[RFC PATCH v1 1/1] mmc: zynq_sdhci: Only evaluate card-stable signal if card was detected

[Abbarapu, Venkatesh]

Hi Lukas,
The polling of card-stable bit alone is enough, as if card-detect bit is not set anyways the card-stable bit won't be set which leads to timeout.
I don’t think it is specific to zynqmp platform.

Could you please let me know if you observe this issue on any of the zynqmp board? 

Thanks
Venkatesh
> -----Original Message-----
> From: Simek, Michal <michal.simek at amd.com>
> Sent: Wednesday, May 29, 2024 8:33 PM
> To: lukas.funke-oss at weidmueller.com; u-boot at lists.denx.de; Abbarapu,
> Venkatesh <venkatesh.abbarapu at amd.com>
> Cc: Stefan Herbrechtsmeier <Stefan.Herbrechtsmeier at weidmueller.com>;
> Ashok Reddy Soma <ashok.reddy.soma at amd.com>; Lukas Funke
> <lukas.funke at weidmueller.com>; Jaehoon Chung
> <jh80.chung at samsung.com>; Johan Jonker <jbx6244 at gmail.com>; Peng Fan
> <peng.fan at nxp.com>; Simon Glass <sjg at chromium.org>; Tom Rini
> <trini at konsulko.com>
> Subject: Re: [RFC PATCH v1 1/1] mmc: zynq_sdhci: Only evaluate card-stable
> signal if card was detected
> 
> 
> 
> On 4/24/24 10:23, lukas.funke-oss at weidmueller.com wrote:
> > From: Lukas Funke <lukas.funke at weidmueller.com>
> >
> > On ZynqMp there seems to be a dependency between the card-stable bit
> > and the card-detect bit. The card-stable bit is set *if and only if*
> > the card-detect bit was set before, indicating that the signal was
> > stable and reliable during card insertion.
> >
> > If the card-detect bit is *not* evaluated the corresponding check
> > leads to a timeout indicating that the card-detect was not stable.
> >
> > Signed-off-by: Lukas Funke <lukas.funke at weidmueller.com>
> > ---
> >
> >   drivers/mmc/zynq_sdhci.c | 7 +++++--
> >   1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mmc/zynq_sdhci.c b/drivers/mmc/zynq_sdhci.c index
> > 935540d171..d0bccd41cc 100644
> > --- a/drivers/mmc/zynq_sdhci.c
> > +++ b/drivers/mmc/zynq_sdhci.c
> > @@ -1168,11 +1168,14 @@ static int arasan_sdhci_probe(struct udevice
> *dev)
> >   	 */
> >   	if (IS_ENABLED(CONFIG_ARCH_ZYNQMP) ||
> IS_ENABLED(CONFIG_ARCH_VERSAL)) {
> >   		u32 timeout = 1000000;
> > +		u32 value;
> >
> > -		while (((sdhci_readl(host, SDHCI_PRESENT_STATE) &
> > -			 SDHCI_CARD_STATE_STABLE) == 0) && timeout) {
> > +		value = sdhci_readl(host, SDHCI_PRESENT_STATE);
> > +		while ((value & SDHCI_CARD_PRESENT) &&
> > +		       ((value & SDHCI_CARD_STATE_STABLE) == 0) && timeout)
> {
> >   			udelay(1);
> >   			timeout--;
> > +			value = sdhci_readl(host, SDHCI_PRESENT_STATE);
> >   		}
> >   		if (!timeout) {
> >   			dev_err(dev, "Sdhci card detect state not stable\n");
> 
> Venkatesh: Can you please take a look at this?
> 
> Thanks,
> Michal