RE: [PATCH v2 13/21] ipmi: kcs_bmc: Decouple the IPMI chardev from the core

[ChiaWei Wang <chiawei_wang@xxxxxxxxxxxxxx>]

I have tried this patch on Intel EGS CRB with AST2600 A1 as the BMC.
Chiawei

Tested-by: Chia-Wei Wang <chiawei_wang@xxxxxxxxxxxxxx>

> -----Original Message-----
> From: Andrew Jeffery <andrew@xxxxxxxx>
> Sent: Friday, March 19, 2021 2:28 PM
> To: openipmi-developer@xxxxxxxxxxxxxxxxxxxxx; openbmc@xxxxxxxxxxxxxxxx;
> minyard@xxxxxxx
> Subject: [PATCH v2 13/21] ipmi: kcs_bmc: Decouple the IPMI chardev from the
> core
> 
> 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           | 78
> ++++++++++++++++++++++++++-
>  drivers/char/ipmi/kcs_bmc.h           |  4 --
>  drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 33 +++++++++---
>  drivers/char/ipmi/kcs_bmc_client.h    | 14 +++++
>  6 files changed, 132 insertions(+), 13 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
> 266ebec71d6f..694db6ee2a92 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 probed devices and cdevs */
> +static DEFINE_MUTEX(kcs_bmc_lock);
> +static LIST_HEAD(kcs_bmc_devices);
> +static LIST_HEAD(kcs_bmc_cdevs);
> +
>  /* Consumer data access */
> 
>  u8 kcs_bmc_read_data(struct kcs_bmc_device *kcs_bmc) @@ -100,16
> +107,83 @@ 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);
> +	struct kcs_bmc_cdev *cdev;
> +	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(cdev, &kcs_bmc_cdevs, entry) {
> +		rc = cdev->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);
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL(kcs_bmc_add_device);
> 
>  int kcs_bmc_remove_device(struct kcs_bmc_device *kcs_bmc)  {
> -	return kcs_bmc_ipmi_detach_cdev(kcs_bmc);
> +	struct kcs_bmc_cdev *cdev;
> +	int rc;
> +
> +	mutex_lock(&kcs_bmc_lock);
> +	list_del(&kcs_bmc->entry);
> +	list_for_each_entry(cdev, &kcs_bmc_cdevs, entry) {
> +		rc = cdev->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);
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL(kcs_bmc_remove_device);
> 
> +int kcs_bmc_register_cdev(struct kcs_bmc_cdev *cdev) {
> +	struct kcs_bmc_device *kcs_bmc;
> +	int rc;
> +
> +	mutex_lock(&kcs_bmc_lock);
> +	list_add(&cdev->entry, &kcs_bmc_cdevs);
> +	list_for_each_entry(kcs_bmc, &kcs_bmc_devices, entry) {
> +		rc = cdev->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);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(kcs_bmc_register_cdev);
> +
> +int kcs_bmc_unregister_cdev(struct kcs_bmc_cdev *cdev) {
> +	struct kcs_bmc_device *kcs_bmc;
> +	int rc;
> +
> +	mutex_lock(&kcs_bmc_lock);
> +	list_del(&cdev->entry);
> +	list_for_each_entry(kcs_bmc, &kcs_bmc_devices, entry) {
> +		rc = cdev->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);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL(kcs_bmc_unregister_cdev);
> +
>  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.h b/drivers/char/ipmi/kcs_bmc.h index
> 3f266740c759..5deb9a0b8e60 100644
> --- a/drivers/char/ipmi/kcs_bmc.h
> +++ b/drivers/char/ipmi/kcs_bmc.h
> @@ -42,8 +42,4 @@ struct kcs_bmc_device {
>  	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_cdev_ipmi.c
> b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
> index 58c42e76483d..df83d67851ac 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_attach_cdev(struct kcs_bmc_device *kcs_bmc); -int
> kcs_bmc_ipmi_attach_cdev(struct kcs_bmc_device *kcs_bmc)
> +static int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc_device *kcs_bmc)
>  {
>  	struct kcs_bmc_ipmi *priv;
>  	int rc;
> @@ -512,10 +511,8 @@ int kcs_bmc_ipmi_attach_cdev(struct
> kcs_bmc_device *kcs_bmc)
> 
>  	return 0;
>  }
> -EXPORT_SYMBOL(kcs_bmc_ipmi_attach_cdev);
> 
> -int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc); -int
> kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc)
> +static int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc_device *kcs_bmc)
>  {
>  	struct kcs_bmc_ipmi *priv = NULL, *pos;
> 
> @@ -541,7 +538,31 @@ int kcs_bmc_ipmi_detach_cdev(struct
> kcs_bmc_device *kcs_bmc)
> 
>  	return 0;
>  }
> -EXPORT_SYMBOL(kcs_bmc_ipmi_detach_cdev);
> +
> +static const struct kcs_bmc_cdev_ops kcs_bmc_ipmi_cdev_ops = {
> +	.add_device = kcs_bmc_ipmi_attach_cdev,
> +	.remove_device = kcs_bmc_ipmi_detach_cdev, };
> +
> +static struct kcs_bmc_cdev kcs_bmc_ipmi_cdev = {
> +	.ops = &kcs_bmc_ipmi_cdev_ops,
> +};
> +
> +static int kcs_bmc_ipmi_init(void)
> +{
> +	return kcs_bmc_register_cdev(&kcs_bmc_ipmi_cdev);
> +}
> +module_init(kcs_bmc_ipmi_init);
> +
> +static void kcs_bmc_ipmi_exit(void)
> +{
> +	int rc;
> +
> +	rc = kcs_bmc_unregister_cdev(&kcs_bmc_ipmi_cdev);
> +	if (rc)
> +		pr_warn("Failed to remove KCS BMC client: %d", rc); }
> +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 2dd710f4b4aa..d0a7404ff584 100644
> --- a/drivers/char/ipmi/kcs_bmc_client.h
> +++ b/drivers/char/ipmi/kcs_bmc_client.h
> @@ -10,6 +10,17 @@
> 
>  #include "kcs_bmc.h"
> 
> +struct kcs_bmc_cdev_ops {
> +	int (*add_device)(struct kcs_bmc_device *kcs_bmc);
> +	int (*remove_device)(struct kcs_bmc_device *kcs_bmc); };
> +
> +struct kcs_bmc_cdev {
> +	struct list_head entry;
> +
> +	const struct kcs_bmc_cdev_ops *ops;
> +};
> +
>  struct kcs_bmc_client_ops {
>  	int (*event)(struct kcs_bmc_client *client);  }; @@ -20,6 +31,9 @@
> struct kcs_bmc_client {
>  	struct kcs_bmc_device *dev;
>  };
> 
> +int kcs_bmc_register_cdev(struct kcs_bmc_cdev *cdev); int
> +kcs_bmc_unregister_cdev(struct kcs_bmc_cdev *cdev);
> +
>  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