A3720 - Disable slot when eMMC is not present

["Pali Rohár" <pali@kernel.org>]

Hello!

On Monday 14 December 2020 13:38:07 Andre Heider wrote:
> On 08/12/2020 11:08, Pali Roh?r wrote:
> > Hello! I looked at what is initialized and enabled for sd/emmc slots and
> > I found out that comphy mmc needs to be enabled if at least one slot is
> > used (e.g. SD card) and then remaining part is slot initialization in
> > xenon driver.
> > 
> > I wrote quick patch to disable slot when unregistering mmc device from
> > U-Boot and also unregister emmc on A3720 from U-Boot when it is not
> > present. But I have not tested it yet.
> > 
> > What do you think about it?
> 
> I haven't tested this yet, but it looks like it should leave the hw in a
> state as it was on a non-emmc board before the emmc/non-emmc merge. So I
> like the idea!

Now I have tested this patch on Espressobin v5 without eMMC and mmc
device was correctly removed, it even does not show in 'mmc list'
output. From uSD card is working fine as before.

I do not observe any slowdown of init sequence. And I still have a
problem to catch output and press key to stop uboot booting :D So I
think initialization is still very fast.

> You can merge your xenon_mmc_disable_slot() with xenon_mmc_enable_slot()
> though, and instead add a 'bool enable' as with xenon_mmc_set_acg() above.

I was thinking about it and I chosen separate function as separated it
is also in the linux kernel driver.

But I have no problem to choose any variant. Stefan (or any other
maintainer of this sdhc code), please let me know what style would you
like to see or if you have any other comments for changes.

> Thanks,
> Andre
> 
> > 
> > diff --git a/board/Marvell/mvebu_armada-37xx/board.c b/board/Marvell/mvebu_armada-37xx/board.c
> > index f67b04b78c..1b9e7520cc 100644
> > --- a/board/Marvell/mvebu_armada-37xx/board.c
> > +++ b/board/Marvell/mvebu_armada-37xx/board.c
> > @@ -5,6 +5,7 @@
> >   #include <common.h>
> >   #include <dm.h>
> > +#include <dm/device-internal.h>
> >   #include <env.h>
> >   #include <i2c.h>
> >   #include <init.h>
> > @@ -84,12 +85,10 @@ int board_init(void)
> >   #ifdef CONFIG_BOARD_LATE_INIT
> >   int board_late_init(void)
> >   {
> > +	struct udevice *dev;
> >   	struct mmc *mmc_dev;
> >   	bool ddr4, emmc;
> > -	if (env_get("fdtfile"))
> > -		return 0;
> > -
> >   	if (!of_machine_is_compatible("globalscale,espressobin"))
> >   		return 0;
> > @@ -101,6 +100,16 @@ int board_late_init(void)
> >   	mmc_dev = find_mmc_device(1);
> >   	emmc = (mmc_dev && mmc_init(mmc_dev) == 0);
> > +	/* if eMMC is not present then remove it from DM */
> > +	if (!emmc && mmc_dev) {
> > +		dev = mmc_dev->dev;
> > +		device_remove(dev, DM_REMOVE_NORMAL);
> > +		device_unbind(dev);
> > +	}
> > +
> > +	if (env_get("fdtfile"))
> > +		return 0;
> > +
> >   	if (ddr4 && emmc)
> >   		env_set("fdtfile", "marvell/armada-3720-espressobin-v7-emmc.dtb");
> >   	else if (ddr4)
> > diff --git a/drivers/mmc/xenon_sdhci.c b/drivers/mmc/xenon_sdhci.c
> > index 6ce9d00d0a..da9882cbf6 100644
> > --- a/drivers/mmc/xenon_sdhci.c
> > +++ b/drivers/mmc/xenon_sdhci.c
> > @@ -350,6 +350,16 @@ static void xenon_mmc_enable_slot(struct sdhci_host *host, u8 slot)
> >   	sdhci_writel(host, var, SDHC_SYS_OP_CTRL);
> >   }
> > +/* Disable specific slot */
> > +static void xenon_mmc_disable_slot(struct sdhci_host *host, u8 slot)
> > +{
> > +	u32 var;
> > +
> > +	var = sdhci_readl(host, SDHC_SYS_OP_CTRL);
> > +	var &= ~(SLOT_MASK(slot) << SLOT_ENABLE_SHIFT);
> > +	sdhci_writel(host, var, SDHC_SYS_OP_CTRL);
> > +}
> > +
> >   /* Enable Parallel Transfer Mode */
> >   static void xenon_mmc_enable_parallel_tran(struct sdhci_host *host, u8 slot)
> >   {
> > @@ -515,6 +525,14 @@ static int xenon_sdhci_probe(struct udevice *dev)
> >   	return ret;
> >   }
> > +static int xenon_sdhci_remove(struct udevice *dev)
> > +{
> > +	struct sdhci_host *host = dev_get_priv(dev);
> > +
> > +	xenon_mmc_disable_slot(host, XENON_MMC_SLOT_ID_HYPERION);
> > +	return 0;
> > +}
> > +
> >   static int xenon_sdhci_ofdata_to_platdata(struct udevice *dev)
> >   {
> >   	struct sdhci_host *host = dev_get_priv(dev);
> > @@ -564,6 +582,7 @@ U_BOOT_DRIVER(xenon_sdhci_drv) = {
> >   	.ops		= &sdhci_ops,
> >   	.bind		= xenon_sdhci_bind,
> >   	.probe		= xenon_sdhci_probe,
> > +	.remove		= xenon_sdhci_remove,
> >   	.priv_auto_alloc_size = sizeof(struct xenon_sdhci_priv),
> >   	.platdata_auto_alloc_size = sizeof(struct xenon_sdhci_plat),
> >   };
> > 
>