iommu/ipmmu-vmsa: Add optional root device feature

Add root device handling to the IPMMU driver by allowing certain
DT compat strings to enable has_cache_leaf_nodes that in turn will
support both root devices with interrupts and leaf devices that
face the actual IPMMU consumer devices.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 5ce7879..5db853b 100644 (file)
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -41,12 +41,14 @@
 
 struct ipmmu_features {
        bool use_ns_alias_offset;
+       bool has_cache_leaf_nodes;
 };
 
 struct ipmmu_vmsa_device {
        struct device *dev;
        void __iomem *base;
        struct iommu_device iommu;
+       struct ipmmu_vmsa_device *root;
        const struct ipmmu_features *features;
        unsigned int num_utlbs;
        spinlock_t lock;                        /* Protects ctx and domains[] */
@@ -199,6 +201,36 @@ static struct ipmmu_vmsa_device *to_ipmmu(struct device *dev)
 #define IMUASID_ASID0_SHIFT            0
 
 /* -----------------------------------------------------------------------------
+ * Root device handling
+ */
+
+static struct platform_driver ipmmu_driver;
+
+static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
+{
+       return mmu->root == mmu;
+}
+
+static int __ipmmu_check_device(struct device *dev, void *data)
+{
+       struct ipmmu_vmsa_device *mmu = dev_get_drvdata(dev);
+       struct ipmmu_vmsa_device **rootp = data;
+
+       if (ipmmu_is_root(mmu))
+               *rootp = mmu;
+
+       return 0;
+}
+
+static struct ipmmu_vmsa_device *ipmmu_find_root(void)
+{
+       struct ipmmu_vmsa_device *root = NULL;
+
+       return driver_for_each_device(&ipmmu_driver.driver, NULL, &root,
+                                     __ipmmu_check_device) == 0 ? root : NULL;
+}
+
+/* -----------------------------------------------------------------------------
  * Read/Write Access
  */
 
@@ -215,13 +247,15 @@ static void ipmmu_write(struct ipmmu_vmsa_device *mmu, unsigned int offset,
 
 static u32 ipmmu_ctx_read(struct ipmmu_vmsa_domain *domain, unsigned int reg)
 {
-       return ipmmu_read(domain->mmu, domain->context_id * IM_CTX_SIZE + reg);
+       return ipmmu_read(domain->mmu->root,
+                         domain->context_id * IM_CTX_SIZE + reg);
 }
 
 static void ipmmu_ctx_write(struct ipmmu_vmsa_domain *domain, unsigned int reg,
                            u32 data)
 {
-       ipmmu_write(domain->mmu, domain->context_id * IM_CTX_SIZE + reg, data);
+       ipmmu_write(domain->mmu->root,
+                   domain->context_id * IM_CTX_SIZE + reg, data);
 }
 
 /* -----------------------------------------------------------------------------
@@ -369,12 +403,12 @@ static int ipmmu_domain_init_context(struct ipmmu_vmsa_domain *domain)
         * TODO: Add support for coherent walk through CCI with DVM and remove
         * cache handling. For now, delegate it to the io-pgtable code.
         */
-       domain->cfg.iommu_dev = domain->mmu->dev;
+       domain->cfg.iommu_dev = domain->mmu->root->dev;
 
        /*
         * Find an unused context.
         */
-       ret = ipmmu_domain_allocate_context(domain->mmu, domain);
+       ret = ipmmu_domain_allocate_context(domain->mmu->root, domain);
        if (ret == IPMMU_CTX_MAX)
                return -EBUSY;
 
@@ -383,7 +417,8 @@ static int ipmmu_domain_init_context(struct ipmmu_vmsa_domain *domain)
        domain->iop = alloc_io_pgtable_ops(ARM_32_LPAE_S1, &domain->cfg,
                                           domain);
        if (!domain->iop) {
-               ipmmu_domain_free_context(domain->mmu, domain->context_id);
+               ipmmu_domain_free_context(domain->mmu->root,
+                                         domain->context_id);
                return -EINVAL;
        }
 
@@ -437,7 +472,7 @@ static void ipmmu_domain_destroy_context(struct ipmmu_vmsa_domain *domain)
         */
        ipmmu_ctx_write(domain, IMCTR, IMCTR_FLUSH);
        ipmmu_tlb_sync(domain);
-       ipmmu_domain_free_context(domain->mmu, domain->context_id);
+       ipmmu_domain_free_context(domain->mmu->root, domain->context_id);
 }
 
 /* -----------------------------------------------------------------------------
@@ -824,6 +859,7 @@ static void ipmmu_device_reset(struct ipmmu_vmsa_device *mmu)
 
 static const struct ipmmu_features ipmmu_features_default = {
        .use_ns_alias_offset = true,
+       .has_cache_leaf_nodes = false,
 };
 
 static const struct of_device_id ipmmu_of_ids[] = {
@@ -878,19 +914,39 @@ static int ipmmu_probe(struct platform_device *pdev)
                mmu->base += IM_NS_ALIAS_OFFSET;
 
        irq = platform_get_irq(pdev, 0);
-       if (irq < 0) {
-               dev_err(&pdev->dev, "no IRQ found\n");
-               return irq;
-       }
 
-       ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
-                              dev_name(&pdev->dev), mmu);
-       if (ret < 0) {
-               dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
-               return ret;
-       }
+       /*
+        * Determine if this IPMMU instance is a root device by checking for
+        * the lack of has_cache_leaf_nodes flag or renesas,ipmmu-main property.
+        */
+       if (!mmu->features->has_cache_leaf_nodes ||
+           !of_find_property(pdev->dev.of_node, "renesas,ipmmu-main", NULL))
+               mmu->root = mmu;
+       else
+               mmu->root = ipmmu_find_root();
 
-       ipmmu_device_reset(mmu);
+       /*
+        * Wait until the root device has been registered for sure.
+        */
+       if (!mmu->root)
+               return -EPROBE_DEFER;
+
+       /* Root devices have mandatory IRQs */
+       if (ipmmu_is_root(mmu)) {
+               if (irq < 0) {
+                       dev_err(&pdev->dev, "no IRQ found\n");
+                       return irq;
+               }
+
+               ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
+                                      dev_name(&pdev->dev), mmu);
+               if (ret < 0) {
+                       dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
+                       return ret;
+               }
+
+               ipmmu_device_reset(mmu);
+       }
 
        ret = iommu_device_sysfs_add(&mmu->iommu, &pdev->dev, NULL,
                                     dev_name(&pdev->dev));