drm/amd/display: Linux hook test pattern through debufs

bug fix: phy test PLTAT is special 80bit test pattern. The 80bit
data should be hard coded within driver so that user does not
need input the deata. previous driver does not have hard coded
80 bits pattern data for PLTPAT. Other than this PLTPAT, user
has to input 80 bits pattern data. In case user input less than
10 bytes data, un-input data byte will be filled by 0x00.
Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -483,16 +483,22 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
 	char *wr_buf = NULL;
 	char *wr_buf_ptr = NULL;
 	uint32_t wr_buf_size = 100;
+	uint32_t wr_buf_count = 0;
 	int r;
 	int bytes_from_user;
-	char *sub_str;
+	char *sub_str = NULL;
 	uint8_t param_index = 0;
-	long param[11];
+	uint8_t param_nums = 0;
+	long param[11] = {0x0};
 	const char delimiter[3] = {' ', '\n', '\0'};
 	enum dp_test_pattern test_pattern = DP_TEST_PATTERN_UNSUPPORTED;
 	bool disable_hpd = false;
 	bool valid_test_pattern = false;
-	uint8_t custom_pattern[10] = {0};
+	/* init with defalut 80bit custom pattern */
+	uint8_t custom_pattern[10] = {
+			0x1f, 0x7c, 0xf0, 0xc1, 0x07,
+			0x1f, 0x7c, 0xf0, 0xc1, 0x07
+			};
 	struct dc_link_settings prefer_link_settings = {LANE_COUNT_UNKNOWN,
 			LINK_RATE_UNKNOWN, LINK_SPREAD_DISABLED};
 	struct dc_link_settings cur_link_settings = {LANE_COUNT_UNKNOWN,
@@ -519,25 +525,51 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
 
 	bytes_from_user = wr_buf_size - r;
 
-	while (isspace(*wr_buf_ptr))
+	/* check number of parameters. isspace could not differ space and \n */
+	while ((*wr_buf_ptr != 0xa) && (wr_buf_count < wr_buf_size)) {
+		/* skip space*/
+		while (isspace(*wr_buf_ptr) && (wr_buf_count < wr_buf_size)) {
+			wr_buf_ptr++;
+			wr_buf_count++;
+			}
+
+		if (wr_buf_count == wr_buf_size)
+			break;
+
+		/* skip non-space*/
+		while ((!isspace(*wr_buf_ptr)) && (wr_buf_count < wr_buf_size)) {
 			wr_buf_ptr++;
+			wr_buf_count++;
+			}
+
+		param_nums++;
+
+		if (wr_buf_count == wr_buf_size)
+			break;
+	}
+
+	/* max 11 parameters */
+	if (param_nums > 11)
+		param_nums = 11;
+
+	wr_buf_ptr = wr_buf; /* reset buf pinter */
+	wr_buf_count = 0; /* number of char already checked */
 
-	while ((*wr_buf_ptr != '\0') && (param_index < 1)) {
+	while (isspace(*wr_buf_ptr) && (wr_buf_count < wr_buf_size)) {
+		wr_buf_ptr++;
+		wr_buf_count++;
+	}
+
+	while (param_index < param_nums) {
+		/* after strsep, wr_buf_ptr will be moved to after space */
 		sub_str = strsep(&wr_buf_ptr, delimiter);
+
 		r = kstrtol(sub_str, 16, &param[param_index]);
 
 		if (r)
 			DRM_DEBUG_DRIVER("string to int convert error code: %d\n", r);
 
 		param_index++;
-		while (isspace(*wr_buf_ptr))
-			wr_buf_ptr++;
-
-		/* DP_TEST_PATTERN_80BIT_CUSTOM need extra 80 bits
-		 * whci are 10 bytes separte by space
-		 */
-		if (param[0] != 0x4)
-			break;
 	}
 
 	test_pattern = param[0];
@@ -575,9 +607,17 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
 	}
 
 	if (test_pattern == DP_TEST_PATTERN_80BIT_CUSTOM) {
+		for (i = 0; i < 10; i++) {
+			if ((uint8_t) param[i + 1] != 0x0)
+				break;
+		}
+
+		if (i < 10) {
+			/* not use default value */
 			for (i = 0; i < 10; i++)
 				custom_pattern[i] = (uint8_t) param[i + 1];
 		}
+	}
 
 	/* Usage: set DP physical test pattern using debugfs with normal DP
 	 * panel. Then plug out DP panel and connect a scope to measure