/*
 * A hwmon driver for the Intel 5000 series chipset FB-DIMM AMB
 * temperature sensors
 * Copyright (C) 2007 IBM
 *
 * Author: Darrick J. Wong <djwong@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define DRVNAME "i5k_amb"

#define I5K_REG_AMB_BASE_ADDR		0x48
#define I5K_REG_AMB_LEN_ADDR		0x50
#define I5K_REG_CHAN0_PRESENCE_ADDR	0x64
#define I5K_REG_CHAN1_PRESENCE_ADDR	0x66

#define AMB_REG_TEMP_MIN_ADDR		0x80
#define AMB_REG_TEMP_MID_ADDR		0x81
#define AMB_REG_TEMP_MAX_ADDR		0x82
#define AMB_REG_TEMP_STATUS_ADDR	0x84
#define AMB_REG_TEMP_ADDR		0x85

#define AMB_CONFIG_SIZE			2048
#define AMB_FUNC_3_OFFSET		768

static unsigned long amb_reg_temp_status(unsigned int amb)
{
	return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_STATUS_ADDR +
	       AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_min(unsigned int amb)
{
	return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MIN_ADDR +
	       AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_mid(unsigned int amb)
{
	return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MID_ADDR +
	       AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_max(unsigned int amb)
{
	return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MAX_ADDR +
	       AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp(unsigned int amb)
{
	return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_ADDR +
	       AMB_CONFIG_SIZE * amb;
}

#define MAX_MEM_CHANNELS		4
#define MAX_AMBS_PER_CHANNEL		16
#define MAX_AMBS			(MAX_MEM_CHANNELS * \
					 MAX_AMBS_PER_CHANNEL)
#define CHANNEL_SHIFT			4
#define DIMM_MASK			0xF
/*
 * Ugly hack: For some reason the highest bit is set if there
 * are _any_ DIMMs in the channel.  Attempting to read from
 * this "high-order" AMB results in a memory bus error, so
 * for now we'll just ignore that top bit, even though that
 * might prevent us from seeing the 16th DIMM in the channel.
 */
#define REAL_MAX_AMBS_PER_CHANNEL	15
#define KNOBS_PER_AMB			6

static unsigned long amb_num_from_reg(unsigned int byte_num, unsigned int bit)
{
	return byte_num * MAX_AMBS_PER_CHANNEL + bit;
}

#define AMB_SYSFS_NAME_LEN		16
struct i5k_device_attribute {
	struct sensor_device_attribute s_attr;
	char name[AMB_SYSFS_NAME_LEN];
};

struct i5k_amb_data {
	struct device *hwmon_dev;

	unsigned long amb_base;
	unsigned long amb_len;
	u16 amb_present[MAX_MEM_CHANNELS];
	void __iomem *amb_mmio;
	struct i5k_device_attribute *attrs;
	unsigned int num_attrs;
	unsigned long chipset_id;
};

static ssize_t show_name(struct device *dev, struct device_attribute *devattr,
			 char *buf)
{
	return sprintf(buf, "%s\n", DRVNAME);
}


static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static struct platform_device *amb_pdev;

static u8 amb_read_byte(struct i5k_amb_data *data, unsigned long offset)
{
	return ioread8(data->amb_mmio + offset);
}

static void amb_write_byte(struct i5k_amb_data *data, unsigned long offset,
			   u8 val)
{
	iowrite8(val, data->amb_mmio + offset);
}

static ssize_t show_amb_alarm(struct device *dev,
			     struct device_attribute *devattr,
			     char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);

	if (!(amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x20) &&
	     (amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x8))
		return sprintf(buf, "1\n");
	else
		return sprintf(buf, "0\n");
}

static ssize_t store_amb_min(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf,
			     size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	unsigned long temp = simple_strtoul(buf, NULL, 10) / 500;

	if (temp > 255)
		temp = 255;

	amb_write_byte(data, amb_reg_temp_min(attr->index), temp);
	return count;
}

static ssize_t store_amb_mid(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf,
			     size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	unsigned long temp = simple_strtoul(buf, NULL, 10) / 500;

	if (temp > 255)
		temp = 255;

	amb_write_byte(data, amb_reg_temp_mid(attr->index), temp);
	return count;
}

static ssize_t store_amb_max(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf,
			     size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	unsigned long temp = simple_strtoul(buf, NULL, 10) / 500;

	if (temp > 255)
		temp = 255;

	amb_write_byte(data, amb_reg_temp_max(attr->index), temp);
	return count;
}

static ssize_t show_amb_min(struct device *dev,
			     struct device_attribute *devattr,
			     char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
		500 * amb_read_byte(data, amb_reg_temp_min(attr->index)));
}

static ssize_t show_amb_mid(struct device *dev,
			     struct device_attribute *devattr,
			     char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
		500 * amb_read_byte(data, amb_reg_temp_mid(attr->index)));
}

static ssize_t show_amb_max(struct device *dev,
			     struct device_attribute *devattr,
			     char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
		500 * amb_read_byte(data, amb_reg_temp_max(attr->index)));
}

static ssize_t show_amb_temp(struct device *dev,
			     struct device_attribute *devattr,
			     char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct i5k_amb_data *data = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
		500 * amb_read_byte(data, amb_reg_temp(attr->index)));
}

static ssize_t show_label(struct device *dev,
			  struct device_attribute *devattr,
			  char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);

	return sprintf(buf, "Ch. %d DIMM %d\n", attr->index >> CHANNEL_SHIFT,
		       attr->index & DIMM_MASK);
}

static int __devinit i5k_amb_hwmon_init(struct platform_device *pdev)
{
	int i, j, k, d = 0;
	u16 c;
	int res = 0;
	int num_ambs = 0;
	struct i5k_amb_data *data = platform_get_drvdata(pdev);

	/* Count the number of AMBs found */
	/* ignore the high-order bit, see "Ugly hack" comment above */
	for (i = 0; i < MAX_MEM_CHANNELS; i++)
		num_ambs += hweight16(data->amb_present[i] & 0x7fff);

	/* Set up sysfs stuff */
	data->attrs = kzalloc(sizeof(*data->attrs) * num_ambs * KNOBS_PER_AMB,
				GFP_KERNEL);
	if (!data->attrs)
		return -ENOMEM;
	data->num_attrs = 0;

	for (i = 0; i < MAX_MEM_CHANNELS; i++) {
		c = data->amb_present[i];
		for (j = 0; j < REAL_MAX_AMBS_PER_CHANNEL; j++, c >>= 1) {
			struct i5k_device_attribute *iattr;

			k = amb_num_from_reg(i, j);
			if (!(c & 0x1))
				continue;
			d++;

			/* sysfs label */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_label", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IRUGO;
			iattr->s_attr.dev_attr.show = show_label;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;

			/* Temperature sysfs knob */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_input", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IRUGO;
			iattr->s_attr.dev_attr.show = show_amb_temp;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;

			/* Temperature min sysfs knob */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_min", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IWUSR | S_IRUGO;
			iattr->s_attr.dev_attr.show = show_amb_min;
			iattr->s_attr.dev_attr.store = store_amb_min;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;

			/* Temperature mid sysfs knob */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_mid", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IWUSR | S_IRUGO;
			iattr->s_attr.dev_attr.show = show_amb_mid;
			iattr->s_attr.dev_attr.store = store_amb_mid;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;

			/* Temperature max sysfs knob */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_max", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IWUSR | S_IRUGO;
			iattr->s_attr.dev_attr.show = show_amb_max;
			iattr->s_attr.dev_attr.store = store_amb_max;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;

			/* Temperature alarm sysfs knob */
			iattr = data->attrs + data->num_attrs;
			snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
				 "temp%d_alarm", d);
			iattr->s_attr.dev_attr.attr.name = iattr->name;
			iattr->s_attr.dev_attr.attr.mode = S_IRUGO;
			iattr->s_attr.dev_attr.show = show_amb_alarm;
			iattr->s_attr.index = k;
			sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
			res = device_create_file(&pdev->dev,
						 &iattr->s_attr.dev_attr);
			if (res)
				goto exit_remove;
			data->num_attrs++;
		}
	}

	res = device_create_file(&pdev->dev, &dev_attr_name);
	if (res)
		goto exit_remove;

	data->hwmon_dev = hwmon_device_register(&pdev->dev);
	if (IS_ERR(data->hwmon_dev)) {
		res = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return res;

exit_remove:
	device_remove_file(&pdev->dev, &dev_attr_name);
	for (i = 0; i < data->num_attrs; i++)
		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
	kfree(data->attrs);

	return res;
}

static int __devinit i5k_amb_add(void)
{
	int res = -ENODEV;

	/* only ever going to be one of these */
	amb_pdev = platform_device_alloc(DRVNAME, 0);
	if (!amb_pdev)
		return -ENOMEM;

	res = platform_device_add(amb_pdev);
	if (res)
		goto err;
	return 0;

err:
	platform_device_put(amb_pdev);
	return res;
}

static int __devinit i5k_find_amb_registers(struct i5k_amb_data *data,
					    unsigned long devid)
{
	struct pci_dev *pcidev;
	u32 val32;
	int res = -ENODEV;

	/* Find AMB register memory space */
	pcidev = pci_get_device(PCI_VENDOR_ID_INTEL,
				devid,
				NULL);
	if (!pcidev)
		return -ENODEV;

	if (pci_read_config_dword(pcidev, I5K_REG_AMB_BASE_ADDR, &val32))
		goto out;
	data->amb_base = val32;

	if (pci_read_config_dword(pcidev, I5K_REG_AMB_LEN_ADDR, &val32))
		goto out;
	data->amb_len = val32;

	/* Is it big enough? */
	if (data->amb_len < AMB_CONFIG_SIZE * MAX_AMBS) {
		dev_err(&pcidev->dev, "AMB region too small!\n");
		goto out;
	}

	data->chipset_id = devid;

	res = 0;
out:
	pci_dev_put(pcidev);
	return res;
}

static int __devinit i5k_channel_probe(u16 *amb_present, unsigned long dev_id)
{
	struct pci_dev *pcidev;
	u16 val16;
	int res = -ENODEV;

	/* Copy the DIMM presence map for these two channels */
	pcidev = pci_get_device(PCI_VENDOR_ID_INTEL, dev_id, NULL);
	if (!pcidev)
		return -ENODEV;

	if (pci_read_config_word(pcidev, I5K_REG_CHAN0_PRESENCE_ADDR, &val16))
		goto out;
	amb_present[0] = val16;

	if (pci_read_config_word(pcidev, I5K_REG_CHAN1_PRESENCE_ADDR, &val16))
		goto out;
	amb_present[1] = val16;

	res = 0;

out:
	pci_dev_put(pcidev);
	return res;
}

static unsigned long i5k_channel_pci_id(struct i5k_amb_data *data,
					unsigned long channel)
{
	switch (data->chipset_id) {
	case PCI_DEVICE_ID_INTEL_5000_ERR:
		return PCI_DEVICE_ID_INTEL_5000_FBD0 + channel;
	case PCI_DEVICE_ID_INTEL_5400_ERR:
		return PCI_DEVICE_ID_INTEL_5400_FBD0 + channel;
	default:
		BUG();
	}
}

static unsigned long chipset_ids[] = {
	PCI_DEVICE_ID_INTEL_5000_ERR,
	PCI_DEVICE_ID_INTEL_5400_ERR,
	0
};

static struct pci_device_id i5k_amb_ids[] __devinitdata = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5400_ERR) },
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, i5k_amb_ids);

static int __devinit i5k_amb_probe(struct platform_device *pdev)
{
	struct i5k_amb_data *data;
	struct resource *reso;
	int i;
	int res = -ENODEV;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	/* Figure out where the AMB registers live */
	i = 0;
	do {
		res = i5k_find_amb_registers(data, chipset_ids[i]);
		i++;
	} while (res && chipset_ids[i]);

	if (res)
		goto err;

	/* Copy the DIMM presence map for the first two channels */
	res = i5k_channel_probe(&data->amb_present[0],
				i5k_channel_pci_id(data, 0));
	if (res)
		goto err;

	/* Copy the DIMM presence map for the optional second two channels */
	i5k_channel_probe(&data->amb_present[2],
			  i5k_channel_pci_id(data, 1));

	/* Set up resource regions */
	reso = request_mem_region(data->amb_base, data->amb_len, DRVNAME);
	if (!reso) {
		res = -EBUSY;
		goto err;
	}

	data->amb_mmio = ioremap_nocache(data->amb_base, data->amb_len);
	if (!data->amb_mmio) {
		res = -EBUSY;
		goto err_map_failed;
	}

	platform_set_drvdata(pdev, data);

	res = i5k_amb_hwmon_init(pdev);
	if (res)
		goto err_init_failed;

	return res;

err_init_failed:
	iounmap(data->amb_mmio);
	platform_set_drvdata(pdev, NULL);
err_map_failed:
	release_mem_region(data->amb_base, data->amb_len);
err:
	kfree(data);
	return res;
}

static int __devexit i5k_amb_remove(struct platform_device *pdev)
{
	int i;
	struct i5k_amb_data *data = platform_get_drvdata(pdev);

	hwmon_device_unregister(data->hwmon_dev);
	device_remove_file(&pdev->dev, &dev_attr_name);
	for (i = 0; i < data->num_attrs; i++)
		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
	kfree(data->attrs);
	iounmap(data->amb_mmio);
	release_mem_region(data->amb_base, data->amb_len);
	platform_set_drvdata(pdev, NULL);
	kfree(data);
	return 0;
}

static struct platform_driver i5k_amb_driver = {
	.driver = {
		.owner = THIS_MODULE,
		.name = DRVNAME,
	},
	.probe = i5k_amb_probe,
	.remove = __devexit_p(i5k_amb_remove),
};

static int __init i5k_amb_init(void)
{
	int res;

	res = platform_driver_register(&i5k_amb_driver);
	if (res)
		return res;

	res = i5k_amb_add();
	if (res)
		platform_driver_unregister(&i5k_amb_driver);

	return res;
}

static void __exit i5k_amb_exit(void)
{
	platform_device_unregister(amb_pdev);
	platform_driver_unregister(&i5k_amb_driver);
}

MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
MODULE_DESCRIPTION("Intel 5000 chipset FB-DIMM AMB temperature sensor");
MODULE_LICENSE("GPL");

module_init(i5k_amb_init);
module_exit(i5k_amb_exit);