every-struct-mtd_info.patch
@@ -0,0 +1,58 @@
+From 1186af457cc186c5ed01708da71b1ffbdf0a2638 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 20 Nov 2018 09:55:45 +0100
+Subject: [PATCH] mtd: keep original flags for every struct mtd_info
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When allocating a new partition mtd subsystem runs internal tests in the
+allocate_partition(). They may result in modifying specified flags (e.g.
+dropping some /features/ like write access).
+
+Those constraints don't have to be necessary true for subpartitions. It
+may happen parent partition isn't block aligned (effectively disabling
+write access) while subpartition may fit blocks nicely. In such case all
+checks should be run again (starting with original flags value).
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
+---
+ drivers/mtd/mtdcore.c   | 2 ++
+ drivers/mtd/mtdpart.c   | 3 ++-
+ include/linux/mtd/mtd.h | 1 +
+ 3 files changed, 5 insertions(+), 1 deletion(-)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -650,6 +650,8 @@ static void mtd_set_dev_defaults(struct
+ 	} else {
+ 		pr_debug("mtd device won't show a device symlink in sysfs\n");
+ 	}
++
++	mtd->orig_flags = mtd->flags;
+ }
+ 
+ /**
+--- a/drivers/mtd/mtdpart.c
++++ b/drivers/mtd/mtdpart.c
+@@ -394,7 +394,8 @@ static struct mtd_part *allocate_partiti
+ 
+ 	/* set up the MTD object for this partition */
+ 	slave->mtd.type = parent->type;
+-	slave->mtd.flags = parent->flags & ~part->mask_flags;
++	slave->mtd.flags = parent->orig_flags & ~part->mask_flags;
++	slave->mtd.orig_flags = slave->mtd.flags;
+ 	slave->mtd.size = part->size;
+ 	slave->mtd.writesize = parent->writesize;
+ 	slave->mtd.writebufsize = parent->writebufsize;
+--- a/include/linux/mtd/mtd.h
++++ b/include/linux/mtd/mtd.h
+@@ -218,6 +218,7 @@ struct mtd_debug_info {
+ struct mtd_info {
+ 	u_char type;
+ 	uint32_t flags;
++	uint32_t orig_flags; /* Flags as before running mtd checks */
+ 	uint64_t size;	 // Total size of the MTD
+ 
+ 	/* "Major" erase size for the device. Naïve users may take this
diff --git a/target/linux/generic/backport-4.14/048-v4.21-mtd-improve-calculating-partition-boundaries-when-ch.patch b/target/linux/generic/backport-4.14/048-v4.21-mtd-improve-calculating-partition-boundaries-when-ch.patch
new file mode 100644
index 0000000000..58163e6935
--- /dev/null
+++ b/target/linux/generic/backport-4.14/048-v4.21-mtd-improve-calculating-partition-boundaries-when-ch.patch
@@ -0,0 +1,55 @@
+From 6750f61a13a0197c40e4a40739117493b15f19e8 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 20 Nov 2018 10:24:09 +0100
+Subject: [PATCH] mtd: improve calculating partition boundaries when checking
+ for alignment
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When checking for alignment mtd should check absolute offsets. It's
+important for subpartitions as it doesn't make sense to check their
+relative addresses.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
+---
+ drivers/mtd/mtdpart.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+--- a/drivers/mtd/mtdpart.c
++++ b/drivers/mtd/mtdpart.c
+@@ -61,6 +61,15 @@ static inline struct mtd_part *mtd_to_pa
+ 	return container_of(mtd, struct mtd_part, mtd);
+ }
+ 
++static u64 part_absolute_offset(struct mtd_info *mtd)
++{
++	struct mtd_part *part = mtd_to_part(mtd);
++
++	if (!mtd_is_partition(mtd))
++		return 0;
++
++	return part_absolute_offset(part->parent) + part->offset;
++}
+ 
+ /*
+  * MTD methods which simply translate the effective address and pass through
+@@ -562,7 +571,7 @@ static struct mtd_part *allocate_partiti
+ 	if (!(slave->mtd.flags & MTD_NO_ERASE))
+ 		wr_alignment = slave->mtd.erasesize;
+ 
+-	tmp = slave->offset;
++	tmp = part_absolute_offset(parent) + slave->offset;
+ 	remainder = do_div(tmp, wr_alignment);
+ 	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
+ 		/* Doesn't start on a boundary of major erase size */
+@@ -573,7 +582,7 @@ static struct mtd_part *allocate_partiti
+ 			part->name);
+ 	}
+ 
+-	tmp = slave->mtd.size;
++	tmp = part_absolute_offset(parent) + slave->mtd.size;
+ 	remainder = do_div(tmp, wr_alignment);
+ 	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
+ 		slave->mtd.flags &= ~MTD_WRITEABLE;