diff options
Diffstat (limited to 'target/linux/at91/image/dfboot/src/asm_isr.S')
| -rw-r--r-- | target/linux/at91/image/dfboot/src/asm_isr.S | 75 |
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}^ + |