[PATCH] ARM: i.MX: prevent use of imx_cpu_type in PBL

[PATCH] ARM: i.MX: prevent use of imx_cpu_type in PBL

[Ahmad Fatoum]

Functions like cpu_is_mx6q internally call cpu_is_mx6() first,
which can be evaluated at compile-time if only i.MX6 boards are enabled.

This allowed calling cpu_is_mx6q in PBL entry points as long as barebox was
compiled for only a single SoC.

Since the multi-arch/multi-platform support was added however,
cpu_is_mx6 became a runtime check that's never true in PBL, leading all
cpu_is_mx* in 32-boards to silently fail at runtime.

We have no in-tree boards that are affected by this, so until some
out-of-tree user is bothered enough to fix is, acknowledge that this no
longer works and turn the silent breakage into a loud compile-time error
whenever anything ends up referencing __imx_cpu_type.

Fixes: 1826809f122e ("ARM: i.MX: fix cpu_is_imx on CONFIG_ARM_MULTIARCH configurations")
Fixes: 60a3fd36fa1e ("arm: mach-imx: set cpu type in pbl")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/mach-imx/Makefile |  4 ++--
 include/mach/imx/generic.h | 11 +++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index a7d60068b954..5c26af577504 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_ARCH_VF610) += vf610.o
 obj-pbl-$(CONFIG_ARCH_IMX8M) += imx8m.o
 obj-pbl-$(CONFIG_ARCH_IMX_SCRATCHMEM) += scratch.o
 obj-$(CONFIG_ARCH_IMX9) += imx9.o imx-v3-image.o
-lwl-$(CONFIG_ARCH_IMX_ATF) += atf.o
+lwl-$(CONFIG_ARCH_IMX_ATF) += atf.o imx.o
 obj-pbl-$(CONFIG_ARCH_IMX_TZASC) += tzasc.o
 obj-pbl-$(CONFIG_ARCH_IMX_ROMAPI) += romapi.o
 obj-$(CONFIG_IMX_IIM)	+= iim.o
@@ -28,7 +28,7 @@ obj-$(CONFIG_NAND_IMX) += nand.o
 lwl-$(CONFIG_ARCH_IMX_EXTERNAL_BOOT_NAND) += external-nand-boot.o
 obj-y += imx.o
 obj-$(CONFIG_CMD_BOOTROM) += bootrom-cmd.o
-obj-pbl-y += esdctl.o boot.o imx.o
+obj-pbl-y += esdctl.o boot.o
 obj-$(CONFIG_BAREBOX_UPDATE) += imx-bbu-internal.o
 obj-$(CONFIG_BAREBOX_UPDATE_IMX_EXTERNAL_NAND) += imx-bbu-external-nand.o
 pbl-$(CONFIG_USB_GADGET_DRIVER_ARC_PBL) += imx-udc.o
diff --git a/include/mach/imx/generic.h b/include/mach/imx/generic.h
index 5f81aa65a745..0b06c00ac46d 100644
--- a/include/mach/imx/generic.h
+++ b/include/mach/imx/generic.h
@@ -86,12 +86,23 @@ static inline bool imx8mp_keep_compatible_soc_uid(void)
 /* range e.g. GPIO_1_5 is gpio 5 under linux */
 #define IMX_GPIO_NR(bank, nr)		(((bank) - 1) * 32 + (nr))
 
+#if IN_PROPER || defined(CONFIG_ARCH_IMX_ATF)
 extern unsigned int __imx_cpu_type;
 
 static __always_inline void imx_set_cpu_type(unsigned int cpu_type)
 {
 	__imx_cpu_type = cpu_type;
 }
+#else
+/*
+ * If you need this in your PBL entry point, consider using functions
+ * that only query the hardware directly like __cpu_mx6_is_*().
+ */
+extern int __imx_cpu_type(void) __compiletime_error("This API is not available in PBL");
+
+#define __imx_cpu_type __imx_cpu_type()
+#endif
+
 
 #ifdef CONFIG_ARCH_IMX1
 # ifdef imx_cpu_type
-- 
2.47.3