drivers/core/acpi.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Core driver model support for ACPI table generation
 *
 * Copyright 2019 Google LLC
 * Written by Simon Glass <sjg@chromium.org>
 */

#define LOG_CATEOGRY	LOGC_ACPI

#include <common.h>
#include <malloc.h>
#include <dm.h>
#include <log.h>
#include <dm/acpi.h>
#include <dm/device-internal.h>
#include <dm/root.h>

#define MAX_ACPI_ITEMS	100

/* Type of table that we collected */
enum gen_type_t {
	TYPE_NONE,
	TYPE_SSDT,
};

/* Type of method to call */
enum method_t {
	METHOD_WRITE_TABLES,
	METHOD_FILL_SSDT,
};

/* Prototype for all methods */
typedef int (*acpi_method)(const struct udevice *dev, struct acpi_ctx *ctx);

/**
 * struct acpi_item - Holds info about ACPI data generated by a driver method
 *
 * @dev: Device that generated this data
 * @type: Table type it refers to
 * @buf: Buffer containing the data
 * @size: Size of the data in bytes
 */
struct acpi_item {
	struct udevice *dev;
	enum gen_type_t type;
	char *buf;
	int size;
};

/* List of ACPI items collected */
static struct acpi_item acpi_item[MAX_ACPI_ITEMS];
static int item_count;

int acpi_copy_name(char *out_name, const char *name)
{
	strncpy(out_name, name, ACPI_NAME_LEN);
	out_name[ACPI_NAME_LEN] = '\0';

	return 0;
}

int acpi_get_name(const struct udevice *dev, char *out_name)
{
	struct acpi_ops *aops;

	aops = device_get_acpi_ops(dev);
	if (aops && aops->get_name)
		return aops->get_name(dev, out_name);

	return -ENOSYS;
}

/**
 * acpi_add_item() - Add a new item to the list of data collected
 *
 * @ctx: ACPI context
 * @dev: Device that generated the data
 * @type: Table type it refers to
 * @start: The start of the data (the end is obtained from ctx->current)
 * @return 0 if OK, -ENOSPC if too many items, -ENOMEM if out of memory
 */
static int acpi_add_item(struct acpi_ctx *ctx, struct udevice *dev,
			 enum gen_type_t type, void *start)
{
	struct acpi_item *item;
	void *end = ctx->current;

	if (item_count == MAX_ACPI_ITEMS) {
		log_err("Too many items\n");
		return log_msg_ret("mem", -ENOSPC);
	}

	item = &acpi_item[item_count];
	item->dev = dev;
	item->type = type;
	item->size = end - start;
	if (!item->size)
		return 0;
	item->buf = malloc(item->size);
	if (!item->buf)
		return log_msg_ret("mem", -ENOMEM);
	memcpy(item->buf, start, item->size);
	item_count++;
	log_debug("* %s: Added type %d, %p, size %x\n", dev->name, type, start,
		  item->size);

	return 0;
}

static struct acpi_item *find_acpi_item(const char *devname)
{
	int i;

	for (i = 0; i < item_count; i++) {
		struct acpi_item *item = &acpi_item[i];

		if (!strcmp(devname, item->dev->name))
			return item;
	}

	return NULL;
}

/**
 * sort_acpi_item_type - Sort the ACPI items into the desired order
 *
 * This looks up the ordering in the device tree and then adds each item one by
 * one into the supplied buffer
 *
 * @ctx: ACPI context
 * @start: Start position to put the sorted items. The items will follow each
 *	other in sorted order
 * @type: Type of items to sort
 * @return 0 if OK, -ve on error
 */
static int sort_acpi_item_type(struct acpi_ctx *ctx, void *start,
			       enum gen_type_t type)
{
	const u32 *order;
	int size;
	int count;
	void *ptr;
	void *end = ctx->current;

	ptr = start;
	order = ofnode_read_chosen_prop("u-boot,acpi-ssdt-order", &size);
	if (!order) {
		log_warning("Failed to find ordering, leaving as is\n");
		return 0;
	}

	/*
	 * This algorithm rewrites the context buffer without changing its
	 * length. So there is no need to update ctx-current
	 */
	count = size / sizeof(u32);
	while (count--) {
		struct acpi_item *item;
		const char *name;
		ofnode node;

		node = ofnode_get_by_phandle(fdt32_to_cpu(*order++));
		name = ofnode_get_name(node);
		item = find_acpi_item(name);
		if (!item) {
			log_err("Failed to find item '%s'\n", name);
			return log_msg_ret("find", -ENOENT);
		}
		if (item->type == type) {
			log_debug("   - add %s\n", item->dev->name);
			memcpy(ptr, item->buf, item->size);
			ptr += item->size;
		}
	}

	/*
	 * If the sort order is missing an item then the output will be too
	 * small. Report this error since the item needs to be added to the
	 * ordering for the ACPI tables to be complete.
	 */
	if (ptr != end) {
		log_warning("*** Missing bytes: ptr=%p, end=%p\n", ptr, end);
		return -ENXIO;
	}

	return 0;
}

acpi_method acpi_get_method(struct udevice *dev, enum method_t method)
{
	struct acpi_ops *aops;

	aops = device_get_acpi_ops(dev);
	if (aops) {
		switch (method) {
		case METHOD_WRITE_TABLES:
			return aops->write_tables;
		case METHOD_FILL_SSDT:
			return aops->fill_ssdt;
		}
	}

	return NULL;
}

int acpi_recurse_method(struct acpi_ctx *ctx, struct udevice *parent,
			enum method_t method, enum gen_type_t type)
{
	struct udevice *dev;
	acpi_method func;
	int ret;

	func = acpi_get_method(parent, method);
	if (func) {
		void *start = ctx->current;

		log_debug("\n");
		log_debug("- %s %p\n", parent->name, func);
		ret = device_ofdata_to_platdata(parent);
		if (ret)
			return log_msg_ret("ofdata", ret);
		ret = func(parent, ctx);
		if (ret)
			return log_msg_ret("func", ret);

		/* Add the item to the internal list */
		if (type != TYPE_NONE) {
			ret = acpi_add_item(ctx, parent, type, start);
			if (ret)
				return log_msg_ret("add", ret);
		}
	}
	device_foreach_child(dev, parent) {
		ret = acpi_recurse_method(ctx, dev, method, type);
		if (ret)
			return log_msg_ret("recurse", ret);
	}

	return 0;
}

int acpi_fill_ssdt(struct acpi_ctx *ctx)
{
	void *start = ctx->current;
	int ret;

	log_debug("Writing SSDT tables\n");
	item_count = 0;
	ret = acpi_recurse_method(ctx, dm_root(), METHOD_FILL_SSDT, TYPE_SSDT);
	log_debug("Writing SSDT finished, err=%d\n", ret);
	ret = sort_acpi_item_type(ctx, start, TYPE_SSDT);
	if (ret)
		return log_msg_ret("build", ret);

	return ret;
}

int acpi_write_dev_tables(struct acpi_ctx *ctx)
{
	int ret;

	log_debug("Writing device tables\n");
	ret = acpi_recurse_method(ctx, dm_root(), METHOD_WRITE_TABLES,
				  TYPE_NONE);
	log_debug("Writing finished, err=%d\n", ret);

	return ret;
}