Re: [PATCH v3 1/3] acpi: arm64: add iort support for PMCG

[Robin Murphy <robin.murphy@arm.com>]

On 04/10/18 17:43, Lorenzo Pieralisi wrote:
> On Fri, Sep 21, 2018 at 04:08:01PM +0100, Shameer Kolothum wrote:
>> From: Neil Leeder <nleeder@codeaurora.org>
>>
>> Add support for the SMMU Performance Monitor Counter Group
>> information from ACPI. This is in preparation for its use
>> in the SMMUv3 PMU driver.
>>
>> Signed-off-by: Neil Leeder <nleeder@codeaurora.org>
>> Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
>> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>> ---
>>   drivers/acpi/arm64/iort.c | 78 +++++++++++++++++++++++++++++++++++++++--------
>>   1 file changed, 66 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>> index 08f26db..b979c86 100644
>> --- a/drivers/acpi/arm64/iort.c
>> +++ b/drivers/acpi/arm64/iort.c
>> @@ -356,7 +356,8 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
>>   	if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
>>   		if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
>>   		    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX ||
>> -		    node->type == ACPI_IORT_NODE_SMMU_V3) {
>> +		    node->type == ACPI_IORT_NODE_SMMU_V3 ||
>> +		    node->type == ACPI_IORT_NODE_PMCG) {
>>   			*id_out = map->output_base;
>>   			return parent;
>>   		}
>> @@ -394,6 +395,8 @@ static int iort_get_id_mapping_index(struct acpi_iort_node *node)
>>   		}
>>   
>>   		return smmu->id_mapping_index;
>> +	case ACPI_IORT_NODE_PMCG:
>> +		return 0;
>>   	default:
>>   		return -EINVAL;
>>   	}
>> @@ -1309,6 +1312,50 @@ static bool __init arm_smmu_is_coherent(struct acpi_iort_node *node)
>>   	return smmu->flags & ACPI_IORT_SMMU_COHERENT_WALK;
>>   }
>>   
>> +static void __init arm_smmu_common_dma_configure(struct device *dev,
>> +						enum dev_dma_attr attr)
>> +{
>> +	/* We expect the dma masks to be equivalent for all SMMUs set-ups */
>> +	dev->dma_mask = &dev->coherent_dma_mask;
>> +
>> +	/* Configure DMA for the page table walker */
>> +	acpi_dma_configure(dev, attr);
>> +}
> 
> It looks like we can't get rid of this acpi_dma_configure() call
> given that the platform device we create has no ACPI companion
> (and I am not looking forward to fabricating one to make the
> code homogeneous :)).

Yeah, given that this is essentially only for SMMUs, the alternatives 
all end up looking like too much bother to be worthwhile.

> Still, having two methods per IORT node type (dev_is_coherent() and
> dev_dma_configure()) does not make much sense, we can merge it into one
> I think.

Good point - looks the attr from dev_is_coherent is only ever passed 
through dev_dma_configure, so we may as well just have per-SMMU-type 
dev_dma_configure methods which retrieve their own relevant coherency 
directly. FWIW, on v2 I was tempted to suggest just wrapping the DMA 
setup in "if (node->type != ACPI_IORT_NODE_PMCG)..." rather than messing 
with more callbacks, but that clearly wouldn't fit well with the local 
style here.

Robin.

> 
> Thanks,
> Lorenzo
> 
>> +static int __init arm_smmu_v3_pmcg_count_resources(struct acpi_iort_node *node)
>> +{
>> +	struct acpi_iort_pmcg *pmcg;
>> +
>> +	/* Retrieve PMCG specific data */
>> +	pmcg = (struct acpi_iort_pmcg *)node->node_data;
>> +
>> +	/*
>> +	 * There are always 2 memory resources.
>> +	 * If the overflow_gsiv is present then add that for a total of 3.
>> +	 */
>> +	return pmcg->overflow_gsiv ? 3 : 2;
>> +}
>> +
>> +static void __init arm_smmu_v3_pmcg_init_resources(struct resource *res,
>> +					       struct acpi_iort_node *node)
>> +{
>> +	struct acpi_iort_pmcg *pmcg;
>> +
>> +	/* Retrieve PMCG specific data */
>> +	pmcg = (struct acpi_iort_pmcg *)node->node_data;
>> +
>> +	res[0].start = pmcg->page0_base_address;
>> +	res[0].end = pmcg->page0_base_address + SZ_4K - 1;
>> +	res[0].flags = IORESOURCE_MEM;
>> +	res[1].start = pmcg->page1_base_address;
>> +	res[1].end = pmcg->page1_base_address + SZ_4K - 1;
>> +	res[1].flags = IORESOURCE_MEM;
>> +
>> +	if (pmcg->overflow_gsiv)
>> +		acpi_iort_register_irq(pmcg->overflow_gsiv, "overflow",
>> +				       ACPI_EDGE_SENSITIVE, &res[2]);
>> +}
>> +
>>   struct iort_dev_config {
>>   	const char *name;
>>   	int (*dev_init)(struct acpi_iort_node *node);
>> @@ -1318,6 +1365,8 @@ struct iort_dev_config {
>>   				     struct acpi_iort_node *node);
>>   	void (*dev_set_proximity)(struct device *dev,
>>   				    struct acpi_iort_node *node);
>> +	void (*dev_dma_configure)(struct device *dev,
>> +					enum dev_dma_attr attr);
>>   };
>>   
>>   static const struct iort_dev_config iort_arm_smmu_v3_cfg __initconst = {
>> @@ -1326,23 +1375,34 @@ static const struct iort_dev_config iort_arm_smmu_v3_cfg __initconst = {
>>   	.dev_count_resources = arm_smmu_v3_count_resources,
>>   	.dev_init_resources = arm_smmu_v3_init_resources,
>>   	.dev_set_proximity = arm_smmu_v3_set_proximity,
>> +	.dev_dma_configure = arm_smmu_common_dma_configure,
>>   };
>>   
>>   static const struct iort_dev_config iort_arm_smmu_cfg __initconst = {
>>   	.name = "arm-smmu",
>>   	.dev_is_coherent = arm_smmu_is_coherent,
>>   	.dev_count_resources = arm_smmu_count_resources,
>> -	.dev_init_resources = arm_smmu_init_resources
>> +	.dev_init_resources = arm_smmu_init_resources,
>> +	.dev_dma_configure = arm_smmu_common_dma_configure,
>> +};
>> +
>> +static const struct iort_dev_config iort_arm_smmu_v3_pmcg_cfg __initconst = {
>> +	.name = "arm-smmu-v3-pmu",
>> +	.dev_count_resources = arm_smmu_v3_pmcg_count_resources,
>> +	.dev_init_resources = arm_smmu_v3_pmcg_init_resources,
>>   };
>>   
>>   static __init const struct iort_dev_config *iort_get_dev_cfg(
>>   			struct acpi_iort_node *node)
>>   {
>> +
>>   	switch (node->type) {
>>   	case ACPI_IORT_NODE_SMMU_V3:
>>   		return &iort_arm_smmu_v3_cfg;
>>   	case ACPI_IORT_NODE_SMMU:
>>   		return &iort_arm_smmu_cfg;
>> +	case ACPI_IORT_NODE_PMCG:
>> +		return &iort_arm_smmu_v3_pmcg_cfg;
>>   	default:
>>   		return NULL;
>>   	}
>> @@ -1398,12 +1458,6 @@ static int __init iort_add_platform_device(struct acpi_iort_node *node,
>>   	if (ret)
>>   		goto dev_put;
>>   
>> -	/*
>> -	 * We expect the dma masks to be equivalent for
>> -	 * all SMMUs set-ups
>> -	 */
>> -	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
>> -
>>   	fwnode = iort_get_fwnode(node);
>>   
>>   	if (!fwnode) {
>> @@ -1413,11 +1467,11 @@ static int __init iort_add_platform_device(struct acpi_iort_node *node,
>>   
>>   	pdev->dev.fwnode = fwnode;
>>   
>> -	attr = ops->dev_is_coherent && ops->dev_is_coherent(node) ?
>> +	if (ops->dev_dma_configure) {
>> +		attr = ops->dev_is_coherent && ops->dev_is_coherent(node) ?
>>   			DEV_DMA_COHERENT : DEV_DMA_NON_COHERENT;
>> -
>> -	/* Configure DMA for the page table walker */
>> -	acpi_dma_configure(&pdev->dev, attr);
>> +		ops->dev_dma_configure(&pdev->dev, attr);
>> +	}
>>   
>>   	iort_set_device_domain(&pdev->dev, node);
>>   
>> -- 
>> 2.7.4
>>
>>