drm/amd/display: Add function and debugfs to dump DCC_EN bit

[why]
Currently to view the DCC_EN bit the entire DTN log
must be dumped. A compact method to view the DCC_EN
bit is desirable.

[how]
Introduce new debugfs interface that only dumps the
DCC_EN bit.

Example usage:
cat /sys/kernel/debug/dri/0/amdgpu_dm_dcc_en

Signed-off-by: Victor Lu <[e-mail]>
Reviewed-by: Harry Wentland <[e-mail]>
Acked-by: Qingqing Zhuo <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

···
 DEFINE_DEBUGFS_ATTRIBUTE(visual_confirm_fops, visual_confirm_get,
 			 visual_confirm_set, "%llu\n");
 
+/*
+ * Dumps the DCC_EN bit for each pipe.
+ * Example usage: cat /sys/kernel/debug/dri/0/amdgpu_dm_dcc_en
+ */
+static ssize_t dcc_en_bits_read(
+	struct file *f,
+	char __user *buf,
+	size_t size,
+	loff_t *pos)
+{
+	struct amdgpu_device *adev = file_inode(f)->i_private;
+	struct dc *dc = adev->dm.dc;
+	char *rd_buf = NULL;
+	const uint32_t rd_buf_size = 32;
+	uint32_t result = 0;
+	int offset = 0;
+	int num_pipes = dc->res_pool->pipe_count;
+	int *dcc_en_bits;
+	int i, r;
+
+	dcc_en_bits = kcalloc(num_pipes, sizeof(int), GFP_KERNEL);
+	if (!dcc_en_bits)
+		return -ENOMEM;
+
+	if (!dc->hwss.get_dcc_en_bits) {
+		kfree(dcc_en_bits);
+		return 0;
+	}
+
+	dc->hwss.get_dcc_en_bits(dc, dcc_en_bits);
+
+	rd_buf = kcalloc(rd_buf_size, sizeof(char), GFP_KERNEL);
+	if (!rd_buf)
+		return -ENOMEM;
+
+	for (i = 0; i < num_pipes; i++)
+		offset += snprintf(rd_buf + offset, rd_buf_size - offset,
+				   "%d  ", dcc_en_bits[i]);
+	rd_buf[strlen(rd_buf)] = '\n';
+
+	kfree(dcc_en_bits);
+
+	while (size) {
+		if (*pos >= rd_buf_size)
+			break;
+		r = put_user(*(rd_buf + result), buf);
+		if (r)
+			return r; /* r = -EFAULT */
+		buf += 1;
+		size -= 1;
+		*pos += 1;
+		result += 1;
+	}
+
+	kfree(rd_buf);
+	return result;
+}
+
 void dtn_debugfs_init(struct amdgpu_device *adev)
 {
 	static const struct file_operations dtn_log_fops = {
 		.owner = THIS_MODULE,
 		.read = dtn_log_read,
 		.write = dtn_log_write,
+		.llseek = default_llseek
+	};
+	static const struct file_operations dcc_en_bits_fops = {
+		.owner = THIS_MODULE,
+		.read = dcc_en_bits_read,
 		.llseek = default_llseek
 	};
 
···
 
 	debugfs_create_file_unsafe("amdgpu_dm_dmcub_trace_event_en", 0644, root,
 				   adev, &dmcub_trace_event_state_fops);
+
+	debugfs_create_file_unsafe("amdgpu_dm_dcc_en", 0644, root, adev,
+				   &dcc_en_bits_fops);
 }

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

···
 				dc->clk_mgr->funcs->get_clock(dc->clk_mgr, context, clock_type, clock_cfg);
 
 }
+
+void dcn10_get_dcc_en_bits(struct dc *dc, int *dcc_en_bits)
+{
+	struct resource_pool *pool = dc->res_pool;
+	int i;
+
+	for (i = 0; i < pool->pipe_count; i++) {
+		struct hubp *hubp = pool->hubps[i];
+		struct dcn_hubp_state *s = &(TO_DCN10_HUBP(hubp)->state);
+
+		hubp->funcs->hubp_read_state(hubp);
+
+		if (!s->blank_en)
+			dcc_en_bits[i] = s->dcc_en ? 1 : 0;
+	}
+}

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.h

···
 /*
-* Copyright 2016 Advanced Micro Devices, Inc.
+* Copyright 2016-2020 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
···
 		struct dc_state *context);
 void dcn10_set_hdr_multiplier(struct pipe_ctx *pipe_ctx);
 void dcn10_verify_allow_pstate_change_high(struct dc *dc);
+
+void dcn10_get_dcc_en_bits(struct dc *dc, int *dcc_en_bits);
 
 #endif /* __DC_HWSS_DCN10_H__ */

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_init.c

···
 /*
- * Copyright 2016 Advanced Micro Devices, Inc.
+ * Copyright 2016-2020 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
···
 	.set_backlight_level = dce110_set_backlight_level,
 	.set_abm_immediate_disable = dce110_set_abm_immediate_disable,
 	.set_pipe = dce110_set_pipe,
+	.get_dcc_en_bits = dcn10_get_dcc_en_bits,
 };
 
 static const struct hwseq_private_funcs dcn10_private_funcs = {

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_init.c

···
 	.optimize_timing_for_fsft = dcn20_optimize_timing_for_fsft,
 #endif
 	.set_disp_pattern_generator = dcn20_set_disp_pattern_generator,
+	.get_dcc_en_bits = dcn10_get_dcc_en_bits,
 };
 
 static const struct hwseq_private_funcs dcn20_private_funcs = {

drivers/gpu/drm/amd/display/dc/dcn21/dcn21_init.c

···
 /*
- * Copyright 2016 Advanced Micro Devices, Inc.
+ * Copyright 2016-2020 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
···
 #endif
 	.is_abm_supported = dcn21_is_abm_supported,
 	.set_disp_pattern_generator = dcn20_set_disp_pattern_generator,
+	.get_dcc_en_bits = dcn10_get_dcc_en_bits,
 };
 
 static const struct hwseq_private_funcs dcn21_private_funcs = {

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_init.c

···
 /*
- * Copyright 2020 Advanced Micro Devices, Inc.
+ * Copyright 2016-2020 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
···
 	.hardware_release = dcn30_hardware_release,
 	.set_pipe = dcn21_set_pipe,
 	.set_disp_pattern_generator = dcn30_set_disp_pattern_generator,
+	.get_dcc_en_bits = dcn10_get_dcc_en_bits,
 };
 
 static const struct hwseq_private_funcs dcn30_private_funcs = {

drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c

···
 /*
- * Copyright 2020 Advanced Micro Devices, Inc.
+ * Copyright 2016-2020 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
···
 	.set_abm_immediate_disable = dcn21_set_abm_immediate_disable,
 	.set_pipe = dcn21_set_pipe,
 	.set_disp_pattern_generator = dcn30_set_disp_pattern_generator,
+	.get_dcc_en_bits = dcn10_get_dcc_en_bits,
 };
 
 static const struct hwseq_private_funcs dcn301_private_funcs = {

drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h

···
 
 	void (*set_pipe)(struct pipe_ctx *pipe_ctx);
 
+	void (*get_dcc_en_bits)(struct dc *dc, int *dcc_en_bits);
+
 	/* Idle Optimization Related */
 	bool (*apply_idle_power_optimizations)(struct dc *dc, bool enable);