Hi Joerg, In case of PAMU, geometry would be meaningless without specifying the number of subwindows. If the API user specifies a geometry but fails to specify the number of required subwindows, we would assume a default (max supported) value, which may be incorrect. It's going to be really ugly. I think we should add the number of sub windows to the domain geometry. This parameter would be used in case of a window based iommu. So, a separate set_window API wouldn't be required.
We can still implement the get_windows API for getting the maximum number of subwindows supported by the window based IOMMU. Regards Varun > -----Original Message----- > From: Joerg Roedel [mailto:j...@8bytes.org] > Sent: Monday, February 04, 2013 6:49 PM > To: Sethi Varun-B16395; Stuart Yoder > Cc: io...@lists.linux-foundation.org; linux-kernel@vger.kernel.org; Joerg > Roedel > Subject: [PATCH 5/5] iommu: Add DOMAIN_ATTR_WINDOWS domain attribute > > This attribute can be used to set and get the number of subwindows on > IOMMUs that are window-based. > > Signed-off-by: Joerg Roedel <j...@8bytes.org> > --- > drivers/iommu/iommu.c | 33 ++++++++++++++++++++++++++++++--- > include/linux/iommu.h | 5 +++++ > 2 files changed, 35 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index > 0fdb7db..66402f7 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -891,6 +891,7 @@ int iommu_domain_get_attr(struct iommu_domain > *domain, > struct iommu_domain_geometry *geometry; > bool *paging; > int ret = 0; > + u32 *count; > > switch (attr) { > case DOMAIN_ATTR_GEOMETRY: > @@ -902,6 +903,15 @@ int iommu_domain_get_attr(struct iommu_domain > *domain, > paging = data; > *paging = (domain->ops->pgsize_bitmap != 0UL); > break; > + case DOMAIN_ATTR_WINDOWS: > + count = data; > + > + if (domain->ops->domain_get_windows != NULL) > + *count = domain->ops->domain_get_windows(domain); > + else > + ret = -ENODEV; > + > + break; > default: > if (!domain->ops->domain_get_attr) > return -EINVAL; > @@ -916,9 +926,26 @@ EXPORT_SYMBOL_GPL(iommu_domain_get_attr); > int iommu_domain_set_attr(struct iommu_domain *domain, > enum iommu_attr attr, void *data) > { > - if (!domain->ops->domain_set_attr) > - return -EINVAL; > + int ret = 0; > + u32 *count; > + > + switch (attr) { > + case DOMAIN_ATTR_WINDOWS: > + count = data; > + > + if (domain->ops->domain_set_windows != NULL) > + ret = domain->ops->domain_set_windows(domain, *count); > + else > + ret = -ENODEV; > > - return domain->ops->domain_set_attr(domain, attr, data); > + break; > + default: > + if (domain->ops->domain_set_attr == NULL) > + return -EINVAL; > + > + ret = domain->ops->domain_set_attr(domain, attr, data); > + } > + > + return ret; > } > EXPORT_SYMBOL_GPL(iommu_domain_set_attr); > diff --git a/include/linux/iommu.h b/include/linux/iommu.h index > 0cba2d8..8330df1 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -60,6 +60,7 @@ struct iommu_domain { > enum iommu_attr { > DOMAIN_ATTR_GEOMETRY, > DOMAIN_ATTR_PAGING, > + DOMAIN_ATTR_WINDOWS, > DOMAIN_ATTR_MAX, > }; > > @@ -106,6 +107,10 @@ struct iommu_ops { > int (*domain_window_enable)(struct iommu_domain *domain, u32 > wnd_nr, > phys_addr_t paddr, size_t size); > void (*domain_window_disable)(struct iommu_domain *domain, u32 > wnd_nr); > + /* Set the numer of window per domain */ > + int (*domain_set_windows)(struct iommu_domain *domain, u32 > w_count); > + /* Get the numer of window per domain */ > + u32 (*domain_get_windows)(struct iommu_domain *domain); > > unsigned long pgsize_bitmap; > }; > -- > 1.7.9.5 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
