>> autoconfig_16550a() is doing all kinds of weird checks to detect different >> hardware by writing a lot of register values which are documented as >> reserved in the AR7242 datasheet (there's a leaked version going around >> that can be easily googled...), no idea if any of those are problematic. >> Just setting UPF_FIXED_TYPE as suggested by Peter would avoid that code >> altogether. > > That's just a debugging patch and not appropriate for permanent use, > the reason being that this uart is _not_ 16550 compatible (or even 16450 > compatible). > > The three options for 8250 driver support for this part are: > 1. Similar to the debugging patch, set UPF_FIXED_TYPE but set port type > to PORT_8250 instead. This will lose FIFO support so 115K won't be > possible and likely neither will 38400. > > 2. Set UPF_FIXED_TYPE but define a new PORT_* value and add support for > this PORT_* value to uart_config array, uapi headers, and anywhere > the scratch register is used. > > 3. As with 2. above but don't set UPF_FIXED_TYPE and add a probe function > that detects ports of this type to autoconfig(). I don't recommend this > method. > > This requirement is independent of fixing prom_putchar_ar71xx(). > I can send patches for all of this, and I think that 2. would be the nicest solution. I've noticed though that include/uapi/linux/serial_core.h is experiencing a little "overflow": PORT_MAX_8250 has grown just below the first non-8250 entry. Should I just add the new entry at the bottom (and thus grow the uart_config array by ~85 unused entries)? What about PORT_MAX_8250 (used at least in drivers/tty/serial/8250/8250_of.c)? Regards, Matthias
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