IMX6UL eMMC初始化流程

环境

在uboot中分析emmc初始化流程代码，emmc在uboot中方便添加命令和打印调试，uboot版本：2017.03

开机打印

uboot启动打印

	U-Boot 2017.03-g101318f (Jan 09 2019 - 17:37:10 +0800)

	CPU:   Freescale i.MX6UL rev1.2 696 MHz (running at 396 MHz)
	CPU:   Automotive temperature grade (-40C to 125C) at 58C
	Reset cause: WDOG
	Model: Freescale i.MX6 UltraLite 14x14 EVK Board
	Board: MX6UL 14x14 EVK
	DRAM:  256 MiB
	SF: Detected n25q256 with page size 256 Bytes, erase size 4 KiB, total 32 MiB
	Hardware version: 0x0401
	MMC:   board_mmc_init
	CONFIG_MX6UL_14X14_EVK_EMMC_REWORK
	FSL_SDHC: 0
	Using default environment

	SF: Detected n25q256 with page size 256 Bytes, erase size 4 KiB, total 32 MiB
	In:    serial
	Out:   serial
	Err:   serial
	SF: Detected n25q256 with page size 256 Bytes, erase size 4 KiB, total 32 MiB
	Net:   eth1: ethernet@020b4000, eth0: ethernet@02188000 [PRIME]
	Normal Boot
	Hit any key to stop autoboot:  0 

内核启动打印

	mmc1: new DDR MMC card at address 0001
	mmcblk1: mmc1:0001 P1XXXX 7.20 GiB 
	mmcblk1boot0: mmc1:0001 P1XXXX partition 1 16.0 MiB
	mmcblk1boot1: mmc1:0001 P1XXXX partition 2 16.0 MiB
	mmcblk1rpmb: mmc1:0001 P1XXXX partition 3 128 KiB
	 mmcblk1: p1 p2

 启动参数

	=> pri
	baudrate=115200
	board_name=EVK
	board_rev=14X14
	boot_fdt=try
	bootcmd=run kernel_env;if test ${default_image} = system1; then echo Booting from ${default_image}......;sf probe 0; sf read ${itb_addr} 0x90000 0xF30000; bootm ${itb_addr}; fi;if test ${default_image} = system2; then echo Booting from ${default_image}......;sf probe 0; sf read ${itb_addr} 0xFC0000 0xF30000; bootm ${itb_addr}; fi; 
	bootdelay=1
	console=ttymxc0
	default_image=system1
	eth1addr=08:ed:02:37:10:02
	ethact=ethernet@02188000
	ethaddr=08:ed:03:37:10:02
	ethprime=eth0
	fdt_addr=0x83000000
	fdt_file=undefined
	fdt_high=0xffffffff
	fdtcontroladdr=8ef58068
	initrd_high=0xffffffff
	ip_dyn=yes
	itb_addr=0x86800000
	kernel_env=setenv bootargs initrd=0x84800000,0x2000000 init=/etc/preinit console=${console},115200 root=/dev/ram0 ro rootfstype=ext4 image=${default_image} cma=64M mtdparts=21e0000.qspi:512k(uboot),64k(boardcfg),15552k(system1),15552k(system2),1024k(rootfs_data),60k(crashlog),4k(flags)
	loadaddr=0x80800000

EMMC信息

	=> mmcinfo 
	Device: FSL_SDHC
	Manufacturer ID: fe
	OEM: 14e
	Name: P1XXX 
	Tran Speed: 52000000
	Rd Block Len: 512
	MMC version 4.5
	High Capacity: Yes
	Capacity: 7.2 GiB
	Bus Width: 8-bit
	Erase Group Size: 512 KiB
	HC WP Group Size: 8 MiB
	User Capacity: 7.2 GiB
	Boot Capacity: 16 MiB ENH
	RPMB Capacity: 128 KiB ENH

EMMC初始化代码分析

emmc初始化函数

	struct mmc *mmc;		定义一个结构体指针
	mmc = init_mmc_device(curr_device, false);
		struct mmc *mmc;	定义一个结构体指针
		mmc = find_mmc_device(dev);	返回一个全局静态结构体地址：static struct mmc mmc_static;
			return &mmc_static;
		mmc_init(mmc)
		return mmc;
	
	mmc_init(struct mmc *mmc)	
		mmc_start_init(mmc);
			mmc_power_init(mmc);
			
			mmc->ddr_mode = 0;
			mmc_set_bus_width(mmc, 1);
			mmc_set_clock(mmc, 1);

			/* Reset the Card */
			err = mmc_go_idle(mmc);
				struct mmc_cmd cmd;
				#define MMC_CMD_GO_IDLE_STATE		0
				cmd.cmdidx = MMC_CMD_GO_IDLE_STATE;
				cmd.cmdarg = 0;
				cmd.resp_type = MMC_RSP_NONE;

				err = mmc_send_cmd(mmc, &cmd, NULL);
					mmc->cfg->ops->send_cmd(mmc, cmd, data);

probe探测函数，文件fsl_esdhc.c，赋值操作函数指针。

	static const struct mmc_ops esdhc_ops = {
		.send_cmd	= esdhc_send_cmd,
		.set_ios	= esdhc_set_ios,
		.init		= esdhc_init,
		.getcd		= esdhc_getcd,
	};	
	
	static const struct udevice_id fsl_esdhc_ids[] = {
		{ .compatible = "fsl,imx6ul-usdhc", },	
	
	fsl_esdhc_probe
		fsl_esdhc_init(priv);
			struct mmc *mmc;
			memset(&priv->cfg, 0, sizeof(priv->cfg));
			priv->cfg.name = "FSL_SDHC";
			priv->cfg.ops = &esdhc_ops;
			【怎么与mmc里面的mmc->cfg->ops对应？见下面】
			mmc = mmc_create(&priv->cfg, priv);
				struct mmc *mmc = &mmc_static;
				mmc->cfg = cfg;	等同于mmc->cfg = priv->cfg
				mmc->priv = priv;
				return mmc;				
			priv->mmc = mmc;

dts表配置

	arch/arm/dts/imx6ul.dtsi	
		usdhc2: usdhc@02194000 {
			compatible = "fsl,imx6ul-usdhc", "fsl,imx6sx-usdhc";
			reg = <0x02194000 0x4000>;
			interrupts = <GIC_SPI 23 IRQ_TYPE_LEVEL_HIGH>;
			clocks = <&clks IMX6UL_CLK_USDHC2>,
				 <&clks IMX6UL_CLK_USDHC2>,
				 <&clks IMX6UL_CLK_USDHC2>;
			clock-names = "ipg", "ahb", "per";
			bus-width = <4>;
			status = "disabled";
		};
		
	arch/arm/dts/imx6ul-14x14-evk.dts	
		&usdhc2 {
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_usdhc2_8bit>;
			bus-width = <8>;
			non-removable;
			status = "okay";
		};

uboot启动到emmc初始化流程

common/board_r.c
	#ifdef CONFIG_GENERIC_MMC
	static int initr_mmc(void)
	{
		puts("MMC:   ");
		mmc_initialize(gd->bd);
		return 0;
	}
	#endif	

drivers/mmc/mmc.c
	mmc_initialize
		mmc_probe(bis);
			board_mmc_init(bis)
			cpu_mmc_init(bis);
				fsl_esdhc_mmc_init	
		mmc_do_preinit();
			struct mmc *m = &mmc_static;
			mmc_start_init(m);

board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c
	board_mmc_init
		printf("board_mmc_init\n");
		fsl_esdhc_initialize(bis, &usdhc_cfg[i]);
			
drivers/mmc/fsl_esdhc.c		
	fsl_esdhc_initialize	
		fsl_esdhc_init(priv)
	fsl_esdhc_mmc_init	
		fsl_esdhc_initialize