path: root/drivers/macintosh/rack-meter.c

/*
 * 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/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 <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;
	cputime64_t		prev_wall;
	cputime64_t		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 cputime64_t get_cpu_idle_time(unsigned int cpu)
{
	cputime64_t retval;

	retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
			kstat_cpu(cpu).cpustat.iowait);

	if (rackmeter_ignore_nice)
		retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);

	return retval;
}

static void rackmeter_setup_i2s(struct rackmeter *rm)
{
	struct macio_chip *macio = rm->mdev->bus->chip;

	/* First whack magic GPIO */
	pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);


	/* Call feature code to enable the sound channel and the proper
	 * clock sources
	 */
	pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);

	/* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now.
	 * This is a bit racy, thus we should add new platform functions to
	 * handle that. snd-aoa needs that too
	 */
	MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
	MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
	(void)MACIO_IN32(KEYLARGO_FCR1);
	udelay(10);

	/* Then setup i2s. For now, we use the same magic value that
	 * the OS X driver seems to use. We might want to play around
	 * with the clock divisors later
	 */
	out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
	(void)in_le32(rm->i2s_regs + 0x10);
	udelay(10);

	/* Fully restart i2s*/
	MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE |
		  KL1_I2S0_CLK_ENABLE_BIT);
	(void)MACIO_IN32(KEYLARGO_FCR1);
	udelay(10);
}

static void rackmeter_set_default_pattern(struct rackmeter *rm)
{
	int i;

	for (i = 0; i < 16; i++) {
		if (i < 8)
			rm->ubuf[i] = (i & 1) * 255;
		else
			rm->ubuf[i] = ((~i) & 1) * 255;
	}
}

static void rackmeter_do_pause(struct rackmeter *rm, int pause)
{
	struct rackmeter_dma *rdma = rm->dma_buf_v;

	pr_debug("rackmeter: %s\n", pause ? "paused" : "started");

	rm->paused = pause;
	if (pause) {
		DBDMA_DO_STOP(rm->dma_regs);
		return;
	}
	memset(rdma->buf1, 0, SAMPLE_COUNT & sizeof(u32));
	memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));

	rm->dma_buf_v->mark = 0;

	mb();
	out_le32(&rm->dma_regs->cmdptr_hi, 0);
	out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p);
	out_le32(&rm->dma_regs->control, (RUN << 16) | RUN);
}

static void rackmeter_setup_dbdma(struct rackmeter *rm)
{
	struct rackmeter_dma *db = rm->dma_buf_v;
	struct dbdma_cmd *cmd = db->cmd;

	/* Make sure dbdma is reset */
	DBDMA_DO_RESET(rm->dma_regs);

	pr_debug("rackmeter: mark offset=0x%zx\n",
		 offsetof(struct rackmeter_dma, mark));
	pr_debug("rackmeter: buf1 offset=0x%zx\n",
		 offsetof(struct rackmeter_dma, buf1));
	pr_debug("rackmeter: buf2 offset=0x%zx\n",
		 offsetof(struct rackmeter_dma, buf2));

	/* Prepare 4 dbdma commands for the 2 buffers */
	memset(cmd, 0, 4 * sizeof(struct dbdma_cmd));
	st_le16(&cmd->req_count, 4);
	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
	st_le32(&cmd->phy_addr, rm->dma_buf_p +
		offsetof(struct rackmeter_dma, mark));
	st_le32(&cmd->cmd_dep, 0x02000000);
	cmd++;

	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
	st_le16(&cmd->command, OUTPUT_MORE);
	st_le32(&cmd->phy_addr, rm->dma_buf_p +
		offsetof(struct rackmeter_dma, buf1));
	cmd++;

	st_le16(&cmd->req_count, 4);
	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
	st_le32(&cmd->phy_addr, rm->dma_buf_p +
		offsetof(struct rackmeter_dma, mark));
	st_le32(&cmd->cmd_dep, 0x01000000);
	cmd++;

	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
	st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS);
	st_le32(&cmd->phy_addr, rm->dma_buf_p +
		offsetof(struct rackmeter_dma, buf2));
	st_le32(&cmd->cmd_dep, rm->dma_buf_p);

	rackmeter_do_pause(rm, 0);
}

static void rackmeter_do_timer(struct work_struct *work)
{
	struct rackmeter_cpu *rcpu =
		container_of(work, struct rackmeter_cpu, sniffer.work);
	struct rackmeter *rm = rcpu->rm;
	unsigned int cpu = smp_processor_id();
	cputime64_t cur_jiffies, total_idle_ticks;
	unsigned int total_ticks, idle_ticks;
	int i, offset, load, cumm, pause;

	cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());