iommu/ipmmu-vmsa: Refactor micro-TLB lookup

Cache the micro-TLB number in archdata allocated in the .add_device
handler instead of looking it up when the deviced is attached and
detached. This simplifies the .attach_dev and .detach_dev operations and
prepares for DT support.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 52 insertions, 40 deletions

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index b084530babf4..1949f3c55679 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -44,6 +44,11 @@ struct ipmmu_vmsa_domain {
         pgd_t *pgd;
 };
 
+struct ipmmu_vmsa_archdata {
+        struct ipmmu_vmsa_device *mmu;
+        unsigned int utlb;
+};
+
 static DEFINE_SPINLOCK(ipmmu_devices_lock);
 static LIST_HEAD(ipmmu_devices);
 
@@ -265,14 +270,19 @@ static void ipmmu_tlb_invalidate(struct ipmmu_vmsa_domain *domain)
  * Enable MMU translation for the microTLB.
  */
 static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
-                              const struct ipmmu_vmsa_master *master)
+                              unsigned int utlb)
 {
         struct ipmmu_vmsa_device *mmu = domain->mmu;
 
+        /*
+         * TODO: Reference-count the microTLB as several bus masters can be
+         * connected to the same microTLB.
+         */
+
         /* TODO: What should we set the ASID to ? */
-        ipmmu_write(mmu, IMUASID(master->utlb), 0);
+        ipmmu_write(mmu, IMUASID(utlb), 0);
         /* TODO: Do we need to flush the microTLB ? */
-        ipmmu_write(mmu, IMUCTR(master->utlb),
+        ipmmu_write(mmu, IMUCTR(utlb),
                     IMUCTR_TTSEL_MMU(domain->context_id) | IMUCTR_FLUSH |
                     IMUCTR_MMUEN);
 }
@@ -281,11 +291,11 @@ static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
  * Disable MMU translation for the microTLB.
  */
 static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain *domain,
-                               const struct ipmmu_vmsa_master *master)
+                               unsigned int utlb)
 {
         struct ipmmu_vmsa_device *mmu = domain->mmu;
 
-        ipmmu_write(mmu, IMUCTR(master->utlb), 0);
+        ipmmu_write(mmu, IMUCTR(utlb), 0);
 }
 
 static void ipmmu_flush_pgtable(struct ipmmu_vmsa_device *mmu, void *addr,
@@ -674,21 +684,6 @@ static int ipmmu_handle_mapping(struct ipmmu_vmsa_domain *domain,
  * IOMMU Operations
  */
 
-static const struct ipmmu_vmsa_master *
-ipmmu_find_master(struct ipmmu_vmsa_device *ipmmu, struct device *dev)
-{
-        const struct ipmmu_vmsa_master *master = ipmmu->pdata->masters;
-        const char *devname = dev_name(dev);
-        unsigned int i;
-
-        for (i = 0; i < ipmmu->pdata->num_masters; ++i, ++master) {
-                if (strcmp(master->name, devname) == 0)
-                        return master;
-        }
-
-        return NULL;
-}
-
 static int ipmmu_domain_init(struct iommu_domain *io_domain)
 {
         struct ipmmu_vmsa_domain *domain;
@@ -727,9 +722,9 @@ static void ipmmu_domain_destroy(struct iommu_domain *io_domain)
 static int ipmmu_attach_device(struct iommu_domain *io_domain,
                                struct device *dev)
 {
-        struct ipmmu_vmsa_device *mmu = dev->archdata.iommu;
+        struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
+        struct ipmmu_vmsa_device *mmu = archdata->mmu;
         struct ipmmu_vmsa_domain *domain = io_domain->priv;
-        const struct ipmmu_vmsa_master *master;
         unsigned long flags;
         int ret = 0;
 
@@ -759,11 +754,7 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain,
         if (ret < 0)
                 return ret;
 
-        master = ipmmu_find_master(mmu, dev);
-        if (!master)
-                return -EINVAL;
-
-        ipmmu_utlb_enable(domain, master);
+        ipmmu_utlb_enable(domain, archdata->utlb);
 
         return 0;
 }
@@ -771,14 +762,10 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain,
 static void ipmmu_detach_device(struct iommu_domain *io_domain,
                                 struct device *dev)
 {
+        struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
         struct ipmmu_vmsa_domain *domain = io_domain->priv;
-        const struct ipmmu_vmsa_master *master;
 
-        master = ipmmu_find_master(domain->mmu, dev);
-        if (!master)
-                return;
-
-        ipmmu_utlb_disable(domain, master);
+        ipmmu_utlb_disable(domain, archdata->utlb);
 
         /*
          * TODO: Optimize by disabling the context when no device is attached.
@@ -839,11 +826,26 @@ static phys_addr_t ipmmu_iova_to_phys(struct iommu_domain *io_domain,
         return __pfn_to_phys(pte_pfn(pte)) | (iova & ~PAGE_MASK);
 }
 
+static int ipmmu_find_utlb(struct ipmmu_vmsa_device *mmu, struct device *dev)
+{
+        const struct ipmmu_vmsa_master *master = mmu->pdata->masters;
+        const char *devname = dev_name(dev);
+        unsigned int i;
+
+        for (i = 0; i < mmu->pdata->num_masters; ++i, ++master) {
+                if (strcmp(master->name, devname) == 0)
+                        return master->utlb;
+        }
+
+        return -1;
+}
+
 static int ipmmu_add_device(struct device *dev)
 {
-        const struct ipmmu_vmsa_master *master = NULL;
+        struct ipmmu_vmsa_archdata *archdata;
         struct ipmmu_vmsa_device *mmu;
         struct iommu_group *group;
+        int utlb = -1;
         int ret;
 
         if (dev->archdata.iommu) {
@@ -856,10 +858,10 @@ static int ipmmu_add_device(struct device *dev)
         spin_lock(&ipmmu_devices_lock);
 
         list_for_each_entry(mmu, &ipmmu_devices, list) {
-                master = ipmmu_find_master(mmu, dev);
-                if (master) {
+                utlb = ipmmu_find_utlb(mmu, dev);
+                if (utlb >= 0) {
                         /*
-                         * TODO Take a reference to the master to protect
+                         * TODO Take a reference to the MMU to protect
                          * against device removal.
                          */
                         break;
@@ -868,10 +870,10 @@ static int ipmmu_add_device(struct device *dev)
 
         spin_unlock(&ipmmu_devices_lock);
 
-        if (!master)
+        if (utlb < 0)
                 return -ENODEV;
 
-        if (!master->utlb >= mmu->num_utlbs)
+        if (utlb >= mmu->num_utlbs)
                 return -EINVAL;
 
         /* Create a device group and add the device to it. */
@@ -889,7 +891,15 @@ static int ipmmu_add_device(struct device *dev)
                 return ret;
         }
 
-        dev->archdata.iommu = mmu;
+        archdata = kzalloc(sizeof(*archdata), GFP_KERNEL);
+        if (!archdata) {
+                ret = -ENOMEM;
+                goto error;
+        }
+
+        archdata->mmu = mmu;
+        archdata->utlb = utlb;
+        dev->archdata.iommu = archdata;
 
         /*
          * Create the ARM mapping, used by the ARM DMA mapping core to allocate
@@ -923,6 +933,7 @@ static int ipmmu_add_device(struct device *dev)
         return 0;
 
 error:
+        kfree(dev->archdata.iommu);
         dev->archdata.iommu = NULL;
         iommu_group_remove_device(dev);
         return ret;
@@ -932,6 +943,7 @@ static void ipmmu_remove_device(struct device *dev)
 {
         arm_iommu_detach_device(dev);
         iommu_group_remove_device(dev);
+        kfree(dev->archdata.iommu);
         dev->archdata.iommu = NULL;
 }