diff options
| author | Jens Taprogge <jens.taprogge@taprogge.org> | 2012-09-11 11:35:03 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-11 19:18:11 (GMT) |
| commit | a92caeb8e1189f190ac13bb5e745446b25b09ae5 (patch) | |
| tree | ecdc6c7dccfa29ed9703aa5d4226b63f16d7d9f9 /drivers/staging/ipack | |
| parent | 8a3ae16e60fb78e0bf062c243ffba5575b64a412 (diff) | |
| download | linux-a92caeb8e1189f190ac13bb5e745446b25b09ae5.tar.xz | |
Staging: ipack: check the device ID space CRC.
We check the CRC and store the result of the check in struct ipac_device.
A warning is emitted if the check fails. However we leave it to the
IPack module device to refuse to initialize due to a bad CRC. I have seen
otherwise good modules with bad CRCs.
Signed-off-by: Jens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/ipack')
| -rw-r--r-- | drivers/staging/ipack/ipack.c | 59 | ||||
| -rw-r--r-- | drivers/staging/ipack/ipack.h | 1 |
2 files changed, 59 insertions, 1 deletions
diff --git a/drivers/staging/ipack/ipack.c b/drivers/staging/ipack/ipack.c index 08b122d..26dc976 100644 --- a/drivers/staging/ipack/ipack.c +++ b/drivers/staging/ipack/ipack.c @@ -253,20 +253,71 @@ void ipack_driver_unregister(struct ipack_driver *edrv) } EXPORT_SYMBOL_GPL(ipack_driver_unregister); +static u16 ipack_crc_byte(u16 crc, u8 c) +{ + int i; + + crc ^= c << 8; + for (i = 0; i < 8; i++) + crc = (crc << 1) ^ ((crc & 0x8000) ? 0x1021 : 0); + return crc; +} + +/* + * The algorithm in lib/crc-ccitt.c does not seem to apply since it uses the + * opposite bit ordering. + */ +static u8 ipack_calc_crc1(struct ipack_device *dev) +{ + u8 c; + u16 crc; + unsigned int i; + + crc = 0xffff; + for (i = 0; i < dev->id_avail; i++) { + c = (i != 11) ? dev->id[i] : 0; + crc = ipack_crc_byte(crc, c); + } + crc = ~crc; + return crc & 0xff; +} + +static u16 ipack_calc_crc2(struct ipack_device *dev) +{ + u8 c; + u16 crc; + unsigned int i; + + crc = 0xffff; + for (i = 0; i < dev->id_avail; i++) { + c = ((i != 0x18) && (i != 0x19)) ? dev->id[i] : 0; + crc = ipack_crc_byte(crc, c); + } + crc = ~crc; + return crc; +} + static void ipack_parse_id1(struct ipack_device *dev) { u8 *id = dev->id; + u8 crc; dev->id_vendor = id[4]; dev->id_device = id[5]; dev->speed_8mhz = 1; dev->speed_32mhz = (id[7] == 'H'); + crc = ipack_calc_crc1(dev); + dev->id_crc_correct = (crc == id[11]); + if (!dev->id_crc_correct) { + dev_warn(&dev->dev, "ID CRC invalid found 0x%x, expected 0x%x.\n", + id[11], crc); + } } static void ipack_parse_id2(struct ipack_device *dev) { __be16 *id = (__be16 *) dev->id; - u16 flags; + u16 flags, crc; dev->id_vendor = ((be16_to_cpu(id[3]) & 0xff) << 16) + be16_to_cpu(id[4]); @@ -274,6 +325,12 @@ static void ipack_parse_id2(struct ipack_device *dev) flags = be16_to_cpu(id[10]); dev->speed_8mhz = !!(flags & 2); dev->speed_32mhz = !!(flags & 4); + crc = ipack_calc_crc2(dev); + dev->id_crc_correct = (crc == be16_to_cpu(id[12])); + if (!dev->id_crc_correct) { + dev_warn(&dev->dev, "ID CRC invalid found 0x%x, expected 0x%x.\n", + id[11], crc); + } } static int ipack_device_read_id(struct ipack_device *dev) diff --git a/drivers/staging/ipack/ipack.h b/drivers/staging/ipack/ipack.h index ad4c3bf..77d8075 100644 --- a/drivers/staging/ipack/ipack.h +++ b/drivers/staging/ipack/ipack.h @@ -77,6 +77,7 @@ struct ipack_device { u32 id_vendor; u32 id_device; u8 id_format; + unsigned int id_crc_correct:1; unsigned int speed_8mhz:1; unsigned int speed_32mhz:1; }; |