The solution is to make the interrupt actually register. They're 137 and 138, if memory serves.
Code is on musenki.com's CVS tree. jim Frederic Soulier writes: > > Hi, > > I'm using kernel linux-2.4.17-mvl21 on a custom board based on a MPC8241. > Everything looks ok until my ramdisk shell is executed : it is *very* > slow. > For my tests I use simple-Ramdisk (available on the Denx ftp site). > > I use the internal UART of the MPC8241 (IRQ 137). It looks to work fine > for U-Boot and for displaying Linux boot messages. > > I've found some threads from this mailing-list about the same problem. > Solutions were about EPIC configuration. > I use only the internal EPIC (no external 8259), my EPIC configuration is > very simple and no external interrupts are generated at this time. > > Here are the modifications that I've applied to my kernel in order to take > care of the internal UART (as described in > http://lists.linuxppc.org/linuxppc-embedded/200202/msg00056.html) > > 1. Leave EUMBAR @ 0xFC000000 > 2. Call io_block_mapping(0xfc000000, 0xfc000000, 0x04000000, _PAGE_IO); in > <platform>_map_io() > 3. Call mpc10x_bridge_init() w/ 0xfc000000 as the last parameter in > <platform>_find_bridge() > > I've alse defined this UART to work with IRQ 137 : > > #define STD_SERIAL_PORT_DFNS \ > { 0, BASE_BAUD, PPC200_SERIAL, 137, STD_COM_FLAGS, \ > iomem_base: (u8 *)PPC200_SERIAL, io_type: SERIAL_IO_MEM } > > w/ PPC200_SERIAL == 0xFC004500 (internal DUART channel #1) > > After that the UART was working for the kernel boot messages before the > shell is executed. > The shell is awfully slow (16 caracters in one time every 30 seconds > approx.). > > I've tried to add the openpic_set_sources() as described in other threads > in order to take care of the IRQ #137 : > > 1. Add openpic_set_sources(0, 138, NULL); in <platform>_init_irq() but in > this case there is no more display from the shell. > > Please note that to do this modification I've had to replace > arch/ppc/kernel/open_pic.c and arch/ppc/kernel/open_pic_defs.h in order to > add the openpic_set_sources() function. > The new open_pic.c and open_pic_defs.h came from linuxppc-2.4.18. > > Any advice will be welcomed, > > Best regards, > > Frederic Soulier > > > > -- ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
