Hi all,<br>I am working on porting 2.6.24 on IBM SPRUCE board. There is some problem that is not allowing serial console to come up.<br>I am not sure where the problem lies, it may be with 8250 serial driver or cpc700 programmable interrupt controller driver.<br>
CPC700 consists of 16550A type UART.<br>I tried with various versions and succeeded in getting serial console on Linux-2.6.8. <br>My requirement is <a href="http://2.6.24." target="_blank">2.6.24.</a> I tried with various other versions starting from 2.6.16 and all seems to have same problem.<br>
<br>I am trying to mount the root file system on ramdisk. This ramdisk image works with other PowerPC boards. <br>It looks like kernel will execute "init" and hung after reaching first printf, which involves serial port. Here are my Linux boot messages for your reference. I request your suggestion for finding out the problem.<br>
<br>I put some debug messages in 8250.c, serial_core.c and cpc700_pic.c<br><br>## Transferring control to Linux (at address 00000000) ...<br>id mach(): done<br>MMU:enter<br>MMU:hw init<br>hash:enter<br>hash:find piece<br>
hash:patch<br>hash:done<br>MMU:mapin<br>MMU:setio<br>MMU:exit<br>setup_arch: enter<br>setup_arch: bootmem<br>arch: exit<br>Total memory = 128MB; using 256kB for hash table (at c0240000)<br>Linux version <a href="http://2.6.24.7" target="_blank">2.6.24.7</a> (suresh@mannava) (gcc version 4.0.0 (DENX ELDK 4.0 4.0.0)) #20 Sat May 17 15:21:00 IST 2008<br>
System Identification: IBM Spruce<br>Port by MontaVista Software, Inc. (<a href="mailto:source@mvista.com" target="_blank">source@mvista.com</a>)<br>Zone PFN ranges:<br> DMA 0 -> 32768<br> Normal 32768 -> 32768<br>
HighMem 32768 -> 32768<br>Movable zone start PFN for each node<br>early_node_map[1] active PFN ranges<br> 0: 0 -> 32768<br>Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512<br>
Kernel command line: console=ttyS0,57600 root=/dev/ram0 rw<br>PID hash table entries: 512 (order: 9, 2048 bytes)<br> ENTER serial8250_set_termios<br> 8 char<br> baud is 57600<br> quot is 9<br> EXIT serial8250_set_termios<br>
console [ttyS0] enabled<br>Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)<br>Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)<br>Memory: 125852k available (1420k kernel code, 608k data, 104k init, 0k highmem)<br>
Mount-cache hash table entries: 512<br>net_namespace: 64 bytes<br>NET: Registered protocol family 16<br><br>PCI: Probing PCI hardware<br>devfn is 0x20 idsel is 0x4 pin is 0x1<br>returned IRQ is 22<br>devfn is 0x28 idsel is 0x5 pin is 0x1<br>
returned IRQ is 23<br>devfn is 0x30 idsel is 0x6 pin is 0x1<br>returned IRQ is 24<br>devfn is 0x31 idsel is 0x6 pin is 0x1<br>returned IRQ is 24<br>devfn is 0x32 idsel is 0x6 pin is 0x1<br>returned IRQ is 24<br>devfn is 0x38 idsel is 0x7 pin is 0x1<br>
returned IRQ is 25<br>PCI: Cannot allocate resource region 1 of device 0000:00:00.0<br>checking if image is initramfs...it isn't (no cpio magic); looks like an initrd<br>Freeing initrd memory: 1541k freed<br>io scheduler noop registered<br>
io scheduler anticipatory registered<br>io scheduler deadline registered<br>io scheduler cfq registered (default)<br>Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled<br>serial8250: ttyS0 at MMIO 0x0 (irq = 3) is a 16550A<br>
serial8250: ttyS1 at MMIO 0x0 (irq = 4) is a 16550A<br>RAMDISK driver initialized: 16 RAM disks of 16384K size 1024 blocksize<br>RAMDISK: Compressed image found at block 0<br>VFS: Mounted root (ext2 filesystem).<br>Freeing unused kernel memory: 104k init<br>
ENTER uart_open(0) called<br> ENTER uart_startup<br> ENTER serial8250_startup<br> ENTER cpc700_unmask_irq<br> EXIT cpc700_unmask_irq<br> ENTER cpc700_get_IRQ<br> EXIT cpc700_get_IRQ 3<br> ENTER __do_IRQ<br> ENTER cpc700_mask_and_ack_irq<br>
EXIT cpc700_mask_and_ack_irq<br>serial8250_interrupt(3)...end.<br> OUT __do_IRQ<br> EXIT serial8250_startup<br> EXIT uart_startup<br> ENTER serial8250_set_termios<br> 8 char<br> baud is 57600<br> quot is 9<br> EXIT serial8250_set_termios<br>
EXIT uart_open<br>