add new dfboot loader - a complete revison of romboot code.

[openwrt/svn-archive/archive.git] / target / linux / at91-2.6 / image / dfboot / src / asm_isr.S

diff --git a/target/linux/at91-2.6/image/dfboot/src/asm_isr.S b/target/linux/at91-2.6/image/dfboot/src/asm_isr.S
new file mode 100644 (file)
index 0000000..8d1d52e
--- /dev/null
+++ b/target/linux/at91-2.6/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}^
+