iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops

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. Initialize the device
from ->xlate() when CONFIG_IOMMU_DMA=y.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

2 files changed, 156 insertions, 9 deletions

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 6ee3a25ae731..504ba025a54c 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -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
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index eb5008596051..8b648f6e0e4d 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -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"
 
@@ -57,6 +60,8 @@ struct ipmmu_vmsa_archdata {
         struct ipmmu_vmsa_device *mmu;
         unsigned int *utlbs;
         unsigned int num_utlbs;
+        struct device *dev;
+        struct list_head list;
 };
 
 static DEFINE_SPINLOCK(ipmmu_devices_lock);
@@ -522,14 +527,6 @@ static struct iommu_domain *__ipmmu_domain_alloc(unsigned type)
         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);
@@ -572,7 +569,8 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain,
                 dev_err(dev, "Can't attach IPMMU %s to domain on IPMMU %s\n",
                         dev_name(mmu->dev), dev_name(domain->mmu->dev));
                 ret = -EINVAL;
-        }
+        } else
+                dev_info(dev, "Reusing IPMMU context %u\n", domain->context_id);
 
         spin_unlock_irqrestore(&domain->lock, flags);
 
@@ -708,6 +706,7 @@ static int ipmmu_init_platform_device(struct device *dev)
         archdata->mmu = mmu;
         archdata->utlbs = utlbs;
         archdata->num_utlbs = num_utlbs;
+        archdata->dev = dev;
         dev->archdata.iommu = archdata;
         return 0;
 
@@ -716,6 +715,16 @@ error:
         return ret;
 }
 
+#if defined(CONFIG_ARM) && !defined(CONFIG_IOMMU_DMA)
+
+static struct iommu_domain *ipmmu_domain_alloc(unsigned type)
+{
+        if (type != IOMMU_DOMAIN_UNMANAGED)
+                return NULL;
+
+        return __ipmmu_domain_alloc(type);
+}
+
 static int ipmmu_add_device(struct device *dev)
 {
         struct ipmmu_vmsa_archdata *archdata;
@@ -825,6 +834,141 @@ 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 DEFINE_SPINLOCK(ipmmu_slave_devices_lock);
+static LIST_HEAD(ipmmu_slave_devices);
+
+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 ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
+        struct iommu_group *group;
+
+        /* The device has been verified in xlate() */
+        if (!archdata)
+                return -ENODEV;
+
+        group = iommu_group_get_for_dev(dev);
+        if (IS_ERR(group))
+                return PTR_ERR(group);
+
+        spin_lock(&ipmmu_slave_devices_lock);
+        list_add(&archdata->list, &ipmmu_slave_devices);
+        spin_unlock(&ipmmu_slave_devices_lock);
+        return 0;
+}
+
+static void ipmmu_remove_device_dma(struct device *dev)
+{
+        struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
+
+        spin_lock(&ipmmu_slave_devices_lock);
+        list_del(&archdata->list);
+        spin_unlock(&ipmmu_slave_devices_lock);
+
+        iommu_group_remove_device(dev);
+}
+
+static struct device *ipmmu_find_sibling_device(struct device *dev)
+{
+        struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
+        struct ipmmu_vmsa_archdata *sibling_archdata = NULL;
+        bool found = false;
+
+        spin_lock(&ipmmu_slave_devices_lock);
+
+        list_for_each_entry(sibling_archdata, &ipmmu_slave_devices, list) {
+                if (archdata == sibling_archdata)
+                        continue;
+                if (sibling_archdata->mmu == archdata->mmu) {
+                        found = true;
+                        break;
+                }
+        }
+
+        spin_unlock(&ipmmu_slave_devices_lock);
+
+        return found ? sibling_archdata->dev : NULL;
+}
+
+static struct iommu_group *ipmmu_find_group_dma(struct device *dev)
+{
+        struct iommu_group *group;
+        struct device *sibling;
+
+        sibling = ipmmu_find_sibling_device(dev);
+        if (sibling)
+                group = iommu_group_get(sibling);
+        if (!sibling || IS_ERR(group))
+                group = generic_device_group(dev);
+
+        return group;
+}
+
+static int ipmmu_of_xlate_dma(struct device *dev,
+                              struct of_phandle_args *spec)
+{
+        /* If the IPMMU device is disabled in DT then return error
+         * to make sure the of_iommu code does not install ops
+         * even though the iommu device is disabled
+         */
+        if (!of_device_is_available(spec->np))
+                return -ENODEV;
+
+        return ipmmu_init_platform_device(dev);
+}
+
+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_find_group_dma,
+        .pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
+        .of_xlate = ipmmu_of_xlate_dma,
+};
+
+#endif /* CONFIG_IOMMU_DMA */
+
 /* -----------------------------------------------------------------------------
  * Probe/remove and init
  */
@@ -914,7 +1058,9 @@ static int ipmmu_remove(struct platform_device *pdev)
         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);