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From 5fb4e8d7287ac8fcb33aae8b1e9e22c5a3c392bd Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jonas.gorski@gmail.com>
Date: Thu, 10 Nov 2011 17:33:40 +0100
Subject: [PATCH 51/79] MTD: DEVICES: m25p80: add support for limiting reads
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
---
drivers/mtd/devices/m25p80.c | 29 +++++++++++++++++++++++++++--
include/linux/spi/flash.h | 4 ++++
2 files changed, 31 insertions(+), 2 deletions(-)
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -31,6 +31,7 @@
struct m25p {
struct spi_device *spi;
struct spi_nor spi_nor;
+ int max_transfer_len;
u8 command[MAX_CMD_SIZE];
};
@@ -119,7 +120,7 @@ static inline unsigned int m25p80_rx_nbi
* Read an address range from the nor chip. The address range
* may be any size provided it is within the physical boundaries.
*/
-static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
+static int __m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct m25p *flash = nor->priv;
@@ -174,6 +175,29 @@ static int m25p80_read(struct spi_nor *n
return 0;
}
+static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct m25p *flash = nor->priv;
+ size_t off;
+ size_t read_len = flash->max_transfer_len;
+ size_t part_len;
+ int ret = 0;
+
+ if (!read_len)
+ return __m25p80_read(nor, from, len, retlen, buf);
+
+ *retlen = 0;
+
+ for (off = 0; off < len && !ret; off += read_len) {
+ ret = __m25p80_read(nor, from + off, min(len - off, read_len),
+ &part_len, buf + off);
+ *retlen += part_len;
+ }
+
+ return ret;
+}
+
static int m25p80_erase(struct spi_nor *nor, loff_t offset)
{
struct m25p *flash = nor->priv;
@@ -245,6 +269,9 @@ static int m25p_probe(struct spi_device
else
flash_name = spi->modalias;
+ if (data)
+ flash->max_transfer_len = data->max_transfer_len;
+
ret = spi_nor_scan(nor, flash_name, mode);
if (ret)
return ret;
--- a/include/linux/spi/flash.h
+++ b/include/linux/spi/flash.h
@@ -13,6 +13,8 @@ struct mtd_part_parser_data;
* @part_probe_types: optional list of MTD parser names to use for
* partitioning
*
+ * @max_transfer_len: option maximum read/write length limitation for
+ * SPI controllers not able to transfer any length commands.
* Board init code (in arch/.../mach-xxx/board-yyy.c files) can
* provide information about SPI flash parts (such as DataFlash) to
* help set up the device and its appropriate default partitioning.
@@ -28,6 +30,8 @@ struct flash_platform_data {
char *type;
const char **part_probe_types;
+
+ unsigned int max_transfer_len;
/* we'll likely add more ... use JEDEC IDs, etc */
};
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