[PATCH 7/7] sandbox: hostfile: add feature controller support

[Ahmad Fatoum <ahmad@a3f.at>]

Keeping the tradition of making the sandbox more complex than it needs
to in order to exercise more parts of barebox, let's allow hostfiles to
be feature controllers: This allows specifying optional hostfiles in the
DT: If the hostfile is unavailable, the nodes pointing at the hostfile
can be gated by it, so they behaves as if they were disabled.

This is useful for the stickypage, which results in a number of ugly
errors whenever it's unavailable.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 arch/sandbox/board/hostfile.c          | 30 +++++++++++++++++++++++---
 arch/sandbox/configs/sandbox_defconfig |  2 ++
 arch/sandbox/dts/sandbox.dts           |  4 ++++
 drivers/base/Kconfig                   |  2 +-
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/arch/sandbox/board/hostfile.c b/arch/sandbox/board/hostfile.c
index 424f16acd5fc..d0f400787d7a 100644
--- a/arch/sandbox/board/hostfile.c
+++ b/arch/sandbox/board/hostfile.c
@@ -24,6 +24,7 @@
 #include <errno.h>
 #include <linux/err.h>
 #include <mach/hostfile.h>
+#include <featctrl.h>
 #include <xfuncs.h>
 
 struct hf_priv {
@@ -33,6 +34,7 @@ struct hf_priv {
 	};
 	const char *filename;
 	int fd;
+	struct feature_controller feat;
 };
 
 static ssize_t hf_read(struct hf_priv *priv, void *buf, size_t count, loff_t offset, ulong flags)
@@ -96,18 +98,41 @@ static void hf_info(struct device *dev)
 	printf("file: %s\n", priv->filename);
 }
 
+static int hostfile_feat_check(struct feature_controller *feat, int idx)
+{
+	struct hf_priv *priv = container_of(feat, struct hf_priv, feat);
+
+	return priv->fd >= 0 ? FEATCTRL_OKAY : FEATCTRL_GATED;
+}
+
 static int hf_probe(struct device *dev)
 {
 	struct device_node *np = dev->of_node;
 	struct hf_priv *priv = xzalloc(sizeof(*priv));
 	struct cdev *cdev;
-	bool is_blockdev;
+	bool is_featctrl = false, is_blockdev;
 	u64 reg[2];
 	int err;
 
 	if (!np)
 		return -ENODEV;
 
+	dev->priv = priv;
+	priv->fd = -1;
+
+	if (IS_ENABLED(CONFIG_FEATURE_CONTROLLER) &&
+	    of_property_read_bool(np, "barebox,feature-controller")) {
+		priv->feat.dev = dev;
+		priv->feat.check = hostfile_feat_check;
+
+		err = feature_controller_register(&priv->feat);
+		if (err)
+			return err;
+
+		is_featctrl = true;
+	}
+
+
 	err = of_property_read_u64_array(np, "reg", reg, ARRAY_SIZE(reg));
 	if (err)
 		return err;
@@ -120,10 +145,9 @@ static int hf_probe(struct device *dev)
 		return err;
 
 	if (priv->fd < 0)
-		return priv->fd;
+		return is_featctrl ? 0 : priv->fd;
 
 	dev->info = hf_info;
-	dev->priv = priv;
 
 	is_blockdev = of_property_read_bool(np, "barebox,blockdev");
 
diff --git a/arch/sandbox/configs/sandbox_defconfig b/arch/sandbox/configs/sandbox_defconfig
index 16138d9274c4..1bb98c550c43 100644
--- a/arch/sandbox/configs/sandbox_defconfig
+++ b/arch/sandbox/configs/sandbox_defconfig
@@ -96,7 +96,9 @@ CONFIG_NET_NFS=y
 CONFIG_NET_NETCONSOLE=y
 CONFIG_NET_SNTP=y
 CONFIG_NET_FASTBOOT=y
+CONFIG_FEATURE_CONTROLLER=y
 CONFIG_OFDEVICE=y
+# CONFIG_FEATURE_CONTROLLER_FIXUP is not set
 CONFIG_OF_BAREBOX_DRIVERS=y
 CONFIG_OF_BAREBOX_ENV_IN_FS=y
 CONFIG_OF_OVERLAY_LIVE=y
diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
index 5b2cab219e2a..75c633c5909f 100644
--- a/arch/sandbox/dts/sandbox.dts
+++ b/arch/sandbox/dts/sandbox.dts
@@ -31,6 +31,8 @@
 		backend = <&part_state>;
 		backend-storage-type = "direct";
 		backend-stridesize = <64>;
+		/* suppres sandbox warnings when stickypage is missing */
+		barebox,feature-gates = <&stickypage>;
 
 		#address-cells = <1>;
 		#size-cells = <1>;
@@ -58,6 +60,8 @@
 		barebox,filename = "$build/stickypage.bin";
 		reg = <0 0 0 4096>;
 		barebox,cdev; /* no caching allowed */
+		barebox,feature-controller;
+		#feature-cells = <0>;
 
 		bmode: reboot-mode {
 			compatible = "nvmem-reboot-mode";
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 3788231b6e82..612a84be33e7 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -4,6 +4,6 @@ config PM_GENERIC_DOMAINS
 	bool
 
 config FEATURE_CONTROLLER
-	bool "Feature controller support" if COMPILE_TEST
+	bool "Feature controller support" if COMPILE_TEST || SANDBOX
 
 source "drivers/base/regmap/Kconfig"
-- 
2.38.4