Date:   Fri, 18 Nov 2016 18:03:56 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Robin Murphy <robin.murphy@....com>
Cc:     iommu@...ts.linux-foundation.org,
        Will Deacon <will.deacon@....com>,
        Joerg Roedel <joro@...tes.org>,
        Marc Zyngier <marc.zyngier@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Tomasz Nowicki <tn@...ihalf.com>,
        Hanjun Guo <hanjun.guo@...aro.org>,
        Jon Masters <jcm@...hat.com>,
        Eric Auger <eric.auger@...hat.com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Nate Watterson <nwatters@...eaurora.org>,
        Prem Mallappa <prem.mallappa@...adcom.com>,
        Dennis Chen <dennis.chen@....com>, linux-acpi@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v8 13/16] drivers: iommu: arm-smmu: add IORT configuration

On Fri, Nov 18, 2016 at 05:36:46PM +0000, Robin Murphy wrote:
> On 16/11/16 15:29, Lorenzo Pieralisi wrote:
> > In ACPI bases systems, in order to be able to create platform
> 
>           based?

Ok.

> > 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@....com>
> > Reviewed-by: Tomasz Nowicki <tn@...ihalf.com>
> > Tested-by: Hanjun Guo <hanjun.guo@...aro.org>
> > Tested-by: Tomasz Nowicki <tn@...ihalf.com>
> > Cc: Will Deacon <will.deacon@....com>
> > Cc: Robin Murphy <robin.murphy@....com>
> > Cc: Joerg Roedel <joro@...tes.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?

I added its parsing to bring the same capabilities present in DT to
ACPI, from what you are saying I think that we'd better ignore it
and add its parsing later if we _ever_ need to handle 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.

I do not think we are missing functionality if for the time being
we just ignore the configuration access interrupt so that's what
I will do for this first version.

Thanks !
Lorenzo

> > +
> > +	/* 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@....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);
> > 
> 

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