Subject: Re: Any way to get virtual addr from pci_mapreg_map()?
To: Dave Huang <firstname.lastname@example.org>
From: Ignatios Souvatzis <email@example.com>
Date: 08/12/1997 14:05:04
firstname.lastname@example.org (Dave Huang) writes:
> I'm using pci_mapreg_map() to map the chip's RAM, passing it
> PCI_MAPREG_TYPE_MEM | PCI_MAPREG_MEM_TYPE_32BIT for the "expected"
> argument. This gets me a tag and handle that I can use with the
> bus_space_* macros/functions to access the memory. However, the driver
> wants to be able to access the memory as a struct, and do stuff like
> "scriptstruct->member = somevalue". I could use the bus_space_write*
> macros, but that kinda seems like it'd make the code harder to read,
> so I'm wondering if it's possible to get a virtual address out of the
> tag and handle that I can assign to a pointer.
You don't want to do this.
Ok, maybe you do want to do this, but I don't think any NetBSD driver
(especially for machine-independent busses like PCI, ISA or SBUS) should
be written linke this.
Even if it were guaranteed to work by the bus_xxx() stuff, which it isn't and
can't be, it would be non-portable code, working only on a single cpu with
a single compiler.