• msm8953 LK通过cmdline向Kernel传递LCD参数过程分析

    本文主要是基于高通msm8953对lcd在lk阶段通过cmdline向kernel传递参数的过程进行分析。

    一、LK阶段分析

    相关文件：

    app/aboot/aboot.c

    Target/msm8953/Target_display.c

    Dev/gcdb/display/gcdb_display_param.c

    Target/msm8953/oem_panel.c

    在gcdb_display_cmdline_arg函数中将屏信息保存到display_panel_buf 中，并通过boot_linux->update_cmdline函数中整合其他模块信息后，在update_device_tree函数中附加到bootargs中，从而想kernel传递信息。相关代码如下：

    1、整个过程主要发生在update_cmdline中，如下：

    1. App/aboot/aboot.c
    2. Boot_linux
    3. 	->Update_cmdline
    4. 		->target_display_panel_node
    5. 			->gcdb_display_cmdline_arg
    6.                 //获取主屏信息（存储在panelstruct结构中），具体如1.1分析：
    7. 				->mdss_dsi_get_panel_data 
    8.                 //oem_data存储的是副屏的信息，
    9.                 //而由于oem_data.skip为false，
    10.                 //故在这个函数中是返回false，且slave_panel_node此时还未赋值，具体如1.2分析：
    11.                 ->mdss_dsi_set_panel_node
    12.                 //将主屏名称拷到panel_node中存储
    13.                 ->	->panel_node = panelstruct.paneldata->panel_node_id
    14.                 //根据副屏名称查找lookup_skip_panels数组，
    15.                 //返回panel_dt_string成员存到slave_panel_node中，具体如1.3分析：
    16.                 ->panel_name_to_dt_string 
    17.                 ->最终将panel_node + lookup_skip_panels + 其他信息 存到pbuf，即display_panel_buf中
    18.                 //在update_cmdline中将display_panel_buf+其他数据整合
    19.                 ->update_cmdline
    20.     //将上述update_cmdline整合后的各信息附加到设备树的bootargs信息中，具体如1.4分析：
    21.     ->update_device_tree
    22.                 
    23.  
    24.

    1.1）panelstruct是在oem_panel.c中_panel_data函数赋值，如下：

    1. struct panel_struct mdss_dsi_get_panel_data(void)
    2. {
    3. 	return panelstruct;
    4. }
    5.  
    6. case LT8911B_1080P_VIDEO_PANEL:
    7.         panelstruct->paneldata    = <8911b_1080p_video_panel_data;
    8.         /*
    10.         static struct panel_config lt8911b_1080p_video_panel_data = {
    11. 	        "qcom,mdss_dsi_lt8911b_1080p_video", "dsi:0:", "qcom,mdss-dsi-panel",
    12. 	        10, 0, "DISPLAY_1", 0, 0, 60, 0, 0, 0, 1, 10000, 0, 0, 0, 0, 0, 0, NULL
    13.         };
    15.         */
    16. 		panelstruct->panelres     = <8911b_1080p_video_panel_res;
    17. 		panelstruct->color        = <8911b_1080p_video_color;
    18. 		panelstruct->videopanel   = <8911b_1080p_video_video_panel;
    19. 		panelstruct->commandpanel = <8911b_1080p_video_command_panel;
    20. 		panelstruct->state        = <8911b_1080p_video_state;
    21. 		panelstruct->laneconfig   = <8911b_1080p_video_lane_config;
    22. 		panelstruct->paneltiminginfo
    23. 			= <8911b_1080p_video_timing_info;
    24. 		panelstruct->panelresetseq
    25. 					 = <8911b_1080p_video_reset_seq;
    26. 		panelstruct->backlightinfo = <8911b_1080p_video_backlight;
    27. 	
    28.         pinfo->mipi.panel_on_cmds = lt8911b_1080p_video_on_command;
    29.         pinfo->mipi.num_of_panel_on_cmds
    30.                                 = LT8911B_1080P_VIDEO_ON_COMMAND;
    31.       
    32. 		pinfo->mipi.panel_off_cmds = NULL;
    33. 		pinfo->mipi.num_of_panel_off_cmds
    34. 			= 0;
    35. 		memcpy(phy_db->timing,
    36. 			lt8911b_1080p_video_timings,
    37. 			MAX_TIMING_CONFIG * sizeof(uint32_t));
    38. 		pinfo->mipi.signature = LT8911B_1080P_VIDEO_SIGNATURE;		
    39. 		panelstruct->paneldata->panel_operating_mode &= ~USE_DSI1_PLL_FLAG;
    40. 		break;

    相关结构体定义如下：

    1. struct panel_struct {
    2. 	struct panel_config         *paneldata;
    3. 	struct panel_resolution     *panelres;
    4. 	struct color_info           *color;
    5. 	struct videopanel_info      *videopanel;
    6. 	struct commandpanel_info    *commandpanel;
    7. 	struct command_state        *state;
    8. 	struct lane_configuration   *laneconfig;
    9. 	struct panel_timing         *paneltiminginfo;
    10. 	struct panel_reset_sequence *panelresetseq;
    11. 	struct backlight            *backlightinfo;
    12. 	struct fb_compression	    fbcinfo;
    13. 	struct topology_config	    *config;
    14. };
    15.  
    16. struct panel_config{
    17.  
    18. 	char  *panel_node_id;
    19. 	char  *panel_controller;
    20. 	char  *panel_compatible;
    21. 	uint16_t panel_interface;
    22. 	uint16_t panel_type;
    23. 	char   *panel_destination;
    24. 	uint32_t panel_orientation;
    25. 	/* panel_clockrate is deprecated in favor of panel_bitclock_freq */
    26. 	uint32_t panel_clockrate;
    27. 	uint16_t panel_framerate;
    28. 	uint16_t panel_channelid;
    29. 	uint16_t dsi_virtualchannel_id;
    30. 	uint16_t panel_broadcast_mode;
    31. 	uint16_t panel_lp11_init;
    32. 	uint16_t panel_init_delay;
    33. 	uint16_t dsi_stream;
    34. 	uint8_t  interleave_mode;
    35. 	uint32_t panel_bitclock_freq;
    36. 	uint32_t panel_operating_mode;
    37. 	uint32_t panel_with_enable_gpio;
    38. 	uint8_t  mode_gpio_state;
    39. 	char  *slave_panel_node_id;
    40. };

    因此执行 panel_node = panelstruct.paneldata->panel_node_id时，实际为将主屏名称信息赋值给panel_node，即panel_node = qcom,mdss_dsi_lt8911b_1080p_video。

    1.2）mdss_dsi_set_panel_node主要涉及oem_data数据，而oem_data数据是在set_panel_cmd_string中赋值，如下：

    1. struct oem_panel_data oem_data = {{'\0'}, {'\0'}, false, false, false, SIM_NONE,
    2. 	"dual_dsi", DSI_PLL_DEFAULT, {-1, -1}};
    3.  
    4. struct oem_panel_data  {
    5. 	char panel[MAX_PANEL_ID_LEN];
    6. 	char sec_panel[MAX_PANEL_ID_LEN];
    7. 	bool cont_splash;
    8. 	bool skip;
    9. 	bool swap_dsi_ctrl;
    10. 	uint32_t sim_mode;
    11. 	char dsi_config[DSI_CFG_SIZE];
    12. 	uint32_t dsi_pll_src;
    13. 	/* If dual-DSI, slave cfg will use 2nd index */
    14. 	int cfg_num[2]; /* -ve number means no overide */
    15. };
    16.  
    17. void set_panel_cmd_string(const char *panel_name)
    18. {
    19.     //省略无关代码
    20.     ch = strstr((char *) panel_name, "sec:");
    21. 	if (ch) {
    22. 		ch += 4;
    23. 		ch_tmp = get_panel_token_end((const char*) ch);
    24. 		if (!ch_tmp)
    25. 			ch_tmp = ch + strlen(ch);
    26. 		for (i = 0; (ch + i) < ch_tmp; i++)
    27. 			oem_data.sec_panel[i] = *(ch + i);
    28. 		oem_data.sec_panel[i] = '\0';
    29.  
    30. 		/* Topology configuration for secondary panel */
    31. 		ch_tmp = strstr((char *) ch, ":cfg");
    32. 		if (ch_tmp)
    33. 			oem_data.cfg_num[1] = atoi((const char*)(ch_tmp + 4));
    34. 	} else {
    35. 		oem_data.sec_panel[0] = '\0';
    36. 	}
    37.     
    38.     	/* Skip LK configuration */
    39. 	ch = strstr((char *) panel_name, ":skip");
    40. 	oem_data.skip = ch ? true : false;
    41.  
    42. }
    43.  
    44. 传入的参数格式为：set_panel_cmd_string("sec:dsi_lt8911b_1080p_dsi1_video");
    45.

    因此，oem_data.skip实际为false，oem_data.sec_panel 实际为"dsi_lt8911b_1080p_dsi1_video"字符串。

    1.3）panel_name_to_dt_string是根据oem_data.sec_panel匹配lookup_skip_panels数组中的panel_dt_string成员，从而找到节点名称，如下:

    1. //oem_data.sec_panel在init_panel_data中调用set_panel_cmd_string进行赋值
    2. ret_val = panel_name_to_dt_string(lookup_skip_panels,
    3. 				ARRAY_SIZE(lookup_skip_panels), oem_data.sec_panel,
    4. 				&slave_panel_node);
    5.  
    6.  
    7. static int panel_name_to_dt_string(struct panel_lookup_list supp_panels[],
    8. 			  uint32_t supp_panels_size,
    9. 			  const char *panel_name, char **panel_node)
    10. {
    11. 	uint32_t i;
    12.     //省略无关代码
    13. 	for (i = 0; i < supp_panels_size; i++) {
    14. 		if (!strncmp(panel_name, supp_panels[i].name,
    15. 			MAX_PANEL_ID_LEN)) {
    16. 			*panel_node = supp_panels[i].panel_dt_string;
    17. 			return supp_panels[i].is_split_dsi;
    18. 		}
    19. 	}
    20.  
    21. 	return ERR_NOT_FOUND;
    22. }
    23. 形如：
    24. struct panel_lookup_list lookup_skip_panels[] = {
    25.     {"dsi_lt8911b_1080p_dsi1_video", "qcom,mdss_dsi_lt8911b_1080p_dsi1_video", false},
    26. }

    因此，slave_panel_node = qcom,mdss_dsi_lt8911b_1080p_dsi1_video。

    故在update_cmdline 函数时 display_panel_buf的大致数据为：

    mdss_mdp.panel=1:dsi:0:qcom,mdss_dsi_lt8911exb_1080p_video:1:qcom,mdss_dsi_lt8911exb_1080p_dsi1_video:cfg:dual_dsi

    1.4）先在update_cmdline中display_panel_buf赋值，再update_device_tree中将cmdline的信息追加到bootargs中，如下：

    1. unsigned char *update_cmdline(const char * cmdline)
    2. {
    3.     //省略无关代码
    4.     if (cmdline) {
    5. 		if ((strstr(cmdline, DISPLAY_DEFAULT_PREFIX) == NULL) &&
    6. 			target_display_panel_node(display_panel_buf,
    7. 			MAX_PANEL_BUF_SIZE) &&
    8. 			strlen(display_panel_buf)) {
    9. 			cmdline_len += strlen(display_panel_buf);
    10. 		}
    11. 	}
    12. }
    13.  
    14. int update_device_tree(void *fdt, const char *cmdline,
    15. 					   void *ramdisk, uint32_t ramdisk_size)
    16. {
    17.     //省略无关代码
    18.     if (cmdline)
    19. 	{
    20. 		/* Adding the cmdline to the chosen node */
    21. 		ret = fdt_appendprop_string(fdt, offset, (const char*)"bootargs", (const void*)cmdline);
    22. 		if (ret)
    23. 		{
    24. 			dprintf(CRITICAL, "ERROR: Cannot update chosen node [bootargs]\n");
    25. 			return ret;
    26. 		}
    27. 	}
    28. }

    二、kernel阶段分析
    1、在Start_kernel函数中获取传到内核的buf，并将buf写入_param段中，如下：

    1. init/main.c
    2. Start_kernel
    3. 	->setup_arch(&command_line);
    4. 		->mdesc = setup_machine_tags(__atags_pointer, __machine_arch_type);
    5. 		->parse_args
    6. 			->parse_one
    7.                 将lk中传递的数据写到__param段中
    8. 				->params[i].ops->set(val, ¶ms[i])=param_set_copystring

    而param的定义如下：

    1. struct kernel_param {
    2. 	const char *name;
    3. 	struct module *mod;
    4. 	const struct kernel_param_ops *ops;
    5. 	const u16 perm;
    6. 	s8 level;
    7. 	u8 flags;
    8. 	union {
    9. 		void *arg;
    10. 		const struct kparam_string *str;
    11. 		const struct kparam_array *arr;
    12. 	};
    13. };
    14.  
    15. const struct kernel_param_ops param_ops_string = {
    16. 	.set = param_set_copystring,
    17. 	.get = param_get_string,
    18. };
    19.  
    20. int param_set_copystring(const char *val, const struct kernel_param *kp)
    21. {
    22. 	const struct kparam_string *kps = kp->str;
    23.  
    24. 	if (strlen(val)+1 > kps->maxlen) {
    25. 		pr_err("%s: string doesn't fit in %u chars.\n",
    26. 		       kp->name, kps->maxlen-1);
    27. 		return -ENOSPC;
    28. 	}
    29. 	strcpy(kps->string, val);
    30. 	return 0;
    31. }
    32.  
    33. int param_get_string(char *buffer, const struct kernel_param *kp)
    34. {
    35. 	const struct kparam_string *kps = kp->str;
    36. 	return strlcpy(buffer, kps->string, kps->maxlen);
    37. }

    因此，boot_command_line中存储的是从lk传到kernel的参数，并将传参的参数写入_param段中，等待驱动加载时通过module_param_string使用。

    2、分析如何使用_param段中的数据，主要从LCD驱动分析。

    2.1）在mdss_mdp.c中存在驱动的传参定义，并且展开相应的宏定义后就是根据模块名在_param段中匹配屏的信息，如下；

    1. module_param_string(panel, mdss_mdp_panel, MDSS_MAX_PANEL_LEN, 0600);
    2. 参数说明：
    3. panel：模块名 mdss-mdp 
    4. mdss_mdp_panel：存储屏相关的信息
    5. MDSS_MAX_PANEL_LEN：256
    6.  
    7. module_param_string定义：
    8. #define module_param_string(name, string, len, perm)			\
    9. 	static const struct kparam_string __param_string_##name		\
    10. 		= { len, string };					\
    11. 	__module_param_call(MODULE_PARAM_PREFIX, name,			\
    12. 			    ¶m_ops_string,				\
    13. 			    .str = &__param_string_##name, perm, -1, 0);\
    14. __MODULE_PARM_TYPE(name, "string")
    15.  
    16. //若是模块编译的为空，不是模块编译的话为 "模块名."
    17. //由于makefile中定义为：obj-$(CONFIG_FB_MSM_MDSS) += mdss-mdp.o
    18. //因此 模块名为mdss-mdp.o，即kernel传参数的时候，参数名为 mdss-mdp.panel
    19. #ifdef MODULE
    20. #define MODULE_PARAM_PREFIX /* empty */
    21. #else
    22. #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
    23. #endif
    24.  
    25. #define __module_param_call(prefix, name, ops, arg, perm, level, flags)	\
    26. 	/* Default value instead of permissions? */			\
    27. 	static const char __param_str_##name[] = prefix #name;		\
    28. 	static struct kernel_param __moduleparam_const __param_##name	\
    29. 	__used								\
    30.     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
    31. 	= { __param_str_##name, THIS_MODULE, ops,			\
    32.     VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
    33.  
    34. 故：
    35. module_param_string(panel, mdss_mdp_panel, MDSS_MAX_PANEL_LEN, 0600);
    36. 等价于：
    37. #define module_param_string(name, string, len, perm) \
    38. 	static const struct kparam_string __param_string_panel = {MDSS_MAX_PANEL_LEN, mdss_mdp_panel}; \
    39. 	static const char __param_str_panel[] = mdss_mdp.panel;
    40. 	static struct kernel_param __moduleparam_const __param_panel \
    41. 	__used __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
    42. 	= { 
    43. 	__param_str_panel,
    44. 	THIS_MODULE, 
    45. 	param_ops_string,
    46. 	VERIFY_OCTAL_PERMISSIONS(0600), 
    47. 	-1,
    48. 	0, 
    49. 	.str = &__param_string_panel
    50.  }

    2.2）mdss_mdp_panel数组的使用过程如下：

    1. Video/fbdev/msm/Mdss_dsi.c
    2. mdss_dsi_ctrl_probe->//由于主副屏原因，该函数会执行两轮
    3. 	->mdss_dsi_config_panel
    4. 		->mdss_dsi_get_panel_cfg
    5. 			->ctrl->mdss_util->panel_intf_type(MDSS_PANEL_INTF_DSI)=mdss_panel_intf_type
    6. 				->mdss_res->pan_cfg //在mdss_mdp_get_cmdline_config函数中赋值
    7. 					->mdss_mdp_get_cmdline_config
    8.                         //具体如2.3分析：
    9. 						->mdss_mdp_get_pan_cfg
    10. 							->mdss_mdp_panel//数组
    11.     //由于执行两轮，因此第一轮解析的cmdline是主屏信息，
    12.     //第二轮时解析的是副屏信息
    13.     //具体如2.4分析：
    14.     ->mdss_dsi_find_panel_of_node

    2.3 mdss_mdp_get_pan_cfg分析：

    将参数mdss_mdp_panel进行解析到pan_cfg中，如下：

    1. static int mdss_mdp_get_pan_cfg(struct mdss_panel_cfg *pan_cfg)
    2. {
    3. 	char *t = NULL;
    4. 	char pan_intf_str[MDSS_MAX_PANEL_LEN];
    5. 	int rc, i, panel_len;
    6. 	char pan_name[MDSS_MAX_PANEL_LEN] = {'\0'};
    7.  
    8. 	if (!pan_cfg)
    9. 		return -EINVAL;
    10.  
    11. 	if (mdss_mdp_panel[0] == '0') {
    12. 		pr_debug("panel name is not set\n");
    13. 		pan_cfg->lk_cfg = false;
    14. 		pan_cfg->pan_intf = MDSS_PANEL_INTF_INVALID;
    15. 		return -EINVAL;
    16. 	} else if (mdss_mdp_panel[0] == '1') {
    17. 		pan_cfg->lk_cfg = true;
    18. 	} else {
    19. 		/* read from dt */
    20. 		pan_cfg->lk_cfg = true;
    21. 		pan_cfg->pan_intf = MDSS_PANEL_INTF_INVALID;
    22. 		return -EINVAL;
    23. 	}
    24.  
    25. 	/* skip lk cfg and delimiter; ex: "1:" */
    26. 	strlcpy(pan_name, &mdss_mdp_panel[2], MDSS_MAX_PANEL_LEN);
    27. 	t = strnstr(pan_name, ":", MDSS_MAX_PANEL_LEN);
    28. 	if (!t) {
    29. 		pr_err("pan_name=[%s] invalid\n", pan_name);
    30. 		pan_cfg->pan_intf = MDSS_PANEL_INTF_INVALID;
    31. 		return -EINVAL;
    32. 	}
    33.  
    34. 	for (i = 0; ((pan_name + i) < t) && (i < 4); i++)
    35. 		pan_intf_str[i] = *(pan_name + i);
    36. 	pan_intf_str[i] = 0;
    37. 	pr_debug("%d panel intf %s\n", __LINE__, pan_intf_str);
    38. 	/* point to the start of panel name */
    39. 	t = t + 1;
    40. 	strlcpy(&pan_cfg->arg_cfg[0], t, sizeof(pan_cfg->arg_cfg));
    41. 	pr_debug("%d: t=[%s] panel name=[%s]\n", __LINE__,
    42. 		t, pan_cfg->arg_cfg);
    43.  
    44. 	panel_len = strlen(pan_cfg->arg_cfg);
    45. 	if (!panel_len) {
    46. 		pr_err("Panel name is invalid\n");
    47. 		pan_cfg->pan_intf = MDSS_PANEL_INTF_INVALID;
    48. 		return -EINVAL;
    49. 	}
    50.  
    51. 	rc = mdss_mdp_get_pan_intf(pan_intf_str);
    52. 	pan_cfg->pan_intf = (rc < 0) ?  MDSS_PANEL_INTF_INVALID : rc;
    53. 	return 0;
    54. }

    2.4）mdss_dsi_find_panel_of_node过程分析 

    1. static struct device_node *mdss_dsi_find_panel_of_node(
    2. 		struct platform_device *pdev, char *panel_cfg)
    3. {
    4. 	int len, i = 0;
    5. 	int ctrl_id = pdev->id - 1;
    6. 	char panel_name[MDSS_MAX_PANEL_LEN] = "";
    7. 	char ctrl_id_stream[3] =  "0:";
    8. 	char *str1 = NULL, *str2 = NULL, *override_cfg = NULL;
    9. 	char cfg_np_name[MDSS_MAX_PANEL_LEN] = "";
    10. 	struct device_node *dsi_pan_node = NULL, *mdss_node = NULL;
    11. 	struct mdss_dsi_ctrl_pdata *ctrl_pdata = platform_get_drvdata(pdev);
    12. 	struct mdss_panel_info *pinfo = &ctrl_pdata->panel_data.panel_info;
    13.  
    14. 	len = strlen(panel_cfg);
    15. 	ctrl_pdata->panel_data.dsc_cfg_np_name[0] = '\0';
    16. 	if (!len) {
    17. 		/* no panel cfg chg, parse dt */
    18. 		pr_debug("%s:%d: no cmd line cfg present\n",
    19. 			 __func__, __LINE__);
    20. 		goto end;
    21. 	} else {
    22. 		/* check if any override parameters are set */
    23. 		pinfo->sim_panel_mode = 0;
    24. 		override_cfg = strnstr(panel_cfg, "#" OVERRIDE_CFG, len);
    25. 		if (override_cfg) {
    26. 			*override_cfg = '\0';
    27. 			if (mdss_dsi_set_override_cfg(override_cfg + 1,
    28. 					ctrl_pdata, panel_cfg))
    29. 				return NULL;
    30. 			len = strlen(panel_cfg);
    31. 		}
    32.  
    33. 		if (ctrl_id == 1)
    34. 			strlcpy(ctrl_id_stream, "1:", 3);
    35.  
    36. 		/* get controller number */
    37. 		str1 = strnstr(panel_cfg, ctrl_id_stream, len);
    38. 		if (!str1) {
    39. 			pr_err("%s: controller %s is not present in %s\n",
    40. 				__func__, ctrl_id_stream, panel_cfg);
    41. 			goto end;
    42. 		}
    43. 		if ((str1 != panel_cfg) && (*(str1-1) != ':')) {
    44. 			str1 += CMDLINE_DSI_CTL_NUM_STRING_LEN;
    45. 			pr_debug("false match with config node name in \"%s\". search again in \"%s\"\n",
    46. 				panel_cfg, str1);
    47. 			str1 = strnstr(str1, ctrl_id_stream, len);
    48. 			if (!str1) {
    49. 				pr_err("%s: 2. controller %s is not present in %s\n",
    50. 					__func__, ctrl_id_stream, str1);
    51. 				goto end;
    52. 			}
    53. 		}
    54. 		str1 += CMDLINE_DSI_CTL_NUM_STRING_LEN;
    55.  
    56. 		/* get panel name */
    57. 		str2 = strnchr(str1, strlen(str1), ':');
    58. 		if (!str2) {
    59. 			strlcpy(panel_name, str1, MDSS_MAX_PANEL_LEN);
    60. 		} else {
    61. 			for (i = 0; (str1 + i) < str2; i++)
    62. 				panel_name[i] = *(str1 + i);
    63. 			panel_name[i] = 0;
    64. 		}
    65. 		pr_info("%s: cmdline:%s panel_name:%s\n",
    66. 			__func__, panel_cfg, panel_name);
    67. 		if (!strcmp(panel_name, NONE_PANEL))
    68. 			goto exit;
    69.  
    70. 		mdss_node = of_parse_phandle(pdev->dev.of_node,
    71. 			"qcom,mdss-mdp", 0);
    72. 		if (!mdss_node) {
    73. 			pr_err("%s: %d: mdss_node null\n",
    74. 			       __func__, __LINE__);
    75. 			return NULL;
    76. 		}
    77. 		dsi_pan_node = of_find_node_by_name(mdss_node, panel_name);
    78. 		if (!dsi_pan_node) {
    79. 			pr_err("%s: invalid pan node \"%s\"\n",
    80. 			       __func__, panel_name);
    81. 			goto end;
    82. 		} else {
    83. 			/* extract config node name if present */
    84. 			str1 += i;
    85. 			str2 = strnstr(str1, "config", strlen(str1));
    86. 			if (str2) {
    87. 				str1 = strnchr(str2, strlen(str2), ':');
    88. 				if (str1) {
    89. 					for (i = 0; ((str2 + i) < str1) &&
    90. 					     i < (MDSS_MAX_PANEL_LEN - 1); i++)
    91. 						cfg_np_name[i] = *(str2 + i);
    92. 					if ((i >= 0)
    93. 						&& (i < MDSS_MAX_PANEL_LEN))
    94. 						cfg_np_name[i] = 0;
    95. 				} else {
    96. 					strlcpy(cfg_np_name, str2,
    97. 						MDSS_MAX_PANEL_LEN);
    98. 				}
    99. 				strlcpy(ctrl_pdata->panel_data.dsc_cfg_np_name,
    100. 					cfg_np_name, MDSS_MAX_PANEL_LEN);
    101. 			}
    102. 		}
    103.  
    104. 		return dsi_pan_node;
    105. 	}
    106. end:
    107. 	if (strcmp(panel_name, NONE_PANEL))
    108. 		dsi_pan_node = mdss_dsi_pref_prim_panel(pdev);
    109. exit:
    110. 	return dsi_pan_node;
    111. }

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  • 原文地址：https://blog.csdn.net/qq_33782617/article/details/126312114