[1/4] media: dvb/af9015, implement eeprom hashing
Commit Message
This will be useful for matching of IR tables later.
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(-)
Comments
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
On 01/24/2010 05:16 PM, Antti Palosaari wrote:
>> + 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.
Yes it does. It is computed as a hashed sum of 32-bit numbers (4 bytes)
-- speed (does not matter) and larger space of hashes. Hence the
division by 4. The cast does the trick: ((u32 *)eeprom)[reg] -- reg
index is on a 4-byte basis.
regards,
On 01/24/2010 06:35 PM, Jiri Slaby wrote:
> On 01/24/2010 05:16 PM, Antti Palosaari wrote:
>>> + 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.
>
> Yes it does. It is computed as a hashed sum of 32-bit numbers (4 bytes)
> -- speed (does not matter) and larger space of hashes. Hence the
> division by 4. The cast does the trick: ((u32 *)eeprom)[reg] -- reg
> index is on a 4-byte basis.
OK, true. Anyhow, I don't know if this hashing formula is good enough -
changing it later could be really pain. I compared it to the one used
for em28xx driver and it was different. Could someone with better
knowledge check that?
Generally it is good and ready for submission.
Acked-by: Antti Palosaari <crope@iki.fi>
regards
Antti
@@ -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);
+
+ ret = 0;
+free:
+ kfree(eeprom);
+ return ret;
}
static int af9015_download_ir_table(struct dvb_usb_device *d)
@@ -728,6 +749,11 @@ static int af9015_read_config(struct usb_device *udev)
}
if (ret)
goto error;
+
+ ret = af9015_eeprom_hash(udev);
+ if (ret)
+ goto error;
+
deb_info("%s: IR mode:%d\n", __func__, val);
for (i = 0; i < af9015_properties_count; i++) {
if (val == AF9015_IR_MODE_DISABLED) {
@@ -1125,11 +1151,6 @@ static int af9015_af9013_frontend_attach(struct dvb_usb_adapter *adap)
deb_info("%s: init I2C\n", __func__);
ret = af9015_i2c_init(adap->dev);
-
- /* dump eeprom (debug) */
- ret = af9015_eeprom_dump(adap->dev);
- if (ret)
- return ret;
} else {
/* select I2C adapter */
i2c_adap = &state->i2c_adap;
@@ -107,6 +107,7 @@ struct af9015_config {
u16 mt2060_if1[2];
u16 firmware_size;
u16 firmware_checksum;
+ u32 eeprom_sum;
u8 *ir_table;
u16 ir_table_size;
};