On Fri, Apr 17, 2009 at 11:21 PM, Eddie Dawydiuk <ed...@embeddedarm.com> wrote:
> Hello,
>
> In the past I've worked with ARM architectures where I could setup virtual /
> physical address mappings so I don't have to ioremap then pass around
> pointers. Does PowerPC have an equivalent abstraction? If not whats the
> recommended approach?
>
> That is, is there a better approach to the following...
>
> volatile static unsigned char *my_reg = NULL;
>
> static inline void read_func() {
>
> if (!my_reg)
> my_reg = (unsigned char *)
> ioremap(REG_PHYS_BASE, REG_SIZE);
> //do something with the reg
> }
>
>
> static inline void write_func() {
>
> if (!my_reg)
> my_reg = (unsigned char *)
> ioremap(REG_PHYS_BASE, REG_SIZE);
> //do something with the reg
> }
>
> --
> Best Regards,
> ________________________________________________________________
> Eddie Dawydiuk, Technologic Systems | voice: (480) 837-5200
> 16525 East Laser Drive | fax: (480) 837-5300
> Fountain Hills, AZ 85268 | web: www.embeddedARM.com
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
In general you set devices up a dts file. You can reach its contents
using openfirmware functions (of_*). In general you use an of_*
function to look up your periperhal in the device tree. Once you have
its node you would able to do e.g. of_iomap (which uses ioremap with
the right offsets behind its back) to map the device. So you don't
hard code physical addresses anymore in the code.
Regards,
Roderick Colenbrander
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
