drivers/staging/greybus/hd.c

/*
 * Greybus Host Device
 *
 * Copyright 2014-2015 Google Inc.
 * Copyright 2014-2015 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>

#include "greybus.h"


static struct ida gb_hd_bus_id_map;

static void gb_hd_release(struct device *dev)
{
	struct gb_host_device *hd = to_gb_host_device(dev);

	ida_simple_remove(&gb_hd_bus_id_map, hd->bus_id);
	ida_destroy(&hd->cport_id_map);
	kfree(hd);
}

struct device_type greybus_hd_type = {
	.name		= "greybus_host_device",
	.release	= gb_hd_release,
};

struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,
					struct device *parent,
					size_t buffer_size_max,
					size_t num_cports)
{
	struct gb_host_device *hd;
	int ret;

	/*
	 * Validate that the driver implements all of the callbacks
	 * so that we don't have to every time we make them.
	 */
	if ((!driver->message_send) || (!driver->message_cancel)) {
		pr_err("Must implement all gb_hd_driver callbacks!\n");
		return ERR_PTR(-EINVAL);
	}

	if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
		dev_err(parent, "greybus host-device buffers too small\n");
		return ERR_PTR(-EINVAL);
	}

	if (num_cports == 0 || num_cports > CPORT_ID_MAX + 1) {
		dev_err(parent, "Invalid number of CPorts: %zu\n", num_cports);
		return ERR_PTR(-EINVAL);
	}

	/*
	 * Make sure to never allocate messages larger than what the Greybus
	 * protocol supports.
	 */
	if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
		dev_warn(parent, "limiting buffer size to %u\n",
			 GB_OPERATION_MESSAGE_SIZE_MAX);
		buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
	}

	hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
	if (!hd)
		return ERR_PTR(-ENOMEM);

	hd->dev.parent = parent;
	hd->dev.bus = &greybus_bus_type;
	hd->dev.type = &greybus_hd_type;
	hd->dev.dma_mask = hd->dev.parent->dma_mask;
	device_initialize(&hd->dev);

	ret = ida_simple_get(&gb_hd_bus_id_map, 1, 0, GFP_KERNEL);
	if (ret < 0) {
		kfree(hd);
		return ERR_PTR(ret);
	}

	hd->bus_id = ret;
	dev_set_name(&hd->dev, "greybus%d", hd->bus_id);

	hd->driver = driver;
	INIT_LIST_HEAD(&hd->interfaces);
	INIT_LIST_HEAD(&hd->connections);
	ida_init(&hd->cport_id_map);
	hd->buffer_size_max = buffer_size_max;
	hd->num_cports = num_cports;

	return hd;
}
EXPORT_SYMBOL_GPL(gb_hd_create);

int gb_hd_add(struct gb_host_device *hd)
{
	int ret;

	ret = device_add(&hd->dev);
	if (ret)
		return ret;

	/*
	 * Initialize AP's SVC protocol connection:
	 *
	 * This is required as part of early initialization of the host device
	 * as we need this connection in order to start any kind of message
	 * exchange between the AP and the SVC. SVC will start with a
	 * 'get-version' request followed by a 'svc-hello' message and at that
	 * time we will create a fully initialized svc-connection, as we need
	 * endo-id and AP's interface id for that.
	 */
	if (!gb_ap_svc_connection_create(hd)) {
		device_del(&hd->dev);
		return -ENOMEM;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(gb_hd_add);

void gb_hd_del(struct gb_host_device *hd)
{
	/*
	 * Tear down all interfaces, modules, and the endo that is associated
	 * with this host controller before freeing the memory associated with
	 * the host controller.
	 */
	gb_interfaces_remove(hd);
	gb_endo_remove(hd->endo);

	/* Is the SVC still using the partially uninitialized connection ? */
	if (hd->initial_svc_connection)
		gb_connection_destroy(hd->initial_svc_connection);

	device_del(&hd->dev);
}
EXPORT_SYMBOL_GPL(gb_hd_del);

void gb_hd_put(struct gb_host_device *hd)
{
	put_device(&hd->dev);
}
EXPORT_SYMBOL_GPL(gb_hd_put);

int __init gb_hd_init(void)
{
	ida_init(&gb_hd_bus_id_map);

	return 0;
}

void gb_hd_exit(void)
{
	ida_destroy(&gb_hd_bus_id_map);
}