linux-imx

/*

 * RackMac vu-meter driver

 *

 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.

 *                    <benh@kernel.crashing.org>

 *

 * Released under the term of the GNU GPL v2.

 *

 * Support the CPU-meter LEDs of the Xserve G5

 *

 * TODO: Implement PWM to do variable intensity and provide userland

 * interface for fun. Also, the CPU-meter could be made nicer by being

 * a bit less "immediate" but giving instead a more average load over

 * time. Patches welcome :-)

 *

 */

#undef DEBUG

​

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/device.h>

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/dma-mapping.h>

#include <linux/kernel_stat.h>

#include <linux/of_address.h>

#include <linux/of_irq.h>

​

#include <asm/io.h>

#include <asm/prom.h>

#include <asm/machdep.h>

#include <asm/pmac_feature.h>

#include <asm/dbdma.h>

#include <asm/macio.h>

#include <asm/keylargo.h>

​

/* Number of samples in a sample buffer */

#define SAMPLE_COUNT        256

​

/* CPU meter sampling rate in ms */

#define CPU_SAMPLING_RATE   250

​

struct rackmeter_dma {

    struct dbdma_cmd    cmd[4]          ____cacheline_aligned;

    u32         mark            ____cacheline_aligned;

    u32         buf1[SAMPLE_COUNT]  ____cacheline_aligned;

    u32         buf2[SAMPLE_COUNT]  ____cacheline_aligned;

} ____cacheline_aligned;

​

struct rackmeter_cpu {

    struct delayed_work sniffer;

    struct rackmeter    *rm;

    u64         prev_wall;

    u64         prev_idle;

    int         zero;

} ____cacheline_aligned;

​

struct rackmeter {

    struct macio_dev        *mdev;

    unsigned int            irq;

    struct device_node      *i2s;

    u8              *ubuf;

    struct dbdma_regs __iomem   *dma_regs;

    void __iomem            *i2s_regs;

    dma_addr_t          dma_buf_p;

    struct rackmeter_dma        *dma_buf_v;

    int             stale_irq;

    struct rackmeter_cpu        cpu[2];

    int             paused;

    struct mutex            sem;

};

​

/* To be set as a tunable */

static int rackmeter_ignore_nice;

​

/* This GPIO is whacked by the OS X driver when initializing */

#define RACKMETER_MAGIC_GPIO    0x78

​

/* This is copied from cpufreq_ondemand, maybe we should put it in

 * a common header somewhere

 */

static inline u64 get_cpu_idle_time(unsigned int cpu)

{

    u64 retval;

​

    retval = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE] +

         kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];

​

    if (rackmeter_ignore_nice)

        retval += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];