[PATCH v3 1/4] firmware: Amlogic: Add secure monitor driver

Carlo Caione [off-list ref] writes:

From: Carlo Caione <redacted>

Introduce a driver to provide calls into secure monitor mode.

In the Amlogic SoCs these calls are used for multiple reasons: access to
NVMEM, set USB boot, enable JTAG, etc...

Signed-off-by: Carlo Caione <redacted>

[...]

+static int meson_sm_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct meson_sm_firmware *fw;
+	u32 sm_phy_in_base, sm_phy_out_base;
+	int cmd_in, cmd_out;
+
+	fw = devm_kzalloc(&pdev->dev, sizeof(*fw), GFP_KERNEL);
+	if (!fw)
+		return -ENOMEM;
+
+	fw->dev = &pdev->dev;
+
+	if (of_property_read_u32(np, "amlogic,sm-cmd-input-base", &cmd_in))
+		return -EINVAL;
+
+	if (of_property_read_u32(np, "amlogic,sm-cmd-output-base", &cmd_out))
+		return -EINVAL;
+
+	sm_phy_in_base = meson_sm_call(cmd_in, 0, 0, 0, 0, 0);

Should there be any error checking here?  Do we have any info on the
return values here in case of error, or in case of missing firmware,
etc.

Kevin