drivers: staging: Add Generic timestamping support

Adds generic hardware timestamping (GTE) support for the T194 SoC.
There are certain applications like robotics which may require more
accurate recording of the occurance of the certain events. GTE driver
will help monitor AON GPIOs and LIC interrupts.

GTE driver also implements char driver for userspace to monitor GPIO
through IOCTL.

Other kernel APIs are exported and defined in the tegra-gte.h file for
kernel client drivers to use. APIs are not stable and subject to change
in the future. It is for this reason GTE driver is provided in the
staging directory.

Since its APIs are not stable, it should not break existing nvpps driver
code from the stage-main which also uses GTE but in limited way. It is
for this reason this driver will not be selected if nvpps is enabled.

Bug 2757864

Change-Id: I0947f2b90232eb6c2a31163e33ec5ad45b7bd415
Signed-off-by: Dipen Patel <dipenp@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2287452
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 105 insertions, 0 deletions

diff --git a/include/linux/tegra-gte.h b/include/linux/tegra-gte.h
new file mode 100644
index 000000000..4862db05d
--- /dev/null
+++ b/include/linux/tegra-gte.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _LINUX_TEGRA_GTE_ENGINE_H
+#define _LINUX_TEGRA_GTE_ENGINE_H
+
+#include <linux/device.h>
+
+struct tegra_gte_ev_desc {
+        int id;
+        int gid;
+        u32 ev_bit;
+        u32 slice;
+};
+
+/* GTE hardware timestamping event details */
+struct tegra_gte_ev_detail {
+        u64 ts_raw; /* raw counter value */
+        u64 ts_ns; /* counter value converted into nano seconds */
+        int dir; /* direction of the event */
+};
+
+#ifdef CONFIG_TEGRA_HTS_GTE
+/*
+ * GTE event registration function
+ *
+ * Parameters:
+ *
+ * Input:
+ * @np:         device node of the interested GTE device
+ * @ev_id:      event id
+ *
+ * Returns:
+ *              Returns ERR_PTR in case of failure or valid
+ *              struct tegra_gte_ev_desc for success.
+ *
+ * Note:        API is not stable and subject to change.
+ */
+struct tegra_gte_ev_desc *tegra_gte_register_event(struct device_node *np,
+                                                   u32 ev_id);
+
+/*
+ * GTE event un-registration function
+ *
+ * Parameters:
+ *
+ * Input:
+ * @desc:       This parameter should be the same as returned from register
+ *
+ * Returns:
+ *              Returns 0 for success and any other value for the failure
+ *
+  * Note:       API is not stable and subject to change.
+ */
+int tegra_gte_unregister_event(struct tegra_gte_ev_desc *desc);
+
+/*
+ * GTE event retrieval function
+ *
+ * Parameters:
+ *
+ * Input:
+ * @desc:       This parameter should be the same as returned from register
+ *
+ * Output:
+ * @hts:        hts event details
+ *
+ * Returns:
+ *              Returns 0 for success and any other value for the failure
+ *
+ * Note:        API is not stable and subject to change.
+ */
+int tegra_gte_retrieve_event(const struct tegra_gte_ev_desc *desc,
+                             struct tegra_gte_ev_detail *hts);
+
+#else /* ! CONFIG_TEGRA_HTS_GTE */
+static inline struct tegra_gte_ev_desc *tegra_gte_register_event(
+                                        struct device_node *np, u32 ev_id)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
+static inline int tegra_gte_unregister_event(struct tegra_gte_ev_desc *desc)
+{
+        return -ENOSYS;
+}
+
+static inline int tegra_gte_retrieve_event(const struct tegra_gte_ev_desc *desc,
+                                           struct tegra_gte_ev_detail *hts)
+{
+        return -ENOSYS;
+}
+
+#endif /* ! CONFIG_TEGRA_HTS_GTE */
+#endif