/*
   * k8temp.c - Linux kernel module for hardware monitoring
   *
   * Copyright (C) 2006 Rudolf Marek <r.marek@assembler.cz>
   *
   * Inspired from the w83785 and amd756 drivers.
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston, MA
   * 02110-1301 USA.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/pci.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <asm/processor.h>
  
  #define TEMP_FROM_REG(val)	(((((val) >> 16) & 0xff) - 49) * 1000)
  #define REG_TEMP	0xe4
  #define SEL_PLACE	0x40
  #define SEL_CORE	0x04
  
  struct k8temp_data {
  	struct device *hwmon_dev;
  	struct mutex update_lock;
  	const char *name;
  	char valid;		/* zero until following fields are valid */
  	unsigned long last_updated;	/* in jiffies */
  
  	/* registers values */
  	u8 sensorsp;		/* sensor presence bits - SEL_CORE, SEL_PLACE */
  	u32 temp[2][2];		/* core, place */
  	u8 swap_core_select;    /* meaning of SEL_CORE is inverted */
  	u32 temp_offset;
  };
  
  static struct k8temp_data *k8temp_update_device(struct device *dev)
  {
  	struct k8temp_data *data = dev_get_drvdata(dev);
  	struct pci_dev *pdev = to_pci_dev(dev);
  	u8 tmp;
  
  	mutex_lock(&data->update_lock);
  
  	if (!data->valid
  	    || time_after(jiffies, data->last_updated + HZ)) {
  		pci_read_config_byte(pdev, REG_TEMP, &tmp);
  		tmp &= ~(SEL_PLACE | SEL_CORE);	/* Select sensor 0, core0 */
  		pci_write_config_byte(pdev, REG_TEMP, tmp);
  		pci_read_config_dword(pdev, REG_TEMP, &data->temp[0][0]);
  
  		if (data->sensorsp & SEL_PLACE) {
  			tmp |= SEL_PLACE;	/* Select sensor 1, core0 */
  			pci_write_config_byte(pdev, REG_TEMP, tmp);
  			pci_read_config_dword(pdev, REG_TEMP,
  					      &data->temp[0][1]);
  		}
  
  		if (data->sensorsp & SEL_CORE) {
  			tmp &= ~SEL_PLACE;	/* Select sensor 0, core1 */
  			tmp |= SEL_CORE;
  			pci_write_config_byte(pdev, REG_TEMP, tmp);
  			pci_read_config_dword(pdev, REG_TEMP,
  					      &data->temp[1][0]);
  
  			if (data->sensorsp & SEL_PLACE) {
  				tmp |= SEL_PLACE; /* Select sensor 1, core1 */
  				pci_write_config_byte(pdev, REG_TEMP, tmp);
  				pci_read_config_dword(pdev, REG_TEMP,
  						      &data->temp[1][1]);
  			}
  		}
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  	return data;
  }
  
  /*
   * Sysfs stuff
   */
  
  static ssize_t show_name(struct device *dev, struct device_attribute
  			 *devattr, char *buf)
  {
  	struct k8temp_data *data = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%s
  ", data->name);
  }
  
  
  static ssize_t show_temp(struct device *dev,
  			 struct device_attribute *devattr, char *buf)
  {
  	struct sensor_device_attribute_2 *attr =
  	    to_sensor_dev_attr_2(devattr);
  	int core = attr->nr;
  	int place = attr->index;
  	int temp;
  	struct k8temp_data *data = k8temp_update_device(dev);
  
  	if (data->swap_core_select && (data->sensorsp & SEL_CORE))
  		core = core ? 0 : 1;
  
  	temp = TEMP_FROM_REG(data->temp[core][place]) + data->temp_offset;
  
  	return sprintf(buf, "%d
  ", temp);
  }
  
  /* core, place */
  
  static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp, NULL, 0, 0);
  static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp, NULL, 0, 1);
  static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp, NULL, 1, 0);
  static SENSOR_DEVICE_ATTR_2(temp4_input, S_IRUGO, show_temp, NULL, 1, 1);
  static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
  
  static const struct pci_device_id k8temp_ids[] = {
  	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
  	{ 0 },
  };
  
  MODULE_DEVICE_TABLE(pci, k8temp_ids);
  
  static int is_rev_g_desktop(u8 model)
  {
  	u32 brandidx;
  
  	if (model < 0x69)
  		return 0;
  
  	if (model == 0xc1 || model == 0x6c || model == 0x7c)
  		return 0;
  
  	/*
  	 * Differentiate between AM2 and ASB1.
  	 * See "Constructing the processor Name String" in "Revision
  	 * Guide for AMD NPT Family 0Fh Processors" (33610).
  	 */
  	brandidx = cpuid_ebx(0x80000001);
  	brandidx = (brandidx >> 9) & 0x1f;
  
  	/* Single core */
  	if ((model == 0x6f || model == 0x7f) &&
  	    (brandidx == 0x7 || brandidx == 0x9 || brandidx == 0xc))
  		return 0;
  
  	/* Dual core */
  	if (model == 0x6b &&
  	    (brandidx == 0xb || brandidx == 0xc))
  		return 0;
  
  	return 1;
  }
  
  static int k8temp_probe(struct pci_dev *pdev,
  				  const struct pci_device_id *id)
  {
  	int err;
  	u8 scfg;
  	u32 temp;
  	u8 model, stepping;
  	struct k8temp_data *data;
  
  	data = devm_kzalloc(&pdev->dev, sizeof(struct k8temp_data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	model = boot_cpu_data.x86_model;
  	stepping = boot_cpu_data.x86_mask;
  
  	/* feature available since SH-C0, exclude older revisions */
  	if ((model == 4 && stepping == 0) ||
  	    (model == 5 && stepping <= 1))
  		return -ENODEV;
  
  	/*
  	 * AMD NPT family 0fh, i.e. RevF and RevG:
  	 * meaning of SEL_CORE bit is inverted
  	 */
  	if (model >= 0x40) {
  		data->swap_core_select = 1;
  		dev_warn(&pdev->dev,
  			 "Temperature readouts might be wrong - check erratum #141
  ");
  	}
  
  	/*
  	 * RevG desktop CPUs (i.e. no socket S1G1 or ASB1 parts) need
  	 * additional offset, otherwise reported temperature is below
  	 * ambient temperature
  	 */
  	if (is_rev_g_desktop(model))
  		data->temp_offset = 21000;
  
  	pci_read_config_byte(pdev, REG_TEMP, &scfg);
  	scfg &= ~(SEL_PLACE | SEL_CORE);	/* Select sensor 0, core0 */
  	pci_write_config_byte(pdev, REG_TEMP, scfg);
  	pci_read_config_byte(pdev, REG_TEMP, &scfg);
  
  	if (scfg & (SEL_PLACE | SEL_CORE)) {
  		dev_err(&pdev->dev, "Configuration bit(s) stuck at 1!
  ");
  		return -ENODEV;
  	}
  
  	scfg |= (SEL_PLACE | SEL_CORE);
  	pci_write_config_byte(pdev, REG_TEMP, scfg);
  
  	/* now we know if we can change core and/or sensor */
  	pci_read_config_byte(pdev, REG_TEMP, &data->sensorsp);
  
  	if (data->sensorsp & SEL_PLACE) {
  		scfg &= ~SEL_CORE;	/* Select sensor 1, core0 */
  		pci_write_config_byte(pdev, REG_TEMP, scfg);
  		pci_read_config_dword(pdev, REG_TEMP, &temp);
  		scfg |= SEL_CORE;	/* prepare for next selection */
  		if (!((temp >> 16) & 0xff)) /* if temp is 0 -49C is unlikely */
  			data->sensorsp &= ~SEL_PLACE;
  	}
  
  	if (data->sensorsp & SEL_CORE) {
  		scfg &= ~SEL_PLACE;	/* Select sensor 0, core1 */
  		pci_write_config_byte(pdev, REG_TEMP, scfg);
  		pci_read_config_dword(pdev, REG_TEMP, &temp);
  		if (!((temp >> 16) & 0xff)) /* if temp is 0 -49C is unlikely */
  			data->sensorsp &= ~SEL_CORE;
  	}
  
  	data->name = "k8temp";
  	mutex_init(&data->update_lock);
  	pci_set_drvdata(pdev, data);
  
  	/* Register sysfs hooks */
  	err = device_create_file(&pdev->dev,
  			   &sensor_dev_attr_temp1_input.dev_attr);
  	if (err)
  		goto exit_remove;
  
  	/* sensor can be changed and reports something */
  	if (data->sensorsp & SEL_PLACE) {
  		err = device_create_file(&pdev->dev,
  				   &sensor_dev_attr_temp2_input.dev_attr);
  		if (err)
  			goto exit_remove;
  	}
  
  	/* core can be changed and reports something */
  	if (data->sensorsp & SEL_CORE) {
  		err = device_create_file(&pdev->dev,
  				   &sensor_dev_attr_temp3_input.dev_attr);
  		if (err)
  			goto exit_remove;
  		if (data->sensorsp & SEL_PLACE) {
  			err = device_create_file(&pdev->dev,
  					   &sensor_dev_attr_temp4_input.
  					   dev_attr);
  			if (err)
  				goto exit_remove;
  		}
  	}
  
  	err = device_create_file(&pdev->dev, &dev_attr_name);
  	if (err)
  		goto exit_remove;
  
  	data->hwmon_dev = hwmon_device_register(&pdev->dev);
  
  	if (IS_ERR(data->hwmon_dev)) {
  		err = PTR_ERR(data->hwmon_dev);
  		goto exit_remove;
  	}
  
  	return 0;
  
  exit_remove:
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp1_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp2_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp3_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp4_input.dev_attr);
  	device_remove_file(&pdev->dev, &dev_attr_name);
  	return err;
  }
  
  static void k8temp_remove(struct pci_dev *pdev)
  {
  	struct k8temp_data *data = pci_get_drvdata(pdev);
  
  	hwmon_device_unregister(data->hwmon_dev);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp1_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp2_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp3_input.dev_attr);
  	device_remove_file(&pdev->dev,
  			   &sensor_dev_attr_temp4_input.dev_attr);
  	device_remove_file(&pdev->dev, &dev_attr_name);
  }
  
  static struct pci_driver k8temp_driver = {
  	.name = "k8temp",
  	.id_table = k8temp_ids,
  	.probe = k8temp_probe,
  	.remove = k8temp_remove,
  };
  
  module_pci_driver(k8temp_driver);
  
  MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
  MODULE_DESCRIPTION("AMD K8 core temperature monitor");
  MODULE_LICENSE("GPL");