[v5,05/07] iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops

Commit Message

Magnus Damm Sept. 20, 2016, 1:44 p.m. UTC

From: Magnus Damm <[e-mail]>

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 <[e-mail]>
---

 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 |  111 ++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 104 insertions(+), 8 deletions(-)

Comments

Joerg Roedel Sept. 22, 2016, 2:45 p.m. UTC | #1

On Tue, Sep 20, 2016 at 10:44:46PM +0900, Magnus Damm wrote:
> +#ifdef CONFIG_IOMMU_DMA
> +
> +static struct iommu_domain *ipmmu_domain_alloc_dma(unsigned type)
> +{
> +	struct iommu_domain *io_domain;
> +
> +	if (type != IOMMU_DOMAIN_DMA)
> +		return NULL;
> +
> +	io_domain = __ipmmu_domain_alloc(type);
> +	if (io_domain)
> +		iommu_get_dma_cookie(io_domain);
> +
> +	return io_domain;
> +}
> +
> +static void ipmmu_domain_free_dma(struct iommu_domain *io_domain)
> +{
> +	iommu_put_dma_cookie(io_domain);
> +	ipmmu_domain_free(io_domain);
> +}

> [...]

> +static const struct iommu_ops ipmmu_ops = {
> +	.domain_alloc = ipmmu_domain_alloc_dma,
> +	.domain_free = ipmmu_domain_free_dma,

Okay, so when CONFIG_IOMMU_DMA is enabled, you only support allocation
of DMA domains, not UNMANAGED domains anymore. Is there a reason for
that?

You can reduce the #ifdef'ed coded by supporting both types of domains
and call into allocation-subfunctions for DMA and UNMANAGED domains. The
#ifdef could then only let the dma-allocation function return NULL.

This would be much more compatible to what other IOMMU drivers do and
will allow VFIO usage in the future.



	Joerg

Magnus Damm Oct. 19, 2016, 11:45 p.m. UTC | #2

Hi Joerg,

On Thu, Sep 22, 2016 at 11:45 PM, Joerg Roedel <[e-mail]> wrote:
> On Tue, Sep 20, 2016 at 10:44:46PM +0900, Magnus Damm wrote:
>> +#ifdef CONFIG_IOMMU_DMA
>> +
>> +static struct iommu_domain *ipmmu_domain_alloc_dma(unsigned type)
>> +{
>> +     struct iommu_domain *io_domain;
>> +
>> +     if (type != IOMMU_DOMAIN_DMA)
>> +             return NULL;
>> +
>> +     io_domain = __ipmmu_domain_alloc(type);
>> +     if (io_domain)
>> +             iommu_get_dma_cookie(io_domain);
>> +
>> +     return io_domain;
>> +}
>> +
>> +static void ipmmu_domain_free_dma(struct iommu_domain *io_domain)
>> +{
>> +     iommu_put_dma_cookie(io_domain);
>> +     ipmmu_domain_free(io_domain);
>> +}
>
>> [...]
>
>> +static const struct iommu_ops ipmmu_ops = {
>> +     .domain_alloc = ipmmu_domain_alloc_dma,
>> +     .domain_free = ipmmu_domain_free_dma,
>
> Okay, so when CONFIG_IOMMU_DMA is enabled, you only support allocation
> of DMA domains, not UNMANAGED domains anymore. Is there a reason for
> that?

Just historical reason migrating from UNMANAGED only to DMA only.

> You can reduce the #ifdef'ed coded by supporting both types of domains
> and call into allocation-subfunctions for DMA and UNMANAGED domains. The
> #ifdef could then only let the dma-allocation function return NULL.
>
> This would be much more compatible to what other IOMMU drivers do and
> will allow VFIO usage in the future.

Thanks for your suggestion. I've now updated the code in V6, hopefully
it would match your expectation better.

Cheers,

/ magnus

Patch

--- 0001/drivers/iommu/Kconfig
+++ work/drivers/iommu/Kconfig	2016-09-20 22:10:15.280607110 +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	2016-09-20 22:08:58.300607110 +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 +826,94 @@  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;
+
+	if (type != IOMMU_DOMAIN_DMA)
+		return NULL;
+
+	io_domain = __ipmmu_domain_alloc(type);
+	if (io_domain)
+		iommu_get_dma_cookie(io_domain);
+
+	return io_domain;
+}
+
+static void ipmmu_domain_free_dma(struct iommu_domain *io_domain)
+{
+	iommu_put_dma_cookie(io_domain);
+	ipmmu_domain_free(io_domain);
+}
+
+static int ipmmu_add_device_dma(struct device *dev)
+{
+	struct iommu_group *group;
+
+	/* only accept devices with iommus property */
+	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() */
+	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,
+};
+
+#endif /* CONFIG_IOMMU_DMA */
+
 /* -----------------------------------------------------------------------------
  * Probe/remove and init
  */
@@ -910,7 +1003,9 @@  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);