On 09/01/2010 02:10 PM, Marc Kleine-Budde wrote:
> Wolfgang Grandegger wrote:
>>> static u16 spear1310_can_read_reg(const struct bosch_ccan_priv *priv,
>>> enum ccan_regs reg)
>>> {
>>> u16 val;
>>>
>>> /* 16 bit registers are aligned at 16-bit boundary */
>>> val = readw(priv->reg_base + reg);
>>> return val;
>>> }
>>>
>>> static void spear1310_can_write_reg(const struct bosch_ccan_priv *priv,
>>> enum ccan_regs reg, u16 val)
>>> {
>>> /* 16 bit registers are aligned at 16-bit boundary */
>>> writew(val, priv->reg_base + reg);
>>> }
>>>
>>> The one for SPEAr320 will look like:
>>> static u16 spear320_can_read_reg(const struct bosch_ccan_priv *priv,
>>> enum ccan_regs reg)
>>> {
>>> u16 val;
>>>
>>> /* shifting 1 place because 16 bit registers are word aligned */
>>> val = readw(priv->reg_base + (reg << 1));
>>> return val;
>>> }
>>>
>>> static void spear320_can_write_reg(const struct bosch_ccan_priv *priv,
>>> enum ccan_regs reg, u16 val)
>>> {
>>> /* shifting 1 place because 16 bit registers are word aligned */
>>> writew(val, priv->reg_base + (reg << 1));
>>> }
>>
>> These functions are still pretty generic and could be handled by a
>> generic platform C_CAN driver via platform data field "reg_shift".
>
> the sja1000 uses IORESOURCE_MEM_xxBIT for this. See [1].
>
> cheers, Marc
>
> [1]
> http://lxr.linux.no/linux+v2.6.35/drivers/net/can/sja1000/sja1000_platform.c#L119
Well, yes and no. I think for the SPEAr *word* accesses are required on
a 2 and 4 byte boundary? Bhupesh? We could use IORESOURCE_MEM_16BIT and
IORESOURCE_MEM_32BIT for these access types. But that might need to be
extended. In the C_CAN manual there is written:
"Up to now the C_CAN module is delivered with three different
interfaces. An 8-bit interface for the Motorola HC08 controller and
two 16-bit interfaces to the AMBA APB bus from ARM. They can easily
be replaced by a user-defined module interface."
Wolfgang.
_______________________________________________
Socketcan-core mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/socketcan-core
