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SubjectRe: [PATCH V7 1/8] ACPI: I/O Remapping Table (IORT) initial support
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On 22.06.2016 12:50, Marc Zyngier wrote:
> On 21/06/16 08:12, Hanjun Guo wrote:
>> Hi Tomasz,
>>
>> Sorry for jumping out late, just one comment below.
>>
>> On 2016/6/20 19:02, Tomasz Nowicki wrote:
>>> IORT shows representation of IO topology for ARM based systems.
>>> It describes how various components are connected together on
>>> parent-child basis e.g. PCI RC -> SMMU -> ITS. Also see IORT spec.
>>>
>>> Initial support allows to detect IORT table presence and save its
>>> root pointer obtained through acpi_get_table(). The pointer validity
>>> depends on acpi_gbl_permanent_mmap because if acpi_gbl_permanent_mmap
>>> is not set while using IORT nodes we would dereference unmapped pointers.
>>>
>>> For the aforementioned reason call iort_table_detect() from acpi_init()
>>> which guarantees acpi_gbl_permanent_mmap to be set at that point.
>>>
>>> Add generic helpers which are helpful for scanning and retrieving
>>> information from IORT table content. List of the most important helpers:
>>> - iort_find_dev_node() finds IORT node for a given device
>>> - iort_node_map_rid() maps device RID and returns IORT node which provides
>>> final translation
>>>
>>> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
>>> ---
>>> drivers/acpi/Kconfig | 3 +
>>> drivers/acpi/Makefile | 1 +
>>> drivers/acpi/bus.c | 2 +
>>> drivers/acpi/iort.c | 220 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>> include/linux/iort.h | 30 +++++++
>>
>> [...]
>>
>>> +static acpi_status
>>> +iort_match_node_callback(struct acpi_iort_node *node, void *context)
>>> +{
>>> + struct device *dev = context;
>>> +
>>> + switch (node->type) {
>>> + case ACPI_IORT_NODE_NAMED_COMPONENT: {
>>> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>>
>> ACPI_ALLOCATE_BUFFER is used here, so ...
>>
>>> + struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
>>> + struct acpi_iort_named_component *ncomp;
>>> +
>>> + if (!adev)
>>> + break;
>>> +
>>> + ncomp = (struct acpi_iort_named_component *)node->node_data;
>>> +
>>> + if (ACPI_FAILURE(acpi_get_name(adev->handle,
>>> + ACPI_FULL_PATHNAME, &buffer))) {
>>> + dev_warn(dev, "Can't get device full path name\n");
>>> + break;
>>> + }
>>> +
>>> + if (!strcmp(ncomp->device_name, (char *)buffer.pointer))
>>> + return AE_OK;
>>
>> ... we need to kfree(buffer.pointer) before we return or break.
>
> For the record, I've queued this patch on top:
>
> diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
> index 496dcf6..3b9e55b 100644
> --- a/drivers/acpi/iort.c
> +++ b/drivers/acpi/iort.c
> @@ -158,11 +158,15 @@ iort_match_node_callback(struct acpi_iort_node *node, void *context)
> if (ACPI_FAILURE(acpi_get_name(adev->handle,
> ACPI_FULL_PATHNAME, &buffer))) {
> dev_warn(dev, "Can't get device full path name\n");
> - break;
> - }
> + } else {
> + int match;
>
> - if (!strcmp(ncomp->device_name, (char *)buffer.pointer))
> - return AE_OK;
> + match = !strcmp(ncomp->device_name, buffer.pointer);
> + acpi_os_free(&buffer);
> +
> + if (match)
> + return AE_OK;
> + }
>
> break;
> }
>
>
> assuming that Rafael is OK with the general approach, of course.
>

Thanks Marc. As Lorenzo pointed out, we need another fix for
iort_node_map_rid(). Do you want me to refresh the whole series or this
patch only?

Tomasz

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