[FEATURE] RPi 4B SD card support

[linguini1]

Is your feature request related to a problem? Please describe.

There is no support for the SD card in the Raspberry Pi 4B initial implementation.

Describe the solution you'd like

The ability to interact with the SD card on the Pi 4B.

Describe alternatives you've considered

No response

Verification

• I have verified before submitting the report.

[linguini1]

https://forums.raspberrypi.com/viewtopic.php?t=288772

[linguini1]

https://www.youtube.com/watch?v=mCuxbI0FqzM&list=PLVxiWMqQvhg9FCteL7I0aohj1_YiUx1x8&index=17

[linguini1]

EMMC 1 & 2 are IRQ 62 according to datasheet.

There is also this Wiki with some helpful links: https://deepwiki.com/raspberrypi/linux/2.2-bcm2711-soc-(raspberry-pi-4)

[linguini1]

Addresses: https://github.com/raspberrypi/linux/blob/cfe137c1/arch/arm/boot/dts/broadcom/bcm2711.dtsi

[linguini1]

The debug output from the boot process is:

MESS:00:00:03.962127:0: arasan: arasan_emmc_open
MESS:00:00:03.963785:0: arasan: arasan_emmc_set_clock C0: 0x00800000 C1: 0x000e0047 emmc: 200000000 actual: 390625 div: 0x00000100 target: 400000 min: 4000005
MESS:00:00:04.084006:0: arasan: arasan_emmc_set_clock C0: 0x00800000 C1: 0x000e0047 emmc: 200000000 actual: 390625 div: 0x00000100 target: 400000 min: 4000005
MESS:00:00:04.096876:0: arasan: arasan_emmc_set_clock C0: 0x00800f00 C1: 0x000e0047 emmc: 200000000 actual: 390625 div: 0x00000100 target: 400000 min: 3900005
MESS:00:00:04.143895:0: boot-part: 0 fs-type: 0
MESS:00:00:04.145309:0: boot-part: 0 fs-type: 3
MESS:00:00:04.149687:0: arasan: arasan_emmc_set_clock C0: 0x00800f06 C1: 0x000e0207 emmc: 200000000 actual: 50000000 div: 0x00000002 target: 50000000 min: 0 1
MESS:00:00:05.224838:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:05.227538:0: brfs: File read: 63 bytes
MESS:00:00:05.253683:0: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.258192:0: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:05.275336:0: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.279839:0: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:05.287440:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:05.781202:0: gpioman: gpioman_get_pin_num: pin DISPLAY_DSI_PORT not defined
MESS:00:00:05.786749:0: gpioman: gpioman_get_pin_num: pin DISPLAY_DSI_PORT not defined
MESS:00:00:05.795785:0: *** Restart logging
MESS:00:00:05.797558:0: brfs: File read: 63 bytes
MESS:00:00:05.807159:0: hdmi: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.812182:0: hdmi: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:05.822806:0: hdmi: HDMI0:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.827836:0: hdmi: HDMI0:EDID giving up on reading EDID block 0
MESS:00:00:05.833434:0: hdmi: HDMI:hdmi_get_state is deprecated, use hdmi_get_display_state instead
MESS:00:00:05.847225:0: hdmi: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.852255:0: hdmi: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:05.862877:0: hdmi: HDMI1:EDID error reading EDID block 0 attempt 0
MESS:00:00:05.867899:0: hdmi: HDMI1:EDID giving up on reading EDID block 0
MESS:00:00:05.873497:0: hdmi: HDMI:hdmi_get_state is deprecated, use hdmi_get_display_state instead
MESS:00:00:05.882262:0: HDMI0: hdmi_pixel_encoding: 300000000
MESS:00:00:05.887729:0: HDMI1: hdmi_pixel_encoding: 300000000
MESS:00:00:05.903009:0: dtb_file 'bcm2711-rpi-4-b.dtb'
MESS:00:00:05.912464:0: brfs: File read: /mfs/sd/bcm2711-rpi-4-b.dtb
MESS:00:00:05.915709:0: Loaded 'bcm2711-rpi-4-b.dtb' to 0x100 size 0xdb93
MESS:00:00:05.936066:0: brfs: File read: 56211 bytes
MESS:00:00:05.965194:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:05.983561:0: brfs: File read: 63 bytes
MESS:00:00:05.985265:0: Failed to open command line file 'cmdline.txt'
MESS:00:00:06.141241:0: brfs: File read: /mfs/sd/nuttx.bin
MESS:00:00:06.143627:0: Loaded 'nuttx.bin' to 0x200000 size 0x51000
MESS:00:00:06.150067:0: Kernel relocated to 0x480000
MESS:00:00:06.154298:0: Device tree loaded to 0x2eff1f00 (size 0xe042)
MESS:00:00:06.162975:0: uart: Set PL011 baud rate to 103448.300000 Hz
MESS:00:00:06.169627:0: uart: Baud rate change done...
MESS:00:00:06.171647:0:- Ready to Boot Primary CPU

For this reason, I believe the microSD card is connected to the EMMC interface.

[linguini1]

https://ultibo.org/wiki/Unit_BCM2711

[linguini1]

It appears that functionality for the mailbox API needs to be added prior to this issue being completed. I will add that and return to this.

[linguini1]

Also @acassis do you happen to know if there is a standard NuttX driver for SDHCI compatible controllers? Something maybe between an upper-half and lower-half that just knows the standard SDHCI registers and can manipulate them?

I did a quick grep for SDHCI but only found a chip-specific one for the cxd56xx. I think NuttX might benefit from a standard SDHCI driver if it doesn't have one already, since from what limited research I've done about it so far, the interface registers are standardized through that specification.

[acassis]

@linguini1 I think cxd56_sdhci.c, kinetis_sdhc.c, sam_sdmmc.c and imx9_usdhc.c are basically SDHCI compatible controllers. Probably sam_sdmmc.c was implemented first because Mr. Greg had a contract with Atmel to add support to their chips (before Microchip acquired them and extinguish the contract).

I think having a common compatible driver is a good idea, but the implementation should be a little bit challenging because the differences. But there are already drivers that implement similar standard interfaces, i.e. drivers/serial/uart_16550.c, drivers/serial/uart_pl011.c, etc.

The EHCI controller also could be a standard driver, recently I had to modify the imxrt EHCI driver to support two controllers because the orignal driver wasn't prepared to it. So, this kind of thing could be implemented in the original driver.