On Mon, Aug 13, 2001 at 10:56:09AM -0500, Andrew Johnson wrote: > > Dan Malek wrote: > > > > James F Dougherty wrote: > > > > > > A while ago, I posted some questions on getting the OpenPIC driver working > > > correctly for the EPIC (Embedded Programmable Interrupt Controller) > > > internal > > > to the MPC8240. After several attempts on open_pic.*, I gave up, and > > > ported a > > > an existing driver. > > > > Ummm, I'm confused. The existing PowerPC OpenPIC works just fine with > > the 8240/8245/MPC107 EPICs, at least on the Sandpoint. > > Not quite - the Sandpoint has an i8259 as well, and the OpenPic code as > shipped with HHL-2.0 assumes that there is one present (at least you have > to link in the i8259 code, although you can arrange that it is never > called). Not all 8240 systems have an 8259 such as the MVME2100, and I > had to #if out some stuff from OpenPic.c to be able to omit the i8259. > > Then there's the problem of accessing the 8240's interrupts for I2C, 2 DMA > channels and Message Unit, which are highly dis-contiguous with the other > interrupts; these would appear at IRQs 129, 130, 131 and 134 in the > current scheme (needing a rather large and sparse interrupt senses > table). Oh, and the 4 Global timer interrupts would have to appear at > negative IRQ numbers, so it's a good thing Linux doesn't need to use > these. > > I haven't looked at James' code, but the OpenPIC stuff certainly does need > some changes to be truly universal.
There's a hack in the OpenPIC code for HHL 2.0 to allow for some of the above situations. The hack was rejected in the public tree in favor of a not yet implemented clean way to handle this stuff. If somebody has time to abstract the OpenPIC code for EPIC correctly, it will get in the tree. -- Matt Porter MontaVista Software, Inc. mporter at mvista.com ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
