linguini1 opened a new pull request, #17245:
URL: https://github.com/apache/nuttx/pull/17245
## Summary
This initial implementation sets up support for the EMMC interfaces on the
BCM2711. Only EMMC2 is tested since it is the interface of interest (connects
to uSD card). MMCSD communication is functional and the boot partition of the
SD card can be mounted and recognized.
Closes #16948.
Closes #16949.
**NOTE:** This is a draft PR for initial review. I still have some changes
to make to stabilize this feature. Writes currently fail, there are no software
time-outs when blocking on the semaphore or polling certain register bits, etc.
I also intend to let the user choose the transfer speed via Kconfig, since this
controller implements a large range of speeds and it appears that the MMCSD
driver doesn't allow that to be re-configured on the fly.
**Does anyone know how to support 8-bit transfer?** The controller is
capable of that, but the widebus functionality of the NuttX upper-half driver
only seems to allow 1b or 4b modes.
## Impact
Users can now interact with the micro-SD card through NuttX! Right now they
are able to mount the boot partition, however I will also add support for
mounting two separate partitions on the micro SD card so that a disk filesystem
exists.
## Testing
Tested using all the code included in this PR:
- Initialize SDIO lower-half properly
- Bind SDIO lower-half to MMCSD driver, verify that `/dev/mmcsd0` is mounted
and that logs from the driver indicate correct operation
- Mount `/dev/mmcsd0` to NuttX at `/sd` and verify that I can see all of the
files in the card with `ls`
- Verify that I can `cat` a file in the SD card
- Verify that I can `echo` to a file on the SD card to create a new one
### Successful mount
```
[ 1.538000] fat_mount: FAT32:
[ 1.541000] fat_mount: HW sector size: 512
[ 1.546000] fat_mount: sectors: 62521344
[ 1.551000] fat_mount: FAT reserved: 32
[ 1.555000] fat_mount: sectors: 62519296
[ 1.561000] fat_mount: start sector: 2080
[ 1.565000] fat_mount: root sector: 2
[ 1.570000] fat_mount: root entries: 0
[ 1.575000] fat_mount: data sector: 32608
[ 1.580000] fat_mount: FSINFO sector: 2049
[ 1.584000] fat_mount: Num FATs: 2
[ 1.589000] fat_mount: FAT sectors: 15264
[ 1.594000] fat_mount: sectors/cluster: 32
[ 1.598000] fat_mount: max clusters: 1952773
[ 1.604000] fat_mount: FSI free count 1952130
[ 1.609000] fat_mount: next free 1417
NuttShell (NSH) NuttX-12.11.0
nsh> ls
/:
dev/
proc/
sd/
nsh> ls /dev
/dev:
console
mmcsd0
null
zero
```
Listing the SD card boot partition:
```
/sd:
bcm2711-rpi-4-b.dtb
config.txt
fixup4cd.dat
fixup4.dat
fixup4db.dat
fixup4x.dat
nuttx.bin
start4cd.elf
start4db.elf
start4.elf
start4x.elf
overlays/
test.txt
nsh>
```
Using `cat` to see file contents of test.txt:
```
nsh> cat /sd/test.txt
This is a test!
```
Using `echo` to append to test.txt:
*Currently fails*
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
