Re: [PATCH 1/5] iommu/omap: Use the cache cleaning API

[Suman Anna <s-anna@xxxxxx>]

Hi Laurent,

On 03/07/2014 06:46 PM, Laurent Pinchart wrote:
> The page table entries must be cleaned from the cache before being
> accessed by the IOMMU. Instead of implementing cache management manually
> (and ignoring L2 cache), use clean_dcache_area() to make sure the
> entries are visible to the device.

Thanks for fixing this, this has been long pending. There have been some 
previous attempts at this as well by Ramesh Gupta, with the last thread 
(a long time now) being
http://marc.info/?t=134752035400001&r=1&w=2

Santosh,
Can you please take a look at this patch and provide your comments?

regards
Suman

> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
>   drivers/iommu/omap-iommu.c | 41 ++++++++++-------------------------------
>   1 file changed, 10 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> index a893eca..bb605c9 100644
> --- a/drivers/iommu/omap-iommu.c
> +++ b/drivers/iommu/omap-iommu.c
> @@ -500,24 +500,9 @@ EXPORT_SYMBOL_GPL(omap_foreach_iommu_device);
>   /*
>    *	H/W pagetable operations
>    */
> -static void flush_iopgd_range(u32 *first, u32 *last)
> +static void flush_pgtable(void *addr, size_t size)
>   {
> -	/* FIXME: L2 cache should be taken care of if it exists */
> -	do {
> -		asm("mcr	p15, 0, %0, c7, c10, 1 @ flush_pgd"
> -		    : : "r" (first));
> -		first += L1_CACHE_BYTES / sizeof(*first);
> -	} while (first <= last);
> -}
> -
> -static void flush_iopte_range(u32 *first, u32 *last)
> -{
> -	/* FIXME: L2 cache should be taken care of if it exists */
> -	do {
> -		asm("mcr	p15, 0, %0, c7, c10, 1 @ flush_pte"
> -		    : : "r" (first));
> -		first += L1_CACHE_BYTES / sizeof(*first);
> -	} while (first <= last);
> +	clean_dcache_area(addr, size);
>   }
>
>   static void iopte_free(u32 *iopte)
> @@ -546,7 +531,7 @@ static u32 *iopte_alloc(struct omap_iommu *obj, u32 *iopgd, u32 da)
>   			return ERR_PTR(-ENOMEM);
>
>   		*iopgd = virt_to_phys(iopte) | IOPGD_TABLE;
> -		flush_iopgd_range(iopgd, iopgd);
> +		flush_pgtable(iopgd, sizeof(*iopgd));
>
>   		dev_vdbg(obj->dev, "%s: a new pte:%p\n", __func__, iopte);
>   	} else {
> @@ -575,7 +560,7 @@ static int iopgd_alloc_section(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
>   	}
>
>   	*iopgd = (pa & IOSECTION_MASK) | prot | IOPGD_SECTION;
> -	flush_iopgd_range(iopgd, iopgd);
> +	flush_pgtable(iopgd, sizeof(*iopgd));
>   	return 0;
>   }
>
> @@ -592,7 +577,7 @@ static int iopgd_alloc_super(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
>
>   	for (i = 0; i < 16; i++)
>   		*(iopgd + i) = (pa & IOSUPER_MASK) | prot | IOPGD_SUPER;
> -	flush_iopgd_range(iopgd, iopgd + 15);
> +	flush_pgtable(iopgd, sizeof(*iopgd) * 16);
>   	return 0;
>   }
>
> @@ -605,7 +590,7 @@ static int iopte_alloc_page(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
>   		return PTR_ERR(iopte);
>
>   	*iopte = (pa & IOPAGE_MASK) | prot | IOPTE_SMALL;
> -	flush_iopte_range(iopte, iopte);
> +	flush_pgtable(iopte, sizeof(*iopte));
>
>   	dev_vdbg(obj->dev, "%s: da:%08x pa:%08x pte:%p *pte:%08x\n",
>   		 __func__, da, pa, iopte, *iopte);
> @@ -619,18 +604,12 @@ static int iopte_alloc_large(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
>   	u32 *iopte = iopte_alloc(obj, iopgd, da);
>   	int i;
>
> -	if ((da | pa) & ~IOLARGE_MASK) {
> -		dev_err(obj->dev, "%s: %08x:%08x should aligned on %08lx\n",
> -			__func__, da, pa, IOLARGE_SIZE);
> -		return -EINVAL;
> -	}
> -
>   	if (IS_ERR(iopte))
>   		return PTR_ERR(iopte);
>
>   	for (i = 0; i < 16; i++)
>   		*(iopte + i) = (pa & IOLARGE_MASK) | prot | IOPTE_LARGE;
> -	flush_iopte_range(iopte, iopte + 15);
> +	flush_pgtable(iopte, sizeof(*iopte) * 16);
>   	return 0;
>   }
>
> @@ -733,7 +712,7 @@ static size_t iopgtable_clear_entry_core(struct omap_iommu *obj, u32 da)
>   		}
>   		bytes *= nent;
>   		memset(iopte, 0, nent * sizeof(*iopte));
> -		flush_iopte_range(iopte, iopte + (nent - 1) * sizeof(*iopte));
> +		flush_pgtable(iopte, sizeof(*iopte) * nent);
>
>   		/*
>   		 * do table walk to check if this table is necessary or not
> @@ -755,7 +734,7 @@ static size_t iopgtable_clear_entry_core(struct omap_iommu *obj, u32 da)
>   		bytes *= nent;
>   	}
>   	memset(iopgd, 0, nent * sizeof(*iopgd));
> -	flush_iopgd_range(iopgd, iopgd + (nent - 1) * sizeof(*iopgd));
> +	flush_pgtable(iopgd, sizeof(*iopgd) * nent);
>   out:
>   	return bytes;
>   }
> @@ -799,7 +778,7 @@ static void iopgtable_clear_entry_all(struct omap_iommu *obj)
>   			iopte_free(iopte_offset(iopgd, 0));
>
>   		*iopgd = 0;
> -		flush_iopgd_range(iopgd, iopgd);
> +		flush_pgtable(iopgd, sizeof(*iopgd));
>   	}
>
>   	flush_iotlb_all(obj);

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