Messages in this thread | | | Date | Fri, 1 Feb 2013 14:54:57 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH v6 1/4] iommu/shmobile: Add iommu driver for Renesas IPMMU modules |
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On Mon, Jan 21, 2013 at 07:54:26PM +0900, Hideki EIRAKU wrote: > This is the Renesas IPMMU driver and IOMMU API implementation. > > The IPMMU module supports the MMU function and the PMB function. The > MMU function provides address translation by pagetable compatible with > ARMv6. The PMB function provides address translation including > tile-linear translation. This patch implements the MMU function. > > The iommu driver does not register a platform driver directly because: > - the register space of the MMU function and the PMB function > have a common register (used for settings flush), so they should ideally > have a way to appropriately share this register. > - the MMU function uses the IOMMU API while the PMB function does not. > - the two functions may be used independently. > > Signed-off-by: Hideki EIRAKU <hdk@igel.co.jp>
The patch looks good in general. Just one question inline.
> +static int pgtable_alloc(struct shmobile_iommu_domain_pgtable *pgtable, > + struct kmem_cache *cache, size_t size) > +{ > + pgtable->pgtable = kmem_cache_zalloc(cache, GFP_ATOMIC); > + if (!pgtable->pgtable) > + return -ENOMEM; > + pgtable->handle = dma_map_single(NULL, pgtable->pgtable, size, > + DMA_TO_DEVICE); > + return 0; > +}
Why is it necessary to call dma_map_single() for IOMMU page-tables? usually the dma_* functions call into IOMMU drivers, so why are they used inside an IOMMU driver?
Regards,
Joerg
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