IPMI: Add one interface to get more info of low-level IPMI device

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 mechansim 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.

Signed-off-by: Zhao Yakui <[e-mail]>
Signed-off-by: Corey Minyard <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/char/ipmi/ipmi_msghandler.c

···
 }
 EXPORT_SYMBOL(ipmi_create_user);
 
+int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *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 = -ENOSYS;
+	if (handlers->get_smi_info)
+		rv = handlers->get_smi_info(intf->send_info, 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);

drivers/char/ipmi/ipmi_si_intf.c

···
 #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"
···
 };
 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" };
···
 	struct task_struct *thread;
 
 	struct list_head link;
+	union ipmi_smi_info_union addr_info;
 };
 
 #define smi_inc_stat(smi, stat) \
···
 	return 0;
 }
 
+static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
+{
+	struct smi_info *smi = send_info;
+
+	data->addr_src = smi->addr_source;
+	data->dev = smi->dev;
+	data->addr_info = smi->addr_info;
+	get_device(smi->dev);
+
+	return 0;
+}
+
 static void set_maintenance_mode(void *send_info, int enable)
 {
 	struct smi_info   *smi_info = send_info;
···
 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,
···
 	printk(KERN_INFO PFX "probing via ACPI\n");
 
 	handle = acpi_dev->handle;
+	info->addr_info.acpi_info.acpi_handle = handle;
 
 	/* _IFT tells us the interface type: KCS, BT, etc */
 	status = acpi_evaluate_integer(handle, "_IFT", NULL, &tmp);

include/linux/ipmi.h

···
 /* Validate that the given IPMI address is valid. */
 int ipmi_validate_addr(struct ipmi_addr *addr, int len);
 
+/*
+ * How did the IPMI driver find out about the device?
+ */
+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_info_union {
+	/*
+	 * the acpi_info element is defined for the SI_ACPI
+	 * address type
+	 */
+	struct {
+		void *acpi_handle;
+	} acpi_info;
+};
+
+struct ipmi_smi_info {
+	enum ipmi_addr_src addr_src;
+
+	/*
+	 * Base device for the interface.  Don't forget to put this when
+	 * you are done.
+	 */
+	struct device *dev;
+
+	/*
+	 * The addr_info provides more detailed info for some IPMI
+	 * devices, depending on the addr_src.  Currently only SI_ACPI
+	 * info is provided.
+	 */
+	union ipmi_smi_info_union addr_info;
+};
+
+/* This is to get the private info of ipmi_smi_t */
+extern int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data);
+
 #endif /* __KERNEL__ */
 
 

include/linux/ipmi_smi.h

···
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
+#include <linux/ipmi.h>
 
 /* This files describes the interface for IPMI system management interface
    drivers to bind into the IPMI message handler. */
···
 	   this call. */
 	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 structure of ipmi_smi_data. For example: the
+	 * ACPI device handle will be returned for the pnp_acpi IPMI device.
+	 */
+	int (*get_smi_info)(void *send_info, struct ipmi_smi_info *data);
 
 	/* Called to enqueue an SMI message to be sent.  This
 	   operation is not allowed to fail.  If an error occurs, it