Re: [PATCH v2 08/17] xen/device-tree: Add dt_get_pci_domain_nr helper

[Rahul Singh <Rahul.Singh@arm.com>]

Hi Stefano,

> On 23 Sep 2021, at 12:50 am, Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> On Wed, 22 Sep 2021, Rahul Singh wrote:
>> Based on tag Linux v5.14.2 commit bbdd3de144fc142f2f4b9834c9241cc4e7f3d3fc
> 
> Please use an upstream commit id
Ack.
> 
> 
>> Import the Linux helper of_get_pci_domain_nr. This function will try to
>> obtain the host bridge domain number by finding a property called
>> "linux,pci-domain" of the given device node.
>> 
>> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
>> ---
>> Change in v2: Patch introduced in v2
>> ---
>> xen/common/device_tree.c      | 12 ++++++++++++
>> xen/include/xen/device_tree.h | 19 +++++++++++++++++++
>> 2 files changed, 31 insertions(+)
>> 
>> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
>> index 53160d61f8..ea93da1725 100644
>> --- a/xen/common/device_tree.c
>> +++ b/xen/common/device_tree.c
>> @@ -2183,6 +2183,18 @@ void __init dt_unflatten_host_device_tree(void)
>>     dt_alias_scan();
>> }
>> 
>> +int dt_get_pci_domain_nr(struct dt_device_node *node)
>> +{
>> +    u32 domain;
>> +    int error;
>> +
>> +    error = dt_property_read_u32(node, "linux,pci-domain", &domain);
>> +    if ( !error )
>> +        return -EINVAL;
>> +
>> +    return (u16)domain;
>> +}
>> +
>> /*
>>  * Local variables:
>>  * mode: C
>> diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
>> index 497144b8a7..9069040ef7 100644
>> --- a/xen/include/xen/device_tree.h
>> +++ b/xen/include/xen/device_tree.h
>> @@ -831,6 +831,25 @@ int dt_count_phandle_with_args(const struct dt_device_node *np,
>>                                const char *list_name,
>>                                const char *cells_name);
>> 
>> +/**
>> + * dt_get_pci_domain_nr - Find the host bridge domain number
>> + *            of the given device node.
>> + * @node: Device tree node with the domain information.
>> + *
>> + * This function will try to obtain the host bridge domain number by finding
>> + * a property called "linux,pci-domain" of the given device node.
>> + *
>> + * Return:
>> + * * > 0    - On success, an associated domain number.
>> + * * -EINVAL    - The property "linux,pci-domain" does not exist.
>> + * * -ENODATA   - The linux,pci-domain" property does not have value.
>> + * * -EOVERFLOW - Invalid "linux,pci-domain" property value.
> 
> This doesn't match reality for us because it can only return EINVAL

I will remove in next version.

Regards,
Rahul
> 
>> + * Returns the associated domain number from DT in the range [0-0xffff], or
>> + * a negative value if the required property is not found.
>> + */
>> +int dt_get_pci_domain_nr(struct dt_device_node *node);
>> +
>> #ifdef CONFIG_DEVICE_TREE_DEBUG
>> #define dt_dprintk(fmt, args...)  \
>>     printk(XENLOG_DEBUG fmt, ## args)
>> -- 
>> 2.17.1