armv8: fsl-layerscape: Support loading 32-bit OS with PSCI enabled
As PSCI and secure monitor firmware framework are enabled, this patch is
to support loading 32-bit OS in such case. The default target exception
level returned to U-Boot is EL2, so the corresponding work to switch to
AArch32 EL2 and jump to 32-bit OS are done in U-Boot and secure firmware
together.
Signed-off-by: Alison Wang <alison.wang@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/arm/cpu/armv8/sec_firmware_asm.S b/arch/arm/cpu/armv8/sec_firmware_asm.S
index 0c6a462..1b39f1d 100644
--- a/arch/arm/cpu/armv8/sec_firmware_asm.S
+++ b/arch/arm/cpu/armv8/sec_firmware_asm.S
@@ -50,4 +50,27 @@
smc #0
ret
ENDPROC(_sec_firmware_support_psci_version)
+
+/*
+ * Switch from AArch64 EL2 to AArch32 EL2
+ * @param inputs:
+ * x0: argument, zero
+ * x1: machine nr
+ * x2: fdt address
+ * x3: kernel entry point
+ * @param outputs for secure firmware:
+ * x0: function id
+ * x1: kernel entry point
+ * x2: machine nr
+ * x3: fdt address
+*/
+ENTRY(armv8_el2_to_aarch32)
+ mov x0, x3
+ mov x3, x2
+ mov x2, x1
+ mov x1, x0
+ ldr x0, =0xc000ff04
+ smc #0
+ ret
+ENDPROC(armv8_el2_to_aarch32)
#endif
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S
index bbccf2b..adb9f35 100644
--- a/arch/arm/cpu/armv8/transition.S
+++ b/arch/arm/cpu/armv8/transition.S
@@ -13,6 +13,14 @@
ENTRY(armv8_switch_to_el2)
switch_el x5, 1f, 0f, 0f
0:
+ cmp x4, #ES_TO_AARCH64
+ b.eq 2f
+ /*
+ * When loading 32-bit kernel, it will jump
+ * to secure firmware again, and never return.
+ */
+ bl armv8_el2_to_aarch32
+2:
/*
* x3 is kernel entry point or switch_to_el1
* if CONFIG_ARMV8_SWITCH_TO_EL1 is defined.
@@ -32,3 +40,7 @@
br x3
1: armv8_switch_to_el1_m x3, x4, x5
ENDPROC(armv8_switch_to_el1)
+
+WEAK(armv8_el2_to_aarch32)
+ ret
+ENDPROC(armv8_el2_to_aarch32)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 287ff5c..01efc43 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -215,6 +215,8 @@
*/
void armv8_switch_to_el1(u64 args, u64 mach_nr, u64 fdt_addr,
u64 entry_point, u64 es_flag);
+void armv8_el2_to_aarch32(u64 args, u64 mach_nr, u64 fdt_addr,
+ u64 entry_point);
void gic_init(void);
void gic_send_sgi(unsigned long sgino);
void wait_for_wakeup(void);