mirror of
				git://git.openwrt.org/openwrt/openwrt.git
				synced 2025-10-30 13:34:27 -04:00 
			
		
		
		
	Backport upstream solution for working around SPI controller maximum message sizes. Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
		
			
				
	
	
		
			104 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			104 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From e5d05cbd6d8b01f08c95c427a36c66aac769af4f Mon Sep 17 00:00:00 2001
 | |
| From: Michal Suchanek <hramrach@gmail.com>
 | |
| Date: Thu, 5 May 2016 17:31:54 -0700
 | |
| Subject: [PATCH 08/10] mtd: spi-nor: simplify write loop
 | |
| 
 | |
| The spi-nor write loop assumes that what is passed to the hardware
 | |
| driver write() is what gets written.
 | |
| 
 | |
| When write() writes less than page size at once data is dropped on the
 | |
| floor. Check the amount of data writen and exit if it does not match
 | |
| requested amount.
 | |
| 
 | |
| Signed-off-by: Michal Suchanek <hramrach@gmail.com>
 | |
| Signed-off-by: Brian Norris <computersforpeace@gmail.com>
 | |
| Tested-by Cyrille Pitchen <cyrille.pitchen@atmel.com>
 | |
| Acked-by: Michal Suchanek <hramrach@gmail.com>
 | |
| Tested-by: Michal Suchanek <hramrach@gmail.com>
 | |
| ---
 | |
|  drivers/mtd/spi-nor/spi-nor.c | 58 +++++++++++++++++++------------------------
 | |
|  1 file changed, 25 insertions(+), 33 deletions(-)
 | |
| 
 | |
| --- a/drivers/mtd/spi-nor/spi-nor.c
 | |
| +++ b/drivers/mtd/spi-nor/spi-nor.c
 | |
| @@ -988,8 +988,8 @@ static int spi_nor_write(struct mtd_info
 | |
|  	size_t *retlen, const u_char *buf)
 | |
|  {
 | |
|  	struct spi_nor *nor = mtd_to_spi_nor(mtd);
 | |
| -	u32 page_offset, page_size, i;
 | |
| -	int ret;
 | |
| +	size_t page_offset, page_remain, i;
 | |
| +	ssize_t ret;
 | |
|  
 | |
|  	dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
 | |
|  
 | |
| @@ -997,45 +997,37 @@ static int spi_nor_write(struct mtd_info
 | |
|  	if (ret)
 | |
|  		return ret;
 | |
|  
 | |
| -	write_enable(nor);
 | |
| +	for (i = 0; i < len; ) {
 | |
| +		ssize_t written;
 | |
|  
 | |
| -	page_offset = to & (nor->page_size - 1);
 | |
| -
 | |
| -	/* do all the bytes fit onto one page? */
 | |
| -	if (page_offset + len <= nor->page_size) {
 | |
| -		ret = nor->write(nor, to, len, buf);
 | |
| -		if (ret < 0)
 | |
| -			goto write_err;
 | |
| -		*retlen += ret;
 | |
| -	} else {
 | |
| +		page_offset = (to + i) & (nor->page_size - 1);
 | |
| +		WARN_ONCE(page_offset,
 | |
| +			  "Writing at offset %zu into a NOR page. Writing partial pages may decrease reliability and increase wear of NOR flash.",
 | |
| +			  page_offset);
 | |
|  		/* the size of data remaining on the first page */
 | |
| -		page_size = nor->page_size - page_offset;
 | |
| -		ret = nor->write(nor, to, page_size, buf);
 | |
| +		page_remain = min_t(size_t,
 | |
| +				    nor->page_size - page_offset, len - i);
 | |
| +
 | |
| +		write_enable(nor);
 | |
| +		ret = nor->write(nor, to + i, page_remain, buf + i);
 | |
|  		if (ret < 0)
 | |
|  			goto write_err;
 | |
| -		*retlen += ret;
 | |
| +		written = ret;
 | |
|  
 | |
| -		/* write everything in nor->page_size chunks */
 | |
| -		for (i = ret; i < len; ) {
 | |
| -			page_size = len - i;
 | |
| -			if (page_size > nor->page_size)
 | |
| -				page_size = nor->page_size;
 | |
| -
 | |
| -			ret = spi_nor_wait_till_ready(nor);
 | |
| -			if (ret)
 | |
| -				goto write_err;
 | |
| -
 | |
| -			write_enable(nor);
 | |
| -
 | |
| -			ret = nor->write(nor, to + i, page_size, buf + i);
 | |
| -			if (ret < 0)
 | |
| -				goto write_err;
 | |
| -			*retlen += ret;
 | |
| -			i += ret;
 | |
| +		ret = spi_nor_wait_till_ready(nor);
 | |
| +		if (ret)
 | |
| +			goto write_err;
 | |
| +		*retlen += written;
 | |
| +		i += written;
 | |
| +		if (written != page_remain) {
 | |
| +			dev_err(nor->dev,
 | |
| +				"While writing %zu bytes written %zd bytes\n",
 | |
| +				page_remain, written);
 | |
| +			ret = -EIO;
 | |
| +			goto write_err;
 | |
|  		}
 | |
|  	}
 | |
|  
 | |
| -	ret = spi_nor_wait_till_ready(nor);
 | |
|  write_err:
 | |
|  	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
 | |
|  	return ret;
 |