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kcs_bmc_serio acts as a bridge between the KCS drivers in the IPMI subsystem and the existing userspace interfaces available through the serio subsystem. This is useful when userspace would like to make use of the BMC KCS devices for purposes that aren't IPMI. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Message-Id: <20210608104757.582199-12-andrew@aj.id.au> Reviewed-by: Zev Weiss <zweiss@equinix.com> Signed-off-by: Corey Minyard <cminyard@mvista.com>
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// SPDX-License-Identifier: GPL-2.0-or-later | ||
/* Copyright (c) 2021 IBM Corp. */ | ||
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#include <linux/delay.h> | ||
#include <linux/device.h> | ||
#include <linux/errno.h> | ||
#include <linux/list.h> | ||
#include <linux/module.h> | ||
#include <linux/sched/signal.h> | ||
#include <linux/serio.h> | ||
#include <linux/slab.h> | ||
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#include "kcs_bmc_client.h" | ||
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struct kcs_bmc_serio { | ||
struct list_head entry; | ||
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struct kcs_bmc_client client; | ||
struct serio *port; | ||
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spinlock_t lock; | ||
}; | ||
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static inline struct kcs_bmc_serio *client_to_kcs_bmc_serio(struct kcs_bmc_client *client) | ||
{ | ||
return container_of(client, struct kcs_bmc_serio, client); | ||
} | ||
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static irqreturn_t kcs_bmc_serio_event(struct kcs_bmc_client *client) | ||
{ | ||
struct kcs_bmc_serio *priv; | ||
u8 handled = IRQ_NONE; | ||
u8 status; | ||
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priv = client_to_kcs_bmc_serio(client); | ||
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spin_lock(&priv->lock); | ||
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status = kcs_bmc_read_status(client->dev); | ||
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if (status & KCS_BMC_STR_IBF) | ||
handled = serio_interrupt(priv->port, kcs_bmc_read_data(client->dev), 0); | ||
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spin_unlock(&priv->lock); | ||
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return handled; | ||
} | ||
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static const struct kcs_bmc_client_ops kcs_bmc_serio_client_ops = { | ||
.event = kcs_bmc_serio_event, | ||
}; | ||
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static int kcs_bmc_serio_open(struct serio *port) | ||
{ | ||
struct kcs_bmc_serio *priv = port->port_data; | ||
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return kcs_bmc_enable_device(priv->client.dev, &priv->client); | ||
} | ||
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static void kcs_bmc_serio_close(struct serio *port) | ||
{ | ||
struct kcs_bmc_serio *priv = port->port_data; | ||
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kcs_bmc_disable_device(priv->client.dev, &priv->client); | ||
} | ||
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static DEFINE_SPINLOCK(kcs_bmc_serio_instances_lock); | ||
static LIST_HEAD(kcs_bmc_serio_instances); | ||
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static int kcs_bmc_serio_add_device(struct kcs_bmc_device *kcs_bmc) | ||
{ | ||
struct kcs_bmc_serio *priv; | ||
struct serio *port; | ||
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priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL); | ||
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/* Use kzalloc() as the allocation is cleaned up with kfree() via serio_unregister_port() */ | ||
port = kzalloc(sizeof(*port), GFP_KERNEL); | ||
if (!(priv && port)) | ||
return -ENOMEM; | ||
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port->id.type = SERIO_8042; | ||
port->open = kcs_bmc_serio_open; | ||
port->close = kcs_bmc_serio_close; | ||
port->port_data = priv; | ||
port->dev.parent = kcs_bmc->dev; | ||
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spin_lock_init(&priv->lock); | ||
priv->port = port; | ||
priv->client.dev = kcs_bmc; | ||
priv->client.ops = &kcs_bmc_serio_client_ops; | ||
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spin_lock_irq(&kcs_bmc_serio_instances_lock); | ||
list_add(&priv->entry, &kcs_bmc_serio_instances); | ||
spin_unlock_irq(&kcs_bmc_serio_instances_lock); | ||
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serio_register_port(port); | ||
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dev_info(kcs_bmc->dev, "Initialised serio client for channel %d", kcs_bmc->channel); | ||
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return 0; | ||
} | ||
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static int kcs_bmc_serio_remove_device(struct kcs_bmc_device *kcs_bmc) | ||
{ | ||
struct kcs_bmc_serio *priv = NULL, *pos; | ||
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spin_lock_irq(&kcs_bmc_serio_instances_lock); | ||
list_for_each_entry(pos, &kcs_bmc_serio_instances, entry) { | ||
if (pos->client.dev == kcs_bmc) { | ||
priv = pos; | ||
list_del(&pos->entry); | ||
break; | ||
} | ||
} | ||
spin_unlock_irq(&kcs_bmc_serio_instances_lock); | ||
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if (!priv) | ||
return -ENODEV; | ||
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/* kfree()s priv->port via put_device() */ | ||
serio_unregister_port(priv->port); | ||
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/* Ensure the IBF IRQ is disabled if we were the active client */ | ||
kcs_bmc_disable_device(kcs_bmc, &priv->client); | ||
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devm_kfree(priv->client.dev->dev, priv); | ||
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return 0; | ||
} | ||
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static const struct kcs_bmc_driver_ops kcs_bmc_serio_driver_ops = { | ||
.add_device = kcs_bmc_serio_add_device, | ||
.remove_device = kcs_bmc_serio_remove_device, | ||
}; | ||
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static struct kcs_bmc_driver kcs_bmc_serio_driver = { | ||
.ops = &kcs_bmc_serio_driver_ops, | ||
}; | ||
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static int kcs_bmc_serio_init(void) | ||
{ | ||
kcs_bmc_register_driver(&kcs_bmc_serio_driver); | ||
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return 0; | ||
} | ||
module_init(kcs_bmc_serio_init); | ||
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static void kcs_bmc_serio_exit(void) | ||
{ | ||
kcs_bmc_unregister_driver(&kcs_bmc_serio_driver); | ||
} | ||
module_exit(kcs_bmc_serio_exit); | ||
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MODULE_LICENSE("GPL v2"); | ||
MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>"); | ||
MODULE_DESCRIPTION("Adapter driver for serio access to BMC KCS devices"); |