nvlink: add support for kernel tests

Add support for NVLINK kernel test modules:
   - Create an NVLINK tests debugfs directory which will be used as the
     parent directory for all test related debugfs nodes
   - Export NVLINK logging APIs
        - Rename the NVLINK_DRV_NAME macros to NVLINK_MODULE_NAME. This
          was done because now the NVLINK logging APIs are being used by
          non-driver modules (i.e. tests) as well.
   - Export an ARM64 cache flush API - this API is needed by the Tegra
     loopback test

Bug 2133882
Jira NVLINK-107

Change-Id: I587b704ff44327ee4d9767156cb87cbe27408e08
Signed-off-by: Adeel Raza <araza@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1704230
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>
Reviewed-by: Petlozu Pravareshwar <petlozup@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

4 files changed, 58 insertions, 17 deletions

diff --git a/drivers/nvlink/nvlink-core.c b/drivers/nvlink/nvlink-core.c
index 5ff8c038f..7e0c0faa3 100644
--- a/drivers/nvlink/nvlink-core.c
+++ b/drivers/nvlink/nvlink-core.c
@@ -25,8 +25,11 @@
 #include <linux/module.h>
 #include <linux/platform/tegra/tegra-nvlink.h>
 
-#define NVLINK_DRV_NAME                         "nvlink-core"
+#include <asm/cacheflush.h>
+
+#define NVLINK_MODULE_NAME                      "nvlink-core"
 #define NVLINK_DEBUGFS_ROOT                     "nvlink"
+#define NVLINK_DEBUGFS_TESTS                    "tests"
 #define DEFAULT_LOOP_SLEEP_US                   100
 #define DEFAULT_LOOP_TIMEOUT_US                 1000000
 #define NVLINK_TRANSITION_HS_TIMEOUT_MS         2000
@@ -52,11 +55,25 @@ struct nvlink_core {
         struct mutex mutex;
 };
 
+/*
+ * We're exporting the NVLINK driver stack's logging APIs to the NVLINK kernel
+ * test modules. The logging APIs use nvlink_log_mask. Therefore, we have to
+ * export nvlink_log_mask along with the logging APIs.
+ */
 u32 nvlink_log_mask = NVLINK_DEFAULT_LOG_MASK;
+EXPORT_SYMBOL(nvlink_log_mask);
 
 #ifdef CONFIG_DEBUG_FS
 /* This is the root debugfs directory for the entire NVLINK driver stack */
-struct dentry *nvlink_debugfs;
+struct dentry *nvlink_debugfs_root;
+
+/*
+ * This is the parent debugfs directory for NVLINK tests. We need to export this
+ * symbol so that the NVLINK kernel test modules can create their debugfs nodes
+ * under the correct path.
+ */
+struct dentry *nvlink_debugfs_tests;
+EXPORT_SYMBOL(nvlink_debugfs_tests);
 #endif /* CONFIG_DEBUG_FS */
 
 static struct nvlink_core nvlink_core;
@@ -244,6 +261,20 @@ success:
         return ret;
 }
 
+/*
+ * This is a wrapper function for an ARM64 cache flush API. This API is used in
+ * NVLINK kernel test modules. We've created this NVLINK wrapper because we
+ * don't want to directly export the ARM64 API. We want to minimize the exposure
+ * of this API outside of the kernel. By creating this NVLINK wrapper we're
+ * trying to ensure that only NVLINK kernel test modules will use this API
+ * outside of the kernel.
+ */
+void __nvlink_dma_flush_area(const void *ptr, size_t size)
+{
+        __dma_flush_area(ptr, size);
+}
+EXPORT_SYMBOL(__nvlink_dma_flush_area);
+
 int nvlink_register_device(struct nvlink_device *ndev)
 {
         int ret = 0;
@@ -1459,13 +1490,21 @@ void nvlink_core_debugfs_init(void)
         struct dentry *core_debugfs = NULL;
         struct dentry *debugfs_node = NULL;
 
-        nvlink_debugfs = debugfs_create_dir(NVLINK_DEBUGFS_ROOT, NULL);
-        if (!nvlink_debugfs) {
+        nvlink_debugfs_root = debugfs_create_dir(NVLINK_DEBUGFS_ROOT, NULL);
+        if (!nvlink_debugfs_root) {
                 nvlink_err("Failed to create NVLINK debugfs root directory");
                 goto fail;
         }
 
-        core_debugfs = debugfs_create_dir(NVLINK_DRV_NAME, nvlink_debugfs);
+        nvlink_debugfs_tests = debugfs_create_dir(NVLINK_DEBUGFS_TESTS,
+                                                nvlink_debugfs_root);
+        if (!nvlink_debugfs_tests) {
+                nvlink_err("Failed to create NVLINK tests debugfs directory");
+                goto fail;
+        }
+
+        core_debugfs = debugfs_create_dir(NVLINK_MODULE_NAME,
+                                        nvlink_debugfs_root);
         if (!core_debugfs) {
                 nvlink_err("Failed to create NVLINK core driver's debugfs directory");
                 goto fail;
@@ -1484,14 +1523,16 @@ void nvlink_core_debugfs_init(void)
 
 fail:
         nvlink_err("Failed to create debugfs nodes");
-        debugfs_remove_recursive(nvlink_debugfs);
-        nvlink_debugfs = NULL;
+        debugfs_remove_recursive(nvlink_debugfs_root);
+        nvlink_debugfs_root = NULL;
+        nvlink_debugfs_tests = NULL;
 }
 
 void nvlink_core_debugfs_deinit(void)
 {
-        debugfs_remove_recursive(nvlink_debugfs);
-        nvlink_debugfs = NULL;
+        debugfs_remove_recursive(nvlink_debugfs_root);
+        nvlink_debugfs_root = NULL;
+        nvlink_debugfs_tests = NULL;
 }
 #endif /* CONFIG_DEBUG_FS */
 
diff --git a/drivers/nvlink/t19x-nvlink-endpt-debugfs.c b/drivers/nvlink/t19x-nvlink-endpt-debugfs.c
index 5eddc3f6b..d1bd3bb93 100644
--- a/drivers/nvlink/t19x-nvlink-endpt-debugfs.c
+++ b/drivers/nvlink/t19x-nvlink-endpt-debugfs.c
@@ -293,13 +293,13 @@ fail:
 
 void t19x_nvlink_endpt_debugfs_init(struct tnvlink_dev *tdev)
 {
-        if (!nvlink_debugfs) {
+        if (!nvlink_debugfs_root) {
                 nvlink_err("Root NVLINK debugfs directory doesn't exist");
                 goto fail;
         }
 
-        tdev->tegra_debugfs = debugfs_create_dir(NVLINK_DRV_NAME,
-                                                nvlink_debugfs);
+        tdev->tegra_debugfs = debugfs_create_dir(NVLINK_MODULE_NAME,
+                                                nvlink_debugfs_root);
         if (!tdev->tegra_debugfs) {
                 nvlink_err("Failed to create Tegra NVLINK endpoint driver's"
                         " debugfs directory");
diff --git a/drivers/nvlink/t19x-nvlink-endpt.c b/drivers/nvlink/t19x-nvlink-endpt.c
index 23b6dca97..617aba9da 100644
--- a/drivers/nvlink/t19x-nvlink-endpt.c
+++ b/drivers/nvlink/t19x-nvlink-endpt.c
@@ -1090,7 +1090,7 @@ static int t19x_nvlink_endpt_probe(struct platform_device *pdev)
 
         tdev->dev = &pdev->dev;
         tdev->class.owner = THIS_MODULE;
-        tdev->class.name = NVLINK_DRV_NAME;
+        tdev->class.name = NVLINK_MODULE_NAME;
 
         /* Create device node */
         ret = class_register(&tdev->class);
@@ -1118,7 +1118,7 @@ static int t19x_nvlink_endpt_probe(struct platform_device *pdev)
                                 NULL,
                                 tdev->dev_t,
                                 NULL,
-                                NVLINK_DRV_NAME);
+                                NVLINK_MODULE_NAME);
         if (IS_ERR(dev)) {
                 nvlink_err("Failed to create device");
                 ret = PTR_ERR(dev);
@@ -1368,7 +1368,7 @@ static struct platform_driver t19x_nvlink_endpt_pdrv = {
         .probe          = t19x_nvlink_endpt_probe,
         .remove         = t19x_nvlink_endpt_remove,
         .driver         = {
-                .name   = NVLINK_DRV_NAME,
+                .name   = NVLINK_MODULE_NAME,
 #if IS_ENABLED(CONFIG_PM_SLEEP)
                 .pm     = &tegra_nvlink_pm_ops,
 #endif
@@ -1397,6 +1397,6 @@ static void __exit t19x_nvlink_endpt_exit(void)
 module_init(t19x_nvlink_endpt_init);
 module_exit(t19x_nvlink_endpt_exit);
 
-MODULE_ALIAS(NVLINK_DRV_NAME);
+MODULE_ALIAS(NVLINK_MODULE_NAME);
 MODULE_DESCRIPTION("T19x NVLINK Endpoint Driver");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/nvlink/t19x-nvlink-endpt.h b/drivers/nvlink/t19x-nvlink-endpt.h
index 0243247c8..0add7e976 100644
--- a/drivers/nvlink/t19x-nvlink-endpt.h
+++ b/drivers/nvlink/t19x-nvlink-endpt.h
@@ -37,7 +37,7 @@
 #include <linux/cdev.h>
 #include <linux/platform/tegra/tegra-nvlink.h>
 
-#define NVLINK_DRV_NAME                         "t19x-nvlink-endpt"
+#define NVLINK_MODULE_NAME                      "t19x-nvlink-endpt"
 #define NVLINK_IP_VERSION                       2 /* NVLINK VERSION 2.0 */
 #define DEFAULT_IS_NEA                          0