ARM: imx: build v7_cpu_resume() unconditionally

BugLink: https://bugs.launchpad.net/bugs/1868628

commit 512a928a upstream.

This function is not only needed by the platform suspend code, but is also
reused as the CPU resume function when the ARM cores can be powered down
completely in deep idle, which is the case on i.MX6SX and i.MX6UL(L).

Providing the static inline stub whenever CONFIG_SUSPEND is disabled means
that those platforms will hang on resume from cpuidle if suspend is disabled.

So there are two problems:

  - The static inline stub masks the linker error
  - The function is not available where needed

Fix both by just building the function unconditionally, when
CONFIG_SOC_IMX6 is enabled. The actual code is three instructions long,
so it's arguably ok to just leave it in for all i.MX6 kernel configurations.

Fixes: 05136f08 ("ARM: imx: support arm power off in cpuidle for i.mx6sx")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

arch/arm/mach-imx/Makefile

@@ -91,6 +91,8 @@ AFLAGS_suspend-imx6.o :=-Wa,-march=armv7-a
 obj-$(CONFIG_SOC_IMX6) += suspend-imx6.o
 obj-$(CONFIG_SOC_IMX53) += suspend-imx53.o
 endif
+AFLAGS_resume-imx6.o :=-Wa,-march=armv7-a
+obj-$(CONFIG_SOC_IMX6) += resume-imx6.o
 obj-$(CONFIG_SOC_IMX6) += pm-imx6.o
 
 obj-$(CONFIG_SOC_IMX50) += mach-imx50.o

arch/arm/mach-imx/common.h

@@ -115,17 +115,17 @@ void imx_cpu_die(unsigned int cpu);
 int imx_cpu_kill(unsigned int cpu);
 
 #ifdef CONFIG_SUSPEND
-void v7_cpu_resume(void);
 void imx53_suspend(void __iomem *ocram_vbase);
 extern const u32 imx53_suspend_sz;
 void imx6_suspend(void __iomem *ocram_vbase);
 #else
-static inline void v7_cpu_resume(void) {}
 static inline void imx53_suspend(void __iomem *ocram_vbase) {}
 static const u32 imx53_suspend_sz;
 static inline void imx6_suspend(void __iomem *ocram_vbase) {}
 #endif
 
+void v7_cpu_resume(void);
+
 void imx6_pm_ccm_init(const char *ccm_compat);
 void imx6q_pm_init(void);
 void imx6dl_pm_init(void);

arch/arm/mach-imx/resume-imx6.S

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright 2014 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
+#include <asm/hardware/cache-l2x0.h>
+#include "hardware.h"
+
+/*
+ * The following code must assume it is running from physical address
+ * where absolute virtual addresses to the data section have to be
+ * turned into relative ones.
+ */
+
+ENTRY(v7_cpu_resume)
+	bl	v7_invalidate_l1
+#ifdef CONFIG_CACHE_L2X0
+	bl	l2c310_early_resume
+#endif
+	b	cpu_resume
+ENDPROC(v7_cpu_resume)

arch/arm/mach-imx/suspend-imx6.S

@@ -333,17 +333,3 @@ resume:
 
 	ret	lr
 ENDPROC(imx6_suspend)
-
-/*
- * The following code must assume it is running from physical address
- * where absolute virtual addresses to the data section have to be
- * turned into relative ones.
- */
-
-ENTRY(v7_cpu_resume)
-	bl	v7_invalidate_l1
-#ifdef CONFIG_CACHE_L2X0
-	bl	l2c310_early_resume
-#endif
-	b	cpu_resume
-ENDPROC(v7_cpu_resume)