In message 20041228013654.47236.qmail@web15602.mail.cnb.yahoo.com you wrote:
The Linux drivers must not make any assumptions about any initialization done or not done by any boot loader. Fix your Linux driver.
But one exception for serial console driver. I found there wasn't enable control of UART receiver in 8xx kerenl serial console driver uart.c. Maybe this driver make a assumption that boot loader does this job? At
It should not. But there are bugs and bugs and ...
Also, sometimes we could initialize some status in U-Boot for ready and then change it in kerenl to finish some special work. I once made the LCD backlight in boot process of my target like PC did to aviod seeing the LCD screen flickering. First enable and then shut down in u-boot, open it later in LCD kernel driver:-)
Of course there are many situations where an (intentional) deviation from these rules may be necessary - loading a splash screen in U-Boot and passing a pre-initialized framebuffer to Linux is one of these areas.
IMHO, if one person did u-boot and kernel port both, he would have the chance to consider the harmony between U-Boot and Kernel. So some initialization like receiver enable in kernel driver could be omitted. Is this an informal idea?
Actually it is a bad idea if the kernel makes assumptions about which boot loader is used, or which initializations the boot loader performes. Yes, we all like U-Boot more than every other boot oader, but why knows what sort of boot loader the next guy booting your kernel wants or has to use? Don't make life more difficult for him than absolutely necessary.
Best regards,
Wolfgang Denk