[PATCH v3 08/16] ipmi: kcs_bmc: Decouple the IPMI chardev from the core

From: Andrew Jeffery
Date: Mon May 10 2021 - 01:44:06 EST


Now that we have untangled the data-structures, split the userspace
interface out into its own module. Userspace interfaces and drivers are
registered to the KCS BMC core to support arbitrary binding of either.

Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
---
drivers/char/ipmi/Kconfig | 13 +++++
drivers/char/ipmi/Makefile | 3 +-
drivers/char/ipmi/kcs_bmc.c | 76 ++++++++++++++++++++++++---
drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 31 ++++++++---
drivers/char/ipmi/kcs_bmc_client.h | 14 +++++
5 files changed, 122 insertions(+), 15 deletions(-)

diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 07847d9a459a..bc5f81899b62 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -124,6 +124,19 @@ config NPCM7XX_KCS_IPMI_BMC
This support is also available as a module. If so, the module
will be called kcs_bmc_npcm7xx.

+config IPMI_KCS_BMC_CDEV_IPMI
+ depends on IPMI_KCS_BMC
+ tristate "IPMI character device interface for BMC KCS devices"
+ help
+ Provides a BMC-side character device implementing IPMI
+ semantics for KCS IPMI devices.
+
+ Say YES if you wish to expose KCS devices on the BMC for IPMI
+ purposes.
+
+ This support is also available as a module. The module will be
+ called kcs_bmc_cdev_ipmi.
+
config ASPEED_BT_IPMI_BMC
depends on ARCH_ASPEED || COMPILE_TEST
depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index a302bc865370..fcfa676afddb 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -22,7 +22,8 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
-obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o kcs_bmc_cdev_ipmi.o
+obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o
+obj-$(CONFIG_IPMI_KCS_BMC_CDEV_IPMI) += kcs_bmc_cdev_ipmi.o
obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
index 70bfeb72c3c7..2ec8312ce766 100644
--- a/drivers/char/ipmi/kcs_bmc.c
+++ b/drivers/char/ipmi/kcs_bmc.c
@@ -5,7 +5,9 @@
*/

#include <linux/device.h>
+#include <linux/list.h>
#include <linux/module.h>
+#include <linux/mutex.h>

#include "kcs_bmc.h"

@@ -13,6 +15,11 @@
#include "kcs_bmc_device.h"
#include "kcs_bmc_client.h"

+/* Record registered devices and drivers */
+static DEFINE_MUTEX(kcs_bmc_lock);
+static LIST_HEAD(kcs_bmc_devices);
+static LIST_HEAD(kcs_bmc_drivers);
+
/* Consumer data access */

u8 kcs_bmc_read_data(struct kcs_bmc_device *kcs_bmc)
@@ -98,24 +105,77 @@ void kcs_bmc_disable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_clien
}
EXPORT_SYMBOL(kcs_bmc_disable_device);

-int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc);
void kcs_bmc_add_device(struct kcs_bmc_device *kcs_bmc)
{
- if (kcs_bmc_ipmi_add_device(kcs_bmc))
- pr_warn("Failed to add device for KCS channel %d\n",
- kcs_bmc->channel);
+ struct kcs_bmc_driver *drv;
+ int rc;
+
+ spin_lock_init(&kcs_bmc->lock);
+ kcs_bmc->client = NULL;
+
+ mutex_lock(&kcs_bmc_lock);
+ list_add(&kcs_bmc->entry, &kcs_bmc_devices);
+ list_for_each_entry(drv, &kcs_bmc_drivers, entry) {
+ rc = drv->ops->add_device(kcs_bmc);
+ if (rc)
+ dev_err(kcs_bmc->dev, "Failed to add chardev for KCS channel %d: %d",
+ kcs_bmc->channel, rc);
+ }
+ mutex_unlock(&kcs_bmc_lock);
}
EXPORT_SYMBOL(kcs_bmc_add_device);

-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",
- kcs_bmc->channel);
+ struct kcs_bmc_driver *drv;
+ int rc;
+
+ mutex_lock(&kcs_bmc_lock);
+ list_del(&kcs_bmc->entry);
+ list_for_each_entry(drv, &kcs_bmc_drivers, entry) {
+ rc = drv->ops->remove_device(kcs_bmc);
+ if (rc)
+ dev_err(kcs_bmc->dev, "Failed to remove chardev for KCS channel %d: %d",
+ kcs_bmc->channel, rc);
+ }
+ mutex_unlock(&kcs_bmc_lock);
}
EXPORT_SYMBOL(kcs_bmc_remove_device);

+void kcs_bmc_register_driver(struct kcs_bmc_driver *drv)
+{
+ struct kcs_bmc_device *kcs_bmc;
+ int rc;
+
+ mutex_lock(&kcs_bmc_lock);
+ list_add(&drv->entry, &kcs_bmc_drivers);
+ list_for_each_entry(kcs_bmc, &kcs_bmc_devices, entry) {
+ rc = drv->ops->add_device(kcs_bmc);
+ if (rc)
+ dev_err(kcs_bmc->dev, "Failed to add chardev for KCS channel %d: %d",
+ kcs_bmc->channel, rc);
+ }
+ mutex_unlock(&kcs_bmc_lock);
+}
+EXPORT_SYMBOL(kcs_bmc_register_driver);
+
+void kcs_bmc_unregister_driver(struct kcs_bmc_driver *drv)
+{
+ struct kcs_bmc_device *kcs_bmc;
+ int rc;
+
+ mutex_lock(&kcs_bmc_lock);
+ list_del(&drv->entry);
+ list_for_each_entry(kcs_bmc, &kcs_bmc_devices, entry) {
+ rc = drv->ops->remove_device(kcs_bmc);
+ if (rc)
+ dev_err(kcs_bmc->dev, "Failed to add chardev for KCS channel %d: %d",
+ kcs_bmc->channel, rc);
+ }
+ mutex_unlock(&kcs_bmc_lock);
+}
+EXPORT_SYMBOL(kcs_bmc_unregister_driver);
+
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
MODULE_AUTHOR("Andrew Jeffery <andrew@xxxxxxxx>");
diff --git a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
index 865d8b93f3b7..486834a962c3 100644
--- a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
+++ b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
@@ -469,8 +469,7 @@ static const struct file_operations kcs_bmc_ipmi_fops = {
static DEFINE_SPINLOCK(kcs_bmc_ipmi_instances_lock);
static LIST_HEAD(kcs_bmc_ipmi_instances);

-int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc);
-int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc)
+static int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc)
{
struct kcs_bmc_ipmi *priv;
int rc;
@@ -512,10 +511,8 @@ int kcs_bmc_ipmi_add_device(struct kcs_bmc_device *kcs_bmc)

return 0;
}
-EXPORT_SYMBOL(kcs_bmc_ipmi_add_device);

-int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc);
-int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc)
+static int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc)
{
struct kcs_bmc_ipmi *priv = NULL, *pos;

@@ -541,7 +538,29 @@ int kcs_bmc_ipmi_remove_device(struct kcs_bmc_device *kcs_bmc)

return 0;
}
-EXPORT_SYMBOL(kcs_bmc_ipmi_remove_device);
+
+static const struct kcs_bmc_driver_ops kcs_bmc_ipmi_driver_ops = {
+ .add_device = kcs_bmc_ipmi_add_device,
+ .remove_device = kcs_bmc_ipmi_remove_device,
+};
+
+static struct kcs_bmc_driver kcs_bmc_ipmi_driver = {
+ .ops = &kcs_bmc_ipmi_driver_ops,
+};
+
+static int kcs_bmc_ipmi_init(void)
+{
+ kcs_bmc_register_driver(&kcs_bmc_ipmi_driver);
+
+ return 0;
+}
+module_init(kcs_bmc_ipmi_init);
+
+static void kcs_bmc_ipmi_exit(void)
+{
+ kcs_bmc_unregister_driver(&kcs_bmc_ipmi_driver);
+}
+module_exit(kcs_bmc_ipmi_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
diff --git a/drivers/char/ipmi/kcs_bmc_client.h b/drivers/char/ipmi/kcs_bmc_client.h
index c0f85c5bdf5c..cb38b56cda85 100644
--- a/drivers/char/ipmi/kcs_bmc_client.h
+++ b/drivers/char/ipmi/kcs_bmc_client.h
@@ -11,6 +11,17 @@

#include "kcs_bmc.h"

+struct kcs_bmc_driver_ops {
+ int (*add_device)(struct kcs_bmc_device *kcs_bmc);
+ int (*remove_device)(struct kcs_bmc_device *kcs_bmc);
+};
+
+struct kcs_bmc_driver {
+ struct list_head entry;
+
+ const struct kcs_bmc_driver_ops *ops;
+};
+
struct kcs_bmc_client_ops {
irqreturn_t (*event)(struct kcs_bmc_client *client);
};
@@ -21,6 +32,9 @@ struct kcs_bmc_client {
struct kcs_bmc_device *dev;
};

+void kcs_bmc_register_driver(struct kcs_bmc_driver *drv);
+void kcs_bmc_unregister_driver(struct kcs_bmc_driver *drv);
+
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);

--
2.27.0