[PATCH v2 5/5] mci: add option to detect non-removable cards during startup

[Sascha Hauer]

We can optionally detect all MMC/SD cards during startup which might
cost some boot time, so this is best disabled. This adds another option
to detect only cards that are marked non-removable in the device tree
during startup. The rationale is that we will likely boot from that
device anyway, so detecting it during startup does not add to the boot
time.

We are aiming to find a good place for the barebox environment without
having to explicitly add it to the device tree. Putting the environment
into a regular partition is a good start, but the device that has the
environment needs to be available when we are searching for it. Enabling
this new option is one way to it.

Link: https://lore.barebox.org/20250602-createnv-v1-5-c3239ff875d5@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/mci/Kconfig    | 21 +++++++++++++++++++--
 drivers/mci/mci-core.c |  6 +++++-
 include/mci.h          |  1 +
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/mci/Kconfig b/drivers/mci/Kconfig
index 44fd4716aade0882264d389cc08547c3f14986c9..c99f29a6db6f52137ae22aa550d752d78d86e80a 100644
--- a/drivers/mci/Kconfig
+++ b/drivers/mci/Kconfig
@@ -19,14 +19,31 @@ config MCI_TUNING
 	  higher clock speeds than 52 MHz SDR. MMC only; SD-Card max
 	  frequency is 50MHz SDR at present.
 
+choice
+	prompt "MMC detection on startup"
+
+config MCI_STARTUP_NONE
+	bool "do not detect cards during system start"
+	help
+	  Choose this if the MCI framework should never detect cards during system
+	  start
+
+config MCI_STARTUP_NONREMOVABLE
+	bool "detect non removable cards on system start"
+	help
+	  Choose this if the MCI framework should detect non removable cards (i.e.
+	  devices which have the non-removable device tree property).
+
 config MCI_STARTUP
-	bool "Force probe on system start"
+	bool "detect all cards on system start"
 	help
-	  Say 'y' here if the MCI framework should always probe for all attached
+	  Choose this if the MCI framework should always probe for all attached
 	  MCI cards on system start up. This may required for some legacy boards.
 	  When this is 'n', probing happens on demand either with "mci*.probe=1"
 	  or with driver/board code calling device_detect.
 
+endchoice
+
 config MCI_INFO
 	bool "MCI Info"
 	depends on CMD_DEVINFO
diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index 5cfa1ab4506de7452d9d0b3b3ead41e4d4f756db..242db78b4d52b25ed83a63aa5f3966a4482055ed 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -3101,7 +3101,9 @@ int mci_register(struct mci_host *host)
 		devinfo_add(&mci->dev, mci_info);
 
 	/* if enabled, probe the attached card immediately */
-	if (IS_ENABLED(CONFIG_MCI_STARTUP))
+	if (IS_ENABLED(CONFIG_MCI_STARTUP) ||
+	   (IS_ENABLED(CONFIG_MCI_STARTUP_NONREMOVABLE) &&
+	    (host->host_caps & MMC_CAP_NONREMOVABLE)))
 		mci_card_probe(mci);
 
 	if (!(host->caps2 & MMC_CAP2_NO_SD) && dev_of_node(host->hw_dev)) {
@@ -3195,6 +3197,8 @@ void mci_of_parse_node(struct mci_host *host,
 		host->caps2 |= MMC_CAP2_NO_SD;
 	if (of_property_read_bool(np, "no-mmc"))
 		host->caps2 |= MMC_CAP2_NO_MMC;
+	if (of_property_read_bool(np, "non-removable"))
+                host->host_caps |= MMC_CAP_NONREMOVABLE;
 	if (IS_ENABLED(CONFIG_MCI_TUNING)) {
 		u32 drv_type;
 
diff --git a/include/mci.h b/include/mci.h
index 82099f118e65191d52ac81bd8bc5e1b24d341092..3db33f9142362fb6910c6d1552accc942497ed7f 100644
--- a/include/mci.h
+++ b/include/mci.h
@@ -58,6 +58,7 @@
 #define MMC_CAP_1_2V_DDR		(1 << 9)	/* Host supports eMMC DDR 1.2V */
 #define MMC_CAP_DDR			(MMC_CAP_3_3V_DDR | MMC_CAP_1_8V_DDR | \
 					 MMC_CAP_1_2V_DDR)
+#define MMC_CAP_NONREMOVABLE	(1 << 8)	/* Nonremovable e.g. eMMC */
 #define MMC_CAP_UHS_SDR12	(1 << 16)	/* Host supports UHS SDR12 mode */
 #define MMC_CAP_UHS_SDR25	(1 << 17)	/* Host supports UHS SDR25 mode */
 #define MMC_CAP_UHS_SDR50	(1 << 18)	/* Host supports UHS SDR50 mode */

-- 
2.39.5