[coreboot] Porting to Asus M4A785-M

[Juhana Helovuo]

On Thu, 2010-06-17 at 07:31 -0600, Myles Watson wrote:
> > Yes, here it is attached. It is copied and modified from AMD Tilapia
> > mainboard, because that seemed to be a close relative.
> Thanks.
> 
> > Meanwhile, I added call to it8712f_kill_watchdog() , like Rudolf Marek
> > suggested. That changed the behavior so that the machine no longer
> > reboots in the middle of iterating through PCI busses and devices, but
> > instead it seems to go on iterating infinitely, or presumably until
> > malloc runs out of memory.
> OK

Hello again,

Infinitely looping PCI scan in pci_device.c was resolved:

I added the following lines to the beginning of pci_scan_bus:

	// Maximum sane devfn is 0xFF
	if (max_devfn > 0xff) {
	  printk(BIOS_DEBUG, "PCI: pci_scan_bus upper limit too big. Using 0xff.\n");
	  max_devfn=0xff;
	}

And then the relevant part of the log is:

PCI: pci_scan_bus for bus 00
PCI: pci_scan_bus limits devfn 0 - devfn ffffffff
PCI: pci_scan_bus upper limit too big. Using 0xff.
POST: 0x24

It seems that the scan loop was not infinite after all, but just tried
to enumerate devices from 0 to 0xffffffff, which seemed like inifinity.
I could not find out who calls pci_scan_bus, nor where does the too
large upper limit come from.


Now the boot process goes through bus probing and starts enabling
devices. This goes on until it is time to enable to LPC controller,
which I suppose is the bridge to the IT8712F Super I/O -chip. At that
point the boot process freezes, or at least there is no more serial
output. I added some debug printouts as follows:

[src/southbridge/amd/sb700/sb700_lpc.c]

static void lpc_init(device_t dev)
{
	u8 byte;
	u32 dword;
	device_t sm_dev;

	printk(BIOS_DEBUG, "sb700 entering lpc_init\n");
	/* Enable the LPC Controller */
	sm_dev = dev_find_slot(0, PCI_DEVFN(0x14, 0));
	dword = pci_read_config32(sm_dev, 0x64);
	dword |= 1 << 20;
	pci_write_config32(sm_dev, 0x64, dword);

	/* Initialize isa dma */
	printk(BIOS_DEBUG, "sb700 initializing isa dma\n");
	isa_dma_init();
	printk(BIOS_DEBUG, "sb700 isa dma initialized\n");

	/* Enable DMA transaction on the LPC bus */
	byte = pci_read_config8(dev, 0x40);
	byte |= (1 << 2);
	pci_write_config8(dev, 0x40, byte);
	printk(BIOS_DEBUG, "sb700 DMA enabled on LPC bus\n");

	/* Disable the timeout mechanism on LPC */
	byte = pci_read_config8(dev, 0x48);
	byte &= ~(1 << 7);
	pci_write_config8(dev, 0x48, byte);
	printk(BIOS_DEBUG, "sb700 LPC Timeout disabled\n");

	/* Disable LPC MSI Capability */
	byte = pci_read_config8(dev, 0x78);
	byte &= ~(1 << 1);
	pci_write_config8(dev, 0x78, byte);
	printk(BIOS_DEBUG, "sb700 exiting lpc_init\n");
}

And the resulting end of boot log is:

[...cut...]
PCI: 00:14.1 init
Check CBFS header at fffffd2e
magic is 4f524243
Found CBFS header at fffffd2e
Check fallback/romstage
CBFS: follow chain: fff00000 + 38 + 14769 + align -> fff147c0
Check fallback/coreboot_ram
CBFS: follow chain: fff147c0 + 38 + ddc2 + align -> fff225c0
Check fallback/payload
CBFS: follow chain: fff225c0 + 38 + 22483 + align -> fff44a80
Check 
CBFS: follow chain: fff44a80 + 28 + bb286 + align -> fffffd40
CBFS:  Could not find file pci1002,439c.rom
PCI: 00:14.2 init
base = 0xd4200000
codec_mask = 05
2(th) codec viddid: ffffffff
0(th) codec viddid: ffffffff
PCI: 00:14.3 init
sb700 entering lpc_init
sb700 initializing isa dma
[log ends here]

PCI tree with the factory BIOS is:

# lspci -tvnn
-[0000:00]-+-00.0  Advanced Micro Devices [AMD] RS780 Host Bridge Alternate [1022:9601]
           +-01.0-[0000:01]--+-05.0  ATI Technologies Inc Device [1002:9710]
           |                 \-05.1  ATI Technologies Inc Device [1002:970f]
           +-0a.0-[0000:02]----00.0  Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller [10ec:8168]
           +-11.0  ATI Technologies Inc SB700/SB800 SATA Controller [IDE mode] [1002:4390]
           +-12.0  ATI Technologies Inc SB700/SB800 USB OHCI0 Controller [1002:4397]
           +-12.1  ATI Technologies Inc SB700 USB OHCI1 Controller [1002:4398]
           +-12.2  ATI Technologies Inc SB700/SB800 USB EHCI Controller [1002:4396]
           +-13.0  ATI Technologies Inc SB700/SB800 USB OHCI0 Controller [1002:4397]
           +-13.1  ATI Technologies Inc SB700 USB OHCI1 Controller [1002:4398]
           +-13.2  ATI Technologies Inc SB700/SB800 USB EHCI Controller [1002:4396]
           +-14.0  ATI Technologies Inc SBx00 SMBus Controller [1002:4385]
           +-14.1  ATI Technologies Inc SB700/SB800 IDE Controller [1002:439c]
           +-14.2  ATI Technologies Inc SBx00 Azalia (Intel HDA) [1002:4383]
           +-14.3  ATI Technologies Inc SB700/SB800 LPC host controller [1002:439d]
           +-14.4-[0000:03]--
           +-14.5  ATI Technologies Inc SB700/SB800 USB OHCI2 Controller [1002:4399]
           +-18.0  Advanced Micro Devices [AMD] Family 10h [Opteron, Athlon64, Sempron] HyperTransport Configuration [1022:1200]
           +-18.1  Advanced Micro Devices [AMD] Family 10h [Opteron, Athlon64, Sempron] Address Map [1022:1201]
           +-18.2  Advanced Micro Devices [AMD] Family 10h [Opteron, Athlon64, Sempron] DRAM Controller [1022:1202]
           +-18.3  Advanced Micro Devices [AMD] Family 10h [Opteron, Athlon64, Sempron] Miscellaneous Control [1022:1203]
           \-18.4  Advanced Micro Devices [AMD] Family 10h [Opteron, Athlon64, Sempron] Link Control [1022:1204]


So it seems that something goes wrong inside isa_dma_init(); 

Now I am not sure what I could try next. As the LPC is needed for Super
I/O access, it seems like it cannot be just left out, and configuring
the LPC controller to "off" will also kill the serial port.

Any suggestions?

Best regards,
Juhana Helovuo