Re: [PATCH v8 13/16] drivers: iommu: arm-smmu: add IORT configuration

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

On 16/11/16 15:29, Lorenzo Pieralisi wrote:
> In ACPI bases systems, in order to be able to create platform

          based?

> devices and initialize them for ARM SMMU components, the IORT
> kernel implementation requires a set of static functions to be
> used by the IORT kernel layer to configure platform devices for
> ARM SMMU components.
> 
> Add static configuration functions to the IORT kernel layer for
> the ARM SMMU components, so that the ARM SMMU driver can
> initialize its respective platform device by relying on the IORT
> kernel infrastructure and by adding a corresponding ACPI device
> early probe section entry.
> 
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> Tested-by: Tomasz Nowicki <tn@semihalf.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> ---
>  drivers/acpi/arm64/iort.c | 81 +++++++++++++++++++++++++++++++++++++++++++++
>  drivers/iommu/arm-smmu.c  | 83 ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/acpi_iort.h |  3 ++
>  3 files changed, 166 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index fd52e4c..4708806 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -548,6 +548,78 @@ static bool __init arm_smmu_v3_is_coherent(struct acpi_iort_node *node)
>  	return smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE;
>  }
>  
> +static int __init arm_smmu_count_resources(struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu *smmu;
> +	int num_irqs;
> +	u64 *glb_irq;
> +
> +	/* Retrieve SMMU specific data */
> +	smmu = (struct acpi_iort_smmu *)node->node_data;
> +
> +	glb_irq = ACPI_ADD_PTR(u64, node, smmu->global_interrupt_offset);
> +	if (!IORT_IRQ_MASK(glb_irq[1]))	/* 0 means not implemented */
> +		num_irqs = 1;
> +	else
> +		num_irqs = 2;

Do we actually need this - I mean, the configuration access interrupt is
of somewhat limited utility, implementation-defined, and we don't have
any handling for it. Nor should it, if present, ever happen anyway,
since it's not like anyone else should be randomly poking our SMMU in
invalid ways. Can we simply ignore it?

> +
> +	num_irqs += smmu->context_interrupt_count;
> +
> +	return num_irqs + 1;
> +}
> +
> +static void __init arm_smmu_init_resources(struct resource *res,
> +					   struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu *smmu;
> +	int i, hw_irq, trigger, num_res = 0;
> +	u64 *ctx_irq, *glb_irq;
> +
> +	/* Retrieve SMMU specific data */
> +	smmu = (struct acpi_iort_smmu *)node->node_data;
> +
> +	res[num_res].start = smmu->base_address;
> +	res[num_res].end = smmu->base_address + smmu->span - 1;
> +	res[num_res].flags = IORESOURCE_MEM;
> +	num_res++;
> +
> +	glb_irq = ACPI_ADD_PTR(u64, node, smmu->global_interrupt_offset);
> +	/* Global IRQs */
> +	hw_irq = IORT_IRQ_MASK(glb_irq[0]);
> +	trigger = IORT_IRQ_TRIGGER_MASK(glb_irq[0]);
> +
> +	acpi_iort_register_irq(hw_irq, "arm-smmu-global", trigger,
> +				     &res[num_res++]);
> +
> +	/* Global IRQs */
> +	hw_irq = IORT_IRQ_MASK(glb_irq[1]);
> +	if (hw_irq) {
> +		trigger = IORT_IRQ_TRIGGER_MASK(glb_irq[1]);
> +		acpi_iort_register_irq(hw_irq, "arm-smmu-global", trigger,
> +					     &res[num_res++]);
> +	}

Related to the above, I think the driver generally assumes these to be
the global fault interrupt. If we *are* going to claim the config
interrupt as well, we should probably disambiguate them, although
admittedly we can't really do that retrospectively on the DT side.

> +
> +	/* Context IRQs */
> +	ctx_irq = ACPI_ADD_PTR(u64, node, smmu->context_interrupt_offset);
> +	for (i = 0; i < smmu->context_interrupt_count; i++) {
> +		hw_irq = IORT_IRQ_MASK(ctx_irq[i]);
> +		trigger = IORT_IRQ_TRIGGER_MASK(ctx_irq[i]);
> +
> +		acpi_iort_register_irq(hw_irq, "arm-smmu-context", trigger,
> +				       &res[num_res++]);
> +	}
> +}
> +
> +static bool __init arm_smmu_is_coherent(struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu *smmu;
> +
> +	/* Retrieve SMMU specific data */
> +	smmu = (struct acpi_iort_smmu *)node->node_data;
> +
> +	return smmu->flags & ACPI_IORT_SMMU_COHERENT_WALK;
> +}
> +
>  struct iort_iommu_config {
>  	const char *name;
>  	int (*iommu_init)(struct acpi_iort_node *node);
> @@ -564,12 +636,21 @@ static const struct iort_iommu_config iort_arm_smmu_v3_cfg __initconst = {
>  	.iommu_init_resources = arm_smmu_v3_init_resources
>  };
>  
> +static const struct iort_iommu_config iort_arm_smmu_cfg __initconst = {
> +	.name = "arm-smmu",
> +	.iommu_is_coherent = arm_smmu_is_coherent,
> +	.iommu_count_resources = arm_smmu_count_resources,
> +	.iommu_init_resources = arm_smmu_init_resources
> +};
> +
>  static __init
>  const struct iort_iommu_config *iort_get_iommu_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;
>  	default:
>  		return NULL;
>  	}
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 573b2b6..21d1892 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -28,6 +28,8 @@
>  
>  #define pr_fmt(fmt) "arm-smmu: " fmt
>  
> +#include <linux/acpi.h>
> +#include <linux/acpi_iort.h>
>  #include <linux/atomic.h>
>  #include <linux/delay.h>
>  #include <linux/dma-iommu.h>
> @@ -1904,6 +1906,70 @@ static const struct of_device_id arm_smmu_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
>  
> +#ifdef CONFIG_ACPI
> +static int acpi_smmu_get_data(u32 model, u32 *version, u32 *impl)
> +{
> +	int ret = 0;
> +
> +	switch (model) {
> +	case ACPI_IORT_SMMU_V1:
> +	case ACPI_IORT_SMMU_CORELINK_MMU400:
> +		*version = ARM_SMMU_V1;
> +		*impl = GENERIC_SMMU;

Further to Will's comment, I'd say just pass the smmu pointer in and set
the fields explicitly here.

Robin.

> +		break;
> +	case ACPI_IORT_SMMU_V2:
> +		*version = ARM_SMMU_V2;
> +		*impl = GENERIC_SMMU;
> +		break;
> +	case ACPI_IORT_SMMU_CORELINK_MMU500:
> +		*version = ARM_SMMU_V2;
> +		*impl = ARM_MMU500;
> +		break;
> +	default:
> +		ret = -ENODEV;
> +	}
> +
> +	return ret;
> +}
> +
> +static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
> +				      struct arm_smmu_device *smmu)
> +{
> +	struct device *dev = smmu->dev;
> +	struct acpi_iort_node *node =
> +		*(struct acpi_iort_node **)dev_get_platdata(dev);
> +	struct acpi_iort_smmu *iort_smmu;
> +	u64 *glb_irq;
> +	int ret;
> +
> +	/* Retrieve SMMU1/2 specific data */
> +	iort_smmu = (struct acpi_iort_smmu *)node->node_data;
> +
> +	ret = acpi_smmu_get_data(iort_smmu->model, &smmu->version,
> +						   &smmu->model);
> +	if (ret < 0)
> +		return ret;
> +
> +	glb_irq = ACPI_ADD_PTR(u64, node, iort_smmu->global_interrupt_offset);
> +
> +	if (!IORT_IRQ_MASK(glb_irq[1]))	/* 0 means not implemented */
> +		smmu->num_global_irqs = 1;
> +	else
> +		smmu->num_global_irqs = 2;
> +
> +	if (iort_smmu->flags & ACPI_IORT_SMMU_COHERENT_WALK)
> +		smmu->features |= ARM_SMMU_FEAT_COHERENT_WALK;
> +
> +	return 0;
> +}
> +#else
> +static inline int arm_smmu_device_acpi_probe(struct platform_device *pdev,
> +					     struct arm_smmu_device *smmu)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
>  static int arm_smmu_device_dt_probe(struct platform_device *pdev,
>  				    struct arm_smmu_device *smmu)
>  {
> @@ -1955,7 +2021,11 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>  	}
>  	smmu->dev = dev;
>  
> -	err = arm_smmu_device_dt_probe(pdev, smmu);
> +	if (dev->of_node)
> +		err = arm_smmu_device_dt_probe(pdev, smmu);
> +	else
> +		err = arm_smmu_device_acpi_probe(pdev, smmu);
> +
>  	if (err)
>  		return err;
>  
> @@ -2103,6 +2173,17 @@ IOMMU_OF_DECLARE(arm_mmu401, "arm,mmu-401", arm_smmu_of_init);
>  IOMMU_OF_DECLARE(arm_mmu500, "arm,mmu-500", arm_smmu_of_init);
>  IOMMU_OF_DECLARE(cavium_smmuv2, "cavium,smmu-v2", arm_smmu_of_init);
>  
> +#ifdef CONFIG_ACPI
> +static int __init arm_smmu_acpi_init(struct acpi_table_header *table)
> +{
> +	if (iort_node_match(ACPI_IORT_NODE_SMMU))
> +		return arm_smmu_init();
> +
> +	return 0;
> +}
> +IORT_ACPI_DECLARE(arm_smmu, ACPI_SIG_IORT, arm_smmu_acpi_init);
> +#endif
> +
>  MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
>  MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
>  MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
> index 17bb078..79ba1bb 100644
> --- a/include/linux/acpi_iort.h
> +++ b/include/linux/acpi_iort.h
> @@ -23,6 +23,9 @@
>  #include <linux/fwnode.h>
>  #include <linux/irqdomain.h>
>  
> +#define IORT_IRQ_MASK(irq)		(irq & 0xffffffffULL)
> +#define IORT_IRQ_TRIGGER_MASK(irq)	((irq >> 32) & 0xffffffffULL)
> +
>  int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
>  void iort_deregister_domain_token(int trans_id);
>  struct fwnode_handle *iort_find_domain_token(int trans_id);
>