Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 634242b8 authored by Mitchel Humpherys's avatar Mitchel Humpherys Committed by Matt Wagantall
Browse files

iommu: io-pgtable-arm: implement .map_sg 



Mapping an entire scatterlist at once is faster than calling iommu_map
on each link individually.  Implement .map_sg in the ARM LPAE page table
allocator so that drivers using the allocator can leverage this
performance boost.

Change-Id: I77f62a2566058693c3f58fc0b05d715a780ae5d8
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
parent 9916c5dc

drivers/iommu/io-pgtable-arm.c

+61 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 


#include <linux/iommu.h>

#include <linux/kernel.h>

#include <linux/scatterlist.h>

#include <linux/sizes.h>

#include <linux/slab.h>

#include <linux/types.h>
@@ -317,6 +318,65 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova, 
	return __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep);

}



static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,

			   struct scatterlist *sg, unsigned int nents,

			   int iommu_prot)

{

	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);

	arm_lpae_iopte *ptep = data->pgd;

	int lvl = ARM_LPAE_START_LVL(data);

	arm_lpae_iopte prot;

	struct scatterlist *s;

	size_t mapped = 0;

	int i, ret;

	unsigned int min_pagesz;



	/* If no access, then nothing to do */

	if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))

		return 0;



	prot = arm_lpae_prot_to_pte(data, iommu_prot);



	min_pagesz = 1 << __ffs(data->iop.cfg.pgsize_bitmap);



	for_each_sg(sg, s, nents, i) {

		phys_addr_t phys = page_to_phys(sg_page(s)) + s->offset;

		size_t size = s->length;



		/*

		 * We are mapping on IOMMU page boundaries, so offset within

		 * the page must be 0. However, the IOMMU may support pages

		 * smaller than PAGE_SIZE, so s->offset may still represent

		 * an offset of that boundary within the CPU page.

		 */

		if (!IS_ALIGNED(s->offset, min_pagesz))

			goto out_err;



		while (size) {

			size_t pgsize = iommu_pgsize(

				data->iop.cfg.pgsize_bitmap, iova | phys, size);

			ret = __arm_lpae_map(data, iova, phys, pgsize, prot,

					     lvl, ptep);

			if (ret)

				goto out_err;



			iova += pgsize;

			mapped += pgsize;

			phys += pgsize;

			size -= pgsize;

		}

	}



	return mapped;



out_err:

	/* undo mappings already done */

	if (mapped)

		ops->unmap(ops, iova, mapped);



	return 0;

}



static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,

				    arm_lpae_iopte *ptep)

{
@@ -563,6 +623,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg) 


	data->iop.ops = (struct io_pgtable_ops) {

		.map		= arm_lpae_map,

		.map_sg		= arm_lpae_map_sg,

		.unmap		= arm_lpae_unmap,

		.iova_to_phys	= arm_lpae_iova_to_phys,

	};