1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Copyright (c) 2021 IBM Corp. */
  3
  4#include <linux/delay.h>
  5#include <linux/device.h>
  6#include <linux/errno.h>
  7#include <linux/list.h>
  8#include <linux/module.h>
  9#include <linux/sched/signal.h>
 10#include <linux/serio.h>
 11#include <linux/slab.h>
 12
 13#include "kcs_bmc_client.h"
 14
 15struct kcs_bmc_serio {
 16	struct list_head entry;
 17
 18	struct kcs_bmc_client client;
 19	struct serio *port;
 20
 21	spinlock_t lock;
 22};
 23
 24static inline struct kcs_bmc_serio *client_to_kcs_bmc_serio(struct kcs_bmc_client *client)
 25{
 26	return container_of(client, struct kcs_bmc_serio, client);
 27}
 28
 29static irqreturn_t kcs_bmc_serio_event(struct kcs_bmc_client *client)
 30{
 31	struct kcs_bmc_serio *priv;
 32	u8 handled = IRQ_NONE;
 33	u8 status;
 34
 35	priv = client_to_kcs_bmc_serio(client);
 36
 37	spin_lock(&priv->lock);
 38
 39	status = kcs_bmc_read_status(client->dev);
 40
 41	if (status & KCS_BMC_STR_IBF)
 42		handled = serio_interrupt(priv->port, kcs_bmc_read_data(client->dev), 0);
 43
 44	spin_unlock(&priv->lock);
 45
 46	return handled;
 47}
 48
 49static const struct kcs_bmc_client_ops kcs_bmc_serio_client_ops = {
 50	.event = kcs_bmc_serio_event,
 51};
 52
 53static int kcs_bmc_serio_open(struct serio *port)
 54{
 55	struct kcs_bmc_serio *priv = port->port_data;
 56
 57	return kcs_bmc_enable_device(priv->client.dev, &priv->client);
 58}
 59
 60static void kcs_bmc_serio_close(struct serio *port)
 61{
 62	struct kcs_bmc_serio *priv = port->port_data;
 63
 64	kcs_bmc_disable_device(priv->client.dev, &priv->client);
 65}
 66
 67static DEFINE_SPINLOCK(kcs_bmc_serio_instances_lock);
 68static LIST_HEAD(kcs_bmc_serio_instances);
 69
 70static int kcs_bmc_serio_add_device(struct kcs_bmc_device *kcs_bmc)
 71{
 72	struct kcs_bmc_serio *priv;
 73	struct serio *port;
 74
 75	priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL);
 76	if (!priv)
 77		return -ENOMEM;
 78
 79	/* Use kzalloc() as the allocation is cleaned up with kfree() via serio_unregister_port() */
 80	port = kzalloc(sizeof(*port), GFP_KERNEL);
 81	if (!port)
 82		return -ENOMEM;
 83
 84	port->id.type = SERIO_8042;
 85	port->open = kcs_bmc_serio_open;
 86	port->close = kcs_bmc_serio_close;
 87	port->port_data = priv;
 88	port->dev.parent = kcs_bmc->dev;
 89
 90	spin_lock_init(&priv->lock);
 91	priv->port = port;
 92	priv->client.dev = kcs_bmc;
 93	priv->client.ops = &kcs_bmc_serio_client_ops;
 94
 95	spin_lock_irq(&kcs_bmc_serio_instances_lock);
 96	list_add(&priv->entry, &kcs_bmc_serio_instances);
 97	spin_unlock_irq(&kcs_bmc_serio_instances_lock);
 98
 99	serio_register_port(port);
100
101	dev_info(kcs_bmc->dev, "Initialised serio client for channel %d", kcs_bmc->channel);
102
103	return 0;
104}
105
106static int kcs_bmc_serio_remove_device(struct kcs_bmc_device *kcs_bmc)
107{
108	struct kcs_bmc_serio *priv = NULL, *pos;
109
110	spin_lock_irq(&kcs_bmc_serio_instances_lock);
111	list_for_each_entry(pos, &kcs_bmc_serio_instances, entry) {
112		if (pos->client.dev == kcs_bmc) {
113			priv = pos;
114			list_del(&pos->entry);
115			break;
116		}
117	}
118	spin_unlock_irq(&kcs_bmc_serio_instances_lock);
119
120	if (!priv)
121		return -ENODEV;
122
123	/* kfree()s priv->port via put_device() */
124	serio_unregister_port(priv->port);
125
126	/* Ensure the IBF IRQ is disabled if we were the active client */
127	kcs_bmc_disable_device(kcs_bmc, &priv->client);
128
129	devm_kfree(priv->client.dev->dev, priv);
130
131	return 0;
132}
133
134static const struct kcs_bmc_driver_ops kcs_bmc_serio_driver_ops = {
135	.add_device = kcs_bmc_serio_add_device,
136	.remove_device = kcs_bmc_serio_remove_device,
137};
138
139static struct kcs_bmc_driver kcs_bmc_serio_driver = {
140	.ops = &kcs_bmc_serio_driver_ops,
141};
142
143static int __init kcs_bmc_serio_init(void)
144{
145	kcs_bmc_register_driver(&kcs_bmc_serio_driver);
146
147	return 0;
148}
149module_init(kcs_bmc_serio_init);
150
151static void __exit kcs_bmc_serio_exit(void)
152{
153	kcs_bmc_unregister_driver(&kcs_bmc_serio_driver);
154}
155module_exit(kcs_bmc_serio_exit);
156
157MODULE_LICENSE("GPL v2");
158MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
159MODULE_DESCRIPTION("Adapter driver for serio access to BMC KCS devices");