Android leverages CmdLine to pass parameters from Preloader to kernel

To define the parameter Cus_param as an example, type int variable.

1. Preloader section
Platform.h (mediatek\platform\[$platform]\preloader\src\drivers\inc\platform.h)
Add the Cus_param variable to the following structure, and if it is a char type, note 4byte for it:
typedef struct {
U32 Magic;
boot_mode_t mode;
U32 E_flag;
U32 Log_port;
U32 log_baudrate;
U8 log_enable;
U8 Part_num;
U8 Reserved[2];
U32 Dram_rank_num;
U32 Dram_rank_size[4];
U32 Boot_reason;
U32 Meta_com_type;
U32 meta_com_id;
U32 Boot_time;
da_info_t Da_info;
Sec_limit Sec_limit;
part_hdr_t *part_info;
U8 Md_type[4];
U32 ddr_reserve_enable;
U32 ddr_reserve_success;
U32 Cus_param; MediaTek add
} boot_arg_t;

PLATFORM.C (mediatek\platform\[$platform]\preloader\src\drivers\platform.c)
Add an assignment to the Cus_param in this function, either through a function, or directly to the desired value:
void Platform_set_boot_args ()
{
#if cfg_boot_argument
Bootarg.magic = Boot_argument_magic;
Bootarg.mode = G_boot_mode;
Bootarg.e_flag = Sp_check_platform ();
Bootarg.log_port = Cfg_uart_log;
Bootarg.log_baudrate = cfg_log_baudrate;
Bootarg.log_enable = (U8) log_status ();
Bootarg.dram_rank_num = Get_dram_rank_nr ();
Get_dram_rank_size (bootarg.dram_rank_size);
Bootarg.boot_reason = G_boot_reason;
Bootarg.meta_com_type = (u32) g_meta_com_type;
bootarg.meta_com_id = g_meta_com_id;
Bootarg.boot_time = Get_timer (g_boot_time);

Bootarg.part_num = g_dram_buf->part_num;
Bootarg.part_info = g_dram_buf->part_info;

bootarg.ddr_reserve_enable = g_ddr_reserve_enable;
Bootarg.ddr_reserve_success= g_ddr_reserve_success;

MediaTek Add,mt_get_cus_param This function is customized to get the Cus_param function, please implement it yourself
Bootarg.cus_param = Mt_get_cus_param ();

2.LK part
Boot_mode.h (mediatek\platform\[$platform]\lk\include\platform\boot_mode.h)
Also add the Cus_param variable in the following structure, if it is a char type, note 4byte for it:
typedef struct {
U32 Maggic_number;
Bootmode Boot_mode;
U32 E_flag;
U32 Log_port;
U32 log_baudrate;
U8 log_enable;
U8 Part_num;
U8 Reserved[2];
U32 Dram_rank_num;
U32 Dram_rank_size[4];
U32 Boot_reason;
Meta_com_type Meta_com_type;
U32 meta_com_id;
U32 Boot_time;
da_info_t Da_info;
Sec_limit Sec_limit;
part_hdr_t *part_info;
U8 Md_type[4];
U32 ddr_reserve_enable;
U32 ddr_reserve_success;
U32 Cus_param; MediaTek Add, same as the Preloader section, two structures to be the same
} boot_argument;

MT_BOOT.C (BOOTABLE\BOOTLOADER\LK\APP\MT_BOOT\MT_BOOT.C)
In this function, add the Cus_param information to the CmdLine:
int boot_linux_from_storage (void)
{
.....
Strlen + = sprintf (Commanline, "%s fps=%1d", Commanline, Mt_disp_get_lcd_time ());
Strlen + = sprintf (Commanline, "%s cus_param=%1d", Commanline, G_boot_arg->cus_param); MediaTek add

3.Kernel part
Saved_command_line This is a global variable, in the driver file that you need for this parameter, the extern saved_command_line variable,
By finding the Cus_param string:
char * PTR;
int Cus_param;
ptr = Strstr (saved_command_line, "cus_param=");
PTR + = strlen ("cus_param=");
Cus_param = Simple_strtol (PTR, NULL, 10);
At this point Cus_param is the original int value.

Android leverages CmdLine to pass parameters from Preloader to kernel