/*
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * 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.
   *
   * Copyright (C) 2012 ARM Limited
   */
  
  #include <linux/err.h>
  #include <linux/gpio.h>
  #include <linux/io.h>
  #include <linux/leds.h>
  #include <linux/of_address.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/slab.h>
  #include <linux/stat.h>
  #include <linux/timer.h>
  #include <linux/vexpress.h>
  
  #define SYS_ID			0x000
  #define SYS_SW			0x004
  #define SYS_LED			0x008
  #define SYS_100HZ		0x024
  #define SYS_FLAGS		0x030
  #define SYS_FLAGSSET		0x030
  #define SYS_FLAGSCLR		0x034
  #define SYS_NVFLAGS		0x038
  #define SYS_NVFLAGSSET		0x038
  #define SYS_NVFLAGSCLR		0x03c
  #define SYS_MCI			0x048
  #define SYS_FLASH		0x04c
  #define SYS_CFGSW		0x058
  #define SYS_24MHZ		0x05c
  #define SYS_MISC		0x060
  #define SYS_DMA			0x064
  #define SYS_PROCID0		0x084
  #define SYS_PROCID1		0x088
  #define SYS_CFGDATA		0x0a0
  #define SYS_CFGCTRL		0x0a4
  #define SYS_CFGSTAT		0x0a8
  
  #define SYS_HBI_MASK		0xfff
  #define SYS_ID_HBI_SHIFT	16
  #define SYS_PROCIDx_HBI_SHIFT	0
  
  #define SYS_LED_LED(n)		(1 << (n))
  
  #define SYS_MCI_CARDIN		(1 << 0)
  #define SYS_MCI_WPROT		(1 << 1)
  
  #define SYS_FLASH_WPn		(1 << 0)
  
  #define SYS_MISC_MASTERSITE	(1 << 14)
  
  #define SYS_CFGCTRL_START	(1 << 31)
  #define SYS_CFGCTRL_WRITE	(1 << 30)
  #define SYS_CFGCTRL_DCC(n)	(((n) & 0xf) << 26)
  #define SYS_CFGCTRL_FUNC(n)	(((n) & 0x3f) << 20)
  #define SYS_CFGCTRL_SITE(n)	(((n) & 0x3) << 16)
  #define SYS_CFGCTRL_POSITION(n)	(((n) & 0xf) << 12)
  #define SYS_CFGCTRL_DEVICE(n)	(((n) & 0xfff) << 0)
  
  #define SYS_CFGSTAT_ERR		(1 << 1)
  #define SYS_CFGSTAT_COMPLETE	(1 << 0)
  
  
  static void __iomem *vexpress_sysreg_base;
  static struct device *vexpress_sysreg_dev;
  static int vexpress_master_site;
  
  
  void vexpress_flags_set(u32 data)
  {
  	writel(~0, vexpress_sysreg_base + SYS_FLAGSCLR);
  	writel(data, vexpress_sysreg_base + SYS_FLAGSSET);
  }
  
  u32 vexpress_get_procid(int site)
  {
  	if (site == VEXPRESS_SITE_MASTER)
  		site = vexpress_master_site;
  
  	return readl(vexpress_sysreg_base + (site == VEXPRESS_SITE_DB1 ?
  			SYS_PROCID0 : SYS_PROCID1));
  }
  
  u32 vexpress_get_hbi(int site)
  {
  	u32 id;
  
  	switch (site) {
  	case VEXPRESS_SITE_MB:
  		id = readl(vexpress_sysreg_base + SYS_ID);
  		return (id >> SYS_ID_HBI_SHIFT) & SYS_HBI_MASK;
  	case VEXPRESS_SITE_MASTER:
  	case VEXPRESS_SITE_DB1:
  	case VEXPRESS_SITE_DB2:
  		id = vexpress_get_procid(site);
  		return (id >> SYS_PROCIDx_HBI_SHIFT) & SYS_HBI_MASK;
  	}
  
  	return ~0;
  }
  
  void __iomem *vexpress_get_24mhz_clock_base(void)
  {
  	return vexpress_sysreg_base + SYS_24MHZ;
  }
  
  
  static void vexpress_sysreg_find_prop(struct device_node *node,
  		const char *name, u32 *val)
  {
  	of_node_get(node);
  	while (node) {
  		if (of_property_read_u32(node, name, val) == 0) {
  			of_node_put(node);
  			return;
  		}
  		node = of_get_next_parent(node);
  	}
  }
  
  unsigned __vexpress_get_site(struct device *dev, struct device_node *node)
  {
  	u32 site = 0;
  
  	WARN_ON(dev && node && dev->of_node != node);
  	if (dev && !node)
  		node = dev->of_node;
  
  	if (node) {
  		vexpress_sysreg_find_prop(node, "arm,vexpress,site", &site);
  	} else if (dev && dev->bus == &platform_bus_type) {
  		struct platform_device *pdev = to_platform_device(dev);
  
  		if (pdev->num_resources == 1 &&
  				pdev->resource[0].flags == IORESOURCE_BUS)
  			site = pdev->resource[0].start;
  	} else if (dev && strncmp(dev_name(dev), "ct:", 3) == 0) {
  		site = VEXPRESS_SITE_MASTER;
  	}
  
  	if (site == VEXPRESS_SITE_MASTER)
  		site = vexpress_master_site;
  
  	return site;
  }
  
  
  struct vexpress_sysreg_config_func {
  	u32 template;
  	u32 device;
  };
  
  static struct vexpress_config_bridge *vexpress_sysreg_config_bridge;
  static struct timer_list vexpress_sysreg_config_timer;
  static u32 *vexpress_sysreg_config_data;
  static int vexpress_sysreg_config_tries;
  
  static void *vexpress_sysreg_config_func_get(struct device *dev,
  		struct device_node *node)
  {
  	struct vexpress_sysreg_config_func *config_func;
  	u32 site;
  	u32 position = 0;
  	u32 dcc = 0;
  	u32 func_device[2];
  	int err = -EFAULT;
  
  	if (node) {
  		of_node_get(node);
  		vexpress_sysreg_find_prop(node, "arm,vexpress,site", &site);
  		vexpress_sysreg_find_prop(node, "arm,vexpress,position",
  				&position);
  		vexpress_sysreg_find_prop(node, "arm,vexpress,dcc", &dcc);
  		err = of_property_read_u32_array(node,
  				"arm,vexpress-sysreg,func", func_device,
  				ARRAY_SIZE(func_device));
  		of_node_put(node);
  	} else if (dev && dev->bus == &platform_bus_type) {
  		struct platform_device *pdev = to_platform_device(dev);
  
  		if (pdev->num_resources == 1 &&
  				pdev->resource[0].flags == IORESOURCE_BUS) {
  			site = pdev->resource[0].start;
  			func_device[0] = pdev->resource[0].end;
  			func_device[1] = pdev->id;
  			err = 0;
  		}
  	}
  	if (err)
  		return NULL;
  
  	config_func = kzalloc(sizeof(*config_func), GFP_KERNEL);
  	if (!config_func)
  		return NULL;
  
  	config_func->template = SYS_CFGCTRL_DCC(dcc);
  	config_func->template |= SYS_CFGCTRL_FUNC(func_device[0]);
  	config_func->template |= SYS_CFGCTRL_SITE(site == VEXPRESS_SITE_MASTER ?
  			vexpress_master_site : site);
  	config_func->template |= SYS_CFGCTRL_POSITION(position);
  	config_func->device |= func_device[1];
  
  	dev_dbg(vexpress_sysreg_dev, "func 0x%p = 0x%x, %d
  ", config_func,
  			config_func->template, config_func->device);
  
  	return config_func;
  }
  
  static void vexpress_sysreg_config_func_put(void *func)
  {
  	kfree(func);
  }
  
  static int vexpress_sysreg_config_func_exec(void *func, int offset,
  		bool write, u32 *data)
  {
  	int status;
  	struct vexpress_sysreg_config_func *config_func = func;
  	u32 command;
  
  	if (WARN_ON(!vexpress_sysreg_base))
  		return -ENOENT;
  
  	command = readl(vexpress_sysreg_base + SYS_CFGCTRL);
  	if (WARN_ON(command & SYS_CFGCTRL_START))
  		return -EBUSY;
  
  	command = SYS_CFGCTRL_START;
  	command |= write ? SYS_CFGCTRL_WRITE : 0;
  	command |= config_func->template;
  	command |= SYS_CFGCTRL_DEVICE(config_func->device + offset);
  
  	/* Use a canary for reads */
  	if (!write)
  		*data = 0xdeadbeef;
  
  	dev_dbg(vexpress_sysreg_dev, "command %x, data %x
  ",
  			command, *data);
  	writel(*data, vexpress_sysreg_base + SYS_CFGDATA);
  	writel(0, vexpress_sysreg_base + SYS_CFGSTAT);
  	writel(command, vexpress_sysreg_base + SYS_CFGCTRL);
  	mb();
  
  	if (vexpress_sysreg_dev) {
  		/* Schedule completion check */
  		if (!write)
  			vexpress_sysreg_config_data = data;
  		vexpress_sysreg_config_tries = 100;
  		mod_timer(&vexpress_sysreg_config_timer,
  				jiffies + usecs_to_jiffies(100));
  		status = VEXPRESS_CONFIG_STATUS_WAIT;
  	} else {
  		/* Early execution, no timer available, have to spin */
  		u32 cfgstat;
  
  		do {
  			cpu_relax();
  			cfgstat = readl(vexpress_sysreg_base + SYS_CFGSTAT);
  		} while (!cfgstat);
  
  		if (!write && (cfgstat & SYS_CFGSTAT_COMPLETE))
  			*data = readl(vexpress_sysreg_base + SYS_CFGDATA);
  		status = VEXPRESS_CONFIG_STATUS_DONE;
  
  		if (cfgstat & SYS_CFGSTAT_ERR)
  			status = -EINVAL;
  	}
  
  	return status;
  }
  
  struct vexpress_config_bridge_info vexpress_sysreg_config_bridge_info = {
  	.name = "vexpress-sysreg",
  	.func_get = vexpress_sysreg_config_func_get,
  	.func_put = vexpress_sysreg_config_func_put,
  	.func_exec = vexpress_sysreg_config_func_exec,
  };
  
  static void vexpress_sysreg_config_complete(unsigned long data)
  {
  	int status = VEXPRESS_CONFIG_STATUS_DONE;
  	u32 cfgstat = readl(vexpress_sysreg_base + SYS_CFGSTAT);
  
  	if (cfgstat & SYS_CFGSTAT_ERR)
  		status = -EINVAL;
  	if (!vexpress_sysreg_config_tries--)
  		status = -ETIMEDOUT;
  
  	if (status < 0) {
  		dev_err(vexpress_sysreg_dev, "error %d
  ", status);
  	} else if (!(cfgstat & SYS_CFGSTAT_COMPLETE)) {
  		mod_timer(&vexpress_sysreg_config_timer,
  				jiffies + usecs_to_jiffies(50));
  		return;
  	}
  
  	if (vexpress_sysreg_config_data) {
  		*vexpress_sysreg_config_data = readl(vexpress_sysreg_base +
  				SYS_CFGDATA);
  		dev_dbg(vexpress_sysreg_dev, "read data %x
  ",
  				*vexpress_sysreg_config_data);
  		vexpress_sysreg_config_data = NULL;
  	}
  
  	vexpress_config_complete(vexpress_sysreg_config_bridge, status);
  }
  
  
  void vexpress_sysreg_setup(struct device_node *node)
  {
  	if (WARN_ON(!vexpress_sysreg_base))
  		return;
  
  	if (readl(vexpress_sysreg_base + SYS_MISC) & SYS_MISC_MASTERSITE)
  		vexpress_master_site = VEXPRESS_SITE_DB2;
  	else
  		vexpress_master_site = VEXPRESS_SITE_DB1;
  
  	vexpress_sysreg_config_bridge = vexpress_config_bridge_register(
  			node, &vexpress_sysreg_config_bridge_info);
  	WARN_ON(!vexpress_sysreg_config_bridge);
  }
  
  void __init vexpress_sysreg_early_init(void __iomem *base)
  {
  	vexpress_sysreg_base = base;
  	vexpress_sysreg_setup(NULL);
  }
  
  void __init vexpress_sysreg_of_early_init(void)
  {
  	struct device_node *node;
  
  	if (vexpress_sysreg_base)
  		return;
  
  	node = of_find_compatible_node(NULL, NULL, "arm,vexpress-sysreg");
  	if (node) {
  		vexpress_sysreg_base = of_iomap(node, 0);
  		vexpress_sysreg_setup(node);
  	}
  }
  
  
  #ifdef CONFIG_GPIOLIB
  
  #define VEXPRESS_SYSREG_GPIO(_name, _reg, _value) \
  	[VEXPRESS_GPIO_##_name] = { \
  		.reg = _reg, \
  		.value = _reg##_##_value, \
  	}
  
  static struct vexpress_sysreg_gpio {
  	unsigned long reg;
  	u32 value;
  } vexpress_sysreg_gpios[] = {
  	VEXPRESS_SYSREG_GPIO(MMC_CARDIN,	SYS_MCI,	CARDIN),
  	VEXPRESS_SYSREG_GPIO(MMC_WPROT,		SYS_MCI,	WPROT),
  	VEXPRESS_SYSREG_GPIO(FLASH_WPn,		SYS_FLASH,	WPn),
  	VEXPRESS_SYSREG_GPIO(LED0,		SYS_LED,	LED(0)),
  	VEXPRESS_SYSREG_GPIO(LED1,		SYS_LED,	LED(1)),
  	VEXPRESS_SYSREG_GPIO(LED2,		SYS_LED,	LED(2)),
  	VEXPRESS_SYSREG_GPIO(LED3,		SYS_LED,	LED(3)),
  	VEXPRESS_SYSREG_GPIO(LED4,		SYS_LED,	LED(4)),
  	VEXPRESS_SYSREG_GPIO(LED5,		SYS_LED,	LED(5)),
  	VEXPRESS_SYSREG_GPIO(LED6,		SYS_LED,	LED(6)),
  	VEXPRESS_SYSREG_GPIO(LED7,		SYS_LED,	LED(7)),
  };
  
  static int vexpress_sysreg_gpio_direction_input(struct gpio_chip *chip,
  				       unsigned offset)
  {
  	return 0;
  }
  
  static int vexpress_sysreg_gpio_get(struct gpio_chip *chip,
  				       unsigned offset)
  {
  	struct vexpress_sysreg_gpio *gpio = &vexpress_sysreg_gpios[offset];
  	u32 reg_value = readl(vexpress_sysreg_base + gpio->reg);
  
  	return !!(reg_value & gpio->value);
  }
  
  static void vexpress_sysreg_gpio_set(struct gpio_chip *chip,
  				       unsigned offset, int value)
  {
  	struct vexpress_sysreg_gpio *gpio = &vexpress_sysreg_gpios[offset];
  	u32 reg_value = readl(vexpress_sysreg_base + gpio->reg);
  
  	if (value)
  		reg_value |= gpio->value;
  	else
  		reg_value &= ~gpio->value;
  
  	writel(reg_value, vexpress_sysreg_base + gpio->reg);
  }
  
  static int vexpress_sysreg_gpio_direction_output(struct gpio_chip *chip,
  						unsigned offset, int value)
  {
  	vexpress_sysreg_gpio_set(chip, offset, value);
  
  	return 0;
  }
  
  static struct gpio_chip vexpress_sysreg_gpio_chip = {
  	.label = "vexpress-sysreg",
  	.direction_input = vexpress_sysreg_gpio_direction_input,
  	.direction_output = vexpress_sysreg_gpio_direction_output,
  	.get = vexpress_sysreg_gpio_get,
  	.set = vexpress_sysreg_gpio_set,
  	.ngpio = ARRAY_SIZE(vexpress_sysreg_gpios),
  	.base = 0,
  };
  
  
  #define VEXPRESS_SYSREG_GREEN_LED(_name, _default_trigger, _gpio) \
  	{ \
  		.name = "v2m:green:"_name, \
  		.default_trigger = _default_trigger, \
  		.gpio = VEXPRESS_GPIO_##_gpio, \
  	}
  
  struct gpio_led vexpress_sysreg_leds[] = {
  	VEXPRESS_SYSREG_GREEN_LED("user1",	"heartbeat",	LED0),
  	VEXPRESS_SYSREG_GREEN_LED("user2",	"mmc0",		LED1),
  	VEXPRESS_SYSREG_GREEN_LED("user3",	"cpu0",		LED2),
  	VEXPRESS_SYSREG_GREEN_LED("user4",	"cpu1",		LED3),
  	VEXPRESS_SYSREG_GREEN_LED("user5",	"cpu2",		LED4),
  	VEXPRESS_SYSREG_GREEN_LED("user6",	"cpu3",		LED5),
  	VEXPRESS_SYSREG_GREEN_LED("user7",	"cpu4",		LED6),
  	VEXPRESS_SYSREG_GREEN_LED("user8",	"cpu5",		LED7),
  };
  
  struct gpio_led_platform_data vexpress_sysreg_leds_pdata = {
  	.num_leds = ARRAY_SIZE(vexpress_sysreg_leds),
  	.leds = vexpress_sysreg_leds,
  };
  
  #endif
  
  
  static ssize_t vexpress_sysreg_sys_id_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	return sprintf(buf, "0x%08x
  ", readl(vexpress_sysreg_base + SYS_ID));
  }
  
  DEVICE_ATTR(sys_id, S_IRUGO, vexpress_sysreg_sys_id_show, NULL);
  
  static int vexpress_sysreg_probe(struct platform_device *pdev)
  {
  	int err;
  	struct resource *res = platform_get_resource(pdev,
  			IORESOURCE_MEM, 0);
  
  	if (!devm_request_mem_region(&pdev->dev, res->start,
  			resource_size(res), pdev->name)) {
  		dev_err(&pdev->dev, "Failed to request memory region!
  ");
  		return -EBUSY;
  	}
  
  	if (!vexpress_sysreg_base) {
  		vexpress_sysreg_base = devm_ioremap(&pdev->dev, res->start,
  				resource_size(res));
  		vexpress_sysreg_setup(pdev->dev.of_node);
  	}
  
  	if (!vexpress_sysreg_base) {
  		dev_err(&pdev->dev, "Failed to obtain base address!
  ");
  		return -EFAULT;
  	}
  
  	setup_timer(&vexpress_sysreg_config_timer,
  			vexpress_sysreg_config_complete, 0);
  
  	vexpress_sysreg_dev = &pdev->dev;
  
  #ifdef CONFIG_GPIOLIB
  	vexpress_sysreg_gpio_chip.dev = &pdev->dev;
  	err = gpiochip_add(&vexpress_sysreg_gpio_chip);
  	if (err) {
  		vexpress_config_bridge_unregister(
  				vexpress_sysreg_config_bridge);
  		dev_err(&pdev->dev, "Failed to register GPIO chip! (%d)
  ",
  				err);
  		return err;
  	}
  
  	platform_device_register_data(vexpress_sysreg_dev, "leds-gpio",
  			PLATFORM_DEVID_AUTO, &vexpress_sysreg_leds_pdata,
  			sizeof(vexpress_sysreg_leds_pdata));
  #endif
  
  	device_create_file(vexpress_sysreg_dev, &dev_attr_sys_id);
  
  	return 0;
  }
  
  static const struct of_device_id vexpress_sysreg_match[] = {
  	{ .compatible = "arm,vexpress-sysreg", },
  	{},
  };
  
  static struct platform_driver vexpress_sysreg_driver = {
  	.driver = {
  		.name = "vexpress-sysreg",
  		.of_match_table = vexpress_sysreg_match,
  	},
  	.probe = vexpress_sysreg_probe,
  };
  
  static int __init vexpress_sysreg_init(void)
  {
  	vexpress_sysreg_of_early_init();
  	return platform_driver_register(&vexpress_sysreg_driver);
  }
  core_initcall(vexpress_sysreg_init);