Hi, > Mandeep> 2) where is the PCI I/O & Memory space usually mapped? is it > Mandeep> mapped to a certain portion of the RAM? > > PCI I/O space is usually mapped to IA-32 I/O space > (i.e. in[bwd]/out[bwd] insns). PCI Memory space is mapped to a > physical address. On non IA-32 architectures I/O space is mapped to a > physical address too. And hence we can access the programmed io (PIO) space using "inb", "outb" and associated instructions on IA-32. And when using the memory mapped io we can directly make use of memory (using pointers) after ioremapping the area. > Mandeep> 3) When the PC boots up does my system BIOS configure these > Mandeep> memeory regions i.e is there some place from where my > Mandeep> driver can get an info as to what all memeory regions have > Mandeep> been requested by a NIC? > > *If* the BIOS did this (e.g. when "Boot with PnP OS" is false), these > regions (as well as IRQs) can be obtained by reading configuration > space header. > If we have to get any information about the memory regions which the NIC is having, then we can use apis such as "pci_resource_start", "pci_resource_end" etc. Practically, when we are writing a driver for the NIC we dont have to worry about whether the bios has configured it or not, the linux pci subsystem will make everything available for us. > Mandeep> 4) When my ethernet driver does a probe can it rely on the > Mandeep> BIOS (under intel arch.) to provide it with some usefull > Mandeep> info? > > Generally not, because BIOS can be instructed not to configure > peripherals. When writing pci network drivers, we can depend of the linux pci subsytem for all most all the information (check out the apis such as pci_resource_start, pci_resource_flags, pci_read_config_byte etc) Hope this helps ! Regards, KK. -- HomePage: http://puggy.symonds.net/~krishnakumar -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
