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Re: [RFC PATCH v2 11/15] drivers: iommu: arm-smmu-v3: add IORT iommu configuration

Started byWill Deacon <will.deacon@arm.com>
First post2016-06-14 20:40 +0200
Last post2016-06-15 11:00 +0200
Articles 2 — 2 participants

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  Re: [RFC PATCH v2 11/15] drivers: iommu: arm-smmu-v3: add IORT iommu  configuration Will Deacon <will.deacon@arm.com> - 2016-06-14 20:40 +0200
    Re: [RFC PATCH v2 11/15] drivers: iommu: arm-smmu-v3: add IORT iommu  configuration Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-06-15 11:00 +0200

#1422207 — Re: [RFC PATCH v2 11/15] drivers: iommu: arm-smmu-v3: add IORT iommu configuration

FromWill Deacon <will.deacon@arm.com>
Date2016-06-14 20:40 +0200
SubjectRe: [RFC PATCH v2 11/15] drivers: iommu: arm-smmu-v3: add IORT iommu configuration
Message-ID<rK1pM-88-27@gated-at.bofh.it>
On Tue, Jun 07, 2016 at 02:31:06PM +0100, Lorenzo Pieralisi wrote:
> In ACPI bases systems, in order to be able to create platform
> devices and initialize them for arm-smmu-v3 components, the IORT
> infrastructure requires ARM SMMU drivers to initialize a set of
> operations that are used by the IORT kernel layer to configure platform
> devices for ARM SMMU components in turn.
> 
> This patch adds the IORT IOMMU configuration for the ARM SMMU v3 kernel
> driver.
> 
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> ---
>  drivers/iommu/arm-smmu-v3.c | 101 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/iort.h        |  12 +++++-
>  2 files changed, 112 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 90745a8..7acb6b5 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2687,6 +2687,107 @@ static int __init arm_smmu_of_init(struct device_node *np)
>  }
>  IOMMU_OF_DECLARE(arm_smmuv3, "arm,smmu-v3", arm_smmu_of_init);
>  
> +#ifdef CONFIG_ACPI
> +static int acpi_smmu_init(struct acpi_iort_node *node)
> +{
> +	iort_smmu_set_ops(node, &arm_smmu_ops, NULL);
> +
> +	return 0;
> +}
> +
> +static void acpi_smmu_register_irq(int hwirq, const char *name,
> +				   struct resource *res)
> +{
> +	int irq = acpi_register_gsi(NULL, hwirq, ACPI_EDGE_SENSITIVE,
> +				    ACPI_ACTIVE_HIGH);
> +
> +	if (irq < 0) {
> +		pr_err("could not register gsi hwirq %d name [%s]\n", hwirq,
> +								      name);
> +		return;
> +	}
> +
> +	res->start = irq;
> +	res->end = irq;
> +	res->flags = IORESOURCE_IRQ;
> +	res->name = name;
> +}
> +
> +static int arm_smmu_count_resources(struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu_v3 *smmu;
> +	/* Always present mem resource */
> +	int num_res = 1;
> +
> +	/* Retrieve SMMUv3 specific data */
> +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> +
> +	if (smmu->event_gsiv)
> +		num_res++;
> +
> +	if (smmu->pri_gsiv)
> +		num_res++;
> +
> +	if (smmu->gerr_gsiv)
> +		num_res++;
> +
> +	if (smmu->sync_gsiv)
> +		num_res++;
> +
> +	return num_res;
> +}
> +
> +static void arm_smmu_init_resources(struct resource *res,
> +				    struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu_v3 *smmu;
> +	int num_res = 0;
> +
> +	/* Retrieve SMMUv3 specific data */
> +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> +
> +	res[num_res].start = smmu->base_address;
> +	res[num_res].end = smmu->base_address + SZ_128K - 1;
> +	res[num_res].flags = IORESOURCE_MEM;
> +
> +	num_res++;
> +
> +	if (smmu->event_gsiv)
> +		acpi_smmu_register_irq(smmu->event_gsiv, "eventq",
> +				       &res[num_res++]);
> +
> +	if (smmu->pri_gsiv)
> +		acpi_smmu_register_irq(smmu->pri_gsiv, "priq",
> +				       &res[num_res++]);
> +
> +	if (smmu->gerr_gsiv)
> +		acpi_smmu_register_irq(smmu->gerr_gsiv, "gerror",
> +				       &res[num_res++]);
> +
> +	if (smmu->sync_gsiv)
> +		acpi_smmu_register_irq(smmu->sync_gsiv, "cmdq-sync",
> +				       &res[num_res++]);
> +}
> +
> +static bool arm_smmu_is_coherent(struct acpi_iort_node *node)
> +{
> +	struct acpi_iort_smmu_v3 *smmu;
> +
> +	/* Retrieve SMMUv3 specific data */
> +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> +
> +	return smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE;
> +}
> +
> +const struct iort_iommu_config iort_arm_smmu_v3_cfg = {
> +	.name = "arm-smmu-v3",
> +	.iommu_init = acpi_smmu_init,
> +	.iommu_is_coherent = arm_smmu_is_coherent,
> +	.iommu_count_resources = arm_smmu_count_resources,
> +	.iommu_init_resources = arm_smmu_init_resources
> +};
> +#endif
> +
>  MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
>  MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
>  MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/iort.h b/include/linux/iort.h
> index ced3054..5dcfa09 100644
> --- a/include/linux/iort.h
> +++ b/include/linux/iort.h
> @@ -55,7 +55,17 @@ struct iort_iommu_config {
>  static inline const struct iort_iommu_config *
>  iort_get_iommu_config(struct acpi_iort_node *node)
>  {
> -	return NULL;
> +	switch (node->type) {
> +#if IS_ENABLED(CONFIG_ARM_SMMU_V3)
> +	case ACPI_IORT_NODE_SMMU_V3: {
> +		extern const struct iort_iommu_config iort_arm_smmu_v3_cfg;
> +
> +		return &iort_arm_smmu_v3_cfg;
> +	}
> +#endif

Oh, yuck! I really don't like this mixture of SMMU driver code and IORT
code over two files using a global structure of largely stateless function
pointers.

I think you have two options:

  (1) Move this all into iort.c (my preference)
  (2) Introduce something like SMMU_ACPI_DECLARE which allows drivers to
      register a callback if they're matched in the IORT.

that at least keeps internal data in one place, rather than spreading it
around.

Cheers,

Will

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#1422797

FromLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Date2016-06-15 11:00 +0200
Message-ID<rKeQ2-iF-13@gated-at.bofh.it>
In reply to#1422207
On Tue, Jun 14, 2016 at 07:39:39PM +0100, Will Deacon wrote:
> On Tue, Jun 07, 2016 at 02:31:06PM +0100, Lorenzo Pieralisi wrote:
> > In ACPI bases systems, in order to be able to create platform
> > devices and initialize them for arm-smmu-v3 components, the IORT
> > infrastructure requires ARM SMMU drivers to initialize a set of
> > operations that are used by the IORT kernel layer to configure platform
> > devices for ARM SMMU components in turn.
> > 
> > This patch adds the IORT IOMMU configuration for the ARM SMMU v3 kernel
> > driver.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > Cc: Joerg Roedel <joro@8bytes.org>
> > ---
> >  drivers/iommu/arm-smmu-v3.c | 101 ++++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/iort.h        |  12 +++++-
> >  2 files changed, 112 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > index 90745a8..7acb6b5 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -2687,6 +2687,107 @@ static int __init arm_smmu_of_init(struct device_node *np)
> >  }
> >  IOMMU_OF_DECLARE(arm_smmuv3, "arm,smmu-v3", arm_smmu_of_init);
> >  
> > +#ifdef CONFIG_ACPI
> > +static int acpi_smmu_init(struct acpi_iort_node *node)
> > +{
> > +	iort_smmu_set_ops(node, &arm_smmu_ops, NULL);
> > +
> > +	return 0;
> > +}
> > +
> > +static void acpi_smmu_register_irq(int hwirq, const char *name,
> > +				   struct resource *res)
> > +{
> > +	int irq = acpi_register_gsi(NULL, hwirq, ACPI_EDGE_SENSITIVE,
> > +				    ACPI_ACTIVE_HIGH);
> > +
> > +	if (irq < 0) {
> > +		pr_err("could not register gsi hwirq %d name [%s]\n", hwirq,
> > +								      name);
> > +		return;
> > +	}
> > +
> > +	res->start = irq;
> > +	res->end = irq;
> > +	res->flags = IORESOURCE_IRQ;
> > +	res->name = name;
> > +}
> > +
> > +static int arm_smmu_count_resources(struct acpi_iort_node *node)
> > +{
> > +	struct acpi_iort_smmu_v3 *smmu;
> > +	/* Always present mem resource */
> > +	int num_res = 1;
> > +
> > +	/* Retrieve SMMUv3 specific data */
> > +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> > +
> > +	if (smmu->event_gsiv)
> > +		num_res++;
> > +
> > +	if (smmu->pri_gsiv)
> > +		num_res++;
> > +
> > +	if (smmu->gerr_gsiv)
> > +		num_res++;
> > +
> > +	if (smmu->sync_gsiv)
> > +		num_res++;
> > +
> > +	return num_res;
> > +}
> > +
> > +static void arm_smmu_init_resources(struct resource *res,
> > +				    struct acpi_iort_node *node)
> > +{
> > +	struct acpi_iort_smmu_v3 *smmu;
> > +	int num_res = 0;
> > +
> > +	/* Retrieve SMMUv3 specific data */
> > +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> > +
> > +	res[num_res].start = smmu->base_address;
> > +	res[num_res].end = smmu->base_address + SZ_128K - 1;
> > +	res[num_res].flags = IORESOURCE_MEM;
> > +
> > +	num_res++;
> > +
> > +	if (smmu->event_gsiv)
> > +		acpi_smmu_register_irq(smmu->event_gsiv, "eventq",
> > +				       &res[num_res++]);
> > +
> > +	if (smmu->pri_gsiv)
> > +		acpi_smmu_register_irq(smmu->pri_gsiv, "priq",
> > +				       &res[num_res++]);
> > +
> > +	if (smmu->gerr_gsiv)
> > +		acpi_smmu_register_irq(smmu->gerr_gsiv, "gerror",
> > +				       &res[num_res++]);
> > +
> > +	if (smmu->sync_gsiv)
> > +		acpi_smmu_register_irq(smmu->sync_gsiv, "cmdq-sync",
> > +				       &res[num_res++]);
> > +}
> > +
> > +static bool arm_smmu_is_coherent(struct acpi_iort_node *node)
> > +{
> > +	struct acpi_iort_smmu_v3 *smmu;
> > +
> > +	/* Retrieve SMMUv3 specific data */
> > +	smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> > +
> > +	return smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE;
> > +}
> > +
> > +const struct iort_iommu_config iort_arm_smmu_v3_cfg = {
> > +	.name = "arm-smmu-v3",
> > +	.iommu_init = acpi_smmu_init,
> > +	.iommu_is_coherent = arm_smmu_is_coherent,
> > +	.iommu_count_resources = arm_smmu_count_resources,
> > +	.iommu_init_resources = arm_smmu_init_resources
> > +};
> > +#endif
> > +
> >  MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
> >  MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
> >  MODULE_LICENSE("GPL v2");
> > diff --git a/include/linux/iort.h b/include/linux/iort.h
> > index ced3054..5dcfa09 100644
> > --- a/include/linux/iort.h
> > +++ b/include/linux/iort.h
> > @@ -55,7 +55,17 @@ struct iort_iommu_config {
> >  static inline const struct iort_iommu_config *
> >  iort_get_iommu_config(struct acpi_iort_node *node)
> >  {
> > -	return NULL;
> > +	switch (node->type) {
> > +#if IS_ENABLED(CONFIG_ARM_SMMU_V3)
> > +	case ACPI_IORT_NODE_SMMU_V3: {
> > +		extern const struct iort_iommu_config iort_arm_smmu_v3_cfg;
> > +
> > +		return &iort_arm_smmu_v3_cfg;
> > +	}
> > +#endif
> 
> Oh, yuck! I really don't like this mixture of SMMU driver code and IORT
> code over two files using a global structure of largely stateless function
> pointers.
> 
> I think you have two options:
> 
>   (1) Move this all into iort.c (my preference)
>   (2) Introduce something like SMMU_ACPI_DECLARE which allows drivers to
>       register a callback if they're matched in the IORT.
> 
> that at least keeps internal data in one place, rather than spreading it
> around.

(1) is possible for most of the function pointers. Problem is that iort.c
has to know ARM SMMU v3 driver internals (driver name for platform
device matching and IRQ resources names - I wanted to keep the ARM SMMU
v3 probing routine as FW agnostic as possible), it is obviously doable
but I have to make sure I keep them in sync.

We still need (2) to have an IOMMU_OF_DECLARE() equivalent (ie to
make sure that we can carry out the of_xlate() equivalent when
devices are probed), I did not want to add a linker script section
for two components (ARM SMMUv1/v2 and v3) but that's doable too,
I will make changes for v3.

Thanks for having a look !

Lorenzo

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