Enabling uSDHC1 of i.MX8MM Based On L5.4.24_2.1.0 BSP

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Enabling uSDHC1 of i.MX8MM Based On L5.4.24_2.1.0 BSP

This article will describe how to enable uSDHC1 & uSDHC3 for i.MX8MM+DDR4+eMMC
boards.
We released 2 versions of i.MX8MM EVK board: one is i.MX8MMINILPD4-EVK, the other is
i.MX8MMiniD4-EVK. The main difference between these two development boards is LPDDR4,
DDR4, eMMC and NAND Flash.
--i.MX8MMINILPD4-EVK
LPDDR4
eMMC: uSDHC3 port multiplexed via NAND pads.
--i.MX8MMiniD4-EVK
DDR4
NAND Flash: NAND port muliplexed via NAND pads.
The uSDHC1 and uSDHC2 of these two EVK boards are connected to WIFI and MicrosSD card
slot respectively.
In u-boot, the i.MX8MMINILPD4-EVK board initialized 2 uSDHC ports: uSDHC2 and uSDHC3,
respectively for MicrosSD card and eMMC. The i.MX8MMiniD4-EVK board initialized 1 uSDHC port, uSDHC2 port for MicroSD card.

Open uboot-imx/board/freescale/imx8mm_evk/spl.c, in board_mmc_init () function, We can
see these codes:

----------------------------------------------

for (i = 0; i < CONFIG_SYS_FSL_USDHC_NUM; i++)
switch (i) {
case 0:
init_clk_usdhc(1);
usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC2_CLK);
imx_iomux_v3_setup_multiple_pads(
usdhc2_pads, ARRAY_SIZE(usdhc2_pads));
gpio_request(USDHC2_PWR_GPIO, "usdhc2_reset");
gpio_direction_output(USDHC2_PWR_GPIO, 0);
udelay(500);
gpio_direction_output(USDHC2_PWR_GPIO, 1);
break;
case 1:
init_clk_usdhc(2);
usdhc_cfg[1].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
imx_iomux_v3_setup_multiple_pads(
usdhc3_pads, ARRAY_SIZE(usdhc3_pads));
udelay(1500);
break;
default:
printf("Warning: you configured more USDHC controllers"
"(%d) than supported by the board\n", i + 1);
return -EINVAL;
}

----------------------------------------------

Open ./include/configs/imx8mm_evk.h, we can find CONFIG_SYS_FSL_USDHC_NUM, which
is defined like below:

......

#ifdef CONFIG_TARGET_IMX8MM_DDR4_EVK
#define CONFIG_SYS_FSL_USDHC_NUM 1
#else
#define CONFIG_SYS_FSL_USDHC_NUM 2
#endif

......

      Some customers use the I.MX8MM+DDR4+EMMC solution, and when porting based on
IMX8MMD4-EVK, they will encounter the problem of uSDHC3 not working, because the uSDHC3
clock is not initialized. We must let CONFIG_SYS_FSL_USDHC_NUM=2 to run the uSDHC3 clock initialization code.
      The following is the reference code for enabling uSDHC1 in spl.c and u-boot. Users can try to
debug the board based on these codes and start the board from uSDHC1.

• spl.c

-(1)For eMMC-8bit
static iomux_v3_cfg_t const usdhc1_pads[] = {
IMX8MM_PAD_SD1_CLK_USDHC1_CLK | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_CMD_USDHC1_CMD | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA0_USDHC1_DATA0 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA1_USDHC1_DATA1 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA2_USDHC1_DATA2 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA3_USDHC1_DATA3 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA4_USDHC1_DATA4 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA5_USDHC1_DATA5 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA6_USDHC1_DATA6 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA7_USDHC1_DATA7 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
};
static struct fsl_esdhc_cfg usdhc_cfg[3] = {
    {USDHC1_BASE_ADDR, 0, 8},
    {USDHC2_BASE_ADDR, 0, 4},
    {USDHC3_BASE_ADDR, 0, 8},
};

int board_mmc_getcd(struct mmc *mmc)
{
struct fsl_esdhc_cfg *cfg = (struct fsl_esdhc_cfg *)mmc->priv;
int ret = 0;
switch (cfg->esdhc_base) {
case USDHC1_BASE_ADDR:
case USDHC3_BASE_ADDR:
ret = 1;

break;
case USDHC2_BASE_ADDR:
imx_iomux_v3_setup_pad(usdhc2_cd_pad);
gpio_request(USDHC2_CD_GPIO, "usdhc2 cd");
gpio_direction_input(USDHC2_CD_GPIO);
/*
* Since it is the DAT3 pin, this pin is pulled to
* low voltage if no card
*/
ret = gpio_get_value(USDHC2_CD_GPIO);
imx_iomux_v3_setup_pad(usdhc2_dat3_pad);
return ret;
}
return 1;
}

-(2)For SD card--4bit
#define USDHC1_CD_GPIO IMX_GPIO_NR(2, 5) /* Using SD1_DATA3 TO BE DETECT PIN */
static iomux_v3_cfg_t const usdhc1_pads[] = {
IMX8MM_PAD_SD1_CLK_USDHC1_CLK | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_CMD_USDHC1_CMD | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA0_USDHC1_DATA0 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA1_USDHC1_DATA1 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA2_USDHC1_DATA2 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
IMX8MM_PAD_SD1_DATA3_USDHC1_DATA3 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
};

/* Multipelex SD1_DATA3 To be GPIO for Card detect */
static iomux_v3_cfg_t const usdhc1_cd_pad =
IMX8MM_PAD_SD1_DATA3_GPIO2_IO5 | MUX_PAD_CTRL(USDHC_GPIO_PAD_CTRL);
/* After detection, SD1_DATA3 pin back to DATA3 funtion */
static iomux_v3_cfg_t const usdhc1_dat3_pad =
IMX8MM_PAD_SD1_DATA3_USDHC1_DATA3 |
MUX_PAD_CTRL(USDHC_PAD_CTRL);
static struct fsl_esdhc_cfg usdhc_cfg[3] = {
{USDHC1_BASE_ADDR, 0, 4},
{USDHC2_BASE_ADDR, 0, 4},
{USDHC3_BASE_ADDR, 0, 8},
};
int board_mmc_getcd(struct mmc *mmc)

{
struct fsl_esdhc_cfg *cfg = (struct fsl_esdhc_cfg *)mmc->priv;
int ret = 0;
switch (cfg->esdhc_base) {
case USDHC3_BASE_ADDR:
ret = 1;
break;
case USDHC2_BASE_ADDR:
imx_iomux_v3_setup_pad(usdhc2_cd_pad);
gpio_request(USDHC2_CD_GPIO, "usdhc2 cd");
gpio_direction_input(USDHC2_CD_GPIO);
/*
* Since it is the DAT3 pin, this pin is pulled to
* low voltage if no card
*/
ret = gpio_get_value(USDHC2_CD_GPIO);
imx_iomux_v3_setup_pad(usdhc2_dat3_pad);
return ret;
case USDHC1_BASE_ADDR:
imx_iomux_v3_setup_pad(usdhc1_cd_pad);
gpio_request(USDHC1_CD_GPIO, "usdhc1 cd");
gpio_direction_input(USDHC1_CD_GPIO);
ret = gpio_get_value(USDHC1_CD_GPIO);
imx_iomux_v3_setup_pad(usdhc1_dat3_pad);
return ret;
}

return 1;
}

--(3) clock initialization
int mmc_clock_init(bd_t *bis,int nSD_num)
{
int ret;
switch (i) {
case 0:
init_clk_usdhc(0);
usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC1_CLK);
imx_iomux_v3_setup_multiple_pads(
usdhc1_pads, ARRAY_SIZE(usdhc1_pads));
break;

case 1:
init_clk_usdhc(1);
usdhc_cfg[1].sdhc_clk = mxc_get_clock(MXC_ESDHC2_CLK);
imx_iomux_v3_setup_multiple_pads(
usdhc2_pads, ARRAY_SIZE(usdhc2_pads));
gpio_request(USDHC2_PWR_GPIO, "usdhc2_reset");
gpio_direction_output(USDHC2_PWR_GPIO, 0);
udelay(500);
gpio_direction_output(USDHC2_PWR_GPIO, 1);
break;
case 2:
init_clk_usdhc(2);
usdhc_cfg[2].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
imx_iomux_v3_setup_multiple_pads(
usdhc3_pads, ARRAY_SIZE(usdhc3_pads));
break;
default:
printf("Warning: you configured more USDHC controllers"
"(%d) than supported by the board\n", nSD_num);
return -EINVAL;
}
ret = fsl_esdhc_initialize(bis, &usdhc_cfg[nSD_num]);
if (ret)
return ret;
printf("eSDHC %d controllers have been initialized\n",nSD_num+1);
return 0;
}

int board_mmc_init(bd_t *bis)
{
mmc_clock_init(bis,0); /* initialize eSDHC1 CLOCK */
mmc_clock_init(bis,1); /* initialize eSDHC2 CLOCK */
mmc_clock_init(bis,2); /* initialize eSDHC3 CLOCK */
return 0;
}

• device tree in u-boot(imx8mm-evk.dts)

pinctrl_usdhc1_gpio: usdhc1grpgpio {
fsl,pins = <
MX8MM_IOMUXC_GPIO1_IO06_GPIO1_IO6 0x1c4 /* CD detect */
>;
};
pinctrl_usdhc1: usdhc1grp {
fsl,pins = <
MX8MM_IOMUXC_SD1_CLK_USDHC1_CLK 0x190
MX8MM_IOMUXC_SD1_CMD_USDHC1_CMD 0x1d0
MX8MM_IOMUXC_SD1_DATA0_USDHC1_DATA0 0x1d0
MX8MM_IOMUXC_SD1_DATA1_USDHC1_DATA1 0x1d0
MX8MM_IOMUXC_SD1_DATA2_USDHC1_DATA2 0x1d0
MX8MM_IOMUXC_SD1_DATA3_USDHC1_DATA3 0x1d0
/* if using 4bit microSD card, remove 5 lines below */
MX8MM_IOMUXC_SD1_DATA4_USDHC1_DATA4 0x1d0
MX8MM_IOMUXC_SD1_DATA5_USDHC1_DATA5 0x1d0
MX8MM_IOMUXC_SD1_DATA6_USDHC1_DATA6 0x1d0
MX8MM_IOMUXC_SD1_DATA7_USDHC1_DATA7 0x1d0
MX8MM_IOMUXC_SD1_STROBE_USDHC1_STROBE 0x190
>;
};

pinctrl_usdhc1_100mhz: usdhc1grp100mhz {
fsl,pins = <
MX8MM_IOMUXC_SD1_CLK_USDHC1_CLK 0x194
MX8MM_IOMUXC_SD1_CMD_USDHC1_CMD 0x1d4
MX8MM_IOMUXC_SD1_DATA0_USDHC1_DATA0 0x1d4
MX8MM_IOMUXC_SD1_DATA1_USDHC1_DATA1 0x1d4
MX8MM_IOMUXC_SD1_DATA2_USDHC1_DATA2 0x1d4
MX8MM_IOMUXC_SD1_DATA3_USDHC1_DATA3 0x1d4
/* if using 4bit microSD card, remove 5 lines below */
MX8MM_IOMUXC_SD1_DATA4_USDHC1_DATA4 0x1d4
MX8MM_IOMUXC_SD1_DATA5_USDHC1_DATA5 0x1d4
MX8MM_IOMUXC_SD1_DATA6_USDHC1_DATA6 0x1d4
MX8MM_IOMUXC_SD1_DATA7_USDHC1_DATA7 0x1d4
MX8MM_IOMUXC_SD1_STROBE_USDHC1_STROBE 0x194
>;
};

pinctrl_usdhc3_200mhz: usdhc3grp200mhz {
fsl,pins = <
MX8MM_IOMUXC_SD1_CLK_USDHC1_CLK 0x196
MX8MM_IOMUXC_SD1_CMD_USDHC1_CMD 0x1d6

MX8MM_IOMUXC_SD1_DATA0_USDHC1_DATA0 0x1d6
MX8MM_IOMUXC_SD1_DATA1_USDHC1_DATA1 0x1d6
MX8MM_IOMUXC_SD1_DATA2_USDHC1_DATA2 0x1d6
MX8MM_IOMUXC_SD1_DATA3_USDHC1_DATA3 0x1d6
/* if using 4bit microSD card, remove 5 lines below */
MX8MM_IOMUXC_SD1_DATA4_USDHC1_DATA4 0x1d6
MX8MM_IOMUXC_SD1_DATA5_USDHC1_DATA5 0x1d6
MX8MM_IOMUXC_SD1_DATA6_USDHC1_DATA6 0x1d6
MX8MM_IOMUXC_SD1_DATA7_USDHC1_DATA7 0x1d6
MX8MM_IOMUXC_SD1_STROBE_USDHC1_STROBE 0x196
>;
};

If eMMC is connected:
&usdhc1 {
pinctrl-names = "default", "state_100mhz", "state_200mhz";
pinctrl-0 = <&pinctrl_usdhc1>;
pinctrl-1 = <&pinctrl_usdhc1_100mhz>;
pinctrl-2 = <&pinctrl_usdhc1_200mhz>;
bus-width = <8>;
non-removable;
status = "okay";
};
if microSD card is connected:

&usdhc1 {
pinctrl-names = "default", "state_100mhz", "state_200mhz";
pinctrl-0 = <&pinctrl_usdhc1>, <&pinctrl_usdhc1_gpio>;
pinctrl-1 = <&pinctrl_usdhc1_100mhz>, <&pinctrl_usdhc1_gpio>;
pinctrl-2 = <&pinctrl_usdhc1_200mhz>, <&pinctrl_usdhc1_gpio>;
cd-gpios = <&gpio1 6 GPIO_ACTIVE_LOW>; /* Assume using GPIO1_IO06 to be CD pin */
bus-width = <4>;
status = "okay";
};

• Boot Setting From uSHDC1

--MicroSD card
BOOT_CFG[15]=0
BOOT_CFG[14:12]=001
BOOT_CFG[11:10]=00
BOOT_CFG[9]=0
BOOT_CFG[8]=0
BOOT_CFG[7]=0
BOOT_CFG[6:4]=001
BOOT_CFG[3:1]=000
BOOT_CFG[0]=0

--eMMC
BOOT_CFG[15]=0
BOOT_CFG[14:12]=010
BOOT_CFG[11:10]=00
BOOT_CFG[9]=0
BOOT_CFG[8]=0
BOOT_CFG[7]=0
BOOT_CFG[6:4]=010
BOOT_CFG[3:2]=00
BOOT_CFG[1]=1(0->3.3V IO; 1->1.8V IO)
BOOT_CFG[0]=1(0->3.3V IO; 1->1.8V IO)

Attament is the document in pdf format.

NXP TIC Team
Weidong Sun
11/30/2020