diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 12:17:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 12:17:19 -0700 |
commit | 3fde80e94c2bbffbb13f5faa3340cf438440ebea (patch) | |
tree | 43eeac74dc34596772b9d9883e9208da8ae84184 /arch/m68knommu/platform/coldfire/dma_timer.c | |
parent | ac9f80ad16e6e934b6c1f12f82d27889c0f9abcc (diff) | |
parent | 9b0e74102494971ca37a425c63031fea68bb5b79 (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68knommu: put ColdFire head code into .text.head section
m68knommu: remove last use of CONFIG_FADS and CONFIG_RPXCLASSIC
m68knommu: remove RPXCLASSIC from the m68k tree
m68knommu: fec: remove FADS
m68knommu: MCF5307 PIT GENERIC_CLOCKEVENTS support
m68knommu: add read_barrier_depends() and irqs_disabled_flags()
m68knommu: add byteswap assembly opcode for ISA A+
m68knommu: add ffs and __ffs plattform which support ISA A+ or ISA C
m68knommu: add sched_clock() for the DMA timer
m68knommu: complete generic time
m68knommu: move code within time.c
m68knommu: m68knommu: add old stack trace method
m68knommu: Add Coldfire DMA Timer support
m68knommu: defconfig for M5407C3 board
m68knommu: defconfig for M5307C3 board
m68knommu: defconfig for M5275EVB board
m68knommu: defconfig for M5249EVB board
m68knommu: change to a configs directory for board configurations
Diffstat (limited to 'arch/m68knommu/platform/coldfire/dma_timer.c')
-rw-r--r-- | arch/m68knommu/platform/coldfire/dma_timer.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/arch/m68knommu/platform/coldfire/dma_timer.c b/arch/m68knommu/platform/coldfire/dma_timer.c new file mode 100644 index 00000000000..772578b1084 --- /dev/null +++ b/arch/m68knommu/platform/coldfire/dma_timer.c @@ -0,0 +1,84 @@ +/* + * dma_timer.c -- Freescale ColdFire DMA Timer. + * + * Copyright (C) 2007, Benedikt Spranger <b.spranger@linutronix.de> + * Copyright (C) 2008. Sebastian Siewior, Linutronix + * + */ + +#include <linux/clocksource.h> +#include <linux/io.h> + +#include <asm/machdep.h> +#include <asm/coldfire.h> +#include <asm/mcfpit.h> +#include <asm/mcfsim.h> + +#define DMA_TIMER_0 (0x00) +#define DMA_TIMER_1 (0x40) +#define DMA_TIMER_2 (0x80) +#define DMA_TIMER_3 (0xc0) + +#define DTMR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x400) +#define DTXMR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x402) +#define DTER0 (MCF_IPSBAR + DMA_TIMER_0 + 0x403) +#define DTRR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x404) +#define DTCR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x408) +#define DTCN0 (MCF_IPSBAR + DMA_TIMER_0 + 0x40c) + +#define DMA_FREQ ((MCF_CLK / 2) / 16) + +/* DTMR */ +#define DMA_DTMR_RESTART (1 << 3) +#define DMA_DTMR_CLK_DIV_1 (1 << 1) +#define DMA_DTMR_CLK_DIV_16 (2 << 1) +#define DMA_DTMR_ENABLE (1 << 0) + +static cycle_t cf_dt_get_cycles(void) +{ + return __raw_readl(DTCN0); +} + +static struct clocksource clocksource_cf_dt = { + .name = "coldfire_dma_timer", + .rating = 200, + .read = cf_dt_get_cycles, + .mask = CLOCKSOURCE_MASK(32), + .shift = 20, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init init_cf_dt_clocksource(void) +{ + /* + * We setup DMA timer 0 in free run mode. This incrementing counter is + * used as a highly precious clock source. With MCF_CLOCK = 150 MHz we + * get a ~213 ns resolution and the 32bit register will overflow almost + * every 15 minutes. + */ + __raw_writeb(0x00, DTXMR0); + __raw_writeb(0x00, DTER0); + __raw_writel(0x00000000, DTRR0); + __raw_writew(DMA_DTMR_CLK_DIV_16 | DMA_DTMR_ENABLE, DTMR0); + clocksource_cf_dt.mult = clocksource_hz2mult(DMA_FREQ, + clocksource_cf_dt.shift); + return clocksource_register(&clocksource_cf_dt); +} + +arch_initcall(init_cf_dt_clocksource); + +#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ +#define CYC2NS_SCALE ((1000000 << CYC2NS_SCALE_FACTOR) / (DMA_FREQ / 1000)) + +static unsigned long long cycles2ns(unsigned long cycl) +{ + return (unsigned long long) ((unsigned long long)cycl * + CYC2NS_SCALE) >> CYC2NS_SCALE_FACTOR; +} + +unsigned long long sched_clock(void) +{ + unsigned long cycl = __raw_readl(DTCN0); + + return cycles2ns(cycl); +} |