Commit 3a3d2f6a authored by Andrew Jeffery's avatar Andrew Jeffery Committed by Corey Minyard
Browse files

ipmi: kcs_bmc: Add serio adaptor 



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: default avatarAndrew Jeffery <andrew@aj.id.au>
Message-Id: <20210608104757.582199-12-andrew@aj.id.au>
Reviewed-by: default avatarZev Weiss <zweiss@equinix.com>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent fb6379f5

drivers/char/ipmi/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -137,6 +137,20 @@ config IPMI_KCS_BMC_CDEV_IPMI 
	  This support is also available as a module. The module will be

	  called kcs_bmc_cdev_ipmi.



config IPMI_KCS_BMC_SERIO

	depends on IPMI_KCS_BMC && SERIO

	tristate "SerIO adaptor for BMC KCS devices"

	help

	  Adapts the BMC KCS device for the SerIO subsystem. This allows users

	  to take advantage of userspace interfaces provided by SerIO where

	  appropriate.



	  Say YES if you wish to expose KCS devices on the BMC via SerIO

	  interfaces.



	  This support is also available as a module. The module will be

	  called kcs_bmc_serio.



config ASPEED_BT_IPMI_BMC

	depends on ARCH_ASPEED || COMPILE_TEST

	depends on REGMAP && REGMAP_MMIO && MFD_SYSCON

drivers/char/ipmi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o 
obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o

obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o

obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o

obj-$(CONFIG_IPMI_KCS_BMC_SERIO) += kcs_bmc_serio.o

obj-$(CONFIG_IPMI_KCS_BMC_CDEV_IPMI) += kcs_bmc_cdev_ipmi.o

obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o

obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o

drivers/char/ipmi/kcs_bmc_serio.c

0 → 100644
+157 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/* Copyright (c) 2021 IBM Corp. */



#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>



#include "kcs_bmc_client.h"



struct kcs_bmc_serio {

	struct list_head entry;



	struct kcs_bmc_client client;

	struct serio *port;



	spinlock_t lock;

};



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);

}



static irqreturn_t kcs_bmc_serio_event(struct kcs_bmc_client *client)

{

	struct kcs_bmc_serio *priv;

	u8 handled = IRQ_NONE;

	u8 status;



	priv = client_to_kcs_bmc_serio(client);



	spin_lock(&priv->lock);



	status = kcs_bmc_read_status(client->dev);



	if (status & KCS_BMC_STR_IBF)

		handled = serio_interrupt(priv->port, kcs_bmc_read_data(client->dev), 0);



	spin_unlock(&priv->lock);



	return handled;

}



static const struct kcs_bmc_client_ops kcs_bmc_serio_client_ops = {

	.event = kcs_bmc_serio_event,

};



static int kcs_bmc_serio_open(struct serio *port)

{

	struct kcs_bmc_serio *priv = port->port_data;



	return kcs_bmc_enable_device(priv->client.dev, &priv->client);

}



static void kcs_bmc_serio_close(struct serio *port)

{

	struct kcs_bmc_serio *priv = port->port_data;



	kcs_bmc_disable_device(priv->client.dev, &priv->client);

}



static DEFINE_SPINLOCK(kcs_bmc_serio_instances_lock);

static LIST_HEAD(kcs_bmc_serio_instances);



static int kcs_bmc_serio_add_device(struct kcs_bmc_device *kcs_bmc)

{

	struct kcs_bmc_serio *priv;

	struct serio *port;



	priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL);



	/* 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;



	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;



	spin_lock_init(&priv->lock);

	priv->port = port;

	priv->client.dev = kcs_bmc;

	priv->client.ops = &kcs_bmc_serio_client_ops;



	spin_lock_irq(&kcs_bmc_serio_instances_lock);

	list_add(&priv->entry, &kcs_bmc_serio_instances);

	spin_unlock_irq(&kcs_bmc_serio_instances_lock);



	serio_register_port(port);



	dev_info(kcs_bmc->dev, "Initialised serio client for channel %d", kcs_bmc->channel);



	return 0;

}



static int kcs_bmc_serio_remove_device(struct kcs_bmc_device *kcs_bmc)

{

	struct kcs_bmc_serio *priv = NULL, *pos;



	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);



	if (!priv)

		return -ENODEV;



	/* kfree()s priv->port via put_device() */

	serio_unregister_port(priv->port);



	/* Ensure the IBF IRQ is disabled if we were the active client */

	kcs_bmc_disable_device(kcs_bmc, &priv->client);



	devm_kfree(priv->client.dev->dev, priv);



	return 0;

}



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,

};



static struct kcs_bmc_driver kcs_bmc_serio_driver = {

	.ops = &kcs_bmc_serio_driver_ops,

};



static int kcs_bmc_serio_init(void)

{

	kcs_bmc_register_driver(&kcs_bmc_serio_driver);



	return 0;

}

module_init(kcs_bmc_serio_init);



static void kcs_bmc_serio_exit(void)

{

	kcs_bmc_unregister_driver(&kcs_bmc_serio_driver);

}

module_exit(kcs_bmc_serio_exit);



MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");

MODULE_DESCRIPTION("Adapter driver for serio access to BMC KCS devices");