/* cmode.S: clock mode management
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Woodhouse (dwmw2@infradead.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/ptrace.h>
#include <asm/errno.h>
#include <asm/cache.h>
#include <asm/spr-regs.h>
#define __addr_MASK 0xfeff9820 /* interrupt controller mask */
#define __addr_SDRAMC 0xfe000400 /* SDRAM controller regs */
#define SDRAMC_DSTS 0x28 /* SDRAM status */
#define SDRAMC_DSTS_SSI 0x00000001 /* indicates that the SDRAM is in self-refresh mode */
#define SDRAMC_DRCN 0x30 /* SDRAM refresh control */
#define SDRAMC_DRCN_SR 0x00000001 /* transition SDRAM into self-refresh mode */
#define __addr_CLKC 0xfeff9a00
#define CLKC_SWCMODE 0x00000008
#define __addr_LEDS 0xe1200004
.macro li v r
sethi.p %hi(\v),\r
setlo %lo(\v),\r
.endm
.text
.balign 4
###############################################################################
#
# Change CMODE
# - void frv_change_cmode(int cmode)
#
###############################################################################
.globl frv_change_cmode
.type frv_change_cmode,@function
.macro LEDS v
#ifdef DEBUG_CMODE
setlos #~\v,gr10
sti gr10,@(gr11,#0)
membar
#endif
.endm
frv_change_cmode:
movsg lr,gr9
#ifdef DEBUG_CMODE
li __addr_LEDS,gr11
#endif
dcef @(gr0,gr0),#1
# Shift argument left by 24 bits to fit in SWCMODE register later.
slli gr8,#24,gr8
# (1) Set '0' in the PSR.ET bit, and prohibit interrupts.
movsg psr,gr14
andi gr14,#~PSR_ET,gr3
movgs gr3,psr
#if 0 // Fujitsu recommend to skip this and will update docs.
# (2) Set '0' to all bits of the MASK register of the interrupt
# controller, and mask interrupts.
li __addr_MASK,gr12
ldi @(gr12,#0),gr13
li 0xffff0000,gr4
sti gr4,@(gr12,#0)
#endif
# (3) Stop the transfer function of DMAC. Stop all the bus masters
# to access SDRAM and the internal resources.
# (already done by caller)
# (4) Preload a series of following instructions to the instruction
# cache.
li #__cmode_icache_lock_start,gr3
li #__cmode_icache_lock_end,gr4
1: icpl gr3,gr0,#1
addi gr3,#L1_CACHE_BYTES,gr3
cmp gr4,gr3,icc0
bhi icc0,#0,1b
# Set up addresses in regs for later steps.
setlos SDRAMC_DRCN_SR,gr3
li __addr_SDRAMC,gr4
li __addr_CLKC,gr5
ldi @(gr5,#0),gr6
li #0x80000000,gr7
or gr6,gr7,gr6
bra __cmode_icache_lock_start
.balign L1_CACHE_BYTES
__cmode_icache_lock_start:
# (5) Flush the content of all caches by the DCEF instruction.
dcef @(gr0,gr0),#1
# (6) Execute loading the dummy for SDRAM.
ldi @(gr9,#0),gr0
# (7) Set '1' to the DRCN.SR bit, and change SDRAM to the
# self-refresh mode. Execute the dummy load to all memory
# devices set to cacheable on the external bus side in parallel
# with this.
sti gr3,@(gr4,#SDRAMC_DRCN)
# (8) Execute memory barrier instruction (MEMBAR).
membar
# (9) Read the DSTS register repeatedly until '1' stands in the
# DSTS.SSI field.
1: ldi @(gr4,#SDRAMC_DSTS),gr3
andicc gr3,#SDRAMC_DSTS_SSI,gr3,icc0
beq icc0,#0,1b
# (10) Execute memory barrier instruction (MEMBAR).
membar
#if 1
# (11) Set the value of CMODE that you want to change to
# SWCMODE.SWCM[3:0].
sti gr8,@(gr5,#CLKC_SWCMODE)
# (12) Set '1' to the CLKC.SWEN bit. In that case, do not change
# fields other than SWEN of the CLKC register.
sti gr6,@(gr5,#0)
#endif
# (13) Execute the instruction just after the memory barrier
# instruction that executes the self-loop 256 times. (Meanwhile,
# the CMODE switch is done.)
membar
setlos #256,gr7
2: subicc gr7,#1,gr7,icc0
bne icc0,#2,2b
LEDS 0x36
# (14) Release the self-refresh of SDRAM.
sti gr0,@(gr4,#SDRAMC_DRCN)
# Wait for it...
3: ldi @(gr4,#SDRAMC_DSTS),gr3
andicc gr3,#SDRAMC_DSTS_SSI,gr3,icc0
bne icc0,#2,3b
#if 0
li 0x0100000,gr10
4: subicc gr10,#1,gr10,icc0
bne icc0,#0,4b
#endif
__cmode_icache_lock_end:
li #__cmode_icache_lock_start,gr3
li #__cmode_icache_lock_end,gr4
4: icul gr3
addi gr3,#L1_CACHE_BYTES,gr3
cmp gr4,gr3,icc0
bhi icc0,#0,4b
#if 0 // Fujitsu recommend to skip this and will update docs.
# (15) Release the interrupt mask setting of the MASK register of
# the interrupt controller if necessary.
sti gr13,@(gr12,#0)
#endif
# (16) Set 1' in the PSR.ET bit, and permit interrupt.
movgs gr14,psr
bralr
.size frv_change_cmode, .-frv_change_cmode
