This commit adds debugfs directory and nodes for inspecting internal
state of System MMU.

Signed-off-by: KyongHo Cho <pullip....@samsung.com>
---
 drivers/iommu/exynos-iommu.c | 204 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 198 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 9753e0e..78c0eb7 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -26,12 +26,17 @@
 #include <linux/list.h>
 #include <linux/memblock.h>
 #include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
 #include <linux/string.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 
 #include <asm/cacheflush.h>
 
+#define MODULE_NAME "exynos-sysmmu"
+
 /* We does not consider super section mapping (16MB) */
 #define SECT_ORDER 20
 #define LPAGE_ORDER 16
@@ -223,6 +228,7 @@ struct sysmmu_drvdata {
        struct sysmmu_prefbuf pbufs[MAX_NUM_PBUF];
        int num_pbufs;
        struct sysmmu_version ver;
+       struct dentry *debugfs_root;
        struct iommu_domain *domain;
        unsigned long pgtable;
        bool runtime_active;
@@ -1066,6 +1072,8 @@ static void __init __sysmmu_init_mmuname(struct device 
*sysmmu,
        }
 }
 
+static void __create_debugfs_entry(struct sysmmu_drvdata *drvdata);
+
 static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 {
        int i, ret;
@@ -1134,6 +1142,8 @@ static int __init exynos_sysmmu_probe(struct 
platform_device *pdev)
 
                data->runtime_active = !pm_runtime_enabled(dev);
 
+               __create_debugfs_entry(data);
+
                platform_set_drvdata(pdev, data);
 
                dev->archdata.iommu = &sysmmu_placeholder;
@@ -1238,7 +1248,7 @@ static struct platform_driver exynos_sysmmu_driver 
__refdata = {
        .probe          = exynos_sysmmu_probe,
        .driver         = {
                .owner          = THIS_MODULE,
-               .name           = "exynos-sysmmu",
+               .name           = MODULE_NAME,
                .pm             = &__pm_ops,
                .of_match_table = of_match_ptr(sysmmu_of_match),
        }
@@ -1631,6 +1641,8 @@ static struct iommu_ops exynos_iommu_ops = {
        .pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,
 };
 
+static struct dentry *sysmmu_debugfs_root; /* /sys/kernel/debug/sysmmu */
+
 static int __init exynos_iommu_init(void)
 {
        int ret;
@@ -1642,17 +1654,197 @@ static int __init exynos_iommu_init(void)
                return -ENOMEM;
        }
 
-       ret = platform_driver_register(&exynos_sysmmu_driver);
+       ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
+       if (ret) {
+               kmem_cache_destroy(lv2table_kmem_cache);
+               pr_err("%s: Failed to register IOMMU ops\n", __func__);
+               return -EFAULT;
+       }
 
-       if (ret == 0)
-               ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
+       sysmmu_debugfs_root = debugfs_create_dir("sysmmu", NULL);
+       if (!sysmmu_debugfs_root)
+               pr_err("%s: Failed to create debugfs entry, 'sysmmu'\n",
+                                                       __func__);
+       if (IS_ERR(sysmmu_debugfs_root))
+               sysmmu_debugfs_root = NULL;
 
+       ret = platform_driver_register(&exynos_sysmmu_driver);
        if (ret) {
-               pr_err("%s: Failed to register exynos-iommu driver.\n",
-                                                               __func__);
                kmem_cache_destroy(lv2table_kmem_cache);
+               pr_err("%s: Failed to register System MMU driver\n", __func__);
        }
 
        return ret;
 }
 subsys_initcall(exynos_iommu_init);
+
+static int debug_string_show(struct seq_file *s, void *unused)
+{
+       char *str = s->private;
+
+       seq_printf(s, "%s\n", str);
+
+       return 0;
+}
+
+static int debug_sysmmu_list_show(struct seq_file *s, void *unused)
+{
+       struct sysmmu_drvdata *drvdata = s->private;
+       struct platform_device *pdev = to_platform_device(drvdata->sysmmu);
+       int idx, maj, min, ret;
+
+       seq_printf(s, "SysMMU Name | Ver | SFR Base\n");
+
+       if (pm_runtime_enabled(drvdata->sysmmu)) {
+               ret = pm_runtime_get_sync(drvdata->sysmmu);
+               if (ret < 0)
+                       return ret;
+       }
+
+       for (idx = 0; idx < drvdata->nsfrs; idx++) {
+               struct resource *res;
+
+               res = platform_get_resource(pdev, IORESOURCE_MEM, idx);
+               if (!res)
+                       break;
+
+               maj = __sysmmu_version(drvdata, idx, &min);
+
+               if (drvdata->mmuname) {
+                       if (maj == 0)
+                               seq_printf(s, "%11.s | N/A | 0x%08x\n",
+                                       drvdata->mmuname[idx], res->start);
+                       else
+                               seq_printf(s, "%11.s | %d.%d | 0x%08x\n",
+                               drvdata->mmuname[idx], maj, min, res->start);
+               } else {
+                       if (maj == 0)
+                               seq_printf(s, "N/A | 0x%08x\n", res->start);
+                       else
+                               seq_printf(s, "%d.%d | 0x%08x\n",
+                                                       maj, min, res->start);
+               }
+       }
+
+       if (pm_runtime_enabled(drvdata->sysmmu))
+               pm_runtime_put(drvdata->sysmmu);
+
+       return 0;
+}
+
+static int debug_next_sibling_show(struct seq_file *s, void *unused)
+{
+       struct device *dev = s->private;
+
+       if (dev->parent &&
+               !strncmp(dev_name(dev->parent),
+                       MODULE_NAME, strlen(MODULE_NAME)))
+               seq_printf(s, "%s\n", dev_name(dev->parent));
+       return 0;
+}
+
+static int __show_master(struct device *dev, void *data)
+{
+       struct seq_file *s = data;
+
+       if (strncmp(dev_name(dev), MODULE_NAME, strlen(MODULE_NAME)))
+               seq_printf(s, "%s\n", dev_name(dev));
+       return 0;
+}
+
+static int debug_master_show(struct seq_file *s, void *unused)
+{
+       struct device *dev = s->private;
+
+       device_for_each_child(dev, s, __show_master);
+       return 0;
+}
+
+static int debug_string_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, debug_string_show, inode->i_private);
+}
+
+static int debug_sysmmu_list_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, debug_sysmmu_list_show, inode->i_private);
+}
+
+static int debug_next_sibling_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, debug_next_sibling_show, inode->i_private);
+}
+
+static int debug_master_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, debug_master_show, inode->i_private);
+}
+
+static const struct file_operations debug_string_fops = {
+       .open = debug_string_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
+static const struct file_operations debug_sysmmu_list_fops = {
+       .open = debug_sysmmu_list_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
+static const struct file_operations debug_next_sibling_fops = {
+       .open = debug_next_sibling_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
+static const struct file_operations debug_master_fops = {
+       .open = debug_master_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
+static void __init __create_debugfs_entry(struct sysmmu_drvdata *drvdata)
+{
+       if (!sysmmu_debugfs_root)
+               return;
+
+       drvdata->debugfs_root = debugfs_create_dir(dev_name(drvdata->sysmmu),
+                                                       sysmmu_debugfs_root);
+       if (!drvdata->debugfs_root)
+               dev_err(drvdata->sysmmu, "Failed to create debugfs dentry\n");
+       if (IS_ERR(drvdata->debugfs_root))
+               drvdata->debugfs_root = NULL;
+
+       if (!drvdata->debugfs_root)
+               return;
+
+       if (!debugfs_create_u32("enable", 0664, drvdata->debugfs_root,
+                                               &drvdata->activations))
+               dev_err(drvdata->sysmmu,
+                               "Failed to create debugfs file 'enable'\n");
+
+       if (!debugfs_create_x32("pagetable", 0664, drvdata->debugfs_root,
+                                               (u32 *)&drvdata->pgtable))
+               dev_err(drvdata->sysmmu,
+                               "Failed to create debugfs file 'pagetable'\n");
+
+       if (!debugfs_create_file("sysmmu_list", 0444, drvdata->debugfs_root,
+                                       drvdata, &debug_sysmmu_list_fops))
+               dev_err(drvdata->sysmmu,
+                       "Failed to create debugfs file 'sysmmu_list'\n");
+
+       if (!debugfs_create_file("next_sibling", 0x444, drvdata->debugfs_root,
+                               drvdata->sysmmu, &debug_next_sibling_fops))
+               dev_err(drvdata->sysmmu,
+                       "Failed to create debugfs file 'next_siblings'\n");
+
+       if (!debugfs_create_file("master", 0x444, drvdata->debugfs_root,
+                               drvdata->sysmmu, &debug_master_fops))
+               dev_err(drvdata->sysmmu,
+                       "Failed to create debugfs file 'next_siblings'\n");
+}
-- 
1.8.0


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