On Jul 20, 2012, at 2:17 AM, Joakim Tjernlund wrote:

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Hi Guys
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I see that you have been hacking Freescale PCI before so I send this =

to you(and the list)

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We are using PCIe(as RC) on P2010(basically a mpc85xx) and have PCI =

device that

started from user space (needs advance clock conf) so when linux boots =

there is

no device at all.
Trying to "hotplug" the device after it is enabled fails, no amount of =

recan/remove using

either fake or real hotplug makes a difference.
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I found the cause eventually but I can't fix it properly as I known =

almost nothing about PCI.

Cause:
indirect_pci.c:indirect_read_config() tests for if =

(hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK)

and returns  PCIBIOS_DEVICE_NOT_FOUND
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PPC_INDIRECT_TYPE_NO_PCIE_LINK get set by fsl_pci.c (look for =

fsl_pcie_check_link) but is never cleared.

Clearing it as appropriate makes a small difference. If you
remove the RC and do a few of rescan's then the device appears.
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Hacking some more, like so:
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int fsl_pcie_check_link(struct pci_controller *hose)
{
	u32 val;
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	early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
	hose->indirect_type |=3D PPC_INDIRECT_TYPE_NO_PCIE_LINK;
	if (val < PCIE_LTSSM_L0)
		return 1;
	hose->indirect_type &=3D ~PPC_INDIRECT_TYPE_NO_PCIE_LINK;
	return 0;
}
and then using it carefully(it is easy to make linux hang) in =

indirect_read_config():

indirect_read_config(struct pci_bus *bus, unsigned int devfn, int =

offset,

		     int len, u32 *val)
{
	struct pci_controller *hose =3D pci_bus_to_host(bus);
	volatile void __iomem *cfg_data;
	u8 cfg_type =3D 0;
	u32 bus_no, reg;
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	if (hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK) {
		if (bus->number !=3D hose->first_busno ||
		    devfn !=3D 0) {
			fsl_pcie_check_link(hose);
			return PCIBIOS_DEVICE_NOT_FOUND;
		}
	}
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Now it works, just one rescan and the device appears!
This is a hack, I don't known what other trouble it can cause, I hope =

you can

sort this out.

How are you forcing the re-scan?  We can see if we can add a re-check of =
the link state in that flow somewhere.

Can you do a dump_stack() or something to get a call chain?

- k=