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(lock: &priv->lock);
38
39 status = kcs_bmc_read_status(kcs_bmc: client->dev);
40
41 if (status & KCS_BMC_STR_IBF)
42 handled = serio_interrupt(serio: priv->port, data: kcs_bmc_read_data(kcs_bmc: client->dev), flags: 0);
43
44 spin_unlock(lock: &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(kcs_bmc: priv->client.dev, client: &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(kcs_bmc: priv->client.dev, client: &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(dev: kcs_bmc->dev, size: 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(lock: &kcs_bmc_serio_instances_lock);
96 list_add(new: &priv->entry, head: &kcs_bmc_serio_instances);
97 spin_unlock_irq(lock: &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(lock: &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(entry: &pos->entry);
115 break;
116 }
117 }
118 spin_unlock_irq(lock: &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(serio: priv->port);
125
126 /* Ensure the IBF IRQ is disabled if we were the active client */
127 kcs_bmc_disable_device(kcs_bmc, client: &priv->client);
128
129 devm_kfree(dev: priv->client.dev->dev, p: 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(drv: &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(drv: &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");
160

source code of linux/drivers/char/ipmi/kcs_bmc_serio.c