/*
   * A hwmon driver for the Intel 5000 series chipset FB-DIMM AMB
   * temperature sensors
   * Copyright (C) 2007 IBM
   *
   * Author: Darrick J. Wong <darrick.wong@oracle.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/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.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;
  };
  
  static ssize_t show_name(struct device *dev, struct device_attribute *devattr,
  			 char *buf)
  {
  	return sprintf(buf, "%s
  ", 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
  ");
  	else
  		return sprintf(buf, "0
  ");
  }
  
  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;
  	int ret = kstrtoul(buf, 10, &temp);
  	if (ret < 0)
  		return ret;
  
  	temp = temp / 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;
  	int ret = kstrtoul(buf, 10, &temp);
  	if (ret < 0)
  		return ret;
  
  	temp = temp / 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;
  	int ret = kstrtoul(buf, 10, &temp);
  	if (ret < 0)
  		return ret;
  
  	temp = temp / 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
  ",
  		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
  ",
  		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
  ",
  		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
  ",
  		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
  ", attr->index >> CHANNEL_SHIFT,
  		       attr->index & DIMM_MASK);
  }
  
  static int 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 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 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!
  ");
  		goto out;
  	}
  
  	res = 0;
  out:
  	pci_dev_put(pcidev);
  	return res;
  }
  
  static int 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 struct {
  	unsigned long err;
  	unsigned long fbd0;
  } chipset_ids[]  = {
  	{ PCI_DEVICE_ID_INTEL_5000_ERR, PCI_DEVICE_ID_INTEL_5000_FBD0 },
  	{ PCI_DEVICE_ID_INTEL_5400_ERR, PCI_DEVICE_ID_INTEL_5400_FBD0 },
  	{ 0, 0 }
  };
  
  #ifdef MODULE
  static struct pci_device_id i5k_amb_ids[] = {
  	{ 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);
  #endif
  
  static int i5k_amb_probe(struct platform_device *pdev)
  {
  	struct i5k_amb_data *data;
  	struct resource *reso;
  	int i, res;
  
  	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].err);
  		if (res == 0)
  			break;
  		i++;
  	} while (chipset_ids[i].err);
  
  	if (res)
  		goto err;
  
  	/* Copy the DIMM presence map for the first two channels */
  	res = i5k_channel_probe(&data->amb_present[0], chipset_ids[i].fbd0);
  	if (res)
  		goto err;
  
  	/* Copy the DIMM presence map for the optional second two channels */
  	i5k_channel_probe(&data->amb_present[2], chipset_ids[i].fbd0 + 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);
  err_map_failed:
  	release_mem_region(data->amb_base, data->amb_len);
  err:
  	kfree(data);
  	return res;
  }
  
  static int 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);
  	kfree(data);
  	return 0;
  }
  
  static struct platform_driver i5k_amb_driver = {
  	.driver = {
  		.owner = THIS_MODULE,
  		.name = DRVNAME,
  	},
  	.probe = i5k_amb_probe,
  	.remove = 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 <darrick.wong@oracle.com>");
  MODULE_DESCRIPTION("Intel 5000 chipset FB-DIMM AMB temperature sensor");
  MODULE_LICENSE("GPL");
  
  module_init(i5k_amb_init);
  module_exit(i5k_amb_exit);