ARM: OMAP2+: Block suspend for am3 and am4 if PM is not configured

If the PM related modules are not loaded and PM firmware not configured,
the system suspend fails to resume. Let's fix this by adding initial
platform_suspend_ops to block suspend and warn about missing modules.

When pm33xx and wkup_m3_ipc have been loaded and m3 coprocessor booted
with it's firmware, pm33xx sets up working platform_suspend_ops. Note
that we need to configure at least PM_SUSPEND_STANDBY to have
suspend_set_ops().

Cc: Dave Gerlach <d-gerlach@ti.com>
Cc: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/pm33xx-core.c

@@ -8,6 +8,7 @@
 
 #include <linux/cpuidle.h>
 #include <linux/platform_data/pm33xx.h>
+#include <linux/suspend.h>
 #include <asm/cpuidle.h>
 #include <asm/smp_scu.h>
 #include <asm/suspend.h>
@@ -324,6 +325,44 @@ static struct am33xx_pm_platform_data *am33xx_pm_get_pdata(void)
 		return NULL;
 }
 
+#ifdef CONFIG_SUSPEND
+/*
+ * Block system suspend initially. Later on pm33xx sets up it's own
+ * platform_suspend_ops after probe. That depends also on loaded
+ * wkup_m3_ipc and booted am335x-pm-firmware.elf.
+ */
+static int amx3_suspend_block(suspend_state_t state)
+{
+	pr_warn("PM not initialized for pm33xx, wkup_m3_ipc, or am335x-pm-firmware.elf\n");
+
+	return -EINVAL;
+}
+
+static int amx3_pm_valid(suspend_state_t state)
+{
+	switch (state) {
+	case PM_SUSPEND_STANDBY:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static const struct platform_suspend_ops amx3_blocked_pm_ops = {
+	.begin = amx3_suspend_block,
+	.valid = amx3_pm_valid,
+};
+
+static void __init amx3_block_suspend(void)
+{
+	suspend_set_ops(&amx3_blocked_pm_ops);
+}
+#else
+static inline void amx3_block_suspend(void)
+{
+}
+#endif	/* CONFIG_SUSPEND */
+
 int __init amx3_common_pm_init(void)
 {
 	struct am33xx_pm_platform_data *pdata;
@@ -337,6 +376,7 @@ int __init amx3_common_pm_init(void)
 	devinfo.size_data = sizeof(*pdata);
 	devinfo.id = -1;
 	platform_device_register_full(&devinfo);
+	amx3_block_suspend();
 
 	return 0;
 }