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

[Liviu . Dudau]

On Tue, Oct 27, 2015 at 05:38:42PM +0100, Tomasz Nowicki wrote:
> Because of two patch series:
> 1. Jiang Liu's common interface to support PCI host bridge init
> 2. Refactoring of MMCONFIG, part of this patch set
> now we can think about PCI buses enumeration for ARM64 and ACPI tables.
> 
> This patch introduce ACPI based PCI hostbridge init calls which
> use information from MCFG table (PCI config space regions) and
> _CRS (IO/irq resources) to initialize PCI hostbridge.
> 
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> CC: Arnd Bergmann <arnd@xxxxxxxx>
> CC: Catalin Marinas <catalin.marinas@xxxxxxx>
> CC: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> CC: Lorenzo Pieralisi <Lorenzo.Pieralisi@xxxxxxx>
> CC: Will Deacon <will.deacon@xxxxxxx>
> ---
>  arch/arm64/Kconfig      |   6 ++
>  arch/arm64/kernel/pci.c | 208 +++++++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 202 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 07d1811..bbcc6b1 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -89,6 +89,7 @@ config ARM64
>  	select SPARSE_IRQ
>  	select SYSCTL_EXCEPTION_TRACE
>  	select HAVE_CONTEXT_TRACKING
> +	select HAVE_PCI_ECAM
>  	help
>  	  ARM 64-bit (AArch64) Linux support.
>  
> @@ -202,6 +203,11 @@ source "drivers/pci/Kconfig"
>  source "drivers/pci/pcie/Kconfig"
>  source "drivers/pci/hotplug/Kconfig"
>  
> +config PCI_MMCONFIG
> +	def_bool y
> +	select PCI_ECAM
> +	depends on ACPI
> +
>  endmenu
>  
>  menu "Kernel Features"
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index b3d098b..66cc1ae 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -11,12 +11,15 @@
>   */
>  
>  #include <linux/acpi.h>
> +#include <linux/ecam.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
> +#include <linux/of_address.h>
>  #include <linux/of_pci.h>
>  #include <linux/of_platform.h>
> +#include <linux/pci-acpi.h>
>  #include <linux/slab.h>
>  
>  #include <asm/pci-bridge.h>
> @@ -52,35 +55,216 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>  }
>  
>  /*
> - * Try to assign the IRQ number from DT when adding a new device
> + * Try to assign the IRQ number from DT/ACPI when adding a new device
>   */
>  int pcibios_add_device(struct pci_dev *dev)
>  {
> -	dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> +	if (acpi_disabled)
> +		dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> +#ifdef CONFIG_ACPI
> +	else
> +		acpi_pci_irq_enable(dev);
> +#endif
>  
>  	return 0;
>  }
>  
> +#ifdef CONFIG_ACPI
> +int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
> +{
> +	struct acpi_pci_root *root = bridge->bus->sysdata;
> +
> +	ACPI_COMPANION_SET(&bridge->dev, root->device);
> +	return 0;
> +}
> +
> +void pcibios_add_bus(struct pci_bus *bus)
> +{
> +	acpi_pci_add_bus(bus);
> +}
> +
> +void pcibios_remove_bus(struct pci_bus *bus)
> +{
> +	acpi_pci_remove_bus(bus);
> +}
> +
> +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.

> +}
>  /*
> - * 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() ?

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!  /
  ---------------
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