> -----Original Message----- > From: linux-mips-bounce@xxxxxxxxxxxxxx > [mailto:linux-mips-bounce@xxxxxxxxxxxxxx] On Behalf Of Pete Popov > Sent: Tuesday, November 30, 2004 8:01 PM > To: Gilad Rom > Cc: Maciej W. Rozycki; linux-mips@xxxxxxxxxxxxxx > Subject: Re: CP0 EntryLo > > Maciej W. Rozycki wrote: > > On Tue, 30 Nov 2004, Gilad Rom wrote: > > > > > >>So, what I need to do, if I understand correctly, is to > create a fixed > >>mapping > >>>From a virtual address to a physical address on the tlb, > and use this > >>Virtual address to change the values of EntryLo to 0xD in order to > >>Access the device on the address range I mapped Chip-select 1 to? > >> > >>(Excuse my poor phrasing, I've been googling all day...) > >> > >>Any idea on how I might accomplish that from a driver? > >>I've found a function called add_wired_entry(...), is this > >>What I should be using? > > > > > > ioremap() > > Exactly. You program the CS with a physical address. Make sure that > address does not overlap with anything else. Then you call ioremap > from your driver and you get back a virtual address. You use that > virtual address to access the peripheral. Okay. I've pretty much figured out that part. What I'm puzzled About now is how do change the values of the CP0 EntryLo0/1 Registers, since I've changed the DTY bits to "1" on the MEM_STCFG1 Register (in order to set it to work in "I/O Device" mode) , I need to "change bits 29:26 of CoProcessor 0 to 0xD" (Au1500 Databook quote) since the Databook doesn't specify an offset To these registers, I assume they're not like the other Registers I've been dealing with (Chip Select and GPIO). > > At this stage I would say that probably reading something like the > Linux Kernel book or Linux Device Drivers both by Oreilly will > really help you. Thanks. Already been doing just that all day... ;)
