On Tue, 26 Feb 2008 09:10:06 -0500 "Steven A. Falco" <[EMAIL PROTECTED]> wrote:
> When I saw Josh's question, I thought the irq save/restore was there to > make the read-modify-write atomic; i.e. read SDR0_MFR, "AND" out some > bits, then write it back without the possibility of anything else > touching SDR0_MFR. I'm just starting to get familiar with the kernel, That was probably the intention, yes. > so if you have a chance, please help educate me. Does the irq lock in > mtdcri protect the read-modify-write? Or maybe this R-M-W doesn't need > protecting? Nope, it doesn't. It is possible for something to come in between the first call to mtdcri and the second call to mtdcri and modify the value. The window would be quite small, but I suppose it's theoretically possible. Seems the code will do the right thing since everything is using flags. I suppose my question can be withdrawn. It is slightly confusing to do it that way though. Perhaps a function to do read-modify-writes on DCRs would be welcome. dcr_modify anyone? josh _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
