Re: [PATCH 2/3] can: flexcan.c: Re-write receive path to use MB queue instead of FIFO

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 09/03/2014 09:19 AM, David Jander wrote:
>>>> You make use of the CTRL2 register, which is not present on some older
>>>> (but supported) flexcan IP cores. You increase FLEXCAN_MCR_MAXMB to
>>>> 0x40, which is not supported on older IPs. The register rximr, is also
>>>> not present on older cores. Don't break support for the older CAN cores.
>>>
>>> Oops. Thanks for pointing that out. I will check the reference manual of
>>> the i.MX53 (which should have be the oldest supported version of this IP
>>> core, right?). Of course I do not want to break older CAN cores.
>>> I will check correctness testing the code on an i.MX28 board which I have.
>>
>> Regarding the versions of the IP cores, we should not trust them, as
>> they are not public available..
> 
> Ok. I fear that for this last patch we will need some run-time check for the
> version of the flexcan we have. I suppose the typical table with OF ids and
> flags will do?

Yes, we already track this information in
> struct flexcan_devtype_data {
> 	u32 features;	/* hardware controller features */
> };

There is:
> #define FLEXCAN_HAS_V10_FEATURES	BIT(1) /* For core version >= 10 */

which is probably what you need. Feel free to add another bit, if you
need to.

Marc

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Pengutronix e.K.                  | Marc Kleine-Budde           |
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