therm_pm72.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,340 行 · 第 1/3 页

/*
 * Device driver for the thermostats & fan controller of  the
 * Apple G5 "PowerMac7,2" desktop machines.
 *
 * (c) Copyright IBM Corp. 2003-2004
 *
 * Maintained by: Benjamin Herrenschmidt
 *                <[e-mail]>
 * 
 *
 * The algorithm used is the PID control algorithm, used the same
 * way the published Darwin code does, using the same values that
 * are present in the Darwin 7.0 snapshot property lists.
 *
 * As far as the CPUs control loops are concerned, I use the
 * calibration & PID constants provided by the EEPROM,
 * I do _not_ embed any value from the property lists, as the ones
 * provided by Darwin 7.0 seem to always have an older version that
 * what I've seen on the actual computers.
 * It would be interesting to verify that though. Darwin has a
 * version code of 1.0.0d11 for all control loops it seems, while
 * so far, the machines EEPROMs contain a dataset versioned 1.0.0f
 *
 * Darwin doesn't provide source to all parts, some missing
 * bits like the AppleFCU driver or the actual scale of some
 * of the values returned by sensors had to be "guessed" some
 * way... or based on what Open Firmware does.
 *
 * I didn't yet figure out how to get the slots power consumption
 * out of the FCU, so that part has not been implemented yet and
 * the slots fan is set to a fixed 50% PWM, hoping this value is
 * safe enough ...
 *
 * Note: I have observed strange oscillations of the CPU control
 * loop on a dual G5 here. When idle, the CPU exhaust fan tend to
 * oscillates slowly (over several minutes) between the minimum
 * of 300RPMs and approx. 1000 RPMs. I don't know what is causing
 * this, it could be some incorrect constant or an error in the
 * way I ported the algorithm, or it could be just normal. I
 * don't have full understanding on the way Apple tweaked the PID
 * algorithm for the CPU control, it is definitely not a standard
 * implementation...
 *
 * TODO:  - Check MPU structure version/signature
 *        - Add things like /sbin/overtemp for non-critical
 *          overtemp conditions so userland can take some policy
 *          decisions, like slewing down CPUs
 *	  - Deal with fan and i2c failures in a better way
 *
 * History:
 *
 *  Nov. 13, 2003 : 0.5
 *	- First release
 *
 *  Nov. 14, 2003 : 0.6
 *	- Read fan speed from FCU, low level fan routines now deal
 *	  with errors & check fan status, though higher level don't
 *	  do much.
 *	- Move a bunch of definitions to .h file
 *
 *  Nov. 18, 2003 : 0.7
 *	- Fix build on ppc64 kernel
 *	- Move back statics definitions to .c file
 *	- Avoid calling schedule_timeout with a negative number
 *
 *  Dec. 18, 2003 : 0.8
 *	- Fix typo when reading back fan speed on 2 CPU machines
 *
 *  Mar. 11, 2004 : 0.9
 *	- Rework code accessing the ADC chips, make it more robust and
 *	  closer to the chip spec. Also make sure it is configured properly,
 *        I've seen yet unexplained cases where on startup, I would have stale
 *        values in the configuration register
 *	- Switch back to use of target fan speed for PID, thus lowering
 *        pressure on i2c
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/smp_lock.h>
#include <linux/wait.h>
#include <linux/reboot.h>
#include <linux/kmod.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/sections.h>
#include <asm/of_device.h>

#include "therm_pm72.h"

#define VERSION "0.9"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)	printk(args)
#else
#define DBG(args...)	do { } while(0)
#endif


/*
 * Driver statics
 */

static struct of_device *		of_dev;
static struct i2c_adapter *		u3_0;
static struct i2c_adapter *		u3_1;
static struct i2c_client *		fcu;
static struct cpu_pid_state		cpu_state[2];
static struct backside_pid_state	backside_state;
static struct drives_pid_state		drives_state;
static int				state;
static int				cpu_count;
static pid_t				ctrl_task;
static struct completion		ctrl_complete;
static int				critical_state;
static DECLARE_MUTEX(driver_lock);

/*
 * i2c_driver structure to attach to the host i2c controller
 */

static int therm_pm72_attach(struct i2c_adapter *adapter);
static int therm_pm72_detach(struct i2c_adapter *adapter);

static struct i2c_driver therm_pm72_driver =
{
	.name		= "therm_pm72",
	.id		= 0xDEADBEEF,
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter	= therm_pm72_attach,
	.detach_adapter	= therm_pm72_detach,
};

/*
 * Utility function to create an i2c_client structure and
 * attach it to one of u3 adapters
 */
static struct i2c_client *attach_i2c_chip(int id, const char *name)
{
	struct i2c_client *clt;
	struct i2c_adapter *adap;

	if (id & 0x100)
		adap = u3_1;
	else
		adap = u3_0;
	if (adap == NULL)
		return NULL;

	clt = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
	if (clt == NULL)
		return NULL;
	memset(clt, 0, sizeof(struct i2c_client));

	clt->addr = (id >> 1) & 0x7f;
	clt->adapter = adap;
	clt->driver = &therm_pm72_driver;
	clt->id = 0xDEADBEEF;
	strncpy(clt->name, name, I2C_NAME_SIZE-1);

	if (i2c_attach_client(clt)) {
		printk(KERN_ERR "therm_pm72: Failed to attach to i2c ID 0x%x\n", id);
		kfree(clt);
		return NULL;
	}
	return clt;
}

/*
 * Utility function to get rid of the i2c_client structure
 * (will also detach from the adapter hopepfully)
 */
static void detach_i2c_chip(struct i2c_client *clt)
{
	i2c_detach_client(clt);
	kfree(clt);
}

/*
 * Here are the i2c chip access wrappers
 */

static void initialize_adc(struct cpu_pid_state *state)
{
	int rc;
	u8 buf[2];

	/* Read ADC the configuration register and cache it. We
	 * also make sure Config2 contains proper values, I've seen
	 * cases where we got stale grabage in there, thus preventing
	 * proper reading of conv. values
	 */

	/* Clear Config2 */
	buf[0] = 5;
	buf[1] = 0;
	i2c_master_send(state->monitor, buf, 2);

	/* Read & cache Config1 */
	buf[0] = 1;
	rc = i2c_master_send(state->monitor, buf, 1);
	if (rc > 0) {
		rc = i2c_master_recv(state->monitor, buf, 1);
		if (rc > 0) {
			state->adc_config = buf[0];
			DBG("ADC config reg: %02x\n", state->adc_config);
			/* Disable shutdown mode */
		       	state->adc_config &= 0xfe;
			buf[0] = 1;
			buf[1] = state->adc_config;
			rc = i2c_master_send(state->monitor, buf, 2);
		}
	}
	if (rc <= 0)
		printk(KERN_ERR "therm_pm72: Error reading ADC config"
		       " register !\n");
}

static int read_smon_adc(struct cpu_pid_state *state, int chan)
{
	int rc, data, tries = 0;
	u8 buf[2];

	for (;;) {
		/* Set channel */
		buf[0] = 1;
		buf[1] = (state->adc_config & 0x1f) | (chan << 5);
		rc = i2c_master_send(state->monitor, buf, 2);
		if (rc <= 0)
			goto error;
		/* Wait for convertion */
		msleep(1);
		/* Switch to data register */
		buf[0] = 4;
		rc = i2c_master_send(state->monitor, buf, 1);
		if (rc <= 0)
			goto error;
		/* Read result */
		rc = i2c_master_recv(state->monitor, buf, 2);
		if (rc < 0)
			goto error;
		data = ((u16)buf[0]) << 8 | (u16)buf[1];
		return data >> 6;
	error:
		DBG("Error reading ADC, retrying...\n");
		if (++tries > 10) {
			printk(KERN_ERR "therm_pm72: Error reading ADC !\n");
			return -1;
		}
		msleep(10);
	}
}

static int fan_read_reg(int reg, unsigned char *buf, int nb)
{
	int tries, nr, nw;

	buf[0] = reg;
	tries = 0;
	for (;;) {
		nw = i2c_master_send(fcu, buf, 1);
		if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
			break;
		msleep(10);
		++tries;
	}
	if (nw <= 0) {
		printk(KERN_ERR "Failure writing address to FCU: %d", nw);
		return -EIO;
	}
	tries = 0;
	for (;;) {
		nr = i2c_master_recv(fcu, buf, nb);
		if (nr > 0 || (nr < 0 && nr != ENODEV) || tries >= 100)
			break;
		msleep(10);
		++tries;
	}
	if (nr <= 0)
		printk(KERN_ERR "Failure reading data from FCU: %d", nw);
	return nr;
}

static int fan_write_reg(int reg, const unsigned char *ptr, int nb)
{
	int tries, nw;
	unsigned char buf[16];

	buf[0] = reg;
	memcpy(buf+1, ptr, nb);
	++nb;
	tries = 0;
	for (;;) {
		nw = i2c_master_send(fcu, buf, nb);
		if (nw > 0 || (nw < 0 && nw != EIO) || tries >= 100)
			break;
		msleep(10);
		++tries;
	}
	if (nw < 0)
		printk(KERN_ERR "Failure writing to FCU: %d", nw);
	return nw;
}

static int start_fcu(void)
{
	unsigned char buf = 0xff;
	int rc;

	rc = fan_write_reg(0xe, &buf, 1);
	if (rc < 0)
		return -EIO;
	rc = fan_write_reg(0x2e, &buf, 1);
	if (rc < 0)
		return -EIO;
	return 0;
}

static int set_rpm_fan(int fan, int rpm)
{
	unsigned char buf[2];
	int rc;

	if (rpm < 300)
		rpm = 300;
	else if (rpm > 8191)
		rpm = 8191;
	buf[0] = rpm >> 5;
	buf[1] = rpm << 3;
	rc = fan_write_reg(0x10 + (fan * 2), buf, 2);
	if (rc < 0)
		return -EIO;
	return 0;
}

static int get_rpm_fan(int fan, int programmed)
{
	unsigned char failure;
	unsigned char active;
	unsigned char buf[2];
	int rc, reg_base;

	rc = fan_read_reg(0xb, &failure, 1);
	if (rc != 1)
		return -EIO;
	if ((failure & (1 << fan)) != 0)
		return -EFAULT;
	rc = fan_read_reg(0xd, &active, 1);
	if (rc != 1)
		return -EIO;
	if ((active & (1 << fan)) == 0)
		return -ENXIO;

	/* Programmed value or real current speed */
	reg_base = programmed ? 0x10 : 0x11;
	rc = fan_read_reg(reg_base + (fan * 2), buf, 2);
	if (rc != 2)
		return -EIO;

	return (buf[0] << 5) | buf[1] >> 3;
}

static int set_pwm_fan(int fan, int pwm)
{
	unsigned char buf[2];
	int rc;

	if (pwm < 10)
		pwm = 10;
	else if (pwm > 100)
		pwm = 100;
	pwm = (pwm * 2559) / 1000;
	buf[0] = pwm;
	rc = fan_write_reg(0x30 + (fan * 2), buf, 1);
	if (rc < 0)
		return rc;
	return 0;
}

static int get_pwm_fan(int fan)
{
	unsigned char failure;
	unsigned char active;
	unsigned char buf[2];
	int rc;

	rc = fan_read_reg(0x2b, &failure, 1);
	if (rc != 1)
		return -EIO;
	if ((failure & (1 << fan)) != 0)
		return -EFAULT;
	rc = fan_read_reg(0x2d, &active, 1);
	if (rc != 1)
		return -EIO;
	if ((active & (1 << fan)) == 0)
		return -ENXIO;

	/* Programmed value or real current speed */
	rc = fan_read_reg(0x30 + (fan * 2), buf, 1);
	if (rc != 1)
		return -EIO;

	return (buf[0] * 1000) / 2559;
}

/*
 * Utility routine to read the CPU calibration EEPROM data
 * from the device-tree
 */
static int read_eeprom(int cpu, struct mpu_data *out)
{
	struct device_node *np;
	char nodename[64];
	u8 *data;
	int len;

	/* prom.c routine for finding a node by path is a bit brain dead
	 * and requires exact @xxx unit numbers. This is a bit ugly but
	 * will work for these machines
	 */
	sprintf(nodename, "/u3@0,f8000000/i2c@f8001000/cpuid@a%d", cpu ? 2 : 0);
	np = of_find_node_by_path(nodename);
	if (np == NULL) {
		printk(KERN_ERR "therm_pm72: Failed to retreive cpuid node from device-tree\n");
		return -ENODEV;
	}
	data = (u8 *)get_property(np, "cpuid", &len);
	if (data == NULL) {
		printk(KERN_ERR "therm_pm72: Failed to retreive cpuid property from device-tree\n");
		of_node_put(np);
		return -ENODEV;
	}