From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 5 Mar 2002 23:02:55 -0800 (PST) From: Paul White To: linuxppc-dev@lists.linuxppc.org Subject: MPC7455 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Hello! I've read through the archives of the linuxppc-dev and linuxppc-embedded mailing lists, and didn't see very much information regarding Linux on the Motorolai MPC 7455. I've checked the latest base kernel from kernel.org, 2.4.18, and there is no 7455 support. I've already done the code to bring Linux up on the 7455, adding it to arch/ppc/kernel/cputable.c, as well as writing a new setup_cpu_7455, and a new setup_7455_regs function which sets up the HID0, HID1, and MSSCR0 registers. I am wondering if anyone is interested in these changes. In one of the e-mails in the archives, it was suggested to have Linux configure the 7455 just the same as the 7450, however this will not work properly. HID0 has changed quite a bit, as well as HID1, thus requiring a new setup routine. It looks as though the 7451 and 7455 are very similar, and the same init code and restrictions apply, however between the 7450 and 7451, things have changed quite a bit. If there is no support out there as of yet, I can create a patch file and send it off, if anyone is interested. One thing we ran into regarding the MPC7455, however, is that it does not guarentee Stores before Loads, meaning if you have code that has: Load Instruction Load Instruction - This is OK, they will happen in order as long as its Guarded Store Instruction Store Instruction - This is OK, they will happen in order as long as its Guarded Load Instruction Store Instruction - This is OK, they will happen in order as long as its Guarded Store Instruction Load Instruction - This is not guarenteed in order, even if its Guarded We had to add an eieio to all of our drivers, such as our PCI driver, which requires a write to one register before reading another. The eieio must go between the store and the load. Just a heads up, if no one has tried the 7455 yet! Let me know if anyone is interested in the 7455 changes I've done. Paul White Senior Engineer, Software Bivio Networks, Inc. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/