Messages in this thread |  | | | From | Werner Almesberger <> | | Subject | Hitachi SH-3 port ? | | Date | Wed, 7 Oct 1998 00:04:37 +0200 (MET DST) |
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For many years, I've been the happy owner of a HP100LX. Now that machine is beginning to fall apart and I'm tempted to switch to a CE palmtop. If only it runs Linux ... while daydreaming about that possibility, a few questions have crossed my mind (see below).
Earlier this year, there was a discussion on linux-kernel about porting Linux to machines originally designed for Windows CE. Among the platforms discussed then were machines based on the Hitachi SH-3 CPUs (e.g. the HP360LX, which uses the SH7707).
Hitachi themselves claim on various Web pages that Linux runs on the SH-3 [1], but I've been unsuccessful so far in getting any information about the existance of such a project, let alone its status. So this may just be incorrect information that entered their PR system somehow and then was propagated all over the place.
Q1: Am I on the wrong track here and is there already a place where Linux is happily running on a SH-3 ? Or is anybody currently working on a port ?
If the answer is "no", I might be foolish enough to try my luck myself. Fortunately, gcc seems to support the SuperH family [2]. That's a start at least. Also, fortunately, there's very good documentation on the SH7707 [3,4].
Q2: Are there any known serious problems with gcc's/egcs's support for the SH-3 ?
The next step is to boot anything with the potential of controlling the entire hardware on that CE box. That should be pretty straightforward when taking the LOADLIN idea: write a CE program that loads the kernel (or a fragment of it, or a second-stage loader) from PCMCIA, RS-232, etc., enters privileged mode, and then runs it. From there on, that piece of code could determine its physical location from the TLB, then run itself in physical memory (Area P1), and gradually take over the machine.
Assuming I want to do this (e.g. if the answer to Q1 is "no"), I still have one little problem: I don't have any machines running Windows nor do I intend to acquire any in the forseeable future, so the "standard" development tools for CE are unavailable. However, given that the first stage loader has a fairly simple task (much easier than LOADLIN's), I'm fairly sure that I'll be able to find some generous CE programmer who can write such a thing for me.
The next two questions are fairly specific to CE and should be asked in comp.os.ms-windows.ce, but I'll mention them here anyway for completeness:
Q3: Does Windows CE allow any user-provided piece of software (e.g. a driver) to gain privileged mode ? If not, I'd have to burn ROMs, which puts the project slightly beyond my pain threshold ... Q4: Also, is Windows CE (as on the HP360LX) able with on-board means (e.g. after we've wiped clean all the RAM) to access a PCMCIA Flash card or to download files from a Linux PC (e.g. using Kermit, Zmodem, PPP, ...) over RS-232, and to run or install (if it's a driver) them ? This question may sound trivial, but I haven't bought the machine yet, and I don't know any HP360LX owners in the local area either.
Many of the questions I brought up here are fairly off-topic and I'm not very good at keeping up with linux-kernel anyway, so please send replies to me directly. I'll post a summary to the list.
Thanks, - Werner
[1] http://semiconductor.hitachi.com/windowsce/index.cfm?menuselection=faqs [2] http://www.gnu.org/software/gcc/gcc.html#TOCportandopt [3] http://semiconductor.hitachi.com/products/ h_micon/1_sh/3_sh3/H13TH007D2/pdf/h1307.pdf [4] http://semiconductor.hitachi.com/products/ h_micon/1_sh/3_sh3/H13TP001D2/pdf/h1301.pdf
-- _________________________________________________________________________ / Werner Almesberger, DI-ICA,EPFL,CH werner.almesberger@lrc.di.epfl.ch / /_IN_R_131__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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