On Thursday 28 September 2006 11:45 AM, Stefan wrote:
What you really need, is an U-Boot command to set/get SDR
registers,
indirectly accessed via the DCR 0x0e/0x0f registers. Something like "setsdr/getsdr".
[Leonid] I thought rather of some generic function, allowing
indirect
access to DCR-related registers....
Something like that I guess:
getidcr e f 0x40 setidcr e f 40 0xbadd
where "i" in the middle stays for "indirect". What do you think?
Good idea. Much more flexible this way. I'm just thinking, if we
really
need this 2nd argument for the "DCR data register", since all "DCR
data
registers" I found upon a quick look into on of the AMCC manuals, are located at "DCR address register + 1". This way we would save one parameter, but would loose some flexibility. Best would be, if you
made
the 2nd paramter optional:
getidcr e [f] 0x40 setidcr e [f] 40 0xbadd
This way, you could decide upon the parameter count (argc), if the
"DCR
data register" is supplied or not. What do you think?
I think it would be better to provide both address and data DCR register numbers (DCRNs) in the first parameter, separated by "." or ":", like this:
getidcr e.f 40
or simple (omitted data DCRN will be 0xE+1=0xF as you have suggested):
getidcr e 40
This is more "u-bootish" style I deem (it's used in cp command for example). This way offset will always be the second parameter which is more convenient.
Help line will look like this:
=> help getidcr getidcr addr_dcrn[.data_dcrn] offset - return a value of register, addressed indirectly via DCR. data_dcrn is assumed to be addr_dcrn+1 if not specified.
Now regarding implementation.
Yes, you should definitely disable the interrupts in this function.
What is simplest way of doing that for PPC440? I mean, should I insert asm into C code, or u-boot already has something better to use?
Can you refer me to proper link how I do proceed with patch
submission:
review, help information, actual sources delivering, etc...
This is explained at the end of the README under "Submitting
Patches:".
And please also take a look at "Coding Standards:".
I'll be preparing the patch; it will be ready next week most likely.
Thanks.
Leonid.