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