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Commit 6b2e54f7 authored by Haiyue Wang's avatar Haiyue Wang Committed by Corey Minyard
Browse files

ipmi: add an NPCM7xx KCS BMC driver 



This driver exposes the Keyboard Controller Style (KCS) interface on
Novoton NPCM7xx SoCs as a character device. Such SOCs are commonly used
as a BaseBoard Management Controller (BMC) on a server board, and KCS
interface is commonly used to perform the in-band IPMI communication
between the server and its BMC.

Signed-off-by: default avatarAvi Fishman <avifishman70@gmail.com>
Signed-off-by: default avatarHaiyue Wang <haiyue.wang@linux.intel.com>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
parent 93c303d2

Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt

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* Nuvoton NPCM7xx KCS (Keyboard Controller Style) IPMI interface



The Nuvoton SOCs (NPCM7xx) are commonly used as BMCs

(Baseboard Management Controllers) and the KCS interface can be

used to perform in-band IPMI communication with their host.



Required properties:

- compatible : should be one of

    "nuvoton,npcm750-kcs-bmc"

- interrupts : interrupt generated by the controller

- kcs_chan : The KCS channel number in the controller



Example:



    lpc_kcs: lpc_kcs@f0007000 {

        compatible = "nuvoton,npcm750-lpc-kcs", "simple-mfd", "syscon";

        reg = <0xf0007000 0x40>;

        reg-io-width = <1>;



        #address-cells = <1>;

        #size-cells = <1>;

        ranges = <0x0 0xf0007000 0x40>;



        kcs1: kcs1@0 {

            compatible = "nuvoton,npcm750-kcs-bmc";

            reg = <0x0 0x40>;

            interrupts = <0 9 4>;

            kcs_chan = <1>;

            status = "disabled";

        };



        kcs2: kcs2@0 {

            compatible = "nuvoton,npcm750-kcs-bmc";

            reg = <0x0 0x40>;

            interrupts = <0 9 4>;

            kcs_chan = <2>;

            status = "disabled";

        };

    };
 
 No newline at end of file

drivers/char/ipmi/Kconfig

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@@ -111,6 +111,21 @@ config ASPEED_KCS_IPMI_BMC 
	  The driver implements the BMC side of the KCS contorller, it

	  provides the access of KCS IO space for BMC side.



config NPCM7XX_KCS_IPMI_BMC

	depends on ARCH_NPCM7XX || COMPILE_TEST

	select IPMI_KCS_BMC

	select REGMAP_MMIO

	tristate "NPCM7xx KCS IPMI BMC driver"

	help

	  Provides a driver for the KCS (Keyboard Controller Style) IPMI

	  interface found on Nuvoton NPCM7xx SOCs.



	  The driver implements the BMC side of the KCS contorller, it

	  provides the access of KCS IO space for BMC side.



	  This support is also available as a module.  If so, the module

	  will be called kcs_bmc_npcm7xx.



config ASPEED_BT_IPMI_BMC

	depends on ARCH_ASPEED || COMPILE_TEST

       depends on REGMAP && REGMAP_MMIO && MFD_SYSCON

drivers/char/ipmi/Makefile

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@@ -24,3 +24,4 @@ obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o 
obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o

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

obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o

obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o

drivers/char/ipmi/kcs_bmc_npcm7xx.c

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// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (c) 2018, Nuvoton Corporation.

 * Copyright (c) 2018, Intel Corporation.

 */



#define pr_fmt(fmt) "nuvoton-kcs-bmc: " fmt



#include <linux/atomic.h>

#include <linux/errno.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/mfd/syscon.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/slab.h>



#include "kcs_bmc.h"



#define DEVICE_NAME	"npcm-kcs-bmc"

#define KCS_CHANNEL_MAX	3



#define KCS1ST		0x0C

#define KCS2ST		0x1E

#define KCS3ST		0x30



#define KCS1DO		0x0E

#define KCS2DO		0x20

#define KCS3DO		0x32



#define KCS1DI		0x10

#define KCS2DI		0x22

#define KCS3DI		0x34



#define KCS1CTL		0x18

#define KCS2CTL		0x2A

#define KCS3CTL		0x3C

#define    KCS_CTL_IBFIE	BIT(0)



/*

 * 7.2.4 Core KCS Registers

 * Registers in this module are 8 bits. An 8-bit register must be accessed

 * by an 8-bit read or write.

 *

 * sts: KCS Channel n Status Register (KCSnST).

 * dob: KCS Channel n Data Out Buffer Register (KCSnDO).

 * dib: KCS Channel n Data In Buffer Register (KCSnDI).

 * ctl: KCS Channel n Control Register (KCSnCTL).

 */

struct npcm7xx_kcs_reg {

	u32 sts;

	u32 dob;

	u32 dib;

	u32 ctl;

};



struct npcm7xx_kcs_bmc {

	struct regmap *map;



	const struct npcm7xx_kcs_reg *reg;

};



static const struct npcm7xx_kcs_reg npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {

	{ .sts = KCS1ST, .dob = KCS1DO, .dib = KCS1DI, .ctl = KCS1CTL },

	{ .sts = KCS2ST, .dob = KCS2DO, .dib = KCS2DI, .ctl = KCS2CTL },

	{ .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL },

};



static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)

{

	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);

	u32 val = 0;

	int rc;



	rc = regmap_read(priv->map, reg, &val);

	WARN(rc != 0, "regmap_read() failed: %d\n", rc);



	return rc == 0 ? (u8)val : 0;

}



static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)

{

	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);

	int rc;



	rc = regmap_write(priv->map, reg, data);

	WARN(rc != 0, "regmap_write() failed: %d\n", rc);

}



static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)

{

	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);



	regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,

			   enable ? KCS_CTL_IBFIE : 0);

}



static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)

{

	struct kcs_bmc *kcs_bmc = arg;



	if (!kcs_bmc_handle_event(kcs_bmc))

		return IRQ_HANDLED;



	return IRQ_NONE;

}



static int npcm7xx_kcs_config_irq(struct kcs_bmc *kcs_bmc,

				  struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	int irq;



	irq = platform_get_irq(pdev, 0);

	if (irq < 0)

		return irq;



	return devm_request_irq(dev, irq, npcm7xx_kcs_irq, IRQF_SHARED,

				dev_name(dev), kcs_bmc);

}



static int npcm7xx_kcs_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct npcm7xx_kcs_bmc *priv;

	struct kcs_bmc *kcs_bmc;

	u32 chan;

	int rc;



	rc = of_property_read_u32(dev->of_node, "kcs_chan", &chan);

	if (rc != 0 || chan == 0 || chan > KCS_CHANNEL_MAX) {

		dev_err(dev, "no valid 'kcs_chan' configured\n");

		return -ENODEV;

	}



	kcs_bmc = kcs_bmc_alloc(dev, sizeof(*priv), chan);

	if (!kcs_bmc)

		return -ENOMEM;



	priv = kcs_bmc_priv(kcs_bmc);

	priv->map = syscon_node_to_regmap(dev->parent->of_node);

	if (IS_ERR(priv->map)) {

		dev_err(dev, "Couldn't get regmap\n");

		return -ENODEV;

	}

	priv->reg = &npcm7xx_kcs_reg_tbl[chan - 1];



	kcs_bmc->ioreg.idr = priv->reg->dib;

	kcs_bmc->ioreg.odr = priv->reg->dob;

	kcs_bmc->ioreg.str = priv->reg->sts;

	kcs_bmc->io_inputb = npcm7xx_kcs_inb;

	kcs_bmc->io_outputb = npcm7xx_kcs_outb;



	dev_set_drvdata(dev, kcs_bmc);



	npcm7xx_kcs_enable_channel(kcs_bmc, true);

	rc = npcm7xx_kcs_config_irq(kcs_bmc, pdev);

	if (rc)

		return rc;



	rc = misc_register(&kcs_bmc->miscdev);

	if (rc) {

		dev_err(dev, "Unable to register device\n");

		return rc;

	}



	pr_info("channel=%u idr=0x%x odr=0x%x str=0x%x\n",

		chan,

		kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);



	return 0;

}



static int npcm7xx_kcs_remove(struct platform_device *pdev)

{

	struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);



	misc_deregister(&kcs_bmc->miscdev);



	return 0;

}



static const struct of_device_id npcm_kcs_bmc_match[] = {

	{ .compatible = "nuvoton,npcm750-kcs-bmc" },

	{ }

};

MODULE_DEVICE_TABLE(of, npcm_kcs_bmc_match);



static struct platform_driver npcm_kcs_bmc_driver = {

	.driver = {

		.name		= DEVICE_NAME,

		.of_match_table	= npcm_kcs_bmc_match,

	},

	.probe	= npcm7xx_kcs_probe,

	.remove	= npcm7xx_kcs_remove,

};

module_platform_driver(npcm_kcs_bmc_driver);



MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Avi Fishman <avifishman70@gmail.com>");

MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");

MODULE_DESCRIPTION("NPCM7xx device interface to the KCS BMC device");