Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a92caeb8 authored by Jens Taprogge's avatar Jens Taprogge Committed by Greg Kroah-Hartman
Browse files

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: default avatarJens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: default avatarSamuel Iglesias Gonsálvez <siglesias@igalia.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8a3ae16e

drivers/staging/ipack/ipack.c

+58 −1
Original line number Diff line number Diff line
@@ -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)

drivers/staging/ipack/ipack.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};