Hello linuxppc-embedded, I have xilinx ml310 based development system. It using ml310 reference PCI design and MontaVista linux. Everything work OK I ever tried to work with several PCI cards and everything worked fine (memory and interrupts), but when I tried to write driver for my PCI board I faced strange (for me) problem. Reading and writing in I/O ports of PCI controller causes kernel oopsing with message kernel access of bad area error:
ops: kernel access of bad area, sig: 11 NIP: C9023980 XER: 00000000 LR: C9023950 SP: C7AE3EE0 REGS: c7ae3e30 TRAP: 0800 Not tainted MSR: 00009030 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 11 DEAR: F7FC3D84, ESR: 00800000 TASK = c7ae2000[119] 'io_test3' Last syscall: 54 last math 00000000 last altivec 00000000 GPR00: F7FC3D84 C7AE3EE0 C7AE2000 00000101 C90247EC 00000008 C7AE3EEC 00000000 GPR08: 00000000 F7FB4000 00000555 C0280000 22000222 10019190 00000000 00000000 GPR16: 00000000 00000000 00000000 00000000 00009032 07AE3F40 00000000 C00048B4 GPR24: C0004620 0FFED7E8 C7AE3EE8 00000004 0000FD84 0000FD80 00000000 7FFFFD08 Call backtrace: C9023704 C004FC8C C000467C 00000000 10000894 10000700 0FEB6D84 00000000 I examined sources of ethernet card that is working on this platform (intel e100), but as I understand sources, this card is not working with I/O (it stores value from BAR1 and never use it). Kernel documenatation saids that PowerPC doesn't have special instructions for accessing I/O (like Intel CPUs) and all devices are memory mapped. So maybe I should call ioremap(); As I understand from different sources in internet, there is no need calling ioremap() (but when I calling it kernel is not crashing, but device still doesn doing what it should do) Does reading and writing to I/O, using in*() and out*() should be sufficient? I realy in doubt. Does PowerPC can work with IO regions? If it can, should I call ioremap() beforehand? If I shouldn't why kernel oopsing? However, if I should why reading from I/O register is not working (I'm sure that PCI board is fine because everything is working in Windows)? -- Best regards, Michael mailto:platov at setdsp.ru
