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

[Robin Murphy <robin.murphy@xxxxxxx>]

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@xxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxx>
> > Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx>
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
> > ---
> >   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