| 1 | From 5fb4e8d7287ac8fcb33aae8b1e9e22c5a3c392bd Mon Sep 17 00:00:00 2001 |
| 2 | From: Jonas Gorski <jonas.gorski@gmail.com> |
| 3 | Date: Thu, 10 Nov 2011 17:33:40 +0100 |
| 4 | Subject: [PATCH 51/79] MTD: DEVICES: m25p80: add support for limiting reads |
| 5 | |
| 6 | Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com> |
| 7 | --- |
| 8 | drivers/mtd/devices/m25p80.c | 29 +++++++++++++++++++++++++++-- |
| 9 | include/linux/spi/flash.h | 4 ++++ |
| 10 | 2 files changed, 31 insertions(+), 2 deletions(-) |
| 11 | |
| 12 | --- a/drivers/mtd/devices/m25p80.c |
| 13 | +++ b/drivers/mtd/devices/m25p80.c |
| 14 | @@ -100,6 +100,7 @@ struct m25p { |
| 15 | u16 addr_width; |
| 16 | u8 erase_opcode; |
| 17 | u8 *command; |
| 18 | + int max_transfer_len; |
| 19 | }; |
| 20 | |
| 21 | static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd) |
| 22 | @@ -346,10 +347,9 @@ static int m25p80_erase(struct mtd_info |
| 23 | * Read an address range from the flash chip. The address range |
| 24 | * may be any size provided it is within the physical boundaries. |
| 25 | */ |
| 26 | -static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len, |
| 27 | +static int __m25p80_read(struct m25p *flash, loff_t from, size_t len, |
| 28 | size_t *retlen, u_char *buf) |
| 29 | { |
| 30 | - struct m25p *flash = mtd_to_m25p(mtd); |
| 31 | struct spi_transfer t[2]; |
| 32 | struct spi_message m; |
| 33 | |
| 34 | @@ -408,6 +408,28 @@ static int m25p80_read(struct mtd_info * |
| 35 | return 0; |
| 36 | } |
| 37 | |
| 38 | +static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len, |
| 39 | + size_t *retlen, u_char *buf) |
| 40 | +{ |
| 41 | + struct m25p *flash = mtd_to_m25p(mtd); |
| 42 | + size_t off; |
| 43 | + size_t read_len = flash->max_transfer_len; |
| 44 | + size_t part_len; |
| 45 | + int ret = 0; |
| 46 | + |
| 47 | + if (!read_len) |
| 48 | + return __m25p80_read(flash, from, len, retlen, buf); |
| 49 | + |
| 50 | + *retlen = 0; |
| 51 | + |
| 52 | + for (off = 0; off < len && !ret; off += read_len) { |
| 53 | + ret = __m25p80_read(flash, from + off, min(len - off, read_len), |
| 54 | + &part_len, buf + off); |
| 55 | + *retlen += part_len; |
| 56 | + } |
| 57 | + |
| 58 | + return ret; |
| 59 | +} |
| 60 | /* |
| 61 | * Write an address range to the flash chip. Data must be written in |
| 62 | * FLASH_PAGESIZE chunks. The address range may be any size provided |
| 63 | @@ -897,6 +919,9 @@ static int __devinit m25p_probe(struct s |
| 64 | return -ENOMEM; |
| 65 | } |
| 66 | |
| 67 | + if (data) |
| 68 | + flash->max_transfer_len = data->max_transfer_len; |
| 69 | + |
| 70 | flash->spi = spi; |
| 71 | mutex_init(&flash->lock); |
| 72 | dev_set_drvdata(&spi->dev, flash); |
| 73 | --- a/include/linux/spi/flash.h |
| 74 | +++ b/include/linux/spi/flash.h |
| 75 | @@ -13,6 +13,8 @@ struct mtd_part_parser_data; |
| 76 | * @part_probe_types: optional list of MTD parser names to use for |
| 77 | * partitioning |
| 78 | * |
| 79 | + * @max_transfer_len: option maximum read/write length limitation for |
| 80 | + * SPI controllers not able to transfer any length commands. |
| 81 | * Board init code (in arch/.../mach-xxx/board-yyy.c files) can |
| 82 | * provide information about SPI flash parts (such as DataFlash) to |
| 83 | * help set up the device and its appropriate default partitioning. |
| 84 | @@ -28,6 +30,8 @@ struct flash_platform_data { |
| 85 | char *type; |
| 86 | |
| 87 | const char **part_probe_types; |
| 88 | + |
| 89 | + unsigned int max_transfer_len; |
| 90 | /* we'll likely add more ... use JEDEC IDs, etc */ |
| 91 | }; |
| 92 | |
| 93 | |
