Currently there is a "BROKEN || SPARC" dependency for CONFIG_SERIAL_8250 in drivers/serial/Kconfig. These changes try to eliminate that restriction so that Sparc users can use add-on PCI cards with 8250 serial controllers. The core issue that prevents this from working is that all of the onboard Sun specific serial drivers use the major=TTY_MAJOR, minor=64,65,66,... driver major/minor namespace, just like 8250. They coordinate amongst themselves using an internal allocator for the minor number space. This is contained in drivers/serial/suncore.c This presents two problems: 1) We have to make sure the Sun drivers register first, so that their device indexes don't change and thus people get broken serial consoles and stuff like that. 2) Also, it is necessary for 8250 to partake in this minor number allocation scheme, otherwise it cannot register because it'll try to use '64' as it's base minor number and one of the Sun serial drivers will have taken over that minor already. Working on this and testing it also uncovered another portability bug. The uart_port structure uses an "unsigned int" for the "ioport" member, but even I/O ports in PCI devices are 64-bit on sparc64, so the high bits were being chopped off when 8250 PCI cards were tested. The fix is to use "unsigned long" for this type and that's what the first patch does. The second patch removes the !SPARC dependency for 8250 and adds the hooks to use the Sun serial minor number allocator when registering serial8250_reg with the UART layer. Yes, I know, this part is a bit ugly but I can't think of any workable alternative. I could change all the major/minor numbers all the Sun serial drivers use, to get out of the way of 8250's space. But that will break every single Sparc system out there, all the serial device names will change as will the serial console device. I did write a patch which does such a set of changes, but I can't see any way in which we can consider it seriously. If there are no objections I'd like to toss this into my sparc-next-2.6 tree for 2.6.28 inclusion. Is that OK with everyone? I'd like to thank Josip Rodin for bringing this to my attention, and testing various revisions of these patches. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
