[v4,3/5] mtd: handle partitioning on devices with 0 erasesize
diff mbox

Message ID 20170524234916.16181-4-chris.packham@alliedtelesis.co.nz
State Superseded
Delegated to: Brian Norris
Headers show

Commit Message

Chris Packham May 24, 2017, 11:49 p.m. UTC
erasesize is meaningful for flash devices but for SRAM there is no
concept of an erase block so erasesize is set to 0. When partitioning
these devices instead of ensuring partitions fall on erasesize
boundaries we ensure they fall on writesize boundaries.

Helped-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
Changes in v3:
- new
Changes in v4:
- None

 drivers/mtd/mtdpart.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

Comments

Boris Brezillon May 29, 2017, 9:13 a.m. UTC | #1
On Thu, 25 May 2017 11:49:14 +1200
Chris Packham <chris.packham@alliedtelesis.co.nz> wrote:

> erasesize is meaningful for flash devices but for SRAM there is no
> concept of an erase block so erasesize is set to 0. When partitioning
> these devices instead of ensuring partitions fall on erasesize
> boundaries we ensure they fall on writesize boundaries.
> 
> Helped-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> ---
> Changes in v3:
> - new
> Changes in v4:
> - None
> 
>  drivers/mtd/mtdpart.c | 25 ++++++++++++++++---------
>  1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index ea5e5307f667..5cef1247806c 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -393,8 +393,11 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
>  			const struct mtd_partition *part, int partno,
>  			uint64_t cur_offset)
>  {
> +	int wr_alignment = master->erasesize ? : master->writesize;
>  	struct mtd_part *slave;
> +	u32 remainder;
>  	char *name;
> +	u64 tmp;
>  
>  	/* allocate the partition structure */
>  	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
> @@ -499,10 +502,11 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
>  	if (slave->offset == MTDPART_OFS_APPEND)
>  		slave->offset = cur_offset;
>  	if (slave->offset == MTDPART_OFS_NXTBLK) {
> +		tmp = cur_offset;
>  		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;
> +		remainder = do_div(tmp, wr_alignment);
> +		if (remainder) {
> +			slave->offset += wr_alignment - remainder;
>  			printk(KERN_NOTICE "Moving partition %d: "
>  			       "0x%012llx -> 0x%012llx\n", partno,
>  			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
> @@ -567,19 +571,22 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
>  		slave->mtd.erasesize = master->erasesize;
>  	}
>  
> -	if ((slave->mtd.flags & MTD_WRITEABLE) &&
> -	    mtd_mod_by_eb(slave->offset, &slave->mtd)) {
> +	tmp = 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 */
>  		/* 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",
> +		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
>  			part->name);
>  	}
> -	if ((slave->mtd.flags & MTD_WRITEABLE) &&
> -	    mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
> +
> +	tmp = 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 block -- force read-only\n",
> +		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
>  			part->name);
>  	}
>

Patch
diff mbox

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index ea5e5307f667..5cef1247806c 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -393,8 +393,11 @@  static struct mtd_part *allocate_partition(struct mtd_info *master,
 			const struct mtd_partition *part, int partno,
 			uint64_t cur_offset)
 {
+	int wr_alignment = master->erasesize ? : master->writesize;
 	struct mtd_part *slave;
+	u32 remainder;
 	char *name;
+	u64 tmp;
 
 	/* allocate the partition structure */
 	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
@@ -499,10 +502,11 @@  static struct mtd_part *allocate_partition(struct mtd_info *master,
 	if (slave->offset == MTDPART_OFS_APPEND)
 		slave->offset = cur_offset;
 	if (slave->offset == MTDPART_OFS_NXTBLK) {
+		tmp = cur_offset;
 		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;
+		remainder = do_div(tmp, wr_alignment);
+		if (remainder) {
+			slave->offset += wr_alignment - remainder;
 			printk(KERN_NOTICE "Moving partition %d: "
 			       "0x%012llx -> 0x%012llx\n", partno,
 			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
@@ -567,19 +571,22 @@  static struct mtd_part *allocate_partition(struct mtd_info *master,
 		slave->mtd.erasesize = master->erasesize;
 	}
 
-	if ((slave->mtd.flags & MTD_WRITEABLE) &&
-	    mtd_mod_by_eb(slave->offset, &slave->mtd)) {
+	tmp = 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 */
 		/* 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",
+		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
 			part->name);
 	}
-	if ((slave->mtd.flags & MTD_WRITEABLE) &&
-	    mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
+
+	tmp = 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 block -- force read-only\n",
+		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
 			part->name);
 	}