Re: [RFC PATCH 1/2_v9] IPMI: Add one interface to get more info of low-level IPMI device

[ykzhao <yakui.zhao@intel.com>]

On Mon, 2010-09-27 at 21:27 +0800, Corey Minyard wrote:
> On 09/26/2010 08:34 PM, ykzhao wrote:
> > On Wed, 2010-09-15 at 16:06 +0800, Zhao, Yakui wrote:
> >    
> >> From: Zhao Yakui<yakui.zhao@intel.com>
> >>
> >> The IPMI smi_watcher will be used to catch the IPMI interface as they come or go.
> >> In order to communicate with the correct IPMI device, it should be confirmed
> >>   whether it is what we wanted especially on the system with multiple IPMI
> >> devices. But the new_smi callback function of smi_watcher provides very
> >> limited info(only the interface number and dev pointer) and there is no
> >> detailed info about the low level interface. For example: which mechanism
> >> registers the IPMI interface(ACPI, PCI, DMI and so on).
> >>
> >> This is to add one interface that can get more info of low-level IPMI
> >> device. For example: the ACPI device handle will be returned for the pnp_acpi
> >> IPMI device.
> >>      
> > Hi, Corey
> > 	
> > 	Any comment about this patch? Does the interface make sense?
> >    
> Well, not exactly.  I think you have things in the right places, but the 
> actual design of the interface has some issues.

Thanks for the comments. 

I will follow your comments and update the corresponding data
structure. 

> 
> +enum ipmi_addr_src {
> +	SI_INVALID = 0, SI_HOTMOD, SI_HARDCODED, SI_SPMI, SI_ACPI, SI_SMBIOS,
> +	SI_PCI,	SI_DEVICETREE, SI_DEFAULT
> +};
> +union ipmi_smi_data{
> +	/* If the other type of data is required, please add it	 */
> +	u8 data[16];
> +	struct {
> +		void *acpi_handle;
> +		struct device *dev;
> +	} acpi_data;
> +};
> 
> There's no value in providing a union of this type.  Plus you call it 
> "ipmi_smi_data" and the function is get_smi_info.  I've learned that 
> consistency is a good thing.
> 
> The address source and device are fairly universal, and the address 
> source can be used as a key for the other stuff, so I think the 
> following makes more sense.  Just:
> 
> struct ipmi_smi_info
> {
>          enum ipmi_addr_src add_src;
>          struct device *dev;
> 
>          union {
>                  struct {
>                          acpi_handle acpi_handle;
>                  } acpi_addr_info;
>          } addr_info;
> };
> 
> In the future, if more information is needed, it can be added to the 
> structure.  Since there's no guarantee of a stable binary interface, no 
> need for the character array.
> 
> You will also need ifdefs in here for ACPI, includes so acpi_handle is 
> available, and you need to decide  how to do refcounts on "dev" and 
> document that.
> 
> -corey
> 
> > Thanks.
> >    
> >> Signed-off-by: Zhao Yakui<yakui.zhao@intel.com>
> >> ---
> >> In this patch only the info of pnp_acpi IPMI is provided. If the detailed info
> >> is also required for other mechanism, we can redesign the structure of
> >> ipmi_smi_data and fill it correctly.
> >>
> >>   drivers/char/ipmi/ipmi_msghandler.c |   26 ++++++++++++++++++++++++++
> >>   drivers/char/ipmi/ipmi_si_intf.c    |   24 ++++++++++++++++++++----
> >>   include/linux/ipmi.h                |   16 ++++++++++++++++
> >>   include/linux/ipmi_smi.h            |   11 +++++++++++
> >>   4 files changed, 73 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> >> index 4f3f8c9..f82d426 100644
> >> --- a/drivers/char/ipmi/ipmi_msghandler.c
> >> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> >> @@ -970,6 +970,32 @@ out_kfree:
> >>   }
> >>   EXPORT_SYMBOL(ipmi_create_user);
> >>
> >> +int ipmi_get_smi_info(int if_num, enum ipmi_addr_src type,
> >> +			union ipmi_smi_data *data)
> >> +{
> >> +	int           rv = 0;
> >> +	ipmi_smi_t    intf;
> >> +	struct ipmi_smi_handlers *handlers;
> >> +
> >> +	mutex_lock(&ipmi_interfaces_mutex);
> >> +	list_for_each_entry_rcu(intf,&ipmi_interfaces, link) {
> >> +		if (intf->intf_num == if_num)
> >> +			goto found;
> >> +	}
> >> +	/* Not found, return an error */
> >> +	rv = -EINVAL;
> >> +	mutex_unlock(&ipmi_interfaces_mutex);
> >> +	return rv;
> >> +
> >> +found:
> >> +	handlers = intf->handlers;
> >> +	rv = handlers->get_smi_info(intf->send_info, type, data);
> >> +	mutex_unlock(&ipmi_interfaces_mutex);
> >> +
> >> +	return rv;
> >> +}
> >> +EXPORT_SYMBOL(ipmi_get_smi_info);
> >> +
> >>   static void free_user(struct kref *ref)
> >>   {
> >>   	ipmi_user_t user = container_of(ref, struct ipmi_user, refcount);
> >> diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
> >> index 3822b4f..ebb87b4 100644
> >> --- a/drivers/char/ipmi/ipmi_si_intf.c
> >> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> >> @@ -57,6 +57,7 @@
> >>   #include<asm/irq.h>
> >>   #include<linux/interrupt.h>
> >>   #include<linux/rcupdate.h>
> >> +#include<linux/ipmi.h>
> >>   #include<linux/ipmi_smi.h>
> >>   #include<asm/io.h>
> >>   #include "ipmi_si_sm.h"
> >> @@ -107,10 +108,6 @@ enum si_type {
> >>   };
> >>   static char *si_to_str[] = { "kcs", "smic", "bt" };
> >>
> >> -enum ipmi_addr_src {
> >> -	SI_INVALID = 0, SI_HOTMOD, SI_HARDCODED, SI_SPMI, SI_ACPI, SI_SMBIOS,
> >> -	SI_PCI,	SI_DEVICETREE, SI_DEFAULT
> >> -};
> >>   static char *ipmi_addr_src_to_str[] = { NULL, "hotmod", "hardcoded", "SPMI",
> >>   					"ACPI", "SMBIOS", "PCI",
> >>   					"device-tree", "default" };
> >> @@ -291,6 +288,7 @@ struct smi_info {
> >>   	struct task_struct *thread;
> >>
> >>   	struct list_head link;
> >> +	union ipmi_smi_data smi_data;
> >>   };
> >>
> >>   #define smi_inc_stat(smi, stat) \
> >> @@ -1183,6 +1181,21 @@ static int smi_start_processing(void       *send_info,
> >>   	return 0;
> >>   }
> >>
> >> +static int get_smi_info(void *send_info,
> >> +			enum ipmi_addr_src type,
> >> +			union ipmi_smi_data *data)
> >> +{
> >> +	struct smi_info *new_smi = send_info;
> >> +	union ipmi_smi_data *smi_data =&new_smi->smi_data;
> >> +
> >> +	if (new_smi->addr_source != type)
> >> +		return -EINVAL;
> >> +
> >> +	memcpy(data, smi_data, sizeof(*smi_data));
> >> +
> >> +	return 0;
> >> +}
> >> +
> >>   static void set_maintenance_mode(void *send_info, int enable)
> >>   {
> >>   	struct smi_info   *smi_info = send_info;
> >> @@ -1194,6 +1207,7 @@ static void set_maintenance_mode(void *send_info, int enable)
> >>   static struct ipmi_smi_handlers handlers = {
> >>   	.owner                  = THIS_MODULE,
> >>   	.start_processing       = smi_start_processing,
> >> +	.get_smi_info		= get_smi_info,
> >>   	.sender			= sender,
> >>   	.request_events		= request_events,
> >>   	.set_maintenance_mode   = set_maintenance_mode,
> >> @@ -2140,6 +2154,8 @@ static int __devinit ipmi_pnp_probe(struct pnp_dev *dev,
> >>   		return -ENOMEM;
> >>
> >>   	info->addr_source = SI_ACPI;
> >> +	info->smi_data.acpi_data.acpi_handle = acpi_dev->handle;
> >> +	info->smi_data.acpi_data.dev =&dev->dev;
> >>   	printk(KERN_INFO PFX "probing via ACPI\n");
> >>
> >>   	handle = acpi_dev->handle;
> >> diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
> >> index 65aae34..04e4a90 100644
> >> --- a/include/linux/ipmi.h
> >> +++ b/include/linux/ipmi.h
> >> @@ -454,6 +454,22 @@ unsigned int ipmi_addr_length(int addr_type);
> >>   /* Validate that the given IPMI address is valid. */
> >>   int ipmi_validate_addr(struct ipmi_addr *addr, int len);
> >>
> >> +enum ipmi_addr_src {
> >> +	SI_INVALID = 0, SI_HOTMOD, SI_HARDCODED, SI_SPMI, SI_ACPI, SI_SMBIOS,
> >> +	SI_PCI,	SI_DEVICETREE, SI_DEFAULT
> >> +};
> >> +union ipmi_smi_data{
> >> +	/* If the other type of data is required, please add it	 */
> >> +	u8 data[16];
> >> +	struct {
> >> +		void *acpi_handle;
> >> +		struct device *dev;
> >> +	} acpi_data;
> >> +};
> >> +
> >> +/* This is to get the private info of ipmi_smi_t */
> >> +extern int ipmi_get_smi_info(int if_num, enum ipmi_addr_src type,
> >> +		union ipmi_smi_data *data);
> >>   #endif /* __KERNEL__ */
> >>
> >>
> >> diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
> >> index 4b48318..d5bae83 100644
> >> --- a/include/linux/ipmi_smi.h
> >> +++ b/include/linux/ipmi_smi.h
> >> @@ -86,6 +86,17 @@ struct ipmi_smi_handlers {
> >>   	int (*start_processing)(void       *send_info,
> >>   				ipmi_smi_t new_intf);
> >>
> >> +	/*
> >> +	 * Get the detailed private info of the low level interface and store
> >> +	 * it into the union structure of ipmi_smi_data. For example: the
> >> +	 * ACPI device handle will be returned for the pnp_acpi IPMI device.
> >> +	 * Of course it will firstly compare the interface type of low-level
> >> +	 * interface(Hardcoded type, DMI, ACPI and so on). If the type doesn't
> >> +	 * match, it will return -EINVAL.
> >> +	 */
> >> +	int (*get_smi_info)(void *send_info, enum ipmi_addr_src type,
> >> +				union ipmi_smi_data *data);
> >> +
> >>   	/* Called to enqueue an SMI message to be sent.  This
> >>   	   operation is not allowed to fail.  If an error occurs, it
> >>   	   should report back the error in a received message.  It may
> >>      
> >    
>