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

[Zev Weiss]

On Mon, May 10, 2021 at 12:42:05AM CDT, Andrew Jeffery wrote:
>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);

s/chardev/driver/?

>+	}
>+	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);

s/add chardev/remove driver/?

>+	}
>+	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
>