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	Refreshed all patches. Compile-tested on: cns3xxx Runtime-tested on: cns3xxx Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
		
			
				
	
	
		
			133 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			133 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From: Felix Fietkau <nbd@nbd.name>
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| Subject: mtd: implement write support for partitions covering only a part of an eraseblock (buffer data that would otherwise be erased)
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| 
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| lede-commit: 87a8e8ac1067f58ba831c4aae443f3655c31cd80
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| Signed-off-by: Felix Fietkau <nbd@nbd.name>
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| ---
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|  drivers/mtd/mtdpart.c   | 90 ++++++++++++++++++++++++++++++++++++++++++++-----
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|  include/linux/mtd/mtd.h |  4 +++
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|  2 files changed, 85 insertions(+), 9 deletions(-)
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| 
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| --- a/drivers/mtd/mtdpart.c
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| +++ b/drivers/mtd/mtdpart.c
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| @@ -36,6 +36,8 @@
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|  #include "mtdcore.h"
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|  #include "mtdsplit/mtdsplit.h"
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|  
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| +#define MTD_ERASE_PARTIAL	0x8000 /* partition only covers parts of an erase block */
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| +
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|  /* Our partition linked list */
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|  static LIST_HEAD(mtd_partitions);
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|  static DEFINE_MUTEX(mtd_partitions_mutex);
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| @@ -220,6 +222,53 @@ static int part_erase(struct mtd_info *m
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|  {
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|  	struct mtd_part *part = mtd_to_part(mtd);
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|  	int ret;
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| +	size_t wrlen = 0;
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| +	u8 *erase_buf = NULL;
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| +	u32 erase_buf_ofs = 0;
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| +	bool partial_start = false;
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| +
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| +	if (mtd->flags & MTD_ERASE_PARTIAL) {
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| +		size_t readlen = 0;
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| +		u64 mtd_ofs;
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| +
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| +		erase_buf = kmalloc(part->parent->erasesize, GFP_ATOMIC);
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| +		if (!erase_buf)
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| +			return -ENOMEM;
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| +
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| +		mtd_ofs = part->offset + instr->addr;
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| +		erase_buf_ofs = do_div(mtd_ofs, part->parent->erasesize);
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| +
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| +		if (erase_buf_ofs > 0) {
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| +			instr->addr -= erase_buf_ofs;
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| +			ret = mtd_read(part->parent,
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| +				instr->addr + part->offset,
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| +				part->parent->erasesize,
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| +				&readlen, erase_buf);
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| +
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| +			instr->len += erase_buf_ofs;
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| +			partial_start = true;
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| +		} else {
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| +			mtd_ofs = part->offset + part->mtd.size;
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| +			erase_buf_ofs = part->parent->erasesize -
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| +				do_div(mtd_ofs, part->parent->erasesize);
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| +
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| +			if (erase_buf_ofs > 0) {
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| +				instr->len += erase_buf_ofs;
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| +				ret = mtd_read(part->parent,
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| +					part->offset + instr->addr +
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| +					instr->len - part->parent->erasesize,
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| +					part->parent->erasesize, &readlen,
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| +					erase_buf);
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| +			} else {
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| +				ret = 0;
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| +			}
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| +		}
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| +		if (ret < 0) {
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| +			kfree(erase_buf);
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| +			return ret;
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| +		}
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| +
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| +	}
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|  
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|  	instr->addr += part->offset;
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|  	ret = part->parent->_erase(part->parent, instr);
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| @@ -227,6 +276,24 @@ static int part_erase(struct mtd_info *m
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|  		instr->fail_addr -= part->offset;
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|  	instr->addr -= part->offset;
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|  
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| +	if (mtd->flags & MTD_ERASE_PARTIAL) {
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| +		if (partial_start) {
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| +			part->parent->_write(part->parent,
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| +				instr->addr, erase_buf_ofs,
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| +				&wrlen, erase_buf);
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| +			instr->addr += erase_buf_ofs;
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| +		} else {
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| +			instr->len -= erase_buf_ofs;
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| +			part->parent->_write(part->parent,
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| +				instr->addr + instr->len,
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| +				erase_buf_ofs, &wrlen,
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| +				erase_buf +
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| +				part->parent->erasesize -
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| +				erase_buf_ofs);
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| +		}
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| +		kfree(erase_buf);
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| +	}
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| +
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|  	return ret;
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|  }
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|  
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| @@ -539,19 +606,22 @@ static struct mtd_part *allocate_partiti
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|  	remainder = do_div(tmp, wr_alignment);
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|  	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
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|  		/* Doesn't start on a boundary of major erase size */
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| -		/* FIXME: Let it be writable if it is on a boundary of
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| -		 * _minor_ erase size though */
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| -		slave->mtd.flags &= ~MTD_WRITEABLE;
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| -		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
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| -			part->name);
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| +		slave->mtd.flags |= MTD_ERASE_PARTIAL;
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| +		if (((u32)slave->mtd.size) > parent->erasesize)
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| +			slave->mtd.flags &= ~MTD_WRITEABLE;
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| +		else
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| +			slave->mtd.erasesize = slave->mtd.size;
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|  	}
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|  
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| -	tmp = part_absolute_offset(parent) + slave->mtd.size;
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| +	tmp = part_absolute_offset(parent) + slave->offset + slave->mtd.size;
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|  	remainder = do_div(tmp, wr_alignment);
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|  	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
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| -		slave->mtd.flags &= ~MTD_WRITEABLE;
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| -		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
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| -			part->name);
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| +		slave->mtd.flags |= MTD_ERASE_PARTIAL;
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| +
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| +		if ((u32)slave->mtd.size > parent->erasesize)
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| +			slave->mtd.flags &= ~MTD_WRITEABLE;
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| +		else
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| +			slave->mtd.erasesize = slave->mtd.size;
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|  	}
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|  
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|  	mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
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