58 lines
1.5 KiB
ArmAsm
58 lines
1.5 KiB
ArmAsm
/*
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* linux/arch/arm/plat-omap/sram-fn.S
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*
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* Functions that need to be run in internal SRAM
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/arch/io.h>
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#include <asm/hardware.h>
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.text
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/*
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* Reprograms ULPD and CKCTL.
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*/
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ENTRY(sram_reprogram_clock)
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stmfd sp!, {r0 - r12, lr} @ save registers on stack
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mov r2, #IO_ADDRESS(DPLL_CTL) & 0xff000000
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orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x00ff0000
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orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x0000ff00
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mov r3, #IO_ADDRESS(ARM_CKCTL) & 0xff000000
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orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
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orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
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tst r0, #1 << 4 @ want lock mode?
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beq newck @ nope
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bic r0, r0, #1 << 4 @ else clear lock bit
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strh r0, [r2] @ set dpll into bypass mode
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orr r0, r0, #1 << 4 @ set lock bit again
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newck:
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strh r1, [r3] @ write new ckctl value
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strh r0, [r2] @ write new dpll value
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mov r4, #0x0700 @ let the clocks settle
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orr r4, r4, #0x00ff
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delay: sub r4, r4, #1
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cmp r4, #0
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bne delay
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lock: ldrh r4, [r2], #0 @ read back dpll value
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tst r0, #1 << 4 @ want lock mode?
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beq out @ nope
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tst r4, #1 << 0 @ dpll rate locked?
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beq lock @ try again
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out:
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ldmfd sp!, {r0 - r12, pc} @ restore regs and return
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ENTRY(sram_reprogram_clock_sz)
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.word . - sram_reprogram_clock
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