gpu: nvgpu: Add L2 register read-backs following writes

LTC register write is followed by a register read
and if data doesn't match code will report the error.

Renamed existing nvgpu_writel_check function as
nvgpu_writel_loop as it loops until the write get success.

nvgpu_writel_check function write and read back and
compare the data.

Bug 2039150

Change-Id: I0a49be36aad23936f2d58aa82872710827da1d32
Signed-off-by: Vinod G <vinodg@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1762344
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/common/io_common.c b/drivers/gpu/nvgpu/common/io_common.c
new file mode 100644
index 00000000..e7041eb7
--- /dev/null
+++ b/drivers/gpu/nvgpu/common/io_common.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2018, 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.
+ */
+
+#include <nvgpu/io.h>
+#include <nvgpu/types.h>
+
+#include "gk20a/gk20a.h"
+
+void nvgpu_writel_check(struct gk20a *g, u32 r, u32 v)
+{
+        u32 read_val = 0U;
+
+        nvgpu_writel(g, r, v);
+        read_val = nvgpu_readl(g, r);
+        if (v != read_val) {
+                nvgpu_log(g, gpu_dbg_reg, "r=0x%x rd=0x%x wr=0x%x (mismatch)",
+                                        r, read_val, v);
+        }
+}