dcsimg
Linux Today: Linux News On Internet Time.





iBook boots Linux

Oct 24, 1999, 18:46 (31 Talkback[s])
(Other stories by Benjamin)

[ Benjamin writes: ]

"I've posted a first set of patches with a binary kernel at: http://calvaweb.calvacom.fr/bh40/test.html

This one still contains obvious hacks and my iBook's PMU is shutting down the machine on me way too often, but I managed to boot and use the LinuxPPC Q3 installer with it.

- There are big problems with the PMU. It seems to work with the same basic protocol, but: I get occasional "ack still high" errors, I never get the CB1 interrupt, and it began shutting the machine down on me randomly when probing IDE or USB at boot since this evening. (It worked with no changes from this morning to this evening though). I plan to look into this later tonight.

Basically, I hacked to attach the ADB autopoll to the reception of the 0x40 bit in IFR in addition to the never coming CB1. This bit is theorically a timer, and is asserted approximately every 10ms to my testings. This one is probably the cause for the crash. I[m wondering if the new PMU would be timing sensitive enough to break when interrupts are disabled for too long while the PMU was inside a transaction. If this is the case, we might have to revert to an old-style driver doing the PMU request synchronously...

I've also disabled most of the keyboard/mouse probing stuff which seemed to cause more trouble, the ADB trackpad emulation in the new PMU doesn't like the probing code at all.

It's possible that the ADB interrupt (CB1) no longer exist on this new PMU (which would be stupid) but it's also possible that it either requires a specific command to be enabled (it could be disabled during the BootX shutdown process) or that it goes to one of the new GPIO interrupts.

- The interrupt routing and OpenPIC initialisation requires booting from BootX with the PIC already initialized by MacOS. I'll fix that later, this requires correct handling of the OF interrupt tree and cannot be done when booting with BootX due to lack of phandle in the device tree (MacOS doesn't keep them). That's the reason why I use the new APPL.interrupt-vectors when available (they are created by MacOS). The PIC is an IBM MPIC (it answers with the openpic 8 bits vendorID/deviceID defined for the IBM MPIC2) but apparently either lacks the timer, or the time is not correctly initialized (base set to 0x80000000).

- The FCR management is not done yet (three FCR registers plus still-to-be understood gpio registers).

- PCI config space management is weird but Apple's bridge is weird too. I really need to get rid of this hard-coded 0xf2000000 in the init code, and we should use RTAS when OF-booting.

- The IDE works, but I suggest you use noautotune for the HD. Apparently, they have a new controller (Ultra/ATA ?) which doesn't like the way we do DBDMA (it works but gives you a few errors first, then resets the disk, and goes). The CD worked fine until it began giving me all sort of errors, but it might be my distro CD beeing dirty.

- Ethernet is not done at all yet. There are plenty of OF methods to be decrypted here, it looks like an ordinary tulip-like or pcnet-like ring buffer based controller, se we mostly need to figure out the ring entry format, the OWN bit (and error bits) and enough registers to configure the ring, start it, and kick it.

- I've not tried the serial ports (which are detected) yet, but I beleive the lack of FCR management will prevent the modem from working.

- Sound is not done yet (we need to figure out what I2S is and how it works).

- Video works only with offb, I've not looked in details however.

That's all for now,

Benjamin."