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-rw-r--r--target/linux/at91/image/dfboot/src/asm_isr.S75
1 files changed, 75 insertions, 0 deletions
diff --git a/target/linux/at91/image/dfboot/src/asm_isr.S b/target/linux/at91/image/dfboot/src/asm_isr.S
new file mode 100644
index 0000000000..8d1d52e191
--- /dev/null
+++ b/target/linux/at91/image/dfboot/src/asm_isr.S
@@ -0,0 +1,75 @@
+#include "AT91RM9200_inc.h"
+
+#define ARM_MODE_USER 0x10
+#define ARM_MODE_FIQ 0x11
+#define ARM_MODE_IRQ 0x12
+#define ARM_MODE_SVC 0x13
+#define ARM_MODE_ABORT 0x17
+#define ARM_MODE_UNDEF 0x1B
+#define ARM_MODE_SYS 0x1F
+
+#define I_BIT 0x80
+#define F_BIT 0x40
+#define T_BIT 0x20
+
+
+/* -----------------------------------------------------------------------------
+ AT91F_ASM_SPI_Handler
+ ---------------------
+ Handler called by the AIC
+
+ Save context
+ Call C handler
+ Restore context
+ ----------------------------------------------------------------------------- */
+
+.global AT91F_ST_ASM_HANDLER
+
+AT91F_ST_ASM_HANDLER:
+/* Adjust and save LR_irq in IRQ stack */
+ sub r14, r14, #4
+ stmfd sp!, {r14}
+
+/* Write in the IVR to support Protect Mode
+ No effect in Normal Mode
+ De-assert the NIRQ and clear the source in Protect Mode */
+ ldr r14, =AT91C_BASE_AIC
+ str r14, [r14, #AIC_IVR]
+
+/* Save SPSR and r0 in IRQ stack */
+ mrs r14, SPSR
+ stmfd sp!, {r0, r14}
+
+/* Enable Interrupt and Switch in SYS Mode */
+ mrs r0, CPSR
+ bic r0, r0, #I_BIT
+ orr r0, r0, #ARM_MODE_SYS
+ msr CPSR_c, r0
+
+/* Save scratch/used registers and LR in User Stack */
+ stmfd sp!, { r1-r3, r12, r14}
+
+ ldr r1, =AT91F_ST_HANDLER
+ mov r14, pc
+ bx r1
+
+/* Restore scratch/used registers and LR from User Stack */
+ ldmia sp!, { r1-r3, r12, r14}
+
+/* Disable Interrupt and switch back in IRQ mode */
+ mrs r0, CPSR
+ bic r0, r0, #ARM_MODE_SYS
+ orr r0, r0, #I_BIT | ARM_MODE_IRQ
+ msr CPSR_c, r0
+
+/* Mark the End of Interrupt on the AIC */
+ ldr r0, =AT91C_BASE_AIC
+ str r0, [r0, #AIC_EOICR]
+
+/* Restore SPSR_irq and r0 from IRQ stack */
+ ldmia sp!, {r0, r14}
+ msr SPSR_cxsf, r14
+
+/* Restore adjusted LR_irq from IRQ stack directly in the PC */
+ ldmia sp!, {pc}^
+