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List:       linux-iommu
Subject:    [PATCH 4/4] iommu: Add domain window handling functions
From:       B16395 () freescale ! com (Sethi Varun-B16395)
Date:       2013-01-31 9:32:26
Message-ID: C5ECD7A89D1DC44195F34B25E172658D3670ED () 039-SN2MPN1-013 ! 039d ! mgd ! msft ! net
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> -----Original Message-----
> From: Joerg Roedel [mailto:joro at 8bytes.org]
> Sent: Thursday, January 31, 2013 3:14 AM
> To: Sethi Varun-B16395
> Cc: iommu at lists.linux-foundation.org; linux-kernel at vger.kernel.org; Joerg
> Roedel
> Subject: [PATCH 4/4] iommu: Add domain window handling functions
> 
> Add the iommu_domain_wnd_enable() and iommu_domain_wnd_disable()
> functions to the IOMMU-API. These functions will be used to setup domains
> that are based on subwindows and not on paging.
> 
> Signed-off-by: Joerg Roedel <joro at 8bytes.org>
> ---
> drivers/iommu/iommu.c |   20 ++++++++++++++++++++
> include/linux/iommu.h |   18 ++++++++++++++++++
> 2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index
> ab9dafd..55ae3bf 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -852,6 +852,26 @@ size_t iommu_unmap(struct iommu_domain *domain,
> unsigned long iova, size_t size)  }  EXPORT_SYMBOL_GPL(iommu_unmap);
> 
> +
> +int iommu_domain_wnd_enable(struct iommu_domain *domain, u32 window,
> +			    unsigned long offset, size_t size) {
> +	if (unlikely(domain->ops->domain_wnd_enable == NULL))
> +		return -ENODEV;
> +
> +	return domain->ops->domain_wnd_enable(domain, window, offset,
> size); }
> +EXPORT_SYMBOL_GPL(iommu_domain_wnd_enable);
> +
> +void iommu_domain_wnd_disable(struct iommu_domain *domain, u32 window)
> +{
> +	if (unlikely(domain->ops->domain_wnd_disable == NULL))
> +		return;
> +
> +	return domain->ops->domain_wnd_disable(domain, window); }
> +EXPORT_SYMBOL_GPL(iommu_domain_wnd_disable);
> +
> static int __init iommu_init(void)
> {
> 	iommu_group_kset = kset_create_and_add("iommu_groups",
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h index
> 26066f5..f01657e 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -90,6 +90,9 @@ struct iommu_ops {
> 		   phys_addr_t paddr, size_t size, int prot);
> 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
> 		     size_t size);
> +	int (*domain_wnd_enable)(struct iommu_domain *domain, u32 window,
> +				   unsigned long offset, size_t size);
> +	void (*domain_wnd_disable)(struct iommu_domain *domain, u32
> window);
> 	phys_addr_t (*iova_to_phys)(struct iommu_domain *domain,
> 				    unsigned long iova);
> 	int (*domain_has_cap)(struct iommu_domain *domain, @@ -123,6 +126,9
> @@ extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
> 		     phys_addr_t paddr, size_t size, int prot);  extern
> size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> 		       size_t size);
> +extern int iommu_domain_wnd_enable(struct iommu_domain *domain, u32
> window,
> +				   unsigned long offset, size_t size); extern
> void
> +iommu_domain_wnd_disable(struct iommu_domain *domain, u32 window);
> extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
> 				      unsigned long iova);
> extern int iommu_domain_has_cap(struct iommu_domain *domain, @@ -240,6
> +246,18 @@ static inline int iommu_unmap(struct iommu_domain *domain,
> unsigned long iova,
> 	return -ENODEV;
> }
> 
> +static inline int iommu_domain_wnd_enable(struct iommu_domain *domain,
> +					  u32 window, unsigned long offset,
> +					  size_t size)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline void iommu_domain_wnd_disable(struct iommu_domain *domain,
> +					    u32 window)
> +{
> +}
> +
> static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain
> *domain,
> 					     unsigned long iova)
> {
We would need a corresponding physical address in the iommu_domain_wnd_enable call. \
The sub windows can point to physically discontiguous locations. Also, although we \
support partial mappings where the sub window size < geometry_size/max_sub_windows, \
but the mapping would always start from the sub window base (sub window base address \
would be aligned to (geometry size)/max_sub_windows). The user of the API would have \
to ensure that the iova is aligned to the max sub window size. So, offset is not \
relevant in our case as it would always be zero. The size should be u64 in order to \
accommodate window sizes supported by PAMU.


int iommu_domain_wnd_enable(struct iommu_domain *domain, u32 window, phys_addr_t \
paddr, u64 size)

We need a mechanism to determine the maximum number of subwindows supported by PAMU. \
How about representing it in the iommu_domain structure: struct  iommu_domain {
	struct iommu_ops *ops;
	void *priv;
	iommu_fault_handler_t handler;
	void *handler_token;
	struct iommu_domain_geometry geometry;
	u32 max_sub_windows; -----> maximum number of sub windows supported by the hardware.
}

Also, we would need to set the number of sub windows for a geometry, for that again \
we would need a new domain attribute (DOMAIN_ATTR_SUBWINDOWS).

-Varun


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