From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3BE2C3CB.DB73EF49@aps.anl.gov> Date: Fri, 02 Nov 2001 10:03:23 -0600 From: Andrew Johnson MIME-Version: 1.0 To: linuxppc-embedded@lists.linuxppc.org Subject: Re: EPIC Vs OpenPIC Vs MontaVista References: <20011102134754.29665.qmail@mailweb16.rediffmail.com> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Sarnath Kannan wrote: > > The reason for assigning vector of 16 to PCI > interrupts is because each entry in the "Interrupt Source" is 32 bytes long, 16 * 32 = 512 = 0x200 > which equals the difference in offsets between > the std openPIC layout and EPIC register layout. > This 16 has got NOTHING TO DO with NUM_8259_INTERRUPTS. > But Mvista code seems to assume that this feature > is because of NUM_8259_INTERRUPTS. ( See the > #define for SANDPOINT_SIO_IRQ ). ... unless the register layout for the EPIC was designed to allow an external i8259 to be inserted into the gap, which ISTR is done on some boards. I don't know for sure and I might be completely confused about that, but there must have been some reason why the EPIC was designed like that. Just throwing that idea into the pot... - Andrew -- Perfection is reached, not when there is no longer anything to add, but when there is no longer anything to take away. - Antoine de Saint-Exupery ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/