Subject: Re: [PATCH V6 1/2] PCI/ACPI: Provide acpi_get_rc_resources() for
 ARM64 platform
To: Dongdong Liu <liudongdong3@huawei.com>, helgaas@kernel.org,
        arnd@arndb.de, rafael@kernel.org, Lorenzo.Pieralisi@arm.com,
        wangzhou1@hisilicon.com, pratyush.anand@gmail.com
References: <1479816529-97410-1-git-send-email-liudongdong3@huawei.com>
 <1479816529-97410-2-git-send-email-liudongdong3@huawei.com>
Cc: linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, jcm@redhat.com,
        gabriele.paoloni@huawei.com, charles.chenxin@huawei.com,
        hanjun.guo@linaro.org, linuxarm@huawei.com
From: Tomasz Nowicki <tn@semihalf.com>
Message-ID: <56c1d551-a18d-8ee0-eb3c-b2b7d5341161@semihalf.com>
Date: Tue, 22 Nov 2016 13:32:12 +0100
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Hi Dongdong,

On 22.11.2016 13:08, Dongdong Liu wrote:
> The acpi_get_rc_resources() is used to get the RC register address that can
> not be described in MCFG. It takes the _HID&segment to look for and returns
> the RC address resource. Use PNP0C02 devices to describe such RC address
> resource. Use _UID to match segment to tell which root bus the PNP0C02
> resource belong to.
>
> Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
> ---
>  drivers/pci/pci-acpi.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/pci/pci.h      |  4 +++
>  2 files changed, 73 insertions(+)
>
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index d966d47..76fd6f4 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -29,6 +29,75 @@
>  	0x91, 0x17, 0xea, 0x4d, 0x19, 0xc3, 0x43, 0x4d
>  };
>
> +#ifdef CONFIG_ARM64
> +static struct resource *acpi_get_rc_addr(struct acpi_device *adev)
> +{
> +	struct resource_entry *entry;
> +	struct list_head list;
> +	unsigned long flags;
> +	int ret;
> +	struct resource *res;
> +
> +	INIT_LIST_HEAD(&list);
> +	flags = IORESOURCE_MEM;
> +	ret = acpi_dev_get_resources(adev, &list,
> +				     acpi_dev_filter_resource_type_cb,
> +				     (void *) flags);
> +	if (ret <= 0)
> +		return NULL;
> +
> +	entry = list_first_entry(&list, struct resource_entry, node);
> +	res = entry->res;

You return "res" memory pointer and...

> +	acpi_dev_free_resource_list(&list);

free it here.

> +	return res;
> +}


We either allocate memory for res here or get it from the caller.

Tomasz