Re: Dual SJA1000 can controllers on SMP system.

[Mirza Krak <mirza.krak@hostmobility.com>]

On 06/16/2013 02:39 PM, Wolfgang Grandegger wrote:
> On 06/16/2013 01:20 PM, mirza@hostmobility.com wrote:
>>
>>
>> -------- Ursprungligt meddelande --------
>>> Från: Wolfgang Grandegger <wg@grandegger.com>
>>> Skickat: den 16 juni 2013 11:19
>>> Till: Mirza Krak <mirza.krak@hostmobility.com>
>>> Ämne: Re: Dual SJA1000 can controllers on SMP system.
>>>
>>> On 06/13/2013 02:47 PM, Mirza Krak wrote:
>>>> Dear Sirs.
>>>>
>>>> I am running a 3.1.10 kernel on Nvidia Tegra 2 CPU (Dual Core). Not
>>>> vanilla kernel (Linux4Tegra).
>>>>
>>>> We are using dual can controllers connected on th external data bus on
>>>> our custom hardware. The can controllers are SJA1000.
>>>
>>> What external data bus is the CAN controller connected to?
>>> And which CAN controller board/card?
>>
>> As I mentioned the CAN controllers are SJA1000 and the SJA1000 chip is integrated in our board. No external card/board for SJA1000 chip.
>>
>> It is connected to the Nvidia Tegra 2 externa data bus (a.k.a SNOR).
>>
>>>> Driver that is used is vanilla sja1000 driver (sja1000.c)
>>>
>>> Which bus driver is used and how do you load the module?
>>
>> The bus driver is tegra_snor and is linked in statically in the kernel.
>
> The low-level device initialization and access is not done in sja1000.c
> but by another driver module, e.g., sja1000_isa, sja1000_platform,
> ems_pci.c. What module are you using? What functions are you using to
> access the SNOR bus?

Aah off course. The low-level device driver is sja1000_platform.c. The 
functions I am using are sp_read_reg8 and sp_write_reg8 which I have 
slightly modified. Since I don't use multiplexed bus functionality I 
write the address first.

   static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
{
	iowrite8(reg, priv->reg_base);
	return ioread8(priv->reg_base + 0x20);
}

static void sp_write_reg8(const struct sja1000_priv *priv, int reg, u8 val)
{
	iowrite8(reg, priv->reg_base);
	iowrite8(val, (priv->reg_base + 0x20));
}

>
> Wolfgang.
>
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