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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
@@ -93,6 +93,7 @@ struct m25p {
u8 erase_opcode;
u8 *command;
bool fast_read;
+ int max_transfer_len;
};
static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
@@ -337,10 +338,9 @@ static int m25p80_erase(struct mtd_info
* Read an address range from the flash chip. The address range
* may be any size provided it is within the physical boundaries.
*/
-static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
+static int __m25p80_read(struct m25p *flash, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
- struct m25p *flash = mtd_to_m25p(mtd);
struct spi_transfer t[2];
struct spi_message m;
uint8_t opcode;
@@ -392,6 +392,28 @@ static int m25p80_read(struct mtd_info *
return 0;
}
+static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct m25p *flash = mtd_to_m25p(mtd);
+ size_t off;
+ size_t read_len = flash->max_transfer_len;
+ size_t part_len;
+ int ret = 0;
+
+ if (!read_len)
+ return __m25p80_read(flash, from, len, retlen, buf);
+
+ *retlen = 0;
+
+ for (off = 0; off < len && !ret; off += read_len) {
+ ret = __m25p80_read(flash, from + off, min(len - off, read_len),
+ &part_len, buf + off);
+ *retlen += part_len;
+ }
+
+ return ret;
+}
/*
* Write an address range to the flash chip. Data must be written in
* FLASH_PAGESIZE chunks. The address range may be any size provided
@@ -988,6 +1010,9 @@ static int m25p_probe(struct spi_device
return -ENOMEM;
}
+ if (data)
+ flash->max_transfer_len = data->max_transfer_len;
+
flash->spi = spi;
mutex_init(&flash->lock);
dev_set_drvdata(&spi->dev, flash);
--- 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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