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

[Lukas Funke]

Hi Venkatesh,

On 30.05.2024 07:39, Abbarapu, Venkatesh wrote:
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?

We can observe this behaviour on zu2cg and zu3eg. I haven't tried it on 
an eval-board but this would be the next step.

The main problem is that the stable-bit is not set if there is no 
sd-card plugged in from the beginning, but only if the cd-signal changes.

Is there any documentation how this bit should behave then?

Best regards
- Lukas


Thanks
Venkatesh
-----Original Message-----
From: Simek, Michal <michal.si...@amd.com>
Sent: Wednesday, May 29, 2024 8:33 PM
To: lukas.funke-...@weidmueller.com; u-boot@lists.denx.de; Abbarapu,
Venkatesh <venkatesh.abbar...@amd.com>
Cc: Stefan Herbrechtsmeier <stefan.herbrechtsme...@weidmueller.com>;
Ashok Reddy Soma <ashok.reddy.s...@amd.com>; Lukas Funke
<lukas.fu...@weidmueller.com>; Jaehoon Chung
<jh80.ch...@samsung.com>; Johan Jonker <jbx6...@gmail.com>; Peng Fan
<peng....@nxp.com>; Simon Glass <s...@chromium.org>; Tom Rini
<tr...@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-...@weidmueller.com wrote:
From: Lukas Funke <lukas.fu...@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.fu...@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