Re: [PATCH v2 12/21] ipmi: kcs_bmc: Strip private client data from struct kcs_bmc

[Zev Weiss <zweiss@equinix.com>]

On Fri, Mar 19, 2021 at 01:27:43AM CDT, Andrew Jeffery wrote:
>Move all client-private data out of `struct kcs_bmc` into the KCS client
>implementation.
>
>With this change the KCS BMC core code now only concerns itself with
>abstract `struct kcs_bmc` and `struct kcs_bmc_client` types, achieving
>expected separation of concerns. Further, the change clears the path for
>implementation of alternative userspace interfaces.
>
>The chardev data-structures are rearranged in the same manner applied to
>the KCS device driver data-structures in an earlier patch - `struct
>kcs_bmc_client` is embedded in the client's private data and we exploit
>container_of() to translate as required.
>
>Finally, now that it is free of client data, `struct kcs_bmc` is renamed
>to `struct kcs_bmc_device` to contrast `struct kcs_bmc_client`.
>
>Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>---
> drivers/char/ipmi/kcs_bmc.c           |  68 +++-
> drivers/char/ipmi/kcs_bmc.h           |  86 +-----
> drivers/char/ipmi/kcs_bmc_aspeed.c    |  22 +-
> drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 428 ++++++++++++++++----------
> drivers/char/ipmi/kcs_bmc_client.h    |  28 +-
> drivers/char/ipmi/kcs_bmc_device.h    |  12 +-
> drivers/char/ipmi/kcs_bmc_npcm7xx.c   |  20 +-
> 7 files changed, 368 insertions(+), 296 deletions(-)
>
>diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
>index 1046ce2bbefc..266ebec71d6f 100644
>--- a/drivers/char/ipmi/kcs_bmc.c
>+++ b/drivers/char/ipmi/kcs_bmc.c
>@@ -4,6 +4,7 @@
>  * Copyright (c) 2021, IBM Corp.
>  */
>
>+#include <linux/device.h>
> #include <linux/module.h>
>
> #include "kcs_bmc.h"
>@@ -14,51 +15,96 @@
>
> /* Consumer data access */
>
>-u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc)
>+u8 kcs_bmc_read_data(struct kcs_bmc_device *kcs_bmc)
> {
> 	return kcs_bmc->ops->io_inputb(kcs_bmc, kcs_bmc->ioreg.idr);
> }
> EXPORT_SYMBOL(kcs_bmc_read_data);
>
>-void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data)
>+void kcs_bmc_write_data(struct kcs_bmc_device *kcs_bmc, u8 data)
> {
> 	kcs_bmc->ops->io_outputb(kcs_bmc, kcs_bmc->ioreg.odr, data);
> }
> EXPORT_SYMBOL(kcs_bmc_write_data);
>
>-u8 kcs_bmc_read_status(struct kcs_bmc *kcs_bmc)
>+u8 kcs_bmc_read_status(struct kcs_bmc_device *kcs_bmc)
> {
> 	return kcs_bmc->ops->io_inputb(kcs_bmc, kcs_bmc->ioreg.str);
> }
> EXPORT_SYMBOL(kcs_bmc_read_status);
>
>-void kcs_bmc_write_status(struct kcs_bmc *kcs_bmc, u8 data)
>+void kcs_bmc_write_status(struct kcs_bmc_device *kcs_bmc, u8 data)
> {
> 	kcs_bmc->ops->io_outputb(kcs_bmc, kcs_bmc->ioreg.str, data);
> }
> EXPORT_SYMBOL(kcs_bmc_write_status);
>
>-void kcs_bmc_update_status(struct kcs_bmc *kcs_bmc, u8 mask, u8 val)
>+void kcs_bmc_update_status(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 val)
> {
> 	kcs_bmc->ops->io_updateb(kcs_bmc, kcs_bmc->ioreg.str, mask, val);
> }
> EXPORT_SYMBOL(kcs_bmc_update_status);
>
>-int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc)
>+int kcs_bmc_handle_event(struct kcs_bmc_device *kcs_bmc)
> {
>-	return kcs_bmc->client.ops->event(&kcs_bmc->client);
>+	struct kcs_bmc_client *client;
>+	int rc;
>+
>+	spin_lock(&kcs_bmc->lock);
>+	client = kcs_bmc->client;
>+	if (client) {
>+		rc = client->ops->event(client);
>+	} else {
>+		u8 status;
>+
>+		status = kcs_bmc_read_status(kcs_bmc);
>+		if (status & KCS_BMC_STR_IBF) {
>+			/* Ack the event by reading the data */
>+			kcs_bmc_read_data(kcs_bmc);
>+			rc = KCS_BMC_EVENT_HANDLED;
>+		} else {
>+			rc = KCS_BMC_EVENT_NONE;
>+		}
>+	}
>+	spin_unlock(&kcs_bmc->lock);
>+
>+	return rc;
> }
> EXPORT_SYMBOL(kcs_bmc_handle_event);
>
>-int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc)
>+int kcs_bmc_enable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client)
>+{
>+	int rc;
>+
>+	spin_lock_irq(&kcs_bmc->lock);
>+	if (kcs_bmc->client) {
>+		rc = -EBUSY;
>+	} else {
>+		kcs_bmc->client = client;
>+		rc = 0;
>+	}
>+	spin_unlock_irq(&kcs_bmc->lock);
>+
>+	return rc;
>+}
>+EXPORT_SYMBOL(kcs_bmc_enable_device);
>+
>+void kcs_bmc_disable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client)
>+{
>+	spin_lock_irq(&kcs_bmc->lock);
>+	if (client == kcs_bmc->client)
>+		kcs_bmc->client = NULL;

Is there any situation in which a non-matching client could be passed in
here?  Might we consider issuing a warning of some sort or returning an
error to the caller if so?

>+	spin_unlock_irq(&kcs_bmc->lock);
>+}
>+EXPORT_SYMBOL(kcs_bmc_disable_device);
>+
>+int kcs_bmc_add_device(struct kcs_bmc_device *kcs_bmc)
> {
> 	return kcs_bmc_ipmi_attach_cdev(kcs_bmc);
> }
> EXPORT_SYMBOL(kcs_bmc_add_device);
>
>-int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc)
>+int kcs_bmc_remove_device(struct kcs_bmc_device *kcs_bmc)
> {
> 	return kcs_bmc_ipmi_detach_cdev(kcs_bmc);
> }
>diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
>index a1350e567723..3f266740c759 100644
>--- a/drivers/char/ipmi/kcs_bmc.h
>+++ b/drivers/char/ipmi/kcs_bmc.h
>@@ -6,9 +6,7 @@
> #ifndef __KCS_BMC_H__
> #define __KCS_BMC_H__
>
>-#include <linux/miscdevice.h>
>-
>-#include "kcs_bmc_client.h"
>+#include <linux/list.h>
>
> #define KCS_BMC_EVENT_NONE	0
> #define KCS_BMC_EVENT_HANDLED	1
>@@ -17,53 +15,6 @@
> #define KCS_BMC_STR_IBF		BIT(1)
> #define KCS_BMC_STR_CMD_DAT	BIT(3)
>
>-/* Different phases of the KCS BMC module.
>- *  KCS_PHASE_IDLE:
>- *            BMC should not be expecting nor sending any data.
>- *  KCS_PHASE_WRITE_START:
>- *            BMC is receiving a WRITE_START command from system software.
>- *  KCS_PHASE_WRITE_DATA:
>- *            BMC is receiving a data byte from system software.
>- *  KCS_PHASE_WRITE_END_CMD:
>- *            BMC is waiting a last data byte from system software.
>- *  KCS_PHASE_WRITE_DONE:
>- *            BMC has received the whole request from system software.
>- *  KCS_PHASE_WAIT_READ:
>- *            BMC is waiting the response from the upper IPMI service.
>- *  KCS_PHASE_READ:
>- *            BMC is transferring the response to system software.
>- *  KCS_PHASE_ABORT_ERROR1:
>- *            BMC is waiting error status request from system software.
>- *  KCS_PHASE_ABORT_ERROR2:
>- *            BMC is waiting for idle status afer error from system software.
>- *  KCS_PHASE_ERROR:
>- *            BMC has detected a protocol violation at the interface level.
>- */
>-enum kcs_phases {
>-	KCS_PHASE_IDLE,
>-
>-	KCS_PHASE_WRITE_START,
>-	KCS_PHASE_WRITE_DATA,
>-	KCS_PHASE_WRITE_END_CMD,
>-	KCS_PHASE_WRITE_DONE,
>-
>-	KCS_PHASE_WAIT_READ,
>-	KCS_PHASE_READ,
>-
>-	KCS_PHASE_ABORT_ERROR1,
>-	KCS_PHASE_ABORT_ERROR2,
>-	KCS_PHASE_ERROR
>-};
>-
>-/* IPMI 2.0 - Table 9-4, KCS Interface Status Codes */
>-enum kcs_errors {
>-	KCS_NO_ERROR                = 0x00,
>-	KCS_ABORTED_BY_COMMAND      = 0x01,
>-	KCS_ILLEGAL_CONTROL_CODE    = 0x02,
>-	KCS_LENGTH_ERROR            = 0x06,
>-	KCS_UNSPECIFIED_ERROR       = 0xFF
>-};
>-
> /* IPMI 2.0 - 9.5, KCS Interface Registers
>  * @idr: Input Data Register
>  * @odr: Output Data Register
>@@ -76,36 +27,23 @@ struct kcs_ioreg {
> };
>
> struct kcs_bmc_device_ops;
>+struct kcs_bmc_client;
>+
>+struct kcs_bmc_device {
>+	struct list_head entry;
>
>-struct kcs_bmc {
> 	struct device *dev;
>-
>-	const struct kcs_bmc_device_ops *ops;
>-
>-	struct kcs_bmc_client client;
>-
>-	spinlock_t lock;
>-
> 	u32 channel;
>-	int running;
>
> 	struct kcs_ioreg ioreg;
>
>-	enum kcs_phases phase;
>-	enum kcs_errors error;
>+	const struct kcs_bmc_device_ops *ops;
>
>-	wait_queue_head_t queue;
>-	bool data_in_avail;
>-	int  data_in_idx;
>-	u8  *data_in;
>-
>-	int  data_out_idx;
>-	int  data_out_len;
>-	u8  *data_out;
>-
>-	struct mutex mutex;
>-	u8 *kbuffer;
>-
>-	struct miscdevice miscdev;
>+	spinlock_t lock;
>+	struct kcs_bmc_client *client;
> };
>+
>+/* Temporary exports while refactoring */
>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc_device *kcs_bmc);
>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc);
> #endif /* __KCS_BMC_H__ */
>diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
>index 1b313355b1c8..6f26e7366c0b 100644
>--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
>+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
>@@ -61,7 +61,7 @@
> #define LPC_STR4             0x11C
>
> struct aspeed_kcs_bmc {
>-	struct kcs_bmc kcs_bmc;
>+	struct kcs_bmc_device kcs_bmc;
>
> 	struct regmap *map;
> };
>@@ -71,12 +71,12 @@ struct aspeed_kcs_of_ops {
> 	int (*get_io_address)(struct platform_device *pdev);
> };
>
>-static inline struct aspeed_kcs_bmc *to_aspeed_kcs_bmc(struct kcs_bmc *kcs_bmc)
>+static inline struct aspeed_kcs_bmc *to_aspeed_kcs_bmc(struct kcs_bmc_device *kcs_bmc)
> {
> 	return container_of(kcs_bmc, struct aspeed_kcs_bmc, kcs_bmc);
> }
>
>-static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
>+static u8 aspeed_kcs_inb(struct kcs_bmc_device *kcs_bmc, u32 reg)
> {
> 	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> 	u32 val = 0;
>@@ -88,7 +88,7 @@ static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> 	return rc == 0 ? (u8) val : 0;
> }
>
>-static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
>+static void aspeed_kcs_outb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 data)
> {
> 	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> 	int rc;
>@@ -97,7 +97,7 @@ static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> 	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
> }
>
>-static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val)
>+static void aspeed_kcs_updateb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 mask, u8 val)
> {
> 	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> 	int rc;
>@@ -119,7 +119,7 @@ static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val
>  *     C. KCS4
>  *        D / C : CA4h / CA5h
>  */
>-static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
>+static void aspeed_kcs_set_address(struct kcs_bmc_device *kcs_bmc, u16 addr)
> {
> 	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>
>@@ -153,7 +153,7 @@ static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
> 	}
> }
>
>-static void aspeed_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
>+static void aspeed_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enable)
> {
> 	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>
>@@ -228,7 +228,7 @@ static const struct kcs_bmc_device_ops aspeed_kcs_ops = {
>
> static irqreturn_t aspeed_kcs_irq(int irq, void *arg)
> {
>-	struct kcs_bmc *kcs_bmc = arg;
>+	struct kcs_bmc_device *kcs_bmc = arg;
> 	int rc;
>
> 	rc = kcs_bmc_handle_event(kcs_bmc);
>@@ -238,7 +238,7 @@ static irqreturn_t aspeed_kcs_irq(int irq, void *arg)
> 	return rc == KCS_BMC_EVENT_HANDLED ? IRQ_HANDLED : IRQ_NONE;
> }
>
>-static int aspeed_kcs_config_irq(struct kcs_bmc *kcs_bmc,
>+static int aspeed_kcs_config_irq(struct kcs_bmc_device *kcs_bmc,
> 			struct platform_device *pdev)
> {
> 	struct device *dev = &pdev->dev;
>@@ -338,8 +338,8 @@ static int aspeed_kcs_of_v2_get_io_address(struct platform_device *pdev)
> static int aspeed_kcs_probe(struct platform_device *pdev)
> {
> 	const struct aspeed_kcs_of_ops *ops;
>+	struct kcs_bmc_device *kcs_bmc;
> 	struct aspeed_kcs_bmc *priv;
>-	struct kcs_bmc *kcs_bmc;
> 	struct device_node *np;
> 	int rc, channel, addr;
>
>@@ -400,7 +400,7 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> static int aspeed_kcs_remove(struct platform_device *pdev)
> {
> 	struct aspeed_kcs_bmc *priv = platform_get_drvdata(pdev);
>-	struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
>+	struct kcs_bmc_device *kcs_bmc = &priv->kcs_bmc;
>
> 	kcs_bmc_remove_device(kcs_bmc);
>
>diff --git a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>index fd852d8abe48..58c42e76483d 100644
>--- a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>+++ b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>@@ -8,13 +8,88 @@
> #include <linux/errno.h>
> #include <linux/io.h>
> #include <linux/ipmi_bmc.h>
>+#include <linux/list.h>
>+#include <linux/miscdevice.h>
> #include <linux/module.h>
>+#include <linux/mutex.h>
> #include <linux/platform_device.h>
> #include <linux/poll.h>
> #include <linux/sched.h>
> #include <linux/slab.h>
>
>-#include "kcs_bmc.h"
>+#include "kcs_bmc_client.h"
>+
>+/* Different phases of the KCS BMC module.
>+ *  KCS_PHASE_IDLE:
>+ *            BMC should not be expecting nor sending any data.
>+ *  KCS_PHASE_WRITE_START:
>+ *            BMC is receiving a WRITE_START command from system software.
>+ *  KCS_PHASE_WRITE_DATA:
>+ *            BMC is receiving a data byte from system software.
>+ *  KCS_PHASE_WRITE_END_CMD:
>+ *            BMC is waiting a last data byte from system software.
>+ *  KCS_PHASE_WRITE_DONE:
>+ *            BMC has received the whole request from system software.
>+ *  KCS_PHASE_WAIT_READ:
>+ *            BMC is waiting the response from the upper IPMI service.
>+ *  KCS_PHASE_READ:
>+ *            BMC is transferring the response to system software.
>+ *  KCS_PHASE_ABORT_ERROR1:
>+ *            BMC is waiting error status request from system software.
>+ *  KCS_PHASE_ABORT_ERROR2:
>+ *            BMC is waiting for idle status afer error from system software.
>+ *  KCS_PHASE_ERROR:
>+ *            BMC has detected a protocol violation at the interface level.
>+ */
>+enum kcs_ipmi_phases {
>+	KCS_PHASE_IDLE,
>+
>+	KCS_PHASE_WRITE_START,
>+	KCS_PHASE_WRITE_DATA,
>+	KCS_PHASE_WRITE_END_CMD,
>+	KCS_PHASE_WRITE_DONE,
>+
>+	KCS_PHASE_WAIT_READ,
>+	KCS_PHASE_READ,
>+
>+	KCS_PHASE_ABORT_ERROR1,
>+	KCS_PHASE_ABORT_ERROR2,
>+	KCS_PHASE_ERROR
>+};
>+
>+/* IPMI 2.0 - Table 9-4, KCS Interface Status Codes */
>+enum kcs_ipmi_errors {
>+	KCS_NO_ERROR                = 0x00,
>+	KCS_ABORTED_BY_COMMAND      = 0x01,
>+	KCS_ILLEGAL_CONTROL_CODE    = 0x02,
>+	KCS_LENGTH_ERROR            = 0x06,
>+	KCS_UNSPECIFIED_ERROR       = 0xFF
>+};
>+
>+struct kcs_bmc_ipmi {
>+	struct list_head entry;
>+
>+	struct kcs_bmc_client client;
>+
>+	spinlock_t lock;
>+
>+	enum kcs_ipmi_phases phase;
>+	enum kcs_ipmi_errors error;
>+
>+	wait_queue_head_t queue;
>+	bool data_in_avail;
>+	int  data_in_idx;
>+	u8  *data_in;
>+
>+	int  data_out_idx;
>+	int  data_out_len;
>+	u8  *data_out;
>+
>+	struct mutex mutex;
>+	u8 *kbuffer;
>+
>+	struct miscdevice miscdev;
>+};
>
> #define DEVICE_NAME "ipmi-kcs"
>
>@@ -44,171 +119,169 @@ enum kcs_states {
> #define KCS_CMD_WRITE_END         0x62
> #define KCS_CMD_READ_BYTE         0x68
>
>-static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state)
>+static inline void set_state(struct kcs_bmc_ipmi *priv, u8 state)
> {
>-	kcs_bmc_update_status(kcs_bmc, KCS_STATUS_STATE_MASK,
>-					KCS_STATUS_STATE(state));
>+	kcs_bmc_update_status(priv->client.dev, KCS_STATUS_STATE_MASK, KCS_STATUS_STATE(state));
> }
>
>-static void kcs_bmc_ipmi_force_abort(struct kcs_bmc *kcs_bmc)
>+static void kcs_bmc_ipmi_force_abort(struct kcs_bmc_ipmi *priv)
> {
>-	set_state(kcs_bmc, ERROR_STATE);
>-	kcs_bmc_read_data(kcs_bmc);
>-	kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+	set_state(priv, ERROR_STATE);
>+	kcs_bmc_read_data(priv->client.dev);
>+	kcs_bmc_write_data(priv->client.dev, KCS_ZERO_DATA);
>
>-	kcs_bmc->phase = KCS_PHASE_ERROR;
>-	kcs_bmc->data_in_avail = false;
>-	kcs_bmc->data_in_idx = 0;
>+	priv->phase = KCS_PHASE_ERROR;
>+	priv->data_in_avail = false;
>+	priv->data_in_idx = 0;
> }
>
>-static void kcs_bmc_ipmi_handle_data(struct kcs_bmc *kcs_bmc)
>+static void kcs_bmc_ipmi_handle_data(struct kcs_bmc_ipmi *priv)
> {
>+	struct kcs_bmc_device *dev;
> 	u8 data;
>
>-	switch (kcs_bmc->phase) {
>+	dev = priv->client.dev;
>+
>+	switch (priv->phase) {
> 	case KCS_PHASE_WRITE_START:
>-		kcs_bmc->phase = KCS_PHASE_WRITE_DATA;
>+		priv->phase = KCS_PHASE_WRITE_DATA;
> 		fallthrough;
>
> 	case KCS_PHASE_WRITE_DATA:
>-		if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) {
>-			set_state(kcs_bmc, WRITE_STATE);
>-			kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-			kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
>-						kcs_bmc_read_data(kcs_bmc);
>+		if (priv->data_in_idx < KCS_MSG_BUFSIZ) {
>+			set_state(priv, WRITE_STATE);
>+			kcs_bmc_write_data(dev, KCS_ZERO_DATA);
>+			priv->data_in[priv->data_in_idx++] = kcs_bmc_read_data(dev);
> 		} else {
>-			kcs_bmc_ipmi_force_abort(kcs_bmc);
>-			kcs_bmc->error = KCS_LENGTH_ERROR;
>+			kcs_bmc_ipmi_force_abort(priv);
>+			priv->error = KCS_LENGTH_ERROR;
> 		}
> 		break;
>
> 	case KCS_PHASE_WRITE_END_CMD:
>-		if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) {
>-			set_state(kcs_bmc, READ_STATE);
>-			kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
>-						kcs_bmc_read_data(kcs_bmc);
>-			kcs_bmc->phase = KCS_PHASE_WRITE_DONE;
>-			kcs_bmc->data_in_avail = true;
>-			wake_up_interruptible(&kcs_bmc->queue);
>+		if (priv->data_in_idx < KCS_MSG_BUFSIZ) {
>+			set_state(priv, READ_STATE);
>+			priv->data_in[priv->data_in_idx++] = kcs_bmc_read_data(dev);
>+			priv->phase = KCS_PHASE_WRITE_DONE;
>+			priv->data_in_avail = true;
>+			wake_up_interruptible(&priv->queue);
> 		} else {
>-			kcs_bmc_ipmi_force_abort(kcs_bmc);
>-			kcs_bmc->error = KCS_LENGTH_ERROR;
>+			kcs_bmc_ipmi_force_abort(priv);
>+			priv->error = KCS_LENGTH_ERROR;
> 		}
> 		break;
>
> 	case KCS_PHASE_READ:
>-		if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len)
>-			set_state(kcs_bmc, IDLE_STATE);
>+		if (priv->data_out_idx == priv->data_out_len)
>+			set_state(priv, IDLE_STATE);
>
>-		data = kcs_bmc_read_data(kcs_bmc);
>+		data = kcs_bmc_read_data(dev);
> 		if (data != KCS_CMD_READ_BYTE) {
>-			set_state(kcs_bmc, ERROR_STATE);
>-			kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+			set_state(priv, ERROR_STATE);
>+			kcs_bmc_write_data(dev, KCS_ZERO_DATA);
> 			break;
> 		}
>
>-		if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) {
>-			kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-			kcs_bmc->phase = KCS_PHASE_IDLE;
>+		if (priv->data_out_idx == priv->data_out_len) {
>+			kcs_bmc_write_data(dev, KCS_ZERO_DATA);
>+			priv->phase = KCS_PHASE_IDLE;
> 			break;
> 		}
>
>-		kcs_bmc_write_data(kcs_bmc,
>-			kcs_bmc->data_out[kcs_bmc->data_out_idx++]);
>+		kcs_bmc_write_data(dev, priv->data_out[priv->data_out_idx++]);
> 		break;
>
> 	case KCS_PHASE_ABORT_ERROR1:
>-		set_state(kcs_bmc, READ_STATE);
>-		kcs_bmc_read_data(kcs_bmc);
>-		kcs_bmc_write_data(kcs_bmc, kcs_bmc->error);
>-		kcs_bmc->phase = KCS_PHASE_ABORT_ERROR2;
>+		set_state(priv, READ_STATE);
>+		kcs_bmc_read_data(dev);
>+		kcs_bmc_write_data(dev, priv->error);
>+		priv->phase = KCS_PHASE_ABORT_ERROR2;
> 		break;
>
> 	case KCS_PHASE_ABORT_ERROR2:
>-		set_state(kcs_bmc, IDLE_STATE);
>-		kcs_bmc_read_data(kcs_bmc);
>-		kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-		kcs_bmc->phase = KCS_PHASE_IDLE;
>+		set_state(priv, IDLE_STATE);
>+		kcs_bmc_read_data(dev);
>+		kcs_bmc_write_data(dev, KCS_ZERO_DATA);
>+		priv->phase = KCS_PHASE_IDLE;
> 		break;
>
> 	default:
>-		kcs_bmc_ipmi_force_abort(kcs_bmc);
>+		kcs_bmc_ipmi_force_abort(priv);
> 		break;
> 	}
> }
>
>-static void kcs_bmc_ipmi_handle_cmd(struct kcs_bmc *kcs_bmc)
>+static void kcs_bmc_ipmi_handle_cmd(struct kcs_bmc_ipmi *priv)
> {
> 	u8 cmd;
>
>-	set_state(kcs_bmc, WRITE_STATE);
>-	kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+	set_state(priv, WRITE_STATE);
>+	kcs_bmc_write_data(priv->client.dev, KCS_ZERO_DATA);
>
>-	cmd = kcs_bmc_read_data(kcs_bmc);
>+	cmd = kcs_bmc_read_data(priv->client.dev);
> 	switch (cmd) {
> 	case KCS_CMD_WRITE_START:
>-		kcs_bmc->phase = KCS_PHASE_WRITE_START;
>-		kcs_bmc->error = KCS_NO_ERROR;
>-		kcs_bmc->data_in_avail = false;
>-		kcs_bmc->data_in_idx = 0;
>+		priv->phase = KCS_PHASE_WRITE_START;
>+		priv->error = KCS_NO_ERROR;
>+		priv->data_in_avail = false;
>+		priv->data_in_idx = 0;
> 		break;
>
> 	case KCS_CMD_WRITE_END:
>-		if (kcs_bmc->phase != KCS_PHASE_WRITE_DATA) {
>-			kcs_bmc_ipmi_force_abort(kcs_bmc);
>+		if (priv->phase != KCS_PHASE_WRITE_DATA) {
>+			kcs_bmc_ipmi_force_abort(priv);
> 			break;
> 		}
>
>-		kcs_bmc->phase = KCS_PHASE_WRITE_END_CMD;
>+		priv->phase = KCS_PHASE_WRITE_END_CMD;
> 		break;
>
> 	case KCS_CMD_GET_STATUS_ABORT:
>-		if (kcs_bmc->error == KCS_NO_ERROR)
>-			kcs_bmc->error = KCS_ABORTED_BY_COMMAND;
>+		if (priv->error == KCS_NO_ERROR)
>+			priv->error = KCS_ABORTED_BY_COMMAND;
>
>-		kcs_bmc->phase = KCS_PHASE_ABORT_ERROR1;
>-		kcs_bmc->data_in_avail = false;
>-		kcs_bmc->data_in_idx = 0;
>+		priv->phase = KCS_PHASE_ABORT_ERROR1;
>+		priv->data_in_avail = false;
>+		priv->data_in_idx = 0;
> 		break;
>
> 	default:
>-		kcs_bmc_ipmi_force_abort(kcs_bmc);
>-		kcs_bmc->error = KCS_ILLEGAL_CONTROL_CODE;
>+		kcs_bmc_ipmi_force_abort(priv);
>+		priv->error = KCS_ILLEGAL_CONTROL_CODE;
> 		break;
> 	}
> }
>
>-static inline struct kcs_bmc *client_to_kcs_bmc(struct kcs_bmc_client *client)
>+static inline struct kcs_bmc_ipmi *client_to_kcs_bmc_ipmi(struct kcs_bmc_client *client)
> {
>-	return container_of(client, struct kcs_bmc, client);
>+	return container_of(client, struct kcs_bmc_ipmi, client);
> }
>
> static int kcs_bmc_ipmi_event(struct kcs_bmc_client *client)
> {
>-	struct kcs_bmc *kcs_bmc;
>-	unsigned long flags;
>+	struct kcs_bmc_ipmi *priv;
> 	u8 status;
> 	int ret;
>
>-	kcs_bmc = client_to_kcs_bmc(client);
>+	priv = client_to_kcs_bmc_ipmi(client);
>+	if (!priv)
>+		return KCS_BMC_EVENT_NONE;
>
>-	spin_lock_irqsave(&kcs_bmc->lock, flags);
>+	spin_lock(&priv->lock);
>
>-	status = kcs_bmc_read_status(kcs_bmc);
>+	status = kcs_bmc_read_status(client->dev);
> 	if (status & KCS_STATUS_IBF) {
>-		if (!kcs_bmc->running)
>-			kcs_bmc_ipmi_force_abort(kcs_bmc);
>-		else if (status & KCS_STATUS_CMD_DAT)
>-			kcs_bmc_ipmi_handle_cmd(kcs_bmc);
>+		if (status & KCS_STATUS_CMD_DAT)
>+			kcs_bmc_ipmi_handle_cmd(priv);
> 		else
>-			kcs_bmc_ipmi_handle_data(kcs_bmc);
>+			kcs_bmc_ipmi_handle_data(priv);
>
> 		ret = KCS_BMC_EVENT_HANDLED;
> 	} else {
> 		ret = KCS_BMC_EVENT_NONE;
> 	}
>
>-	spin_unlock_irqrestore(&kcs_bmc->lock, flags);
>+	spin_unlock(&priv->lock);
>
> 	return ret;
> }
>@@ -217,37 +290,29 @@ static const struct kcs_bmc_client_ops kcs_bmc_ipmi_client_ops = {
> 	.event = kcs_bmc_ipmi_event,
> };
>
>-static inline struct kcs_bmc *file_to_kcs_bmc(struct file *filp)
>+static inline struct kcs_bmc_ipmi *to_kcs_bmc(struct file *filp)
> {
>-	return container_of(filp->private_data, struct kcs_bmc, miscdev);
>+	return container_of(filp->private_data, struct kcs_bmc_ipmi, miscdev);
> }
>
> static int kcs_bmc_ipmi_open(struct inode *inode, struct file *filp)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>-	int ret = 0;
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	if (!kcs_bmc->running)
>-		kcs_bmc->running = 1;
>-	else
>-		ret = -EBUSY;
>-	spin_unlock_irq(&kcs_bmc->lock);
>-
>-	return ret;
>+	return kcs_bmc_enable_device(priv->client.dev, &priv->client);
> }
>
> static __poll_t kcs_bmc_ipmi_poll(struct file *filp, poll_table *wait)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
> 	__poll_t mask = 0;
>
>-	poll_wait(filp, &kcs_bmc->queue, wait);
>+	poll_wait(filp, &priv->queue, wait);
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	if (kcs_bmc->data_in_avail)
>+	spin_lock_irq(&priv->lock);
>+	if (priv->data_in_avail)
> 		mask |= EPOLLIN;
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_unlock_irq(&priv->lock);
>
> 	return mask;
> }
>@@ -255,24 +320,24 @@ static __poll_t kcs_bmc_ipmi_poll(struct file *filp, poll_table *wait)
> static ssize_t kcs_bmc_ipmi_read(struct file *filp, char __user *buf,
> 			    size_t count, loff_t *ppos)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
> 	bool data_avail;
> 	size_t data_len;
> 	ssize_t ret;
>
> 	if (!(filp->f_flags & O_NONBLOCK))
>-		wait_event_interruptible(kcs_bmc->queue,
>-					 kcs_bmc->data_in_avail);
>+		wait_event_interruptible(priv->queue,
>+					 priv->data_in_avail);
>
>-	mutex_lock(&kcs_bmc->mutex);
>+	mutex_lock(&priv->mutex);
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	data_avail = kcs_bmc->data_in_avail;
>+	spin_lock_irq(&priv->lock);
>+	data_avail = priv->data_in_avail;
> 	if (data_avail) {
>-		data_len = kcs_bmc->data_in_idx;
>-		memcpy(kcs_bmc->kbuffer, kcs_bmc->data_in, data_len);
>+		data_len = priv->data_in_idx;
>+		memcpy(priv->kbuffer, priv->data_in, data_len);
> 	}
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_unlock_irq(&priv->lock);
>
> 	if (!data_avail) {
> 		ret = -EAGAIN;
>@@ -281,35 +346,35 @@ static ssize_t kcs_bmc_ipmi_read(struct file *filp, char __user *buf,
>
> 	if (count < data_len) {
> 		pr_err("channel=%u with too large data : %zu\n",
>-			kcs_bmc->channel, data_len);
>+			priv->client.dev->channel, data_len);
>
>-		spin_lock_irq(&kcs_bmc->lock);
>-		kcs_bmc_ipmi_force_abort(kcs_bmc);
>-		spin_unlock_irq(&kcs_bmc->lock);
>+		spin_lock_irq(&priv->lock);
>+		kcs_bmc_ipmi_force_abort(priv);
>+		spin_unlock_irq(&priv->lock);
>
> 		ret = -EOVERFLOW;
> 		goto out_unlock;
> 	}
>
>-	if (copy_to_user(buf, kcs_bmc->kbuffer, data_len)) {
>+	if (copy_to_user(buf, priv->kbuffer, data_len)) {
> 		ret = -EFAULT;
> 		goto out_unlock;
> 	}
>
> 	ret = data_len;
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	if (kcs_bmc->phase == KCS_PHASE_WRITE_DONE) {
>-		kcs_bmc->phase = KCS_PHASE_WAIT_READ;
>-		kcs_bmc->data_in_avail = false;
>-		kcs_bmc->data_in_idx = 0;
>+	spin_lock_irq(&priv->lock);
>+	if (priv->phase == KCS_PHASE_WRITE_DONE) {
>+		priv->phase = KCS_PHASE_WAIT_READ;
>+		priv->data_in_avail = false;
>+		priv->data_in_idx = 0;
> 	} else {
> 		ret = -EAGAIN;
> 	}
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_unlock_irq(&priv->lock);
>
> out_unlock:
>-	mutex_unlock(&kcs_bmc->mutex);
>+	mutex_unlock(&priv->mutex);
>
> 	return ret;
> }
>@@ -317,35 +382,35 @@ static ssize_t kcs_bmc_ipmi_read(struct file *filp, char __user *buf,
> static ssize_t kcs_bmc_ipmi_write(struct file *filp, const char __user *buf,
> 			     size_t count, loff_t *ppos)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
> 	ssize_t ret;
>
> 	/* a minimum response size '3' : netfn + cmd + ccode */
> 	if (count < 3 || count > KCS_MSG_BUFSIZ)
> 		return -EINVAL;
>
>-	mutex_lock(&kcs_bmc->mutex);
>+	mutex_lock(&priv->mutex);
>
>-	if (copy_from_user(kcs_bmc->kbuffer, buf, count)) {
>+	if (copy_from_user(priv->kbuffer, buf, count)) {
> 		ret = -EFAULT;
> 		goto out_unlock;
> 	}
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	if (kcs_bmc->phase == KCS_PHASE_WAIT_READ) {
>-		kcs_bmc->phase = KCS_PHASE_READ;
>-		kcs_bmc->data_out_idx = 1;
>-		kcs_bmc->data_out_len = count;
>-		memcpy(kcs_bmc->data_out, kcs_bmc->kbuffer, count);
>-		kcs_bmc_write_data(kcs_bmc, kcs_bmc->data_out[0]);
>+	spin_lock_irq(&priv->lock);
>+	if (priv->phase == KCS_PHASE_WAIT_READ) {
>+		priv->phase = KCS_PHASE_READ;
>+		priv->data_out_idx = 1;
>+		priv->data_out_len = count;
>+		memcpy(priv->data_out, priv->kbuffer, count);
>+		kcs_bmc_write_data(priv->client.dev, priv->data_out[0]);
> 		ret = count;
> 	} else {
> 		ret = -EINVAL;
> 	}
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_unlock_irq(&priv->lock);
>
> out_unlock:
>-	mutex_unlock(&kcs_bmc->mutex);
>+	mutex_unlock(&priv->mutex);
>
> 	return ret;
> }
>@@ -353,22 +418,22 @@ static ssize_t kcs_bmc_ipmi_write(struct file *filp, const char __user *buf,
> static long kcs_bmc_ipmi_ioctl(struct file *filp, unsigned int cmd,
> 			  unsigned long arg)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
> 	long ret = 0;
>
>-	spin_lock_irq(&kcs_bmc->lock);
>+	spin_lock_irq(&priv->lock);
>
> 	switch (cmd) {
> 	case IPMI_BMC_IOCTL_SET_SMS_ATN:
>-		kcs_bmc_update_status(kcs_bmc, KCS_STATUS_SMS_ATN, KCS_STATUS_SMS_ATN);
>+		kcs_bmc_update_status(priv->client.dev, KCS_STATUS_SMS_ATN, KCS_STATUS_SMS_ATN);
> 		break;
>
> 	case IPMI_BMC_IOCTL_CLEAR_SMS_ATN:
>-		kcs_bmc_update_status(kcs_bmc, KCS_STATUS_SMS_ATN, 0);
>+		kcs_bmc_update_status(priv->client.dev, KCS_STATUS_SMS_ATN, 0);
> 		break;
>
> 	case IPMI_BMC_IOCTL_FORCE_ABORT:
>-		kcs_bmc_ipmi_force_abort(kcs_bmc);
>+		kcs_bmc_ipmi_force_abort(priv);
> 		break;
>
> 	default:
>@@ -376,19 +441,17 @@ static long kcs_bmc_ipmi_ioctl(struct file *filp, unsigned int cmd,
> 		break;
> 	}
>
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_unlock_irq(&priv->lock);
>
> 	return ret;
> }
>
> static int kcs_bmc_ipmi_release(struct inode *inode, struct file *filp)
> {
>-	struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
>+	struct kcs_bmc_ipmi *priv = to_kcs_bmc(filp);
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	kcs_bmc->running = 0;
>-	kcs_bmc_ipmi_force_abort(kcs_bmc);
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	kcs_bmc_ipmi_force_abort(priv);
>+	kcs_bmc_disable_device(priv->client.dev, &priv->client);
>
> 	return 0;
> }
>@@ -403,56 +466,78 @@ static const struct file_operations kcs_bmc_ipmi_fops = {
> 	.unlocked_ioctl = kcs_bmc_ipmi_ioctl,
> };
>
>-int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc)
>+static DEFINE_SPINLOCK(kcs_bmc_ipmi_instances_lock);
>+static LIST_HEAD(kcs_bmc_ipmi_instances);
>+
>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc_device *kcs_bmc);
>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc_device *kcs_bmc)
> {
>+	struct kcs_bmc_ipmi *priv;
> 	int rc;
>
>-	spin_lock_init(&kcs_bmc->lock);
>-	mutex_init(&kcs_bmc->mutex);
>-	init_waitqueue_head(&kcs_bmc->queue);
>-
>-	kcs_bmc->client.dev = kcs_bmc;
>-	kcs_bmc->client.ops = &kcs_bmc_ipmi_client_ops;
>-	kcs_bmc->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>-	kcs_bmc->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>-	kcs_bmc->kbuffer = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>-
>-	kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
>-	kcs_bmc->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u",
>-					       DEVICE_NAME, kcs_bmc->channel);
>-	if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer ||
>-	    !kcs_bmc->miscdev.name)
>+	priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL);
>+	if (!priv)
> 		return -ENOMEM;
>
>-	kcs_bmc->miscdev.fops = &kcs_bmc_ipmi_fops;
>+	spin_lock_init(&priv->lock);
>+	mutex_init(&priv->mutex);
>
>-	rc = misc_register(&kcs_bmc->miscdev);
>+	init_waitqueue_head(&priv->queue);
>+
>+	priv->client.dev = kcs_bmc;
>+	priv->client.ops = &kcs_bmc_ipmi_client_ops;
>+	priv->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>+	priv->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>+	priv->kbuffer = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>+
>+	priv->miscdev.minor = MISC_DYNAMIC_MINOR;
>+	priv->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u", DEVICE_NAME,
>+					   kcs_bmc->channel);
>+	if (!priv->data_in || !priv->data_out || !priv->kbuffer || !priv->miscdev.name)
>+		return -EINVAL;
>+
>+	priv->miscdev.fops = &kcs_bmc_ipmi_fops;
>+
>+	rc = misc_register(&priv->miscdev);
> 	if (rc) {
> 		dev_err(kcs_bmc->dev, "Unable to register device: %d\n", rc);
> 		return rc;
> 	}
>
>+	spin_lock_irq(&kcs_bmc_ipmi_instances_lock);
>+	list_add(&priv->entry, &kcs_bmc_ipmi_instances);
>+	spin_unlock_irq(&kcs_bmc_ipmi_instances_lock);
>+
> 	dev_info(kcs_bmc->dev, "Initialised IPMI client for channel %d", kcs_bmc->channel);
>
> 	return 0;
> }
> EXPORT_SYMBOL(kcs_bmc_ipmi_attach_cdev);
>
>-int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc)
>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc);
>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc)
> {
>-	misc_deregister(&kcs_bmc->miscdev);
>+	struct kcs_bmc_ipmi *priv = NULL, *pos;
>
>-	spin_lock_irq(&kcs_bmc->lock);
>-	kcs_bmc->running = 0;
>-	kcs_bmc_ipmi_force_abort(kcs_bmc);
>-	spin_unlock_irq(&kcs_bmc->lock);
>+	spin_lock_irq(&kcs_bmc_ipmi_instances_lock);
>+	list_for_each_entry(pos, &kcs_bmc_ipmi_instances, entry) {
>+		if (pos->client.dev == kcs_bmc) {
>+			priv = pos;
>+			list_del(&pos->entry);
>+			break;
>+		}
>+	}
>+	spin_unlock_irq(&kcs_bmc_ipmi_instances_lock);
>
>-	devm_kfree(kcs_bmc->dev, kcs_bmc->kbuffer);
>-	devm_kfree(kcs_bmc->dev, kcs_bmc->data_out);
>-	devm_kfree(kcs_bmc->dev, kcs_bmc->data_in);
>-	devm_kfree(kcs_bmc->dev, kcs_bmc);
>+	if (!priv)
>+		return 0;

Would -ENOENT or something be appropriate here if the thing we're trying
to detach isn't found?

>+
>+	misc_deregister(&priv->miscdev);
>+	kcs_bmc_disable_device(priv->client.dev, &priv->client);
>+	devm_kfree(kcs_bmc->dev, priv->kbuffer);
>+	devm_kfree(kcs_bmc->dev, priv->data_out);
>+	devm_kfree(kcs_bmc->dev, priv->data_in);
>+	devm_kfree(kcs_bmc->dev, priv);
>
> 	return 0;
> }
>@@ -460,4 +545,5 @@ EXPORT_SYMBOL(kcs_bmc_ipmi_detach_cdev);
>
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");
>+MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
> MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");
>diff --git a/drivers/char/ipmi/kcs_bmc_client.h b/drivers/char/ipmi/kcs_bmc_client.h
>index 140631d157d8..2dd710f4b4aa 100644
>--- a/drivers/char/ipmi/kcs_bmc_client.h
>+++ b/drivers/char/ipmi/kcs_bmc_client.h
>@@ -8,22 +8,24 @@
> #include <linux/notifier.h>
> #include <stdbool.h>
>
>-struct kcs_bmc;
>-struct kcs_bmc_client_ops;
>-
>-struct kcs_bmc_client {
>-	const struct kcs_bmc_client_ops *ops;
>-
>-	struct kcs_bmc *dev;
>-};
>+#include "kcs_bmc.h"
>
> struct kcs_bmc_client_ops {
> 	int (*event)(struct kcs_bmc_client *client);
> };
>
>-u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc);
>-void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data);
>-u8 kcs_bmc_read_status(struct kcs_bmc *kcs_bmc);
>-void kcs_bmc_write_status(struct kcs_bmc *kcs_bmc, u8 data);
>-void kcs_bmc_update_status(struct kcs_bmc *kcs_bmc, u8 mask, u8 val);
>+struct kcs_bmc_client {
>+	const struct kcs_bmc_client_ops *ops;
>+
>+	struct kcs_bmc_device *dev;
>+};
>+
>+int kcs_bmc_enable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client);
>+void kcs_bmc_disable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client);
>+
>+u8 kcs_bmc_read_data(struct kcs_bmc_device *kcs_bmc);
>+void kcs_bmc_write_data(struct kcs_bmc_device *kcs_bmc, u8 data);
>+u8 kcs_bmc_read_status(struct kcs_bmc_device *kcs_bmc);
>+void kcs_bmc_write_status(struct kcs_bmc_device *kcs_bmc, u8 data);
>+void kcs_bmc_update_status(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 val);
> #endif
>diff --git a/drivers/char/ipmi/kcs_bmc_device.h b/drivers/char/ipmi/kcs_bmc_device.h
>index 33462174516d..57b7174b2bac 100644
>--- a/drivers/char/ipmi/kcs_bmc_device.h
>+++ b/drivers/char/ipmi/kcs_bmc_device.h
>@@ -7,13 +7,13 @@
> #include "kcs_bmc.h"
>
> struct kcs_bmc_device_ops {
>-	u8 (*io_inputb)(struct kcs_bmc *kcs_bmc, u32 reg);
>-	void (*io_outputb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 b);
>-	void (*io_updateb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 b);
>+	u8 (*io_inputb)(struct kcs_bmc_device *kcs_bmc, u32 reg);
>+	void (*io_outputb)(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 b);
>+	void (*io_updateb)(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 mask, u8 b);
> };
>
>-int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc);
>-int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc);
>+int kcs_bmc_handle_event(struct kcs_bmc_device *kcs_bmc);
>+int kcs_bmc_add_device(struct kcs_bmc_device *kcs_bmc);
>+int kcs_bmc_remove_device(struct kcs_bmc_device *kcs_bmc);
>
> #endif
>diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>index 1d21697fc585..dce93ec895fc 100644
>--- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>+++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>@@ -65,7 +65,7 @@ struct npcm7xx_kcs_reg {
> };
>
> struct npcm7xx_kcs_bmc {
>-	struct kcs_bmc kcs_bmc;
>+	struct kcs_bmc_device kcs_bmc;
>
> 	struct regmap *map;
>
>@@ -78,12 +78,12 @@ static const struct npcm7xx_kcs_reg npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {
> 	{ .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL, .ie = KCS3IE },
> };
>
>-static inline struct npcm7xx_kcs_bmc *to_npcm7xx_kcs_bmc(struct kcs_bmc *kcs_bmc)
>+static inline struct npcm7xx_kcs_bmc *to_npcm7xx_kcs_bmc(struct kcs_bmc_device *kcs_bmc)
> {
> 	return container_of(kcs_bmc, struct npcm7xx_kcs_bmc, kcs_bmc);
> }
>
>-static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
>+static u8 npcm7xx_kcs_inb(struct kcs_bmc_device *kcs_bmc, u32 reg)
> {
> 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> 	u32 val = 0;
>@@ -95,7 +95,7 @@ static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> 	return rc == 0 ? (u8)val : 0;
> }
>
>-static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
>+static void npcm7xx_kcs_outb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 data)
> {
> 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> 	int rc;
>@@ -104,7 +104,7 @@ static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> 	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
> }
>
>-static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 data)
>+static void npcm7xx_kcs_updateb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 mask, u8 data)
> {
> 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> 	int rc;
>@@ -113,7 +113,7 @@ static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 da
> 	WARN(rc != 0, "regmap_update_bits() failed: %d\n", rc);
> }
>
>-static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
>+static void npcm7xx_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enable)
> {
> 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
>
>@@ -126,7 +126,7 @@ static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
>
> static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)
> {
>-	struct kcs_bmc *kcs_bmc = arg;
>+	struct kcs_bmc_device *kcs_bmc = arg;
> 	int rc;
>
> 	rc = kcs_bmc_handle_event(kcs_bmc);
>@@ -136,7 +136,7 @@ static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)
> 	return rc == KCS_BMC_EVENT_HANDLED ? IRQ_HANDLED : IRQ_NONE;
> }
>
>-static int npcm7xx_kcs_config_irq(struct kcs_bmc *kcs_bmc,
>+static int npcm7xx_kcs_config_irq(struct kcs_bmc_device *kcs_bmc,
> 				  struct platform_device *pdev)
> {
> 	struct device *dev = &pdev->dev;
>@@ -160,7 +160,7 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
> {
> 	struct device *dev = &pdev->dev;
> 	struct npcm7xx_kcs_bmc *priv;
>-	struct kcs_bmc *kcs_bmc;
>+	struct kcs_bmc_device *kcs_bmc;
> 	u32 chan;
> 	int rc;
>
>@@ -207,7 +207,7 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
> static int npcm7xx_kcs_remove(struct platform_device *pdev)
> {
> 	struct npcm7xx_kcs_bmc *priv = platform_get_drvdata(pdev);
>-	struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
>+	struct kcs_bmc_device *kcs_bmc = &priv->kcs_bmc;
>
> 	kcs_bmc_remove_device(kcs_bmc);
>
>-- 
>2.27.0
>