ipmi: kcs_bmc: Strip private client data from struct kcs_bmc

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 <[email protected]>
Reviewed-by: Zev Weiss <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>

Author: amboar

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 +15,98 @@
 
 /* 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);
 
-irqreturn_t kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc)
+irqreturn_t kcs_bmc_handle_event(struct kcs_bmc_device *kcs_bmc)
 {
-	return kcs_bmc->client.ops->event(&kcs_bmc->client);
+	struct kcs_bmc_client *client;
+	irqreturn_t 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 = IRQ_HANDLED;
+		} else {
+			rc = IRQ_NONE;
+		}
+	}
+	spin_unlock(&kcs_bmc->lock);
+
+	return rc;
 }
 EXPORT_SYMBOL(kcs_bmc_handle_event);
 
-int kcs_bmc_ipmi_add_device(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;
+	spin_unlock_irq(&kcs_bmc->lock);
+}
+EXPORT_SYMBOL(kcs_bmc_disable_device);
+
+int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc);
+int kcs_bmc_add_device(struct kcs_bmc_device *kcs_bmc)
 {
 	return kcs_bmc_ipmi_add_device(kcs_bmc);
 }
 EXPORT_SYMBOL(kcs_bmc_add_device);
 
-int kcs_bmc_ipmi_remove_device(struct kcs_bmc *kcs_bmc);
-void kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc)
+int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc);
+void kcs_bmc_remove_device(struct kcs_bmc_device *kcs_bmc)
 {
 	if (kcs_bmc_ipmi_remove_device(kcs_bmc))
 		pr_warn("Failed to remove device for KCS channel %d\n",

drivers/char/ipmi/kcs_bmc.h

@@ -6,61 +6,12 @@
 #ifndef __KCS_BMC_H__
 #define __KCS_BMC_H__
 
-#include <linux/miscdevice.h>
-
-#include "kcs_bmc_client.h"
+#include <linux/list.h>
 
 #define KCS_BMC_STR_OBF		BIT(0)
 #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
@@ -73,36 +24,20 @@ struct kcs_ioreg {
 };
 
 struct kcs_bmc_device_ops;
+struct kcs_bmc_client;
 
-struct kcs_bmc {
-	struct device *dev;
-
-	const struct kcs_bmc_device_ops *ops;
-
-	struct kcs_bmc_client client;
-
-	spinlock_t lock;
+struct kcs_bmc_device {
+	struct list_head entry;
 
+	struct device *dev;
 	u32 channel;
-	int running;
 
 	struct kcs_ioreg ioreg;
 
-	enum kcs_phases phase;
-	enum kcs_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;
+	const struct kcs_bmc_device_ops *ops;
 
-	struct miscdevice miscdev;
+	spinlock_t lock;
+	struct kcs_bmc_client *client;
 };
+
 #endif /* __KCS_BMC_H__ */

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);
 
@@ -228,12 +228,12 @@ 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;
 
 	return kcs_bmc_handle_event(kcs_bmc);
 }
 
-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;
@@ -335,8 +335,8 @@ 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;
 
@@ -399,7 +399,7 @@ 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);