s390/pci: PCI hotplug support via SCLP

Add SCLP PCI configure/deconfigure and implement a PCI hotplug
controller (s390_pci_hpc). The hotplug controller creates a slot
for every PCI function in stand-by or configured state. The PCI
functions are named after the PCI function ID (fid). By writing to
the power attribute in /sys/bus/pci/slots/<fid>/power the PCI function
is moved to stand-by or configured state. If moved to the configured
state the device is automatically scanned by the s390 PCI layer.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 22 insertions, 0 deletions

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index d3597dcfec33..48ce434d6fda 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -95,6 +95,11 @@ struct zpci_dev {
         enum pci_bus_speed max_bus_speed;
 };
 
+struct pci_hp_callback_ops {
+        int (*create_slot)      (struct zpci_dev *zdev);
+        void (*remove_slot)     (struct zpci_dev *zdev);
+};
+
 static inline bool zdev_enabled(struct zpci_dev *zdev)
 {
         return (zdev->fh & (1UL << 31)) ? true : false;
@@ -140,4 +145,10 @@ bool zpci_fid_present(u32);
 int zpci_dma_init(void);
 void zpci_dma_exit(void);
 
+/* Hotplug */
+extern struct mutex zpci_list_lock;
+extern struct list_head zpci_list;
+extern struct pci_hp_callback_ops hotplug_ops;
+extern unsigned int pci_probe;
+
 #endif
diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h
index e62a555557ee..833788693f09 100644
--- a/arch/s390/include/asm/sclp.h
+++ b/arch/s390/include/asm/sclp.h
@@ -55,5 +55,7 @@ int sclp_chp_read_info(struct sclp_chp_info *info);
 void sclp_get_ipl_info(struct sclp_ipl_info *info);
 bool sclp_has_linemode(void);
 bool sclp_has_vt220(void);
+int sclp_pci_configure(u32 fid);
+int sclp_pci_deconfigure(u32 fid);
 
 #endif /* _ASM_S390_SCLP_H */
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 5a2ef9e75c97..c523594a6d45 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -47,7 +47,12 @@
 
 /* list of all detected zpci devices */
 LIST_HEAD(zpci_list);
+EXPORT_SYMBOL_GPL(zpci_list);
 DEFINE_MUTEX(zpci_list_lock);
+EXPORT_SYMBOL_GPL(zpci_list_lock);
+
+struct pci_hp_callback_ops hotplug_ops;
+EXPORT_SYMBOL_GPL(hotplug_ops);
 
 static DECLARE_BITMAP(zpci_domain, ZPCI_NR_DEVICES);
 static DEFINE_SPINLOCK(zpci_domain_lock);
@@ -935,6 +940,8 @@ int zpci_create_device(struct zpci_dev *zdev)
 
         mutex_lock(&zpci_list_lock);
         list_add_tail(&zdev->entry, &zpci_list);
+        if (hotplug_ops.create_slot)
+                hotplug_ops.create_slot(zdev);
         mutex_unlock(&zpci_list_lock);
 
         if (zdev->state == ZPCI_FN_STATE_STANDBY)
@@ -948,6 +955,8 @@ int zpci_create_device(struct zpci_dev *zdev)
 out_start:
         mutex_lock(&zpci_list_lock);
         list_del(&zdev->entry);
+        if (hotplug_ops.remove_slot)
+                hotplug_ops.remove_slot(zdev);
         mutex_unlock(&zpci_list_lock);
 out_bus:
         zpci_free_domain(zdev);