From 716ca530e1c4515d8683c9d5be3d56b301758b66 Mon Sep 17 00:00:00 2001
From: James <>
Date: Wed, 4 Nov 2015 11:49:21 +0000
Subject: trunk-47381

---
 target/linux/at91/image/dfboot/src/asm_isr.S | 75 ++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 target/linux/at91/image/dfboot/src/asm_isr.S

(limited to 'target/linux/at91/image/dfboot/src/asm_isr.S')

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 0000000..8d1d52e
--- /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}^
+
-- 
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