From: Magnus Damm <damm+rene...@opensource.se>

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+rene...@opensource.se>
---

 Changes since V3:
 - Reworked root finding code to make it easier to follow, thanks Geert!
 
 Changes since V2:
 - Fixed a bug in ipmmu_find_root() when only leaf devices are present
 - Broke out __ipmmu_find_root() to allow ->xlate() check for root devices

 Changes since V1:
 - Moved patch to earlier in the series
 - Updated code to work with recent changes in:
   [PATCH v3 00/06] iommu/ipmmu-vmsa: IPMMU multi-arch update V3

 drivers/iommu/ipmmu-vmsa.c |   95 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 78 insertions(+), 17 deletions(-)

--- 0015/drivers/iommu/ipmmu-vmsa.c
+++ work/drivers/iommu/ipmmu-vmsa.c     2017-06-19 13:59:41.050607110 +0900
@@ -36,6 +36,7 @@
 
 struct ipmmu_features {
        bool use_ns_alias_offset;
+       bool has_cache_leaf_nodes;
 };
 
 struct ipmmu_vmsa_device {
@@ -44,6 +45,7 @@ struct ipmmu_vmsa_device {
        struct iommu_device iommu;
        struct list_head list;
        const struct ipmmu_features *features;
+       bool is_leaf;
        unsigned int num_utlbs;
        spinlock_t lock;                        /* Protects ctx and domains[] */
        DECLARE_BITMAP(ctx, IPMMU_CTX_MAX);
@@ -54,6 +56,7 @@ struct ipmmu_vmsa_device {
 
 struct ipmmu_vmsa_domain {
        struct ipmmu_vmsa_device *mmu;
+       struct ipmmu_vmsa_device *root;
        struct iommu_domain io_domain;
 
        struct io_pgtable_cfg cfg;
@@ -203,6 +206,44 @@ static struct ipmmu_vmsa_iommu_priv *to_
 #define IMUASID_ASID0_SHIFT            0
 
 /* 
-----------------------------------------------------------------------------
+ * Root device handling
+ */
+
+static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
+{
+       if (mmu->features->has_cache_leaf_nodes)
+               return mmu->is_leaf ? false : true;
+       else
+               return true; /* older IPMMU hardware treated as single root */
+}
+
+static struct ipmmu_vmsa_device *__ipmmu_find_root(void)
+{
+       struct ipmmu_vmsa_device *mmu;
+       struct ipmmu_vmsa_device *root = NULL;
+
+       spin_lock(&ipmmu_devices_lock);
+
+       list_for_each_entry(mmu, &ipmmu_devices, list) {
+               if (ipmmu_is_root(mmu)) {
+                       root = mmu;
+                       break;
+               }
+       }
+
+       spin_unlock(&ipmmu_devices_lock);
+       return root;
+}
+
+static struct ipmmu_vmsa_device *ipmmu_find_root(struct ipmmu_vmsa_device 
*leaf)
+{
+       if (ipmmu_is_root(leaf))
+               return leaf;
+       else
+               return __ipmmu_find_root();
+}
+
+/* 
-----------------------------------------------------------------------------
  * Read/Write Access
  */
 
@@ -219,13 +260,13 @@ static void ipmmu_write(struct ipmmu_vms
 
 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->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->root, domain->context_id * IM_CTX_SIZE + reg, data);
 }
 
 /* 
-----------------------------------------------------------------------------
@@ -360,7 +401,7 @@ static int ipmmu_domain_init_context(str
         * 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->root->dev;
 
        domain->iop = alloc_io_pgtable_ops(ARM_32_LPAE_S1, &domain->cfg,
                                           domain);
@@ -370,7 +411,7 @@ static int ipmmu_domain_init_context(str
        /*
         * Find an unused context.
         */
-       ret = ipmmu_domain_allocate_context(domain->mmu, domain);
+       ret = ipmmu_domain_allocate_context(domain->root, domain);
        if (ret == IPMMU_CTX_MAX) {
                free_io_pgtable_ops(domain->iop);
                return -EBUSY;
@@ -441,7 +482,7 @@ static void ipmmu_domain_destroy_context
         */
        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->root, domain->context_id);
 }
 
 /* 
-----------------------------------------------------------------------------
@@ -555,7 +596,7 @@ static int ipmmu_attach_device(struct io
 {
        struct ipmmu_vmsa_iommu_priv *priv = to_priv(dev);
        struct iommu_fwspec *fwspec = dev->iommu_fwspec;
-       struct ipmmu_vmsa_device *mmu = priv->mmu;
+       struct ipmmu_vmsa_device *root, *mmu = priv->mmu;
        struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
        unsigned long flags;
        unsigned int i;
@@ -566,11 +607,18 @@ static int ipmmu_attach_device(struct io
                return -ENXIO;
        }
 
+       root = ipmmu_find_root(priv->mmu);
+       if (!root) {
+               dev_err(dev, "Unable to locate root IPMMU\n");
+               return -EAGAIN;
+       }
+
        spin_lock_irqsave(&domain->lock, flags);
 
        if (!domain->mmu) {
                /* The domain hasn't been used yet, initialize it. */
                domain->mmu = mmu;
+               domain->root = root;
                ret = ipmmu_domain_init_context(domain);
        } else if (domain->mmu != mmu) {
                /*
@@ -911,6 +959,7 @@ static void ipmmu_device_reset(struct ip
 
 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[] = {
@@ -965,19 +1014,31 @@ static int ipmmu_probe(struct platform_d
                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 leaf device by checking
+        * if the renesas,ipmmu-main property exists or not.
+        */
+       if (mmu->features->has_cache_leaf_nodes &&
+           of_find_property(pdev->dev.of_node, "renesas,ipmmu-main", NULL))
+               mmu->is_leaf = true;
+
+       /* Root devices have mandatory IRQs */
+       if (ipmmu_is_root(mmu)) {
+               if (irq < 0) {
+                       dev_err(&pdev->dev, "no IRQ found\n");
+                       return irq;
+               }
 
-       ipmmu_device_reset(mmu);
+               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_register(&mmu->iommu);
        if (ret)
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