Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> writes:
> Eric W. Biederman wrote:
>> In general a BIOS may goof or we may hotplug in a hotplug controller.
>> In either case the kernel needs to reserve resources for plugging
>> in more devices in the future instead of creating a minimal resource
>> assignment.
>>
>
> I think we would need the same mechanism also for PCI bus number
> assignment so that we can hot-plug devices containing bridges on
> the leaf hot-plug slots.
Yep that would be handy. I haven't had that case come up as a problem
yet.
> (snip.)
>
>> /**
>> * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
>> * @bus: pointer to PCI bus structure to search
>> @@ -2672,6 +2678,10 @@ static int __init pci_setup(char *str)
>> strlen(str + 19));
>> } else if (!strncmp(str, "ecrc=", 5)) {
>> pcie_ecrc_get_policy(str + 5);
>> + } else if (!strncmp(str, "hpiosize=", 9)) {
>> + pci_hotplug_io_size = memparse(str + 9, &str);
>> + } else if (!strncmp(str, "hpmemsize=", 10)) {
>> + pci_hotplug_mem_size = memparse(str + 10, &str);
>> } else {
>> printk(KERN_ERR "PCI: Unknown option `%s'\n",
>> str);
>
> I think it would be better if we can specify the size per hotplug
> controller driver or per slot or etc.
This happens too early to do anything per driver as this all happens
before the hotplug drivers load. A per slot override seems reasonable
but I am starting with the simplest case an override of the default
allocation.
> (snip.)
>
>> +static int is_pci_hotplug_bridge(struct pci_bus *bus)
>> +{
>> + struct pci_dev *bridge = bus->self;
>> + int pos;
>> +
>> + /* Test for a generic pci hotplug bridge */
>> + pos = pci_find_capability(bridge, PCI_CAP_ID_EXP);
>> + if (pos) {
>> + u32 reg32;
>> + u16 reg16;
>> + pci_read_config_word(bridge, pos + PCI_EXP_FLAGS, ®16);
>> + if (reg16 & PCI_EXP_FLAGS_SLOT) {
>> + pci_read_config_dword(bridge,
>> + pos + PCI_EXP_SLTCAP, ®32);
>> + if (reg32 & PCI_EXP_SLTCAP_HPC)
>> + return 1;
>> + }
>> + }
>> + return 0;
>> +}
>> +
>
> I think it would be better if we can move this kind of hot-plug
> controller specific code into each hotplug driver code.
This happens too early to move it into drivers. At best we can do is
add a flag hotplug_bridge :1 to pci_dev and add quirks to set it.
Eric
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
