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>

2 files changed, 65 insertions, 2 deletions

diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index d7e97ae9ef6d..25bcd4c0ed82 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -1,5 +1,5 @@
 /*
- * Copyright IBM Corp. 1999, 2009
+ * Copyright IBM Corp. 1999,2012
  *
  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
@@ -103,6 +103,7 @@ extern u64 sclp_facilities;
 #define SCLP_HAS_CHP_RECONFIG   (sclp_facilities & 0x2000000000000000ULL)
 #define SCLP_HAS_CPU_INFO       (sclp_facilities & 0x0800000000000000ULL)
 #define SCLP_HAS_CPU_RECONFIG   (sclp_facilities & 0x0400000000000000ULL)
+#define SCLP_HAS_PCI_RECONFIG   (sclp_facilities & 0x0000000040000000ULL)
 
 
 struct gds_subvector {
diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 0dfa88a30118..c44d13f607bc 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright IBM Corp. 2007, 2009
+ * Copyright IBM Corp. 2007,2012
  *
  * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
  *            Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
@@ -12,6 +12,7 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/err.h>
+#include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/mm.h>
@@ -701,6 +702,67 @@ __initcall(sclp_detect_standby_memory);
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 /*
+ * PCI I/O adapter configuration related functions.
+ */
+#define SCLP_CMDW_CONFIGURE_PCI                 0x001a0001
+#define SCLP_CMDW_DECONFIGURE_PCI               0x001b0001
+
+#define SCLP_RECONFIG_PCI_ATPYE                 2
+
+struct pci_cfg_sccb {
+        struct sccb_header header;
+        u8 atype;               /* adapter type */
+        u8 reserved1;
+        u16 reserved2;
+        u32 aid;                /* adapter identifier */
+} __packed;
+
+static int do_pci_configure(sclp_cmdw_t cmd, u32 fid)
+{
+        struct pci_cfg_sccb *sccb;
+        int rc;
+
+        if (!SCLP_HAS_PCI_RECONFIG)
+                return -EOPNOTSUPP;
+
+        sccb = (struct pci_cfg_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
+        if (!sccb)
+                return -ENOMEM;
+
+        sccb->header.length = PAGE_SIZE;
+        sccb->atype = SCLP_RECONFIG_PCI_ATPYE;
+        sccb->aid = fid;
+        rc = do_sync_request(cmd, sccb);
+        if (rc)
+                goto out;
+        switch (sccb->header.response_code) {
+        case 0x0020:
+        case 0x0120:
+                break;
+        default:
+                pr_warn("configure PCI I/O adapter failed: cmd=0x%08x  response=0x%04x\n",
+                        cmd, sccb->header.response_code);
+                rc = -EIO;
+                break;
+        }
+out:
+        free_page((unsigned long) sccb);
+        return rc;
+}
+
+int sclp_pci_configure(u32 fid)
+{
+        return do_pci_configure(SCLP_CMDW_CONFIGURE_PCI, fid);
+}
+EXPORT_SYMBOL(sclp_pci_configure);
+
+int sclp_pci_deconfigure(u32 fid)
+{
+        return do_pci_configure(SCLP_CMDW_DECONFIGURE_PCI, fid);
+}
+EXPORT_SYMBOL(sclp_pci_deconfigure);
+
+/*
  * Channel path configuration related functions.
  */