linux-kernel - Re: [PATCH V7 05/11] acpi, pci: Support IO resources when parsing PCI host bridge resources.

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Date:	Tue, 10 May 2016 20:20:32 +0200
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	Tomasz Nowicki <tn@...ihalf.com>
Cc:	Bjorn Helgaas <helgaas@...nel.org>, Arnd Bergmann <arnd@...db.de>,
	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Hanjun Guo <hanjun.guo@...aro.org>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Sinan Kaya <okaya@...eaurora.org>, jchandra@...adcom.com,
	robert.richter@...iumnetworks.com, mw@...ihalf.com,
	Liviu.Dudau@....com, David Daney <ddaney@...iumnetworks.com>,
	wangyijing@...wei.com,
	Suravee Suthikulanit <Suravee.Suthikulpanit@....com>,
	Mark Salter <msalter@...hat.com>,
	Linux PCI <linux-pci@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linaro-acpi@...ts.linaro.org" <linaro-acpi@...ts.linaro.org>,
	Jon Masters <jcm@...hat.com>, andrea.gallo@...aro.org,
	dhdang@....com, jeremy.linton@....com, liudongdong3@...wei.com,
	Christopher Covington <cov@...eaurora.org>
Subject: Re: [PATCH V7 05/11] acpi, pci: Support IO resources when parsing PCI
 host bridge resources.

On Tue, May 10, 2016 at 5:19 PM, Tomasz Nowicki <tn@...ihalf.com> wrote:
> Platforms that have memory mapped IO port (such as ARM64) need special
> handling for PCI I/O resources. For host bridge's resource probing case
> these resources need to be fixed up with pci_register_io_range/pci_remap_iospace etc.
>
> The same I/O resources need to be released after hotplug
> removal so that it can be re-added back by the pci_remap_iospace
> function during insertion. As a consequence we unmap I/O resources
> with pci_unmap_iospace when we release host bridge resources.
>
> Signed-off-by: Jayachandran C <jchandra@...adcom.com>
> Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
> Signed-off-by: Tomasz Nowicki <tn@...ihalf.com>
> ---
>  drivers/acpi/pci_root.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index ae3fe4e..cb3071d 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -719,6 +719,34 @@ next:
>                         resource_list_add_tail(entry, resources);
>         }
>  }
> +static void acpi_pci_root_remap_iospace(struct resource_entry *entry)
> +{
> +#ifdef PCI_IOBASE

Same comment about the #ifdefs as in the other patch.

> +       struct resource *res = entry->res;
> +       resource_size_t cpu_addr = res->start;
> +       resource_size_t pci_addr = cpu_addr - entry->offset;
> +       resource_size_t length = resource_size(res);
> +       unsigned long port;
> +
> +       if (pci_register_io_range(cpu_addr, length))
> +               goto err;
> +
> +       port = pci_address_to_pio(cpu_addr);
> +       if (port == (unsigned long)-1)
> +               goto err;
> +
> +       res->start = port;
> +       res->end = port + length - 1;
> +       entry->offset = port - pci_addr;
> +
> +       if (pci_remap_iospace(res, cpu_addr) < 0)
> +               goto err;

An empty line here?

> +       pr_info("Remapped I/O %pa to %pR\n", &cpu_addr, res);
> +       return;
> +err:
> +       res->flags |= IORESOURCE_DISABLED;
> +#endif
> +}
>
>  int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
>  {
> @@ -740,6 +768,9 @@ int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
>                         "no IO and memory resources present in _CRS\n");
>         else {
>                 resource_list_for_each_entry_safe(entry, tmp, list) {
> +                       if (entry->res->flags & IORESOURCE_IO)
> +                               acpi_pci_root_remap_iospace(entry);
> +
>                         if (entry->res->flags & IORESOURCE_DISABLED)
>                                 resource_list_destroy_entry(entry);
>                         else
> @@ -811,6 +842,8 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
>
>         resource_list_for_each_entry(entry, &bridge->windows) {
>                 res = entry->res;
> +               if (res->flags & IORESOURCE_IO)
> +                       pci_unmap_iospace(res);
>                 if (res->parent &&
>                     (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
>                         release_resource(res);
> --