Hej,
On Thu, Sep 28, 2023, at 01:47, Jason Gunthorpe wrote:
> This flag just caches if the IO page size is larger than the CPU
> PAGE_SIZE. This only needs to be checked in two places so remove the
> confusingly named cache.
>
> dart would like to not support paging domains at all if the IO page size
> is larger than the CPU page size. In this case we should ideally fail
> domain_alloc_paging(), as there is no point in creating a domain that can
> never be attached. Move the test into apple_dart_finalize_domain().
>
> The check in apple_dart_mod_streams() will prevent the domain from being
> attached to the wrong dart
>
> There is no HW limitation that prevents BLOCKED domains from working,
> remove that test.
>
> The check in apple_dart_of_xlate() is redundant since immediately after
> the pgsize is checked. Remove it.
>
> Remove the variable.
>
> Suggested-by: Janne Grunau <j...@jannau.net>
> Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
> ---
> drivers/iommu/apple-dart.c | 20 ++++++--------------
> 1 file changed, 6 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 126da0d89f0dd4..821b4a3465dfb9 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -196,7 +196,6 @@ struct apple_dart_hw {
> * @lock: lock for hardware operations involving this dart
> * @pgsize: pagesize supported by this DART
> * @supports_bypass: indicates if this DART supports bypass mode
> - * @force_bypass: force bypass mode due to pagesize mismatch?
> * @sid2group: maps stream ids to iommu_groups
> * @iommu: iommu core device
> */
> @@ -217,7 +216,6 @@ struct apple_dart {
> u32 pgsize;
> u32 num_streams;
> u32 supports_bypass : 1;
> - u32 force_bypass : 1;
>
> struct iommu_group *sid2group[DART_MAX_STREAMS];
> struct iommu_device iommu;
> @@ -576,6 +574,9 @@ static int apple_dart_finalize_domain(struct
> apple_dart_domain *dart_domain,
> int ret = 0;
> int i, j;
>
> + if (dart->pgsize > PAGE_SIZE)
> + return -EINVAL;
> +
> mutex_lock(&dart_domain->init_lock);
>
> if (dart_domain->finalized)
> @@ -659,9 +660,6 @@ static int apple_dart_attach_dev_paging(struct
> iommu_domain *domain,
> struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
> struct apple_dart_domain *dart_domain = to_dart_domain(domain);
>
> - if (cfg->stream_maps[0].dart->force_bypass)
> - return -EINVAL;
> -
> ret = apple_dart_finalize_domain(dart_domain, cfg);
> if (ret)
> return ret;
> @@ -706,9 +704,6 @@ static int apple_dart_attach_dev_blocked(struct
> iommu_domain *domain,
> struct apple_dart_stream_map *stream_map;
> int i;
>
> - if (cfg->stream_maps[0].dart->force_bypass)
> - return -EINVAL;
> -
> for_each_stream_map(i, cfg, stream_map)
> apple_dart_hw_disable_dma(stream_map);
> return 0;
> @@ -803,8 +798,6 @@ static int apple_dart_of_xlate(struct device *dev,
> struct of_phandle_args *args)
> if (cfg_dart) {
> if (cfg_dart->supports_bypass != dart->supports_bypass)
> return -EINVAL;
> - if (cfg_dart->force_bypass != dart->force_bypass)
> - return -EINVAL;
> if (cfg_dart->pgsize != dart->pgsize)
> return -EINVAL;
> }
> @@ -946,7 +939,7 @@ static int apple_dart_def_domain_type(struct device
> *dev)
> {
> struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
>
> - if (cfg->stream_maps[0].dart->force_bypass)
> + if (cfg->stream_maps[0].dart->pgsize > PAGE_SIZE)
> return IOMMU_DOMAIN_IDENTITY;
> if (!cfg->stream_maps[0].dart->supports_bypass)
> return IOMMU_DOMAIN_DMA;
> @@ -1146,8 +1139,6 @@ static int apple_dart_probe(struct platform_device
> *pdev)
> goto err_clk_disable;
> }
>
> - dart->force_bypass = dart->pgsize > PAGE_SIZE;
> -
> ret = apple_dart_hw_reset(dart);
> if (ret)
> goto err_clk_disable;
> @@ -1171,7 +1162,8 @@ static int apple_dart_probe(struct
> platform_device *pdev)
> dev_info(
> &pdev->dev,
> "DART [pagesize %x, %d streams, bypass support: %d, bypass
> forced:
> %d] initialized\n",
> - dart->pgsize, dart->num_streams, dart->supports_bypass,
> dart->force_bypass);
> + dart->pgsize, dart->num_streams, dart->supports_bypass,
> + dart->pgsize > PAGE_SIZE);
> return 0;
>
> err_sysfs_remove:
> --
Reviewed-by: Janne Grunau <j...@jannau.net>
thanks,
Janne
