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93 lines
2.8 KiB
Diff
93 lines
2.8 KiB
Diff
From 5fb4e8d7287ac8fcb33aae8b1e9e22c5a3c392bd Mon Sep 17 00:00:00 2001
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From: Jonas Gorski <jonas.gorski@gmail.com>
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Date: Thu, 10 Nov 2011 17:33:40 +0100
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Subject: [PATCH 51/79] MTD: DEVICES: m25p80: add support for limiting reads
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Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
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---
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drivers/mtd/devices/m25p80.c | 29 +++++++++++++++++++++++++++--
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include/linux/spi/flash.h | 4 ++++
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2 files changed, 31 insertions(+), 2 deletions(-)
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--- a/drivers/mtd/devices/m25p80.c
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+++ b/drivers/mtd/devices/m25p80.c
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@@ -93,6 +93,7 @@ struct m25p {
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u8 erase_opcode;
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u8 *command;
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bool fast_read;
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+ int max_transfer_len;
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};
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static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
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@@ -337,10 +338,9 @@ static int m25p80_erase(struct mtd_info
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* Read an address range from the flash chip. The address range
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* may be any size provided it is within the physical boundaries.
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*/
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-static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
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+static int __m25p80_read(struct m25p *flash, loff_t from, size_t len,
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size_t *retlen, u_char *buf)
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{
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- struct m25p *flash = mtd_to_m25p(mtd);
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struct spi_transfer t[2];
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struct spi_message m;
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uint8_t opcode;
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@@ -392,6 +392,28 @@ static int m25p80_read(struct mtd_info *
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return 0;
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}
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+static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
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+ size_t *retlen, u_char *buf)
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+{
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+ struct m25p *flash = mtd_to_m25p(mtd);
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+ size_t off;
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+ size_t read_len = flash->max_transfer_len;
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+ size_t part_len;
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+ int ret = 0;
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+
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+ if (!read_len)
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+ return __m25p80_read(flash, from, len, retlen, buf);
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+
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+ *retlen = 0;
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+
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+ for (off = 0; off < len && !ret; off += read_len) {
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+ ret = __m25p80_read(flash, from + off, min(len - off, read_len),
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+ &part_len, buf + off);
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+ *retlen += part_len;
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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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* Write an address range to the flash chip. Data must be written in
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* FLASH_PAGESIZE chunks. The address range may be any size provided
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@@ -888,6 +910,9 @@ static int m25p_probe(struct spi_device
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return -ENOMEM;
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}
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+ if (data)
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+ flash->max_transfer_len = data->max_transfer_len;
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+
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flash->spi = spi;
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mutex_init(&flash->lock);
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dev_set_drvdata(&spi->dev, flash);
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--- a/include/linux/spi/flash.h
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+++ b/include/linux/spi/flash.h
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@@ -13,6 +13,8 @@ struct mtd_part_parser_data;
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* @part_probe_types: optional list of MTD parser names to use for
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* partitioning
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*
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+ * @max_transfer_len: option maximum read/write length limitation for
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+ * SPI controllers not able to transfer any length commands.
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* Board init code (in arch/.../mach-xxx/board-yyy.c files) can
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* provide information about SPI flash parts (such as DataFlash) to
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* help set up the device and its appropriate default partitioning.
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@@ -28,6 +30,8 @@ struct flash_platform_data {
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char *type;
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const char **part_probe_types;
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+
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+ unsigned int max_transfer_len;
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/* we'll likely add more ... use JEDEC IDs, etc */
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};
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