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SubjectRe: [PATCH 1/4] media: dvb/af9015, implement eeprom hashing
Hei,
Comments below.

On 01/22/2010 05:10 PM, Jiri Slaby wrote:
> We read the eeprom anyway for dumping. Switch the dumping to
> print_hex_dump_bytes and compute hash above that by
> hash = 0;
> for (u32 VAL) in (eeprom):
> hash *= GOLDEN_RATIO_PRIME_32
> hash += VAL; // while preserving endinaness
>
> The computation is moved earlier to the flow, namely from
> af9015_af9013_frontend_attach to af9015_read_config, so that
> we can access the sum in af9015_read_config already.
>
> Signed-off-by: Jiri Slaby<jslaby@suse.cz>
> Cc: Antti Palosaari<crope@iki.fi>
> Cc: Mauro Carvalho Chehab<mchehab@redhat.com>
> Cc: linux-media@vger.kernel.org
> ---
> drivers/media/dvb/dvb-usb/af9015.c | 65 +++++++++++++++++++++++------------
> drivers/media/dvb/dvb-usb/af9015.h | 1 +
> 2 files changed, 44 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/media/dvb/dvb-usb/af9015.c b/drivers/media/dvb/dvb-usb/af9015.c
> index a365c05..616b3ba 100644
> --- a/drivers/media/dvb/dvb-usb/af9015.c
> +++ b/drivers/media/dvb/dvb-usb/af9015.c
> @@ -21,6 +21,8 @@
> *
> */
>
> +#include<linux/hash.h>
> +
> #include "af9015.h"
> #include "af9013.h"
> #include "mt2060.h"
> @@ -553,26 +555,45 @@ exit:
> return ret;
> }
>
> -/* dump eeprom */
> -static int af9015_eeprom_dump(struct dvb_usb_device *d)
> +/* hash (and dump) eeprom */
> +static int af9015_eeprom_hash(struct usb_device *udev)
> {
> - u8 reg, val;
> + static const unsigned int eeprom_size = 256;
> + unsigned int reg;
> + int ret;
> + u8 val, *eeprom;
> + struct req_t req = {READ_I2C, AF9015_I2C_EEPROM, 0, 0, 1, 1,&val};
>
> - for (reg = 0; ; reg++) {
> - if (reg % 16 == 0) {
> - if (reg)
> - deb_info(KERN_CONT "\n");
> - deb_info(KERN_DEBUG "%02x:", reg);
> - }
> - if (af9015_read_reg_i2c(d, AF9015_I2C_EEPROM, reg,&val) == 0)
> - deb_info(KERN_CONT " %02x", val);
> - else
> - deb_info(KERN_CONT " --");
> - if (reg == 0xff)
> - break;
> + eeprom = kmalloc(eeprom_size, GFP_KERNEL);
> + if (eeprom == NULL)
> + return -ENOMEM;
> +
> + for (reg = 0; reg< eeprom_size; reg++) {
> + req.addr = reg;
> + ret = af9015_rw_udev(udev,&req);
> + if (ret)
> + goto free;
> + eeprom[reg] = val;
> }
> - deb_info(KERN_CONT "\n");
> - return 0;
> +
> + if (dvb_usb_af9015_debug& 0x01)
> + print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, eeprom,
> + eeprom_size);
> +
> + BUG_ON(eeprom_size % 4);
> +
> + af9015_config.eeprom_sum = 0;
> + for (reg = 0; reg< eeprom_size / sizeof(u32); reg++) {
> + af9015_config.eeprom_sum *= GOLDEN_RATIO_PRIME_32;
> + af9015_config.eeprom_sum += le32_to_cpu(((u32 *)eeprom)[reg]);
> + }
> +
> + deb_info("%s: eeprom sum=%.8x\n", __func__, af9015_config.eeprom_sum);

Does this sum contain all 256 bytes from EEPROM? 256/4 is 64.

regards
Antti
--
http://palosaari.fi/


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