248 lines
5.2 KiB
ArmAsm
248 lines
5.2 KiB
ArmAsm
/* $NetBSD: iomd_iic.S,v 1.3 2001/11/23 16:53:07 thorpej Exp $ */
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/*
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* Copyright (c) 1994-1996 Mark Brinicombe.
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* Copyright (c) 1994 Brini.
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* All rights reserved.
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*
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* This code is derived from software written for Brini by Mark Brinicombe
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Mark Brinicombe.
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* 4. The name of the company nor the name of the author may be used to
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* endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* RiscBSD kernel project
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*
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* iic.s
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*
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* Low level routines to with IIC devices
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*
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* Created : 13/10/94
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*
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* Based of kate/display/iic.s
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*/
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#include "assym.h" /* for __PROG32 */
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#include <machine/asm.h>
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#include <machine/cpu.h>
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#include <arm/iomd/iomdreg.h>
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#define IIC_BITDELAY 10
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Liomd_base:
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.word _C_LABEL(iomd_base)
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ENTRY(iic_set_state)
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/*
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* Parameters
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* r0 - IIC data bit
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* r1 - IIC clock bit
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*/
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/* Store temporary register */
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/* stmfd sp!, {r4}*/
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/*
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* Mask the data and clock bits
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* Since these routines are only called from iiccontrol.c this is not
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* really needed
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*/
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and r0, r0, #0x00000001
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and r1, r1, #0x00000001
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/* Get address of IOMD control register */
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ldr r2, Liomd_base
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ldr r2, [r2]
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/* Get the current CPSR */
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/* mrs r4, cpsr_all
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orr r3, r4, #(I32_bit | F32_bit)
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msr cpsr_all, r3
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*/
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IRQdisable
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/* Get current value of control register */
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ldrb r3, [r2, #(IOMD_IOCR << 2)]
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/* Preserve non-IIC bits */
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bic r3, r3, #0x00000003
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/* orr r3, r3, #0x000000c0*/
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/* Set the IIC clock and data bits */
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orr r3, r3, r0
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orr r3, r3, r1, lsl #1
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/* Store the new value of control register */
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strb r3, [r2, #(IOMD_IOCR << 2)]
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/* Restore CPSR state */
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/* msr cpsr_all, r4 */
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IRQenable
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/* Restore temporary register */
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/* ldmfd sp!, {r4} */
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/* Pause a bit */
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mov r0, #(IIC_BITDELAY)
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/* Exit via iic_delay routine */
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b _C_LABEL(iic_delay)
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ENTRY(iic_set_state_and_ack)
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/*
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* Parameters
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* r0 - IIC data bit
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* r1 - IIC clock bit
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*/
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/* Store temporary register */
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/* stmfd sp!, {r4} */
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/*
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* Mask the data and clock bits
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* Since these routines are only called from iiccontrol.c this is not
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* really needed
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*/
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and r0, r0, #0x00000001
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and r1, r1, #0x00000001
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/* Get address of IOMD control register */
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ldr r2, Liomd_base
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ldr r2, [r2]
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/* Get the current CPSR */
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/* mrs r4, cpsr_all
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orr r3, r4, #(I32_bit | F32_bit)
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msr cpsr_all, r3
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*/
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IRQdisable
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/* Get current value of control register */
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ldrb r3, [r2, #(IOMD_IOCR << 2)]
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/* Preserve non-IIC bits */
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bic r3, r3, #0x00000003
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/* orr r3, r3, #0x000000c0*/
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/* Set the IIC clock and data bits */
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orr r3, r3, r0
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orr r3, r3, r1, lsl #1
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/* Store the new value of control register */
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strb r3, [r2, #(IOMD_IOCR << 2)]
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Liic_set_state_and_ack_loop:
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ldrb r3, [r2, #(IOMD_IOCR << 2)]
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tst r3, #0x00000002
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beq Liic_set_state_and_ack_loop
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/* Restore CPSR state */
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/* msr cpsr_all, r4 */
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IRQenable
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/* Restore temporary register */
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/* ldmfd sp!, {r4} */
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/* Pause a bit */
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mov r0, #(IIC_BITDELAY)
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/* Exit via iic_delay routine */
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b _C_LABEL(iic_delay)
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ENTRY(iic_delay)
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/*
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* Parameters
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* r0 - time to wait
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*/
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/* Load address of IOMD */
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ldr r2, Liomd_base
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ldr r2, [r2]
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/* Latch current value of timer 1 */
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strb r2, [r2, #(IOMD_T0LATCH << 2)]
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/* Get the latched value */
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ldrb r1, [r2, #(IOMD_T0LOW << 2)]
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/* Loop until timer reaches end value */
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Liic_delay_loop:
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/* Latch the current value of timer1 */
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strb r2, [r2, #(IOMD_T0LATCH << 2)]
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/* Get the latched value */
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ldrb r3, [r2, #(IOMD_T0LOW << 2)]
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/* Loop until timer reached expected value */
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teq r3, r1
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movne r1, r3
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beq Liic_delay_loop
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subs r0, r0, #0x00000001
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bne Liic_delay_loop
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/* Exit */
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mov pc, lr
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ENTRY(iic_getstate)
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/* Load address of IOMD */
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ldr r2, Liomd_base
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ldr r2, [r2]
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/* Read IOCR */
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ldrb r0, [r2, #(IOMD_IOCR << 2)]
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mov pc, lr
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/* End of iomd_iic.S */
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