Re: [PATCH v6 05/07] iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops

Laurent Pinchart
2016-11-11T01:24:43Z

Hi Magnus,

Thank you for the patch.

On Thursday 20 Oct 2016 08:36:23 Magnus Damm wrote:
> From: Magnus Damm <damm+renesas@opensource.se>
>
> Introduce an alternative set of iommu_ops suitable for 64-bit ARM
> as well as 32-bit ARM when CONFIG_IOMMU_DMA=y. Also adjust the
> Kconfig to depend on ARM or IOMMU_DMA.
>
> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
> ---
>
> Changes since V5:
> - Made domain allocation/free code more consistent - thanks Joerg!
>
> Changes since V4:
> - Added Kconfig hunk to depend on ARM or IOMMU_DMA
>
> Changes since V3:
> - Removed group parameter from ipmmu_init_platform_device()
>
> Changes since V2:
> - Included this new patch from the following series:
> [PATCH 00/04] iommu/ipmmu-vmsa: IPMMU CONFIG_IOMMU_DMA update
> - Use only a single iommu_ops structure with #ifdef CONFIG_IOMMU_DMA
> - Folded in #ifdefs to handle CONFIG_ARM and CONFIG_IOMMU_DMA
> - of_xlate() is now used without #ifdefs
> - Made sure code compiles on both 32-bit and 64-bit ARM.
>
> drivers/iommu/Kconfig | 1
> drivers/iommu/ipmmu-vmsa.c | 122 ++++++++++++++++++++++++++++++++++++++---
> 2 files changed, 115 insertions(+), 8 deletions(-)
>
> --- 0001/drivers/iommu/Kconfig
> +++ work/drivers/iommu/Kconfig 2016-10-20 08:16:40.980607110 +0900
> @@ -274,6 +274,7 @@ config EXYNOS_IOMMU_DEBUG
>
> config IPMMU_VMSA
> bool "Renesas VMSA-compatible IPMMU"
> + depends on ARM || IOMMU_DMA
> depends on ARM_LPAE
> depends on ARCH_RENESAS || COMPILE_TEST
> select IOMMU_API
> --- 0006/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c 2016-10-20 08:16:48.440607110 +0900
> @@ -10,6 +10,7 @@
>
> #include <linux/bitmap.h>
> #include <linux/delay.h>
> +#include <linux/dma-iommu.h>
> #include <linux/dma-mapping.h>
> #include <linux/err.h>
> #include <linux/export.h>
> @@ -22,8 +23,10 @@
> #include <linux/sizes.h>
> #include <linux/slab.h>
>
> +#if defined(CONFIG_ARM) && !defined(CONFIG_IOMMU_DMA)
> #include <asm/dma-iommu.h>
> #include <asm/pgalloc.h>
> +#endif
>
> #include "io-pgtable.h"
>
> @@ -520,14 +523,6 @@ static struct iommu_domain *__ipmmu_doma
> return &domain->io_domain;
> }
>
> -static struct iommu_domain *ipmmu_domain_alloc(unsigned type)
> -{
> - if (type != IOMMU_DOMAIN_UNMANAGED)
> - return NULL;
> -
> - return __ipmmu_domain_alloc(type);
> -}
> -
> static void ipmmu_domain_free(struct iommu_domain *io_domain)
> {
> struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
> @@ -714,6 +709,8 @@ error:
> return ret;
> }
>
> +#if defined(CONFIG_ARM) && !defined(CONFIG_IOMMU_DMA)
> +
> static int ipmmu_add_device(struct device *dev)
> {
> struct ipmmu_vmsa_archdata *archdata;
> @@ -807,6 +804,14 @@ static void ipmmu_remove_device(struct d
> dev->archdata.iommu = NULL;
> }
>
> +static struct iommu_domain *ipmmu_domain_alloc(unsigned type)
> +{
> + if (type != IOMMU_DOMAIN_UNMANAGED)
> + return NULL;
> +
> + return __ipmmu_domain_alloc(type);
> +}
> +
> static const struct iommu_ops ipmmu_ops = {
> .domain_alloc = ipmmu_domain_alloc,
> .domain_free = ipmmu_domain_free,
> @@ -821,6 +826,105 @@ static const struct iommu_ops ipmmu_ops
> .pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
> };
>
> +#endif /* !CONFIG_ARM && CONFIG_IOMMU_DMA */
> +
> +#ifdef CONFIG_IOMMU_DMA
> +
> +static struct iommu_domain *ipmmu_domain_alloc_dma(unsigned type)
> +{
> + struct iommu_domain *io_domain = NULL;
> +
> + switch (type) {
> + case IOMMU_DOMAIN_UNMANAGED:
> + io_domain = __ipmmu_domain_alloc(type);
> + break;
> +
> + case IOMMU_DOMAIN_DMA:
> + io_domain = __ipmmu_domain_alloc(type);
> + if (io_domain)
> + iommu_get_dma_cookie(io_domain);
> + break;
> + }
> +
> + return io_domain;
> +}
> +
> +static void ipmmu_domain_free_dma(struct iommu_domain *io_domain)
> +{
> + switch (io_domain->type) {
> + case IOMMU_DOMAIN_DMA:
> + iommu_put_dma_cookie(io_domain);
> + /* fall-through */
> + default:
> + ipmmu_domain_free(io_domain);
> + break;
> + }
> +}
> +
> +static int ipmmu_add_device_dma(struct device *dev)
> +{
> + struct iommu_group *group;
> +
> + /* only accept devices with iommus property */

Nitpicking, comments in the driver are capitalized and end with a period.

> + if (of_count_phandle_with_args(dev->of_node, "iommus",
> + "#iommu-cells") < 0)
> + return -ENODEV;
> +
> + group = iommu_group_get_for_dev(dev);
> + if (IS_ERR(group))
> + return PTR_ERR(group);
> +
> + return 0;
> +}
> +
> +static void ipmmu_remove_device_dma(struct device *dev)
> +{
> + iommu_group_remove_device(dev);
> +}
> +
> +static struct iommu_group *ipmmu_device_group_dma(struct device *dev)
> +{
> + struct iommu_group *group;
> + int ret;
> +
> + group = generic_device_group(dev);
> + if (IS_ERR(group))
> + return group;
> +
> + ret = ipmmu_init_platform_device(dev);
> + if (ret) {
> + iommu_group_put(group);
> + group = ERR_PTR(ret);
> + }
> +
> + return group;
> +}
> +
> +static int ipmmu_of_xlate_dma(struct device *dev,
> + struct of_phandle_args *spec)
> +{
> + /* dummy callback to satisfy of_iommu_configure() */

This is actually where you should parse the utlbs. If you switch to the
iommu_fwspec API as Robin proposed in his review of patch 6/7, I think you can
use iommu_fwspec_add_ids() as a helper function for this. See the arm-smmu-v3
driver for an example.

> + return 0;
> +}
> +
> +static const struct iommu_ops ipmmu_ops = {
> + .domain_alloc = ipmmu_domain_alloc_dma,
> + .domain_free = ipmmu_domain_free_dma,
> + .attach_dev = ipmmu_attach_device,
> + .detach_dev = ipmmu_detach_device,
> + .map = ipmmu_map,
> + .unmap = ipmmu_unmap,
> + .map_sg = default_iommu_map_sg,
> + .iova_to_phys = ipmmu_iova_to_phys,
> + .add_device = ipmmu_add_device_dma,
> + .remove_device = ipmmu_remove_device_dma,
> + .device_group = ipmmu_device_group_dma,
> + .pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
> + .of_xlate = ipmmu_of_xlate_dma,

The ARM implementation should switch to .of_xlate() too. Have you given it a
try by any chance ?

> +};
> +
> +#endif /* CONFIG_IOMMU_DMA */
> +
> /* ------------------------------------------------------------------------
> * Probe/remove and init
> */
> @@ -910,7 +1014,9 @@ static int ipmmu_remove(struct platform_
> list_del(&mmu->list);
> spin_unlock(&ipmmu_devices_lock);
>
> +#if defined(CONFIG_ARM) && !defined(CONFIG_IOMMU_DMA)
> arm_iommu_release_mapping(mmu->mapping);
> +#endif
>
> ipmmu_device_reset(mmu);

--
Regards,

Laurent Pinchart