/*
 * omap_device implementation
 *
 * Copyright (C) 2009-2010 Nokia Corporation
 * Paul Walmsley, Kevin Hilman
 *
 * Developed in collaboration with (alphabetical order): Benoit
 * Cousson, Thara Gopinath, Tony Lindgren, Rajendra Nayak, Vikram
 * Pandita, Sakari Poussa, Anand Sawant, Santosh Shilimkar, Richard
 * Woodruff
 *
 * 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 code provides a consistent interface for OMAP device drivers
 * to control power management and interconnect properties of their
 * devices.
 *
 * In the medium- to long-term, this code should either be
 * a) implemented via arch-specific pointers in platform_data
 * or
 * b) implemented as a proper omap_bus/omap_device in Linux, no more
 *    platform_data func pointers
 *
 *
 * Guidelines for usage by driver authors:
 *
 * 1. These functions are intended to be used by device drivers via
 * function pointers in struct platform_data.  As an example,
 * omap_device_enable() should be passed to the driver as
 *
 * struct foo_driver_platform_data {
 * ...
 *      int (*device_enable)(struct platform_device *pdev);
 * ...
 * }
 *
 * Note that the generic "device_enable" name is used, rather than
 * "omap_device_enable".  This is so other architectures can pass in their
 * own enable/disable functions here.
 *
 * This should be populated during device setup:
 *
 * ...
 * pdata->device_enable = omap_device_enable;
 * ...
 *
 * 2. Drivers should first check to ensure the function pointer is not null
 * before calling it, as in:
 *
 * if (pdata->device_enable)
 *     pdata->device_enable(pdev);
 *
 * This allows other architectures that don't use similar device_enable()/
 * device_shutdown() functions to execute normally.
 *
 * ...
 *
 * Suggested usage by device drivers:
 *
 * During device initialization:
 * device_enable()
 *
 * During device idle:
 * (save remaining device context if necessary)
 * device_idle();
 *
 * During device resume:
 * device_enable();
 * (restore context if necessary)
 *
 * During device shutdown:
 * device_shutdown()
 * (device must be reinitialized at this point to use it again)
 *
 */
#undef DEBUG

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/notifier.h>

#include "omap_device.h"
#include "omap_hwmod.h"

/* These parameters are passed to _omap_device_{de,}activate() */
#define USE_WAKEUP_LAT			0
#define IGNORE_WAKEUP_LAT		1

static int omap_early_device_register(struct platform_device *pdev);

static struct omap_device_pm_latency omap_default_latency[] = {
	{
		.deactivate_func = omap_device_idle_hwmods,
		.activate_func   = omap_device_enable_hwmods,
		.flags = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
	}
};

/* Private functions */

/**
 * _omap_device_activate - increase device readiness
 * @od: struct omap_device *
 * @ignore_lat: increase to latency target (0) or full readiness (1)?
 *
 * Increase readiness of omap_device @od (thus decreasing device
 * wakeup latency, but consuming more power).  If @ignore_lat is
 * IGNORE_WAKEUP_LAT, make the omap_device fully active.  Otherwise,
 * if @ignore_lat is USE_WAKEUP_LAT, and the device's maximum wakeup
 * latency is greater than the requested maximum wakeup latency, step
 * backwards in the omap_device_pm_latency table to ensure the
 * device's maximum wakeup latency is less than or equal to the
 * requested maximum wakeup latency.  Returns 0.
 */
static int _omap_device_activate(struct omap_device *od, u8 ignore_lat)
{
	struct timespec a, b, c;

	dev_dbg(&od->pdev->dev, "omap_device: activating\n");

	while (od->pm_lat_level > 0) {
		struct omap_device_pm_latency *odpl;
		unsigned long long act_lat = 0;

		od->pm_lat_level--;

		odpl = od->pm_lats + od->pm_lat_level;

		if (!ignore_lat &&
		    (od->dev_wakeup_lat <= od->_dev_wakeup_lat_limit))
			break;

		read_persistent_clock(&a);

		/* XXX check return code */
		odpl->activate_func(od);

		read_persistent_clock(&b);

		c = timespec_sub(b, a);
		act_lat = timespec_to_ns(&c);

		dev_dbg(&od->pdev->dev,
			"omap_device: pm_lat %d: activate: elapsed time %llu nsec\n",
			od->pm_lat_level, act_lat);

		if (act_lat > odpl->activate_lat) {
			odpl->activate_lat_worst = act_lat;
			if (odpl->flags & OMAP_DEVICE_LATENCY_AUTO_ADJUST) {
				odpl->activate_lat = act_lat;
				dev_dbg(&od->pdev->dev,
					"new worst case activate latency %d: %llu\n",
					od->pm_lat_level, act_lat);
			} else
				dev_warn(&od->pdev->dev,
					 "activate latency %d higher than expected. (%llu > %d)\n",
					 od->pm_lat_level, act_lat,
					 odpl->activate_lat);
		}

		od->dev_wakeup_lat -= odpl->activate_lat;
	}

	return 0;
}

/**
 * _omap_device_deactivate - decrease device readiness
 * @od: struct omap_device *
 * @ignore_lat: decrease to latency target (0) or full inactivity (1)?
 *
 * Decrease readiness of omap_device @od (thus increasing device
 * wakeup latency, but conserving power).  If @ignore_lat is
 * IGNORE_WAKEUP_LAT, make the omap_device fully inactive.  Otherwise,
 * if @ignore_lat is USE_WAKEUP_LAT, and the device's maximum wakeup
 * latency is less than the requested maximum wakeup latency, step
 * forwards in the omap_device_pm_latency table to ensure the device's
 * maximum wakeup latency is less than or equal to the requested
 * maximum wakeup latency.  Returns 0.
 */
static int _omap_device_deactivate(struct omap_device *od, u8 ignore_lat)
{
	struct timespec a, b, c;

	dev_dbg(&od->pdev->dev, "omap_device: deactivating\n");

	while (od->pm_lat_level < od->pm_lats_cnt) {
		struct omap_device_pm_latency *odpl;
		unsigned long long deact_lat = 0;

		odpl = od->pm_lats + od->pm_lat_level;

		if (!ignore_lat &&
		    ((od->dev_wakeup_lat + odpl->activate_lat) >
		     od->_dev_wakeup_lat_limit))
			break;

		read_persistent_clock(&a);

		/* XXX check return code */
		odpl->deactivate_func(od);

		read_persistent_clock(&b);

		c = timespec_sub(b, a);
		deact_lat = timespec_to_ns(&c);

		dev_dbg(&od->pdev->dev,
			"omap_device: pm_lat %d: deactivate: elapsed time %llu nsec\n",
			od->pm_lat_level, deact_lat);

		if (deact_lat > odpl->deactivate_lat) {
			odpl->deactivate_lat_worst = deact_lat;
			if (odpl->flags & OMAP_DEVICE_LATENCY_AUTO_ADJUST) {
				odpl->deactivate_lat = deact_lat;
				dev_dbg(&od->pdev->dev,
					"new worst case deactivate latency %d: %llu\n",
					od->pm_lat_level, deact_lat);
			} else
				dev_warn(&od->pdev->dev,
					 "deactivate latency %d higher than expected. (%llu > %d)\n",
					 od->pm_lat_level, deact_lat,
					 odpl->deactivate_lat);
		}

		od->dev_wakeup_lat += odpl->activate_lat;

		od->pm_lat_level++;
	}

	return 0;
}

static void _add_clkdev(struct omap_device *od, const char *clk_alias,
		       const char *clk_name)
{
	struct clk *r;
	struct clk_lookup *l;

	if (!clk_alias || !clk_name)
		return;

	dev_dbg(&od->pdev->dev, "Creating %s -> %s\n", clk_alias, clk_name);

	r = clk_get_sys(dev_name(&od->pdev->dev), clk_alias);
	if (!IS_ERR(r)) {
		dev_warn(&od->pdev->dev,
			 "alias %s already exists\n", clk_alias);
		clk_put(r);
		return;
	}

	r = clk_get(NULL, clk_name);
	if (IS_ERR(r)) {
		dev_err(&od->pdev->dev,
			"clk_get for %s failed\n", clk_name);
		return;
	}

	l = clkdev_alloc(r, clk_alias, dev_name(&od->pdev->dev));
	if (!l) {
		dev_err(&od->pdev->dev,
			"clkdev_alloc for %s failed\n", clk_alias);
		return;
	}

	clkdev_add(l);
}

/**
 * _add_hwmod_clocks_clkdev - Add clkdev entry for hwmod optional clocks
 * and main clock
 * @od: struct omap_device *od
 * @oh: struct omap_hwmod *oh
 *
 * For the main clock and every optional clock present per hwmod per
 * omap_device, this function adds an entry in the clkdev table of the
 * form <dev-id=dev_name, con-id=role> if it does not exist already.
 *
 * The function is called from inside omap_device_build_ss(), after
 * omap_device_register.
 *
 * This allows drivers to get a pointer to its optional clocks based on its role
 * by calling clk_get(<dev*>, <role>).
 * In the case of the main clock, a "fck" alias is used.
 *
 * No return value.
 */
static void _add_hwmod_clocks_clkdev(struct omap_device *od,
				     struct omap_hwmod *oh)
{
	int i;

	_add_clkdev(od, "fck", oh->main_clk);

	for (i = 0; i < oh->opt_clks_cnt; i++)
		_add_clkdev(od, oh->opt_clks[i].role, oh->opt_clks[i].clk);
}


/**
 * omap_device_build_from_dt - build an omap_device with multiple hwmods
 * @pdev_name: name of the platform_device driver to use
 * @pdev_id: this platform_device's connection ID
 * @oh: ptr to the single omap_hwmod that backs this omap_device
 * @pdata: platform_data ptr to associate with the platform_device
 * @pdata_len: amount of memory pointed to by @pdata
 * @pm_lats: pointer to a omap_device_pm_latency array for this device
 * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
 * @is_early_device: should the device be registered as an early device or not
 *
 * Function for building an omap_device already registered from device-tree
 *
 * Returns 0 or PTR_ERR() on error.
 */
static int omap_device_build_from_dt(struct platform_device *pdev)
{
	struct omap_hwmod **hwmods;
	struct omap_device *od;
	struct omap_hwmod *oh;
	struct device_node *node = pdev->dev.of_node;
	const char *oh_name;
	int oh_cnt, i, ret = 0;

	oh_cnt = of_property_count_strings(node, "ti,hwmods");
	if (!oh_cnt || IS_ERR_VALUE(oh_cnt)) {
		dev_dbg(&pdev->dev, "No 'hwmods' to build omap_device\n");
		return -ENODEV;
	}

	hwmods = kzalloc(sizeof(struct omap_hwmod *) * oh_cnt, GFP_KERNEL);
	if (!hwmods) {
		ret = -ENOMEM;
		goto odbfd_exit;
	}

	for (i = 0; i < oh_cnt; i++) {
		of_property_read_string_index(node, "ti,hwmods", i, &oh_name);
		oh = omap_hwmod_lookup(oh_name);
		if (!oh) {
			dev_err(&pdev->dev, "Cannot lookup hwmod '%s'\n",
				oh_name);
			ret = -EINVAL;
			goto odbfd_exit1;
		}
		hwmods[i] = oh;
	}

	od = omap_device_alloc(pdev, hwmods, oh_cnt, NULL, 0);
	if (!od) {
		dev_err(&pdev->dev, "Cannot allocate omap_device for :%s\n",
			oh_name);
		ret = PTR_ERR(od);
		goto odbfd_exit1;
	}

	/* Fix up missing resource names */
	for (i = 0; i < pdev->num_resources; i++) {
		struct resource *r = &pdev->resource[i];

		if (r->name == NULL)
			r->name = dev_name(&pdev->dev);
	}

	if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
		omap_device_disable_idle_on_suspend(pdev);

	pdev->dev.pm_domain = &omap_device_pm_domain;

odbfd_exit1:
	kfree(hwmods);
odbfd_exit:
	return ret;
}

static int _omap_device_notifier_call(struct notifier_block *nb,
				      unsigned long event, void *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct omap_device *od;

	switch (event) {
	case BUS_NOTIFY_DEL_DEVICE:
		if (pdev->archdata.od)
			omap_device_delete(pdev->archdata.od);
		break;
	case BUS_NOTIFY_ADD_DEVICE:
		if (pdev->dev.of_node)
			omap_device_build_from_dt(pdev);
		/* fall through */
	default:
		od = to_omap_device(pdev);
		if (od)
			od->_driver_status = event;
	}

	return NOTIFY_DONE;
}


/* Public functions for use by core code */

/**
 * omap_device_get_context_loss_count - get lost context count
 * @od: struct omap_device *
 *
 * Using the primary hwmod, query the context loss count for this
 * device.
 *
 * Callers should consider context for this device lost any time this
 * function returns a value different than the value the caller got
 * the last time it called this function.
 *
 * If any hwmods exist for the omap_device assoiated with @pdev,
 * return the context loss counter for that hwmod, otherwise return
 * zero.
 */
int omap_device_get_context_loss_count(struct platform_device *pdev)
{
	struct omap_device *od;
	u32 ret = 0;

	od = to_omap_device(pdev);

	if (od->hwmods_cnt)
		ret = omap_hwmod_get_context_loss_count(od->hwmods[0]);

	return ret;
}

/**
 * omap_device_count_resources - count number of struct resource entries needed
 * @od: struct omap_device *
 * @flags: Type of resources to include when counting (IRQ/DMA/MEM)
 *
 * Count the number of struct resource entries needed for this
 * omap_device @od.  Used by omap_device_build_ss() to determine how
 * much memory to allocate before calling
 * omap_device_fill_resources().  Returns the count.
 */
static int omap_device_count_resources(struct omap_device *od,
				       unsigned long flags)
{
	int c = 0;
	int i;

	for (i = 0; i < od->hwmods_cnt; i++)
		c += omap_hwmod_count_resources(od->hwmods[i], flags);

	pr_debug("omap_device: %s: counted %d total resources across %d hwmods\n",
		 od->pdev->name, c, od->hwmods_cnt);

	return c;
}

/**
 * omap_device_fill_resources - fill in array of struct resource
 * @od: struct omap_device *
 * @res: pointer to an array of struct resource to be filled in
 *
 * Populate one or more empty struct resource pointed to by @res with
 * the resource data for this omap_device @od.  Used by
 * omap_device_build_ss() after calling omap_device_count_resources().
 * Ideally this function would not be needed at all.  If omap_device
 * replaces platform_device, then we can specify our own
 * get_resource()/ get_irq()/etc functions that use the underlying
 * omap_hwmod information.  Or if platform_device is extended to use
 * subarchitecture-specific function pointers, the various
 * platform_device functions can simply call omap_device internal
 * functions to get device resources.  Hacking around the existing
 * platform_device code wastes memory.  Returns 0.
 */
static int omap_device_fill_resources(struct omap_device *od,
				      struct resource *res)
{
	int i, r;

	for (i = 0; i < od->hwmods_cnt; i++) {
		r = omap_hwmod_fill_resources(od->hwmods[i], res);
		res += r;
	}

	return 0;
}

/**
 * _od_fill_dma_resources - fill in array of struct resource with dma resources
 * @od: struct omap_device *
 * @res: pointer to an array of struct resource to be filled in
 *
 * Populate one or more empty struct resource pointed to by @res with
 * the dma resource data for this omap_device @od.  Used by
 * omap_device_alloc() after calling omap_device_count_resources().
 *
 * Ideally this function would not be needed at all.  If we have
 * mechanism to get dma resources from DT.
 *
 * Returns 0.
 */
static int _od_fill_dma_resources(struct omap_device *od,
				      struct resource *res)
{
	int i, r;

	for (i = 0; i < od->hwmods_cnt; i++) {
		r = omap_hwmod_fill_dma_resources(od->hwmods[i], res);
		res += r;
	}

	return 0;
}

/**
 * omap_device_alloc - allocate an omap_device
 * @pdev: platform_device that will be included in this omap_device
 * @oh: ptr to the single omap_hwmod that backs this omap_device
 * @pdata: platform_data ptr to associate with the platform_device
 * @pdata_len: amount of memory pointed to by @pdata
 * @pm_lats: pointer to a omap_device_pm_latency array for this device
 * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
 *
 * Convenience function for allocating an omap_device structure and filling
 * hwmods, resources and pm_latency attributes.
 *
 * Returns an struct omap_device pointer or ERR_PTR() on error;
 */
struct omap_device *omap_device_alloc(struct platform_device *pdev,
					struct omap_hwmod **ohs, int oh_cnt,
					struct omap_device_pm_latency *pm_lats,
					int pm_lats_cnt)
{
	int ret = -ENOMEM;
	struct omap_device *od;
	struct resource *res = NULL;
	int i, res_count;
	struct omap_hwmod **hwmods;

	od = kzalloc(sizeof(struct omap_device), GFP_KERNEL);
	if (!od) {
		ret = -ENOMEM;
		goto oda_exit1;
	}
	od->hwmods_cnt = oh_cnt;

	hwmods = kmemdup(ohs, sizeof(struct omap_hwmod *) * oh_cnt, GFP_KERNEL);
	if (!hwmods)
		goto oda_exit2;

	od->hwmods = hwmods;
	od->pdev = pdev;

	/*
	 * Non-DT Boot:
	 *   Here, pdev->num_resources = 0, and we should get all the
	 *   resources from hwmod.
	 *
	 * DT Boot:
	 *   OF framework will construct the resource structure (currently
	 *   does for MEM & IRQ resource) and we should respect/use these
	 *   resources, killing hwmod dependency.
	 *   If pdev->num_resources > 0, we assume that MEM & IRQ resources
	 *   have been allocated by OF layer already (through DTB).
	 *   As preparation for the future we examine the OF provided resources
	 *   to see if we have DMA resources provided already. In this case
	 *   there is no need to update the resources for the device, we use the
	 *   OF provided ones.
	 *
	 * TODO: Once DMA resource is available from OF layer, we should
	 *   kill filling any resources from hwmod.
	 */
	if (!pdev->num_resources) {
		/* Count all resources for the device */
		res_count = omap_device_count_resources(od, IORESOURCE_IRQ |
							    IORESOURCE_DMA |
							    IORESOURCE_MEM);
	} else {
		/* Take a look if we already have DMA resource via DT */
		for (i = 0; i < pdev->num_resources; i++) {
			struct resource *r = &pdev->resource[i];

			/* We have it, no need to touch the resources */
			if (r->flags == IORESOURCE_DMA)
				goto have_everything;
		}
		/* Count only DMA resources for the device */
		res_count = omap_device_count_resources(od, IORESOURCE_DMA);
		/* The device has no DMA resource, no need for update */
		if (!res_count)
			goto have_everything;

		res_count += pdev->num_resources;
	}

	/* Allocate resources memory to account for new resources */
	res = kzalloc(sizeof(struct resource) * res_count, GFP_KERNEL);
	if (!res)
		goto oda_exit3;

	if (!pdev->num_resources) {
		dev_dbg(&pdev->dev, "%s: using %d resources from hwmod\n",
			__func__, res_count);
