Hi Simon,
On Fri, Jul 28, 2017 at 11:44 AM, Simon Glass sjg@chromium.org wrote:
Hi Suneel,
On 27 July 2017 at 23:03, Suneel Garapati suneelglinux@gmail.com wrote:
Hi Simon,
I have similar requirement of Cavium boards using two card slots on one host and currently trying to figure out to support it using DM_MMC. Would like to know if you have quick thoughts or seen similar use case with some other boards too?
It should work correctly - what sort of problem do you have?
Each mmc_bind call creates child blk_device and initialize the mmc structure with defaults and further mmc_init or driver_probe would set the rest of the members. For the case, one host and two card slots, assuming card slots put up as child nodes to mmc node in devicetree - driver probe called for once on host, initiates only one mmc_bind call -> only one child blk device(udevice) created - also 'struct mmc' includes card specific data cid csd scr rca which should scale for multiple slots simultaneously - assuming boot up detects two cards on two slots, mmc dev 0 will chose host but not slot - mmc_uclass_priv holds mmc reference but depending on slot it should get updated. - maybe need to split mmc into mmc_host and mmc_card structures like Linux.
Also, mmc dev 0/1 from cmd prompt would choose host and not the card slot.
Please correct me.
Regards, Suneel
Please correct me if I miss something obvious.
Regards, Simon
Regards, Suneel
On Thu, Jul 27, 2017 at 9:19 PM, Simon Glass sjg@chromium.org wrote:
Hi Maxime,
On 17 July 2017 at 03:26, Maxime Ripard maxime.ripard@free-electrons.com wrote:
Hi Simon,
On Fri, Jul 14, 2017 at 07:47:45AM -0600, Simon Glass wrote:
On 5 July 2017 at 14:14, Maxime Ripard maxime.ripard@free-electrons.com wrote:
On Wed, Jul 05, 2017 at 04:57:40PM +0200, Maxime Ripard wrote: > On Tue, Jul 04, 2017 at 01:33:25PM -0600, Simon Glass wrote: > > Hi Maxime, > > > > On 21 June 2017 at 01:31, Maxime Ripard > > maxime.ripard@free-electrons.com wrote: > > > Hi Simon, > > > > > > On Mon, Jun 19, 2017 at 11:11:27AM -0600, Simon Glass wrote: > > >> Add a driver-model version of this driver which mostly uses the existing > > >> code. The old code can be removed once all boards are switched over. > > >> > > >> Signed-off-by: Simon Glass sjg@chromium.org > > > > > > I'm not sure if you tested that, but we have some code that switches > > > the MMC indices when using both an eMMC and an external MMC. > > > > > > http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/board.c#l494 > > > > > > This predates my time, but it seems that it was done to have a > > > consistent boot MMC device ID. > > > > > > I'm not really sure we can get rid of it (even if it creates some > > > issues of it's own), but what would be the impact of a switch to the > > > device model on that logic? > > > > That is a pretty terrible hack. > > Yes, I know. This is especially bad when used together with other > tools that rely on one MMC index for example (such as fastboot). > > I wanted to kill it for quite some time, but I'm a bit reluctant due > to the possible side effects. > > > I'm not sure whether it will continue to work with DM. It does still > > use the device number in the block device, so maybe... Do you have > > a board would use this? > > I guess I do. I'll give it a try or tonight and let you know.
I just tested. Even with an eMMC (which was the first use case for that hack), it works, even things that are not mainline yet (fastboot, etc).
It obviously break the old scripts relying on the mmc index, but I guess that's ok.
There's one regression though. Our eMMC will always be the second one, which means that the distro bootargs will always boot on the external SD first (which is always going to be mmc0).
That's due to the fact that the eMMC controller is the third one, and is thus probed last. We obviously want something deterministic for fastboot for example, but booting partitions of the media you started from make sense I guess. And this is what this hack was trying to address.
OK...so what should we do here?
I guess we should just drop the hack. We'll have to at some point anyway. But I guess we should also find a way to tweak the distro bootcmd at boot time to search for the medium that we booted on first.
I'm not really sure how to do this though.
Well in that case let's drop the hack and someone will pick it up when it hits them.
Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot