iommu/ipmmu-vmsa: Add device tree support

Make platform data optional when the device is instantiated from DT and
look up the micro-TLB number in the bus master DT node.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

1 files changed, 47 insertions, 8 deletions

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 3a61103ef108..368c852d9ee7 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/iommu.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/platform_data/ipmmu-vmsa.h>
 #include <linux/platform_device.h>
 #include <linux/sizes.h>
@@ -58,6 +59,8 @@ static LIST_HEAD(ipmmu_devices);
  * Registers Definition
  */
 
+#define IM_NS_ALIAS_OFFSET              0x800
+
 #define IM_CTX_SIZE                     0x40
 
 #define IMCTR                           0x0000
@@ -1002,16 +1005,33 @@ static phys_addr_t ipmmu_iova_to_phys(struct iommu_domain *io_domain,
 
 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;
+        struct of_phandle_args args;
+        int ret;
+
+        if (mmu->pdata) {
+                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;
+                for (i = 0; i < mmu->pdata->num_masters; ++i, ++master) {
+                        if (strcmp(master->name, devname) == 0)
+                                return master->utlb;
+                }
+
+                return -1;
         }
 
-        return -1;
+        ret = of_parse_phandle_with_args(dev->of_node, "iommus",
+                                         "#iommu-cells", 0, &args);
+        if (ret < 0)
+                return -1;
+
+        of_node_put(args.np);
+
+        if (args.np != mmu->dev->of_node || args.args_count != 1)
+                return -1;
+
+        return args.args[0];
 }
 
 static int ipmmu_add_device(struct device *dev)
@@ -1157,7 +1177,7 @@ static int ipmmu_probe(struct platform_device *pdev)
         int irq;
         int ret;
 
-        if (!pdev->dev.platform_data) {
+        if (!IS_ENABLED(CONFIG_OF) && !pdev->dev.platform_data) {
                 dev_err(&pdev->dev, "missing platform data\n");
                 return -EINVAL;
         }
@@ -1178,6 +1198,20 @@ static int ipmmu_probe(struct platform_device *pdev)
         if (IS_ERR(mmu->base))
                 return PTR_ERR(mmu->base);
 
+        /*
+         * The IPMMU has two register banks, for secure and non-secure modes.
+         * The bank mapped at the beginning of the IPMMU address space
+         * corresponds to the running mode of the CPU. When running in secure
+         * mode the non-secure register bank is also available at an offset.
+         *
+         * Secure mode operation isn't clearly documented and is thus currently
+         * not implemented in the driver. Furthermore, preliminary tests of
+         * non-secure operation with the main register bank were not successful.
+         * Offset the registers base unconditionally to point to the non-secure
+         * alias space for now.
+         */
+        mmu->base += IM_NS_ALIAS_OFFSET;
+
         irq = platform_get_irq(pdev, 0);
         if (irq < 0) {
                 dev_err(&pdev->dev, "no IRQ found\n");
@@ -1223,9 +1257,14 @@ static int ipmmu_remove(struct platform_device *pdev)
         return 0;
 }
 
+static const struct of_device_id ipmmu_of_ids[] = {
+        { .compatible = "renesas,ipmmu-vmsa", },
+};
+
 static struct platform_driver ipmmu_driver = {
         .driver = {
                 .name = "ipmmu-vmsa",
+                .of_match_table = of_match_ptr(ipmmu_of_ids),
         },
         .probe = ipmmu_probe,
         .remove = ipmmu_remove,