/*
 * SS4200-E Hardware API
 * Copyright (c) 2009, Intel Corporation.
 * Copyright IBM Corporation, 2009
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Author: Dave Hansen <dave@sr71.net>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/dmi.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/uaccess.h>

MODULE_AUTHOR("Rodney Girod <rgirod@confocus.com>, Dave Hansen <dave@sr71.net>");
MODULE_DESCRIPTION("Intel NAS/Home Server ICH7 GPIO Driver");
MODULE_LICENSE("GPL");

/*
 * ICH7 LPC/GPIO PCI Config register offsets
 */
#define PMBASE		0x040
#define GPIO_BASE	0x048
#define GPIO_CTRL	0x04c
#define GPIO_EN		0x010

/*
 * The ICH7 GPIO register block is 64 bytes in size.
 */
#define ICH7_GPIO_SIZE	64

/*
 * Define register offsets within the ICH7 register block.
 */
#define GPIO_USE_SEL	0x000
#define GP_IO_SEL	0x004
#define GP_LVL		0x00c
#define GPO_BLINK	0x018
#define GPI_INV		0x030
#define GPIO_USE_SEL2	0x034
#define GP_IO_SEL2	0x038
#define GP_LVL2		0x03c

/*
 * PCI ID of the Intel ICH7 LPC Device within which the GPIO block lives.
 */
static const struct pci_device_id ich7_lpc_pci_id[] =
{
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_0) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_1) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_30) },
	{ } /* NULL entry */
};

MODULE_DEVICE_TABLE(pci, ich7_lpc_pci_id);

static int __init ss4200_led_dmi_callback(const struct dmi_system_id *id)
{
	pr_info("detected '%s'\n", id->ident);
	return 1;
}

static bool __initdata nodetect;
module_param_named(nodetect, nodetect, bool, 0);
MODULE_PARM_DESC(nodetect, "Skip DMI-based hardware detection");

/*
 * struct nas_led_whitelist - List of known good models
 *
 * Contains the known good models this driver is compatible with.
 * When adding a new model try to be as strict as possible. This
 * makes it possible to keep the false positives (the model is
 * detected as working, but in reality it is not) as low as
 * possible.
 */
static struct dmi_system_id __initdata nas_led_whitelist[] = {
	{
		.callback = ss4200_led_dmi_callback,
		.ident = "Intel SS4200-E",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Intel"),
			DMI_MATCH(DMI_PRODUCT_NAME, "SS4200-E"),
			DMI_MATCH(DMI_PRODUCT_VERSION, "1.00.00")
		}
	},
	{}
};

/*
 * Base I/O address assigned to the Power Management register block
 */
static u32 g_pm_io_base;

/*
 * Base I/O address assigned to the ICH7 GPIO register block
 */
static u32 nas_gpio_io_base;

/*
 * When we successfully register a region, we are returned a resource.
 * We use these to identify which regions we need to release on our way
 * back out.
 */
static struct resource *gp_gpio_resource;

struct nasgpio_led {
	char *name;
	u32 gpio_bit;
	struct led_classdev led_cdev;
};

/*
 * gpio_bit(s) are the ICH7 GPIO bit assignments
 */
static struct nasgpio_led nasgpio_leds[] = {
	{ .name = "hdd1:blue:sata",	.gpio_bit = 0 },
	{ .name = "hdd1:amber:sata",	.gpio_bit = 1 },
	{ .name = "hdd2:blue:sata",	.gpio_bit = 2 },
	{ .name = "hdd2:amber:sata",	.gpio_bit = 3 },
	{ .name = "hdd3:blue:sata",	.gpio_bit = 4 },
	{ .name = "hdd3:amber:sata",	.gpio_bit = 5 },
	{ .name = "hdd4:blue:sata",	.gpio_bit = 6 },
	{ .name = "hdd4:amber:sata",	.gpio_bit = 7 },
	{ .name = "power:blue:power",	.gpio_bit = 27},
	{ .name = "power:amber:power",  .gpio_bit = 28},
};

#define NAS_RECOVERY	0x00000400	/* GPIO10 */

static struct nasgpio_led *
led_classdev_to_nasgpio_led(struct led_classdev *led_cdev)
{
	return container_of(led_cdev, struct nasgpio_led, led_cdev);
}

static struct nasgpio_led *get_led_named(char *name)
{
	int i;
	for (i = 0; i < ARRAY_SIZE(nasgpio_leds); i++) {
		if (strcmp(nasgpio_leds[i].name, name))
			continue;
		return &nasgpio_leds[i];
	}
	return NULL;
}

/*
 * This protects access to the gpio ports.
 */
static DEFINE_SPINLOCK(nasgpio_gpio_lock);

/*
 * There are two gpio ports, one for blinking and the other
 * for power.  @port tells us if we're doing blinking or
 * power control.
 *
 * Caller must hold nasgpio_gpio_lock
 */
static void __nasgpio_led_set_attr(struct led_classdev *led_cdev,
				   u32 port, u32 value)
{
	struct nasgpio_led *led = led_classdev_to_nasgpio_led(led_cdev);
	u32 gpio_out;

	gpio_out = inl(nas_gpio_io_base + port);
	if (value)
		gpio_out |= (1<<led->gpio_bit);
	else
		gpio_out &= ~(1<<led->gpio_bit);

	outl(gpio_out, nas_gpio_io_base + port);
}

static void nasgpio_led_set_attr(struct led_classdev *led_cdev,
				 u32 port, u32 value)
{
	spin_lock(&nasgpio_gpio_lock);
	__nasgpio_led_set_attr(led_cdev, port, value);
	spin_unlock(&nasgpio_gpio_lock);
}

u32 nasgpio_led_get_attr(struct led_classdev *led_cdev, u32 port)
{
	struct nasgpio_led *led = led_classdev_to_nasgpio_led(led_cdev);
	u32 gpio_in;

	spin_lock(&nasgpio_gpio_lock);
	gpio_in = inl(nas_gpio_io_base + port);
	spin_unlock(&nasgpio_gpio_lock);
	if (gpio_in & (1<<led->gpio_bit))
		return 1;
	return 0;
}

/*
 * There is actual brightness control in the hardware,
 * but it is via smbus commands and not implemented
 * in this driver.
 */
static void nasgpio_led_set_brightness(struct led_classdev *led_cdev,
				       enum led_brightness brightness)
{
	u32 setting = 0;
	if (brightness >= LED_HALF)
		setting = 1;
	/*
	 * Hold the lock across both operations.  This ensures
	 * consistency so that both the "turn off blinking"
	 * and "turn light off" operations complete as a set.
	 */
	spin_lock(&nasgpio_gpio_lock);
	/*
	 * LED class documentation asks that past blink state
	 * be disabled when brightness is turned to zero.
	 */
	if (brightness == 0)
		__nasgpio_led_set_attr(led_cdev, GPO_BLINK, 0);
	__nasgpio_led_set_attr(led_cdev, GP_LVL, setting);
	spin_unlock(&nasgpio_gpio_lock);
}

static int nasgpio_led_set_blink(struct led_classdev *led_cdev,
				 unsigned long *delay_on,
				 unsigned long *delay_off)
{
	u32 setting = 1;
	if (!(*delay_on == 0 && *delay_off == 0) &&
	    !(*delay_on == 500 && *delay_off == 500))
		return -EINVAL;
	/*
	 * These are very approximate.
	 */
	*delay_on = 500;
	*delay_off = 500;

	nasgpio_led_set_attr(led_cdev, GPO_BLINK, setting);

	return 0;
}


/*
 * Initialize the ICH7 GPIO registers for NAS usage.  The BIOS should have
 * already taken care of this, but we will do so in a non destructive manner
 * so that we have what we need whether the BIOS did it or not.
 */
static int ich7_gpio_init(struct device *dev)
{
	int i;
	u32 config_data = 0;
	u32 all_nas_led = 0;

	for (i = 0; i < ARRAY_SIZE(nasgpio_leds); i++)
		all_nas_led |= (1<<nasgpio_leds[i].gpio_bit);

	spin_lock(&nasgpio_gpio_lock);
	/*
	 * We need to enable all of the GPIO lines used by the NAS box,
	 * so we will read the current Use Selection and add our usage
	 * to it.  This should be benign with regard to the original
	 * BIOS configuration.
	 */
	config_data = inl(nas_gpio_io_base + GPIO_USE_SEL);
	dev_dbg(dev, ": Data read from GPIO_USE_SEL = 0x%08x\n", config_data);
	config_data |= all_nas_led + NAS_RECOVERY;
	outl(config_data, nas_gpio_io_base + GPIO_USE_SEL);
	config_data = inl(nas_gpio_io_base + GPIO_USE_SEL);
	dev_dbg(dev, ": GPIO_USE_SEL = 0x%08x\n\n", config_data);

	/*
	 * The LED GPIO outputs need to be configured for output, so we
	 * will ensure that all LED lines are cleared for output and the
	 * RECOVERY line ready for input.  This too should be benign with
	 * regard to BIOS configuration.
	 */
	config_data = inl(nas_gpio_io_base + GP_IO_SEL);
	dev_dbg(dev, ": Data read from GP_IO_SEL = 0x%08x\n",
					config_data);
	config_data &= ~all_nas_led;
	config_data |= NAS_RECOVERY;
	outl(config_data, nas_gpio_io_base + GP_IO_SEL);
	config_data = inl(nas_gpio_io_base + GP_IO_SEL);
	dev_dbg(dev, ": GP_IO_SEL = 0x%08x\n", config_data);

	/*
	 * In our final system, the BIOS will initialize the state of all
	 * of the LEDs.  For now, we turn them all off (or Low).
	 */
	config_data = inl(nas_gpio_io_base + GP_LVL);
	dev_dbg(dev, ": Data read from GP_LVL = 0x%08x\n", config_data);
	/*
	 * In our final system, the BIOS will initialize the blink state of all
	 * of the LEDs.  For now, we turn blink off for all of them.
	 */
	config_data = inl(nas_gpio_io_base + GPO_BLINK);
	dev_dbg(dev, ": Data read from GPO_BLINK = 0x%08x\n", config_data);

	/*
	 * At this moment, I am unsure if anything needs to happen with GPI_INV
	 */
	config_data = inl(nas_gpio_io_base + GPI_INV);
	dev_dbg(dev, ": Data read from GPI_INV = 0x%08x\n", config_data);

	spin_unlock(&nasgpio_gpio_lock);
	return 0;
}

static void ich7_lpc_cleanup(struct device *dev)
{
	/*
	 * If we were given exclusive use of the GPIO
	 * I/O Address range, we must return it.
	 */
	if (gp_gpio_resource) {
		dev_dbg(dev, ": Releasing GPIO I/O addresses\n");
		release_region(nas_gpio_io_base, ICH7_GPIO_SIZE);
		gp_gpio_resource = NULL;
	}
}

/*
 * The OS has determined that the LPC of the Intel ICH7 Southbridge is present
 * so we can retrive the required operational information and prepare the GPIO.
 */
static struct pci_dev *nas_gpio_pci_dev;
static int ich7_lpc_probe(struct pci_dev *dev,
				    const struct pci_device_id *id)
{
	int status;
	u32 gc = 0;

	status = pci_enable_device(dev);
	if (status) {
		dev_err(&dev->dev, "pci_enable_device failed\n");
		return -EIO;
	}

	nas_gpio_pci_dev = dev;
	status = pci_read_config_dword(dev, PMBASE, &g_pm_io_base);
	if (status)
		goto out;
	g_pm_io_base &= 0x00000ff80;

	status = pci_read_config_dword(dev, GPIO_CTRL, &gc);
	if (!(GPIO_EN & gc)) {
		status = -EEXIST;
		dev_info(&dev->dev,
			   "ERROR: The LPC GPIO Block has not been enabled.\n");
		goto out;
	}

	status = pci_read_config_dword(dev, GPIO_BASE, &nas_gpio_io_base);
	if (0 > status) {
		dev_info(&dev->dev, "Unable to read GPIOBASE.\n");
		goto out;
	}
	dev_dbg(&dev->dev, ": GPIOBASE = 0x%08x\n", nas_gpio_io_base);
	nas_gpio_io_base &= 0x00000ffc0;

	/*
	 * Insure that we have exclusive access to the GPIO I/O address range.
	 */
	gp_gpio_resource = request_region(nas_gpio_io_base, ICH7_GPIO_SIZE,
					  KBUILD_MODNAME);
	if (NULL == gp_gpio_resource) {
		dev_info(&dev->dev,
			 "ERROR Unable to register GPIO I/O addresses.\n");
		status = -1;
		goto out;
	}

	/*
	 * Initialize the GPIO for NAS/Home Server Use
	 */
	ich7_gpio_init(&dev->dev);

out:
	if (status) {
		ich7_lpc_cleanup(&dev->dev);
		pci_disable_device(dev);
	}
	return status;
}

static void ich7_lpc_remove(struct pci_dev *dev)
{
	ich7_lpc_cleanup(&dev->dev);
	pci_disable_device(dev);
}

/*
 * pci_driver structure passed to the PCI modules
 */
static struct pci_driver nas_gpio_pci_driver = {
	.name = KBUILD_MODNAME,
	.id_table = ich7_lpc_pci_id,
	.probe = ich7_lpc_probe,
	.remove = ich7_lpc_remove,
};

static struct led_classdev *get_classdev_for_led_nr(int nr)
{
	struct nasgpio_led *nas_led = &nasgpio_leds[nr];
	struct led_classdev *led = &nas_led->led_cdev;
	return led;
}


static void set_power_light_amber_noblink(void)
{
	struct nasgpio_led *amber = get_led_named("power:amber:power");
	struct nasgpio_led *blue = get_led_named("power:blue:power");

	if (!amber || !blue)
		return;
	/*
	 * LED_OFF implies disabling future blinking
	 */
	pr_debug("setting blue off and amber on\n");

	nasgpio_led_set_brightness(&blue->led_cdev, LED_OFF);
	nasgpio_led_set_brightness(&amber->led_cdev, LED_FULL);
}

static ssize_t nas_led_blink_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct led_classdev *led = dev_get_drvdata(dev);
	int blinking = 0;
	if (nasgpio_led_get_attr(led, GPO_BLINK))
		blinking = 1;
	return sprintf(buf, "%u\n", blinking);
}

static ssize_t nas_led_blink_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t size)
{
	int ret;
	struct led_classdev *led = dev_get_drvdata(dev);
	unsigned long blink_state;

	ret = kstrtoul(buf, 10, &blink_state);
	if (ret)
		return ret;

	nasgpio_led_set_attr(led, GPO_BLINK, blink_state);

	return size;
}

static DEVICE_ATTR(blink, 0644, nas_led_blink_show, nas_led_blink_store);

static int register_nasgpio_led(int led_nr)
{
	int ret;
	struct nasgpio_led *nas_led = &nasgpio_leds[led_nr];
	struct led_classdev *led = get_classdev_for_led_nr(led_nr);

	led->name = nas_led->name;
	led->brightness = LED_OFF;
	if (nasgpio_led_get_attr(led, GP_LVL))
		led->brightness = LED_FULL;
	led->brightness_set = nasgpio_led_set_brightness;
	led->blink_set = nasgpio_led_set_blink;
	ret = led_classdev_register(&nas_gpio_pci_dev->dev, led);
	if (ret)
		return ret;
	ret = device_create_file(led->dev, &dev_attr_blink);
	if (ret)
		led_classdev_unregister(led);
	return ret;
}

static void unregister_nasgpio_led(int led_nr)
{
	struct led_classdev *led = get_classdev_for_led_nr(led_nr);
	led_classdev_unregister(led);
	device_remove_file(led->dev, &dev_attr_blink);
}
/*
 * module load/initialization
 */
static int __init nas_gpio_init(void)
{
	int i;
	int ret = 0;
	int nr_devices = 0;

	nr_devices = dmi_check_system(nas_led_whitelist);
	if (nodetect) {
		pr_info("skipping hardware autodetection\n");
		pr_info("Please send 'dmidecode' output to dave@sr71.net\n");
		nr_devices++;
	}

	if (nr_devices <= 0) {
		pr_info("no LED devices found\n");
		return -ENODEV;
	}

	pr_info("registering PCI driver\n");
	ret = pci_register_driver(&nas_gpio_pci_driver);
	if (ret)
		return ret;
	for (i = 0; i < ARRAY_SIZE(nasgpio_leds); i++) {
		ret = register_nasgpio_led(i);
		if (ret)
			goto out_err;
	}
	/*
	 * When the system powers on, the BIOS leaves the power
	 * light blue and blinking.  This will turn it solid
	 * amber once the driver is loaded.
	 */
	set_power_light_amber_noblink();
	return 0;
out_err:
	for (i--; i >= 0; i--)
		unregister_nasgpio_led(i);
	pci_unregister_driver(&nas_gpio_pci_driver);
	return ret;
}

/*
 * module unload
 */
static void __exit nas_gpio_exit(void)
{
	int i;
	pr_info("Unregistering driver\n");
	for (i = 0; i < ARRAY_SIZE(nasgpio_leds); i++)
		unregister_nasgpio_led(i);
	pci_unregister_driver(&nas_gpio_pci_driver);
}

module_init(nas_gpio_init);
module_exit(nas_gpio_exit);