[BPI-R4] U-boot on NAND but activating eMMC instead SD

Banana Pi Router design BPI-R4(MT7988)
1

Hi all,

I have a short question regarding BPI-R4 boot from NAND. I was able to built my own custom BL2 AT-F and FIP U-boot but regarding what kind of DTB I’m choosing for U-boot, eMMC is not able to be initialized.

Normally I tried to set “mt7988-rfb” DTB for U-boot to be able to use eMMC instead SD slot, but each time I’m booting with DIP switch in position AB = 01 I’m getting this error:

EasyOS(BPi-R4)> mmc info
Card did not respond to voltage select! : -110
mmc_init: -95, time 16

image
image473×543 22.8 KB

There is a restriction when using SPI NAND that MUX for SD/eMMC is not switched to eMMC?

Looking into the DTS sources for mt7988-rfb.dts:

        mmc0_pins_default: mmc0default {
                mux {
                        function = "flash";
                        groups =  "emmc_51";
                };

                conf-cmd-dat {
                        pins = "EMMC_DATA_0", "EMMC_DATA_1", "EMMC_DATA_2",
                               "EMMC_DATA_3", "EMMC_DATA_4", "EMMC_DATA_5",
                               "EMMC_DATA_6", "EMMC_DATA_7", "EMMC_CMD";
                        input-enable;
                };

                conf-clk {
                        pins = "EMMC_CK";
                };

                conf-dsl {
                        pins = "EMMC_DSL";
                };

                conf-rst {
                        pins = "EMMC_RSTB";
                };
        };

and mt7988-sd-rfb.dts:

        mmc1_pins_default: mmc1default {
                mux {
                        function = "flash";
                        groups =  "emmc_45";
                };

                conf-cmd-dat {
                        pins = "SPI2_CSB", "SPI2_MISO", "SPI2_MOSI",
                               "SPI2_CLK", "SPI2_HOLD";
                        input-enable;
                        drive-strength = <MTK_DRIVE_4mA>;
                };

                conf-clk {
                        pins = "SPI2_WP";
                        drive-strength = <MTK_DRIVE_4mA>;
                };
        };

I’m seeing that mux part configuration that sounds like it must switch between eMMC and SD slot. De-compiling the u-boot.dtb after build shows me clearly this:

               mmc0default {
                        phandle = <0x0e>;

                        mux {
                                function = "flash";
                                groups = "emmc_51";
                        };

                        conf-cmd-dat {
                                pins = "EMMC_DATA_0\0EMMC_DATA_1\0EMMC_DATA_2\0EMMC_DATA_3\0EMMC_DATA_4\0EMMC_DATA_5\0EMMC_DATA_6\0EMMC_DATA_7\0EMMC_CMD";
                                input-enable;
                        };

                        conf-clk {
                                pins = "EMMC_CK";
                        };

                        conf-dsl {
                                pins = "EMMC_DSL";
                        };

                        conf-rst {
                                pins = "EMMC_RSTB";
                        };
                };
        };
..
        mmc@11230000 {
                compatible = "mediatek,mt7988-mmc\0mediatek,mt7986-mmc";
                reg = <0x00 0x11230000 0x00 0x1000>;
                interrupts = <0x00 0x8f 0x04>;
                clocks = <0x08 0x3f 0x08 0x40 0x08 0x41 0x08 0x42>;
                clock-names = "source\0hclk\0source_cg\0axi_cg";
                status = "okay";
                pinctrl-names = "default";
                pinctrl-0 = <0x0e>;
                max-frequency = <0x3197500>;
                bus-width = <0x08>;
                cap-mmc-highspeed;
                cap-mmc-hw-reset;
                vmmc-supply = <0x0f>;
                vqmmc-supply = <0x10>;
                non-removable;
                phandle = <0x30>;
        };
..
        regulator-3p3v {
                compatible = "regulator-fixed";
                regulator-name = "fixed-3.3V";
                regulator-min-microvolt = <0x325aa0>;
                regulator-max-microvolt = <0x325aa0>;
                regulator-boot-on;
                regulator-always-on;
                phandle = <0x0f>;
        };

        regulator-1p8v {
                compatible = "regulator-fixed";
                regulator-name = "fixed-1.8V";
                regulator-min-microvolt = <0x1b7740>;
                regulator-max-microvolt = <0x1b7740>;
                regulator-boot-on;
                regulator-always-on;
                phandle = <0x10>;
        };

And soon as I’m inserting the SD card in slot is shows me the external card:

> mmc info
Card did not respond to voltage select! : -110
mmc_init: -95, time 17
EasyOS(BPi-R4)> mmc info
Device: mmc@11230000
Manufacturer ID: 3
OEM: 5344
Name: SC32G 
Bus Speed: 25000000
Mode: MMC legacy
Rd Block Len: 512
SD version 3.0
High Capacity: Yes
Capacity: 29.7 GiB
Bus Width: 4-bit
Erase Group Size: 512 Bytes

Is something that I’m missing out here?

Thank you in advance.

2

Boot from nand has emmc active in hardware not sdcard,so your nand uboot needs the non-sd dts as emmc has completely different settings (not only pinmux,also regulators and other settings like speed,removalble flag,…).

Are you sure uboot uses right dts? Afair there were 2 dts settings in config.

3

I found the issue. The problem was when I tested the new U-boot it wasn’t flashed in FIP partition.

In NAND I still got the old FIP that was using SDMMC. Then, before writing the new FIP, I wanted to test it by loading in RAM the new u-boot.bin and the use go to run the new one. So the board booted initially booted the old FIP with SDMMC DTB and then I used go to run the new U-boot.

Seems that in this case, even the u-boot.bin contains the correct DTB, doesn’t apply it correctly for eMMC/SDMMC.

After I write the FIP partition in NAND, reset U-boot now I got the eMMC:

EasyOS(BPi-R4)> version 
U-Boot 2025.01-rc3-EasyOS-eMMC-gacab6e78aca7-dirty (Dec 14 2024 - 17:12:40 +0100)

EasyOS(BPi-R4)> mmc info
Device: mmc@11230000
Manufacturer ID: 15
OEM: 0
Name: 8GTF4R 
Bus Speed: 52000000
Mode: MMC High Speed (52MHz)
Rd Block Len: 512
MMC version 5.1
High Capacity: Yes
Capacity: 7.3 GiB
Bus Width: 8-bit
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 7.3 GiB WRREL
Boot Capacity: 4 MiB ENH
RPMB Capacity: 512 KiB ENH
Boot area 0 is not write protected
Boot area 1 is not write protected

Do you have an explanation for this behavior?

4

Fip partition is only used on mmc…spi use fixed locations or ubi in openwrt uboot.

When booting from nand the nand-fip should have emmc dts. Which uboot code and defconfig do you use for nand?

5

My NAND has 2 partitions: BL2 starts from 0x0 with 2MB size and the next one FIP partition with a size of 2MB:

+------------+-----------+-----------+-----------+
| Partition  | Offset    | End       | Size      |
+------------+-----------+-----------+-----------+
| BL2        | 0x0       | 0x1FFFFF  | 0x200000  |
|*FIP        | 0x200000  | 0x3FFFFF  | 0x200000  |
| u-boot-env | 0x400000  | 0x43FFFF  | 0x40000   |
| UBI        | 0x440000  | 0x7FFFFFF | 0x7BC0000 |
+------------+-----------+-----------+-----------+
INFO: FIP_BASE address 0x200000 doesn't match with FIP partition start 0x100000
INFO: Overwriting FIP_BASE with address 0x200000. Otherwise BL2 will not find FIP!

As you can see I write my script to verify the FIP partition offset. In case is not correct one (by default for MT7988 is 0x580000 and in my script I set an offset of 0x100000) the script is autocorrecting the FIP offset for AT-F.

But before testing the new FIP U-boot with eMMC, in NAND I had FIP U-Boot with SDMMC DTB.

By default board was booting FIP U-boot with SDMMC. Then I was loading via TFTP the new U-boot eMMC binary which contains the eMMC DTB. But even the new U-boot was running successfully with go command, it didn’t initialize the eMMC and still tried to initialize the SDMMC.

As soon as I write FIP image of U-boot eMMC in NAND and reboot the board, the U-boot initialize the eMMC instead SDMMC.

Why the new u-boot.bin didn’t initialize eMMC if was running via go from a previous U-boot with SDMMC DTB boot, I have no clue.

6

So all working now with emmc dts on nand?

I guess some driver (pinctrl,clk,…) does not reset the specific device

1 Like
7

Possible. But is a good exercise for others in case they step into a same issue.