Hi Marek,
On 3/26/25 2:37 AM, Marek Vasut wrote:
On 3/26/25 1:15 AM, Tom Rini wrote:
On Wed, Mar 26, 2025 at 12:02:08AM +0100, Marek Vasut wrote:
On 3/24/25 1:39 PM, Quentin Schulz wrote:
Hi Marek,
Hi,
On 3/22/25 10:55 PM, Marek Vasut wrote:
Rename the variable and add ENV_ prefix, so that all configuration
options which are related to environment would have an CONFIG_ENV_
prefix. No functional change.
Use ENV_SDMMC_DEVICE_INDEX to clarify this is the SD/MMC device
index, a number, as enumerated by U-Boot. Update the help text
accordingly.
I disagree with this part of the rename (MMC->SDMMC), our drivers all
are using mmc (env/mmc.*, drivers/mmc/*, cmd/mmc.c, ...) for both SD
and
MMC. We also have ENV_IS_IN_MMC which is for both. I don't think it's
worth the confusion.
My main problem is, that it is confusing to call everything _mmc_
even if
most of it also applies to SD . There is no way to discern parts
which are
MMC specific from parts which are common to SD and MMC now.
Do we have support for anything using the MMC part of the standard that
is not storage? I certainly agree it's confusingly named atm, but I
think changing some parts but not other parts will make it worse, not
better.
That's not what I am concerned about. What I am concerned about is that
we are talking about partitions, and only eMMC supports HW partitions,
but both SD and MMC support SW partitions . So we should refer to
CONFIG_..._SDMMC_..._SW_PARTITION here when talking about SW
partitions , but CONFIG_..._MMC_..._HW_PARTITION when talking about eMMC
HW partitions. Currently we are missing the two and it yields a horrid
confusion. That is in fact what prompted this series.
But the controllers handling SD cards or eMMC are both called mmc in
device tree and in U-Boot (see mmc command). So for me, MMC covers both.
As a matter of fact, the mmc command also handles the boot partition
that is specific to eMMC.
Quite interestingly, the MMC (MultiMediaCard) Wikipedia page starts with
"Not to be confused with SD card or eMMC" and then the first sentence in
the history section is "The latest version of the eMMC standard", c.f.
https://en.wikipedia.org/wiki/MultiMediaCard
So essentially, I'm wondering:
- if boot partitions are specific to eMMC and not simpy MMC (and are not
part of SD card). I know eMMC has a separate standard than MMC.
- if there are other things than eMMC (and SD cards) that are supported
by the MMC subsystem (outside of the embedded world). It seems like this
is taking the MMC = eMMC shortcut that I'm not sure is correct?
To add to the confusion, Rockchip often has MMC controllers named SDMMC
(and their use varies depending on the SoC, sometimes for SD, sometimes
for eMMC, sometimes for SDIO).
Cheers,
Quentin
