Re: [PATCH V1 11/11] arm64, pci, acpi: Support for ACPI based PCI hostbridge init

From: Liviu . Dudau
Date: Tue Nov 03 2015 - 11:28:26 EST

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In reply to: Lorenzo Pieralisi: "Re: [PATCH V1 11/11] arm64, pci, acpi: Support for ACPI based PCI hostbridge init"
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On Tue, Nov 03, 2015 at 02:32:14PM +0000, Lorenzo Pieralisi wrote:
> On Wed, Oct 28, 2015 at 11:49:40AM +0000, Liviu.Dudau@xxxxxxx wrote:
> > On Tue, Oct 27, 2015 at 05:38:42PM +0100, Tomasz Nowicki wrote:
>
> [...]
>
> > > +static int __init pcibios_assign_resources(void)
> > > +{
> > > + if (acpi_disabled)
> > > + return 0;
> > > +
> > > + pci_assign_unassigned_resources();
> > > + return 0;
> >
> > You can change this function into:
> > {
> > if (!acpi_disabled)
> > pci_assign_unassigned_resources();
> >
> > return 0;
> > }
> >
> > as the equivalent but shorter form.
>
> I do not think it is a matter of code style here, it is a matter
> of understanding when and if we want to reassign resources on ACPI
> systems, it is an open question on ARM64 that must be sorted out (ie we
> ignore FW/BARs set-up entirely).

I was reviewing the code here, not doing any technical guidance, I'm
leaving that to you as you are more involved around ACPI.

>
> > > +}
> > > /*
> > > - * raw_pci_read/write - Platform-specific PCI config space access.
> > > + * rootfs_initcall comes after subsys_initcall and fs_initcall_sync,
> > > + * so we know acpi scan and PCI_FIXUP_FINAL quirks have both run.
> > > */
> > > -int raw_pci_read(unsigned int domain, unsigned int bus,
> > > - unsigned int devfn, int reg, int len, u32 *val)
> >
> > What happened with raw_pci_{read,write} ? Why do you remove them?
> >
> >
> > > +rootfs_initcall(pcibios_assign_resources);
> >
> > Would you be so kind and explain to me why you need this initcall?
> > Can you not set the PCI_REASSIGN_ALL_RSRC flag before calling
> > pci_scan_root_bus() ?
>
> On what basis ? BTW, PCI core code does not assign unassigned resources
> anyway even if that flag is set, so some policy has to be defined here.

I was thinking that ACPI code can do that if they seem to depend on the resources
being assigned during root bus scan. I was not implying that PCI core code enforces
that.

Best regards,
Liviu

>
> Thanks,
> Lorenzo
>
> > I haven't focused on ACPI before so I'm a bit hazy on the init order when
> > that is enabled. That being said, I don't like adding in the architecture
> > code initcall hooks just to fix up some dependency orders that could / should
> > be fixed some other way.
> >
> > > +
> > > +static void __iomem *
> > > +pci_mcfg_dev_base(struct pci_bus *bus, unsigned int devfn, int offset)
> > > {
> > > - return -ENXIO;
> > > + struct pci_mmcfg_region *cfg;
> > > +
> > > + cfg = pci_mmconfig_lookup(pci_domain_nr(bus), bus->number);
> > > + if (cfg && cfg->virt)
> > > + return cfg->virt +
> > > + (PCI_MMCFG_BUS_OFFSET(bus->number) | (devfn << 12)) +
> > > + offset;
> > > + return NULL;
> > > }
> > >
> > > -int raw_pci_write(unsigned int domain, unsigned int bus,
> > > - unsigned int devfn, int reg, int len, u32 val)
> > > +struct pci_ops pci_root_ops = {
> > > + .map_bus = pci_mcfg_dev_base,
> > > + .read = pci_generic_config_read,
> > > + .write = pci_generic_config_write,
> > > +};
> > > +
> > > +#ifdef CONFIG_PCI_MMCONFIG
> > > +static int pci_add_mmconfig_region(struct acpi_pci_root_info *ci)
> > > {
> > > - return -ENXIO;
> > > + struct pci_mmcfg_region *cfg;
> > > + struct acpi_pci_root *root;
> > > + int seg, start, end, err;
> > > +
> > > + root = ci->root;
> > > + seg = root->segment;
> > > + start = root->secondary.start;
> > > + end = root->secondary.end;
> > > +
> > > + cfg = pci_mmconfig_lookup(seg, start);
> > > + if (cfg)
> > > + return 0;
> > > +
> > > + cfg = pci_mmconfig_alloc(seg, start, end, root->mcfg_addr);
> > > + if (!cfg)
> > > + return -ENOMEM;
> > > +
> > > + err = pci_mmconfig_inject(cfg);
> > > + return err;
> > > }
> > >
> > > -#ifdef CONFIG_ACPI
> > > +static void pci_remove_mmconfig_region(struct acpi_pci_root_info *ci)
> > > +{
> > > + struct acpi_pci_root *root = ci->root;
> > > + struct pci_mmcfg_region *cfg;
> > > +
> > > + cfg = pci_mmconfig_lookup(root->segment, root->secondary.start);
> > > + if (cfg)
> > > + return;
> > > +
> > > + if (cfg->hot_added)
> > > + pci_mmconfig_delete(root->segment, root->secondary.start,
> > > + root->secondary.end);
> > > +}
> > > +#else
> > > +static int pci_add_mmconfig_region(struct acpi_pci_root_info *ci)
> > > +{
> > > + return 0;
> > > +}
> > > +
> > > +static void pci_remove_mmconfig_region(struct acpi_pci_root_info *ci) { }
> > > +#endif
> > > +
> > > +static int pci_acpi_root_init_info(struct acpi_pci_root_info *ci)
> > > +{
> > > + return pci_add_mmconfig_region(ci);
> > > +}
> > > +
> > > +static void pci_acpi_root_release_info(struct acpi_pci_root_info *ci)
> > > +{
> > > + pci_remove_mmconfig_region(ci);
> > > + kfree(ci);
> > > +}
> > > +
> > > +static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
> > > +{
> > > + struct resource_entry *entry, *tmp;
> > > + int ret;
> > > +
> > > + ret = acpi_pci_probe_root_resources(ci);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
> > > + struct resource *res = entry->res;
> > > +
> > > + /*
> > > + * Special handling for ARM IO range
> >
> > There is nothing ARM specific here. It should apply to any memory mapped IO range.
> >
> > > + * TODO: need to move pci_register_io_range() function out
> > > + * of drivers/of/address.c for both used by DT and ACPI
> > > + */
> > > + if (res->flags & IORESOURCE_IO) {
> > > + unsigned long port;
> > > + int err;
> > > + resource_size_t length = res->end - res->start;
> > > +
> > > + err = pci_register_io_range(res->start, length);
> > > + if (err) {
> > > + resource_list_destroy_entry(entry);
> > > + continue;
> > > + }
> > > +
> > > + port = pci_address_to_pio(res->start);
> > > + if (port == (unsigned long)-1) {
> > > + resource_list_destroy_entry(entry);
> > > + continue;
> > > + }
> > > +
> > > + res->start = port;
> > > + res->end = res->start + length - 1;
> > > +
> > > + if (pci_remap_iospace(res, res->start) < 0)
> > > + resource_list_destroy_entry(entry);
> > > + }
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static struct acpi_pci_root_ops acpi_pci_root_ops = {
> > > + .pci_ops = &pci_root_ops,
> > > + .init_info = pci_acpi_root_init_info,
> > > + .release_info = pci_acpi_root_release_info,
> > > + .prepare_resources = pci_acpi_root_prepare_resources,
> > > +};
> > > +
> > > /* Root bridge scanning */
> > > struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
> > > {
> > > - /* TODO: Should be revisited when implementing PCI on ACPI */
> > > - return NULL;
> > > + int node = acpi_get_node(root->device->handle);
> > > + int domain = root->segment;
> > > + int busnum = root->secondary.start;
> > > + struct acpi_pci_root_info *info;
> > > + struct pci_bus *bus;
> > > +
> > > + if (domain && !pci_domains_supported) {
> > > + pr_warn("PCI %04x:%02x: multiple domains not supported.\n",
> > > + domain, busnum);
> > > + return NULL;
> > > + }
> > > +
> > > + info = kzalloc_node(sizeof(*info), GFP_KERNEL, node);
> > > + if (!info) {
> > > + dev_err(&root->device->dev,
> > > + "pci_bus %04x:%02x: ignored (out of memory)\n",
> > > + domain, busnum);
> > > + return NULL;
> > > + }
> > > +
> > > + bus = acpi_pci_root_create(root, &acpi_pci_root_ops, info, root);
> > > +
> > > + /* After the PCI-E bus has been walked and all devices discovered,
> > > + * configure any settings of the fabric that might be necessary.
> > > + */
> > > + if (bus) {
> > > + struct pci_bus *child;
> > > +
> > > + list_for_each_entry(child, &bus->children, node)
> > > + pcie_bus_configure_settings(child);
> > > + }
> > > +
> > > + return bus;
> > > }
> > > #endif
> > > --
> > > 1.9.1
> > >
> >
> > --
> > ====================
> > | I would like to |
> > | fix the world, |
> > | but they're not |
> > | giving me the |
> > \ source code! /
> > ---------------
> > Â\_(ã)_/Â
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Next message: Sinan Kaya: "Re: [PATCH V2 2/3] dmaselftest: add memcpy selftest support functions"
Previous message: Michael BÃsch: "Re: [PATCH] ssb: mark ssb_bus_register as __maybe_unused"
In reply to: Lorenzo Pieralisi: "Re: [PATCH V1 11/11] arm64, pci, acpi: Support for ACPI based PCI hostbridge init"
Next in thread: Lorenzo Pieralisi: "Re: [PATCH V1 11/11] arm64, pci, acpi: Support for ACPI based PCI hostbridge init"
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