[alsa-devel] Old firmware version for Dice II ASIC

[Clemens Ladisch]

Takashi Sakamoto wrote:
> On Apr 19 2018 17:54, Clemens Ladisch wrote:
>> Takashi Sakamoto wrote:
>>> 183 /* Some old firmware versions do not have the following global registers: */
>>> ...
>>> 188 #define GLOBAL_CLOCK_CAPABILITIES       0x064
>>>
>>> But this is not proper in my case because the maximum offset on global
>>> sub-address space is 0x05c in quadlet unit.
>>
>> IIRC that comment was based on the documentation.  Apparently, there was
>> a misunderstanding of "size 0x60" vs. "up to the register at 0x60".
>
> From my curiosity, do you know which version of DICE firstly supports GLOBAL_VERSION register? Can you read it on the documentation?

I misremembered: I did not find anything about this in the documentation.

This is derived from TCAT's host driver, which unconditionally reads everything
up to the clock capabilities register, and checks for a size larger than 0x64
to detect if the firmware supports clock capabilities.

>> The version register is checked only once (in get_subaddrs()) and does not
>> actually affect the behaviour of the driver, so it would not hurt to simply
>> omit that check on the old firmware.
>
> Hm. The check is applied to the other spaces such as rx/tx, so I'd like to
> leave it as is.

Sorry, "that check" meant the version check for 0x01000000.  Your patch
already implements what I suggested.

> With this patch[1], ALSA dice driver can handle the unit. In this weekend, I'll post it. Your reviewing is very helpful.
>
> [1] https://github.com/takaswie/snd-firewire-improve/commit/1889e06b9593e16da2812010ffd5a8e4b9bc777d

> +	/* Old firmware doesn't support these fields. */
> +	if (dice->clock_caps == 0) {
> +		dice->sync_offset = be32_to_cpu(pointers[6]) * 4;
> +		dice->rsrv_offset = be32_to_cpu(pointers[8]) * 4;
> +	}

Shouldn't this be clock_caps!=0?


Regards,
Clemens