Hi,
I have started to look into the possibility of creating a custom Pi HAT that will have eMMC for boot / storage. I plan to use the SDIO interface for the same. With this setup on the RPi 5, I will be able to better utilize the remaining space on the custom Pi HAT for some other interfaces instead of having a m.2 slot for a 2280 NVME SSD. This also leaves the PCIe interface free. I'd rather not use USB for boot / storage, even though there might be benefits in terms of transfer speeds. I am hoping that eMMC on SDIO will do as good as NVME on PCIe or an external SSD on USB 3.0 in terms of random r/w.
So far, I have come across the below information.
From the RP1 Peripherals draft:
From the news introducing the RPi 5:
Now based off the information above, I have the following questions:
Thanks.
I have started to look into the possibility of creating a custom Pi HAT that will have eMMC for boot / storage. I plan to use the SDIO interface for the same. With this setup on the RPi 5, I will be able to better utilize the remaining space on the custom Pi HAT for some other interfaces instead of having a m.2 slot for a 2280 NVME SSD. This also leaves the PCIe interface free. I'd rather not use USB for boot / storage, even though there might be benefits in terms of transfer speeds. I am hoping that eMMC on SDIO will do as good as NVME on PCIe or an external SSD on USB 3.0 in terms of random r/w.
So far, I have come across the below information.
From the RP1 Peripherals draft:
Chapter 4. SDIO
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Clik here to view.
and
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Clik here to view.
Chapter 3.1.1 Function select
Image may be NSFW.
Clik here to view.
From the news introducing the RPi 5:
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Now based off the information above, I have the following questions:
- The RP1 Peripherals draft suggests the presence of 2 SDIO controllers. And the RPi 5 introduction news mentions a direct interface to the processor for the SD Card. Is there an SDIO interface that is unused by SD Card and WiFi-BT?
- If so, is the SDIO0 interface on GPIO22 to GPIO27 the unused interface?
- Can it be used to interface an eMMC?
- If the eMMC can indeed be interfaced over SDIO, will I require to give up the use of SDIO for SD Card interface by any chance?
- The features not supported lists "eMMC Boot Protocol". Can I boot off the eMMC?
- Right now I think the support for RPi 5 secureboot isn't present, but in the future, could I possibly use secureboot with the eMMC?
- On the eMMC, would I see random r/w speeds similar to NVME SSDs or external USB 3.0 SSDs?
Thanks.
Statistics: Posted by pinominator — Mon Feb 12, 2024 11:27 am
