powerpc/pseries: Kernel DLPAR Infrastructure

The Dynamic Logical Partitioning capabilities of the powerpc pseries platform
allows for the addition and removal of resources (i.e. CPU's, memory, and PCI
devices) from a partition. The removal of a resource involves
removing the resource's node from the device tree and then returning the
resource to firmware via the rtas set-indicator call.  To add a resource, it
is first obtained from firmware via the rtas set-indicator call and then a
new device tree node is created using the ibm,configure-coinnector rtas call
and added to the device tree.

This patch provides the kernel DLPAR infrastructure in a new filed named
dlpar.c.  The functionality provided is for acquiring and releasing a resource
from firmware and the parsing of information returned from the
ibm,configure-connector rtas call.  Additionally this exports the pSeries
reconfiguration notifier chain so that it can be invoked when device tree
updates are made.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 346 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 4b1c422b8145..0ff5174ae4f5 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -8,7 +8,7 @@ endif
 
 obj-y                   := lpar.o hvCall.o nvram.o reconfig.o \
                            setup.o iommu.o ras.o \
-                           firmware.o power.o
+                           firmware.o power.o dlpar.o
 obj-$(CONFIG_SMP)       += smp.o
 obj-$(CONFIG_XICS)      += xics.o
 obj-$(CONFIG_SCANLOG)   += scanlog.o
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
new file mode 100644
index 000000000000..c80e8ef0eb58
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -0,0 +1,344 @@
+/*
+ * Support for dynamic reconfiguration for PCI, Memory, and CPU
+ * Hotplug and Dynamic Logical Partitioning on RPA platforms.
+ *
+ * Copyright (C) 2009 Nathan Fontenot
+ * Copyright (C) 2009 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kref.h>
+#include <linux/notifier.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
+#include <linux/cpu.h>
+
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/uaccess.h>
+#include <asm/rtas.h>
+#include <asm/pSeries_reconfig.h>
+
+struct cc_workarea {
+        u32     drc_index;
+        u32     zero;
+        u32     name_offset;
+        u32     prop_length;
+        u32     prop_offset;
+};
+
+static void dlpar_free_cc_property(struct property *prop)
+{
+        kfree(prop->name);
+        kfree(prop->value);
+        kfree(prop);
+}
+
+static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
+{
+        struct property *prop;
+        char *name;
+        char *value;
+
+        prop = kzalloc(sizeof(*prop), GFP_KERNEL);
+        if (!prop)
+                return NULL;
+
+        name = (char *)ccwa + ccwa->name_offset;
+        prop->name = kstrdup(name, GFP_KERNEL);
+
+        prop->length = ccwa->prop_length;
+        value = (char *)ccwa + ccwa->prop_offset;
+        prop->value = kzalloc(prop->length, GFP_KERNEL);
+        if (!prop->value) {
+                dlpar_free_cc_property(prop);
+                return NULL;
+        }
+
+        memcpy(prop->value, value, prop->length);
+        return prop;
+}
+
+static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa)
+{
+        struct device_node *dn;
+        char *name;
+
+        dn = kzalloc(sizeof(*dn), GFP_KERNEL);
+        if (!dn)
+                return NULL;
+
+        /* The configure connector reported name does not contain a
+         * preceeding '/', so we allocate a buffer large enough to
+         * prepend this to the full_name.
+         */
+        name = (char *)ccwa + ccwa->name_offset;
+        dn->full_name = kmalloc(strlen(name) + 2, GFP_KERNEL);
+        if (!dn->full_name) {
+                kfree(dn);
+                return NULL;
+        }
+
+        sprintf(dn->full_name, "/%s", name);
+        return dn;
+}
+
+static void dlpar_free_one_cc_node(struct device_node *dn)
+{
+        struct property *prop;
+
+        while (dn->properties) {
+                prop = dn->properties;
+                dn->properties = prop->next;
+                dlpar_free_cc_property(prop);
+        }
+
+        kfree(dn->full_name);
+        kfree(dn);
+}
+
+static void dlpar_free_cc_nodes(struct device_node *dn)
+{
+        if (dn->child)
+                dlpar_free_cc_nodes(dn->child);
+
+        if (dn->sibling)
+                dlpar_free_cc_nodes(dn->sibling);
+
+        dlpar_free_one_cc_node(dn);
+}
+
+#define NEXT_SIBLING    1
+#define NEXT_CHILD      2
+#define NEXT_PROPERTY   3
+#define PREV_PARENT     4
+#define MORE_MEMORY     5
+#define CALL_AGAIN      -2
+#define ERR_CFG_USE     -9003
+
+struct device_node *dlpar_configure_connector(u32 drc_index)
+{
+        struct device_node *dn;
+        struct device_node *first_dn = NULL;
+        struct device_node *last_dn = NULL;
+        struct property *property;
+        struct property *last_property = NULL;
+        struct cc_workarea *ccwa;
+        int cc_token;
+        int rc;
+
+        cc_token = rtas_token("ibm,configure-connector");
+        if (cc_token == RTAS_UNKNOWN_SERVICE)
+                return NULL;
+
+        spin_lock(&rtas_data_buf_lock);
+        ccwa = (struct cc_workarea *)&rtas_data_buf[0];
+        ccwa->drc_index = drc_index;
+        ccwa->zero = 0;
+
+        rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
+        while (rc) {
+                switch (rc) {
+                case NEXT_SIBLING:
+                        dn = dlpar_parse_cc_node(ccwa);
+                        if (!dn)
+                                goto cc_error;
+
+                        dn->parent = last_dn->parent;
+                        last_dn->sibling = dn;
+                        last_dn = dn;
+                        break;
+
+                case NEXT_CHILD:
+                        dn = dlpar_parse_cc_node(ccwa);
+                        if (!dn)
+                                goto cc_error;
+
+                        if (!first_dn)
+                                first_dn = dn;
+                        else {
+                                dn->parent = last_dn;
+                                if (last_dn)
+                                        last_dn->child = dn;
+                        }
+
+                        last_dn = dn;
+                        break;
+
+                case NEXT_PROPERTY:
+                        property = dlpar_parse_cc_property(ccwa);
+                        if (!property)
+                                goto cc_error;
+
+                        if (!last_dn->properties)
+                                last_dn->properties = property;
+                        else
+                                last_property->next = property;
+
+                        last_property = property;
+                        break;
+
+                case PREV_PARENT:
+                        last_dn = last_dn->parent;
+                        break;
+
+                case CALL_AGAIN:
+                        break;
+
+                case MORE_MEMORY:
+                case ERR_CFG_USE:
+                default:
+                        printk(KERN_ERR "Unexpected Error (%d) "
+                               "returned from configure-connector\n", rc);
+                        goto cc_error;
+                }
+
+                rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
+        }
+
+        spin_unlock(&rtas_data_buf_lock);
+        return first_dn;
+
+cc_error:
+        if (first_dn)
+                dlpar_free_cc_nodes(first_dn);
+        spin_unlock(&rtas_data_buf_lock);
+        return NULL;
+}
+
+static struct device_node *derive_parent(const char *path)
+{
+        struct device_node *parent;
+        char *last_slash;
+
+        last_slash = strrchr(path, '/');
+        if (last_slash == path) {
+                parent = of_find_node_by_path("/");
+        } else {
+                char *parent_path;
+                int parent_path_len = last_slash - path + 1;
+                parent_path = kmalloc(parent_path_len, GFP_KERNEL);
+                if (!parent_path)
+                        return NULL;
+
+                strlcpy(parent_path, path, parent_path_len);
+                parent = of_find_node_by_path(parent_path);
+                kfree(parent_path);
+        }
+
+        return parent;
+}
+
+int dlpar_attach_node(struct device_node *dn)
+{
+        struct proc_dir_entry *ent;
+        int rc;
+
+        of_node_set_flag(dn, OF_DYNAMIC);
+        kref_init(&dn->kref);
+        dn->parent = derive_parent(dn->full_name);
+        if (!dn->parent)
+                return -ENOMEM;
+
+        rc = blocking_notifier_call_chain(&pSeries_reconfig_chain,
+                                          PSERIES_RECONFIG_ADD, dn);
+        if (rc == NOTIFY_BAD) {
+                printk(KERN_ERR "Failed to add device node %s\n",
+                       dn->full_name);
+                return -ENOMEM; /* For now, safe to assume kmalloc failure */
+        }
+
+        of_attach_node(dn);
+
+#ifdef CONFIG_PROC_DEVICETREE
+        ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
+        if (ent)
+                proc_device_tree_add_node(dn, ent);
+#endif
+
+        of_node_put(dn->parent);
+        return 0;
+}
+
+int dlpar_detach_node(struct device_node *dn)
+{
+        struct device_node *parent = dn->parent;
+        struct property *prop = dn->properties;
+
+#ifdef CONFIG_PROC_DEVICETREE
+        while (prop) {
+                remove_proc_entry(prop->name, dn->pde);
+                prop = prop->next;
+        }
+
+        if (dn->pde)
+                remove_proc_entry(dn->pde->name, parent->pde);
+#endif
+
+        blocking_notifier_call_chain(&pSeries_reconfig_chain,
+                            PSERIES_RECONFIG_REMOVE, dn);
+        of_detach_node(dn);
+        of_node_put(dn); /* Must decrement the refcount */
+
+        return 0;
+}
+
+#define DR_ENTITY_SENSE         9003
+#define DR_ENTITY_PRESENT       1
+#define DR_ENTITY_UNUSABLE      2
+#define ALLOCATION_STATE        9003
+#define ALLOC_UNUSABLE          0
+#define ALLOC_USABLE            1
+#define ISOLATION_STATE         9001
+#define ISOLATE                 0
+#define UNISOLATE               1
+
+int dlpar_acquire_drc(u32 drc_index)
+{
+        int dr_status, rc;
+
+        rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
+                       DR_ENTITY_SENSE, drc_index);
+        if (rc || dr_status != DR_ENTITY_UNUSABLE)
+                return -1;
+
+        rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_USABLE);
+        if (rc)
+                return rc;
+
+        rc = rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
+        if (rc) {
+                rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
+                return rc;
+        }
+
+        return 0;
+}
+
+int dlpar_release_drc(u32 drc_index)
+{
+        int dr_status, rc;
+
+        rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
+                       DR_ENTITY_SENSE, drc_index);
+        if (rc || dr_status != DR_ENTITY_PRESENT)
+                return -1;
+
+        rc = rtas_set_indicator(ISOLATION_STATE, drc_index, ISOLATE);
+        if (rc)
+                return rc;
+
+        rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
+        if (rc) {
+                rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
+                return rc;
+        }
+
+        return 0;
+}
+
+
diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
index 5182d2b992c6..a2305d29bbbd 100644
--- a/arch/powerpc/platforms/pseries/reconfig.c
+++ b/arch/powerpc/platforms/pseries/reconfig.c
@@ -96,7 +96,7 @@ static struct device_node *derive_parent(const char *path)
         return parent;
 }
 
-static BLOCKING_NOTIFIER_HEAD(pSeries_reconfig_chain);
+BLOCKING_NOTIFIER_HEAD(pSeries_reconfig_chain);
 
 int pSeries_reconfig_notifier_register(struct notifier_block *nb)
 {