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[ARM] tegra: Add arch-specific udelay using TMRUS

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Change-Id: If075117642a725ee2ee24a622068274e588a5bc1
Signed-off-by: Colin Cross <ccross@android.com>
This commit is contained in:
Colin Cross
2010-04-25 00:29:45 -07:00
parent 8734cdc2da
commit 76f3a19c08
4 changed files with 93 additions and 0 deletions
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1
arch/arm/Kconfig
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@@ -577,6 +577,7 @@ config ARCH_TEGRA
select COMMON_CLKDEV
select ARCH_HAS_BARRIERS if CACHE_L2X0
select ARCH_HAS_CPUFREQ
select ARCH_PROVIDES_UDELAY
help
This enables support for NVIDIA Tegra based systems (Tegra APX,
Tegra 6xx and Tegra 2 series).

1
arch/arm/mach-tegra/Makefile
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@@ -6,6 +6,7 @@ obj-y += timer.o
obj-y += gpio.o
obj-y += pinmux.o
obj-y += devices.o
obj-y += delay.o
obj-y += powergate.o
obj-y += suspend.o
obj-y += fuse.o

50
arch/arm/mach-tegra/delay.S Normal file
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@@ -0,0 +1,50 @@
/*
* arch/arm/mach-tegra/delay.S
*
* Copyright (C) 2010 Google, Inc.
*
* Author:
* Colin Cross <ccross@google.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <mach/iomap.h>
#include <mach/io.h>
.text
ENTRY(__udelay)
ENTRY(__const_udelay)
ldr r3, =(IO_PPSB_VIRT + TEGRA_TMRUS_BASE - IO_PPSB_PHYS)
ldr r1, [r3]
/* r0 - usecs to wait
* r1 - initial value of the counter
*/
loop:
ldr r2, [r3]
sub r2, r2, r1
cmp r2, r0
bls loop
mov pc, lr
ENDPROC(__const_udelay)
ENDPROC(__udelay)
@ Delay routine
ENTRY(__delay)
subs r0, r0, #1
bhi __delay
mov pc, lr
ENDPROC(__delay)

41
arch/arm/mach-tegra/include/mach/delay.h Normal file
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@@ -0,0 +1,41 @@
/*
* arch/arm/mach-tegra/include/mach/delay.h
*
* Copyright (C) 2010 Google, Inc.
*
* Author:
* Colin Cross <ccross@google.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef __MACH_TEGRA_DELAY_H
#define __MACH_TEGRA_DELAY_H
/* needed by loops_per_jiffy calculations */
extern void __delay(int loops);
extern void __udelay(unsigned long usecs);
extern void __const_udelay(unsigned long usecs);
/* we don't have any restrictions on maximum udelay length, but we'll enforce
* the same restriction as the ARM default so we don't introduce any
* incompatibilties in drivers.
*/
extern void __bad_udelay(void);
#define MAX_UDELAY_MS 2
#define udelay(n) \
((__builtin_constant_p(n) && (n) > (MAX_UDELAY_MS * 1000)) ? \
__bad_udelay() : \
__udelay(n))
#endif /* defined(__MACH_TEGRA_DELAY_H) */