From: Sahil Mehta <sahilmeht...@gmail.com>

Indexed-count add for memory hotplug guarantees that a contiguous block
of <count> lmbs beginning at a specified <index> will be assigned (NOT
that <count> lmbs will be added). Because of Qemu's per-DIMM memory
management, the addition of a contiguous block of memory currently
requires a series of individual calls. Indexed-count add reduces
this series into a single call.

Signed-off-by: Sahil Mehta <sahilmeht...@gmail.com>
Signed-off-by: Nathan Fontenot <nf...@linux.vnet.ibm.com>
---
v2:     -remove potential memory leak when parsing command
        -use u32s drc_index and count instead of u32 ic[]
         in dlpar_memory
v3:     -add logic to handle invalid drc_index input
        -update indexed-count trigger to follow naming convention
        -update dlpar_memory to follow kernel if-else style
v4:     -add logic to handle kstrdup failure
        -add logic to handle invalid command format
v5:     -none

 arch/powerpc/include/asm/rtas.h                 |    2 
 arch/powerpc/platforms/pseries/dlpar.c          |   46 +++++++++-
 arch/powerpc/platforms/pseries/hotplug-memory.c |  110 +++++++++++++++++++++--
 3 files changed, 146 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 9c23baa..5d65de7 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -307,6 +307,7 @@ struct pseries_hp_errorlog {
        union {
                __be32  drc_index;
                __be32  drc_count;
+               __be32  indexed_count[2];
                char    drc_name[1];
        } _drc_u;
 };
@@ -322,6 +323,7 @@ struct pseries_hp_errorlog {
 #define PSERIES_HP_ELOG_ID_DRC_NAME    1
 #define PSERIES_HP_ELOG_ID_DRC_INDEX   2
 #define PSERIES_HP_ELOG_ID_DRC_COUNT   3
+#define PSERIES_HP_ELOG_ID_DRC_IC      4
 
 struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
                                              uint16_t section_id);
diff --git a/arch/powerpc/platforms/pseries/dlpar.c 
b/arch/powerpc/platforms/pseries/dlpar.c
index 4748124..ad9c770 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -354,11 +354,17 @@ static int handle_dlpar_errorlog(struct 
pseries_hp_errorlog *hp_elog)
        switch (hp_elog->id_type) {
        case PSERIES_HP_ELOG_ID_DRC_COUNT:
                hp_elog->_drc_u.drc_count =
-                                       be32_to_cpu(hp_elog->_drc_u.drc_count);
+                               be32_to_cpu(hp_elog->_drc_u.drc_count);
                break;
        case PSERIES_HP_ELOG_ID_DRC_INDEX:
                hp_elog->_drc_u.drc_index =
-                                       be32_to_cpu(hp_elog->_drc_u.drc_index);
+                               be32_to_cpu(hp_elog->_drc_u.drc_index);
+               break;
+       case PSERIES_HP_ELOG_ID_DRC_IC:
+               hp_elog->_drc_u.indexed_count[0] =
+                               be32_to_cpu(hp_elog->_drc_u.indexed_count[0]);
+               hp_elog->_drc_u.indexed_count[1] =
+                               be32_to_cpu(hp_elog->_drc_u.indexed_count[1]);
        }
 
        switch (hp_elog->resource) {
@@ -459,7 +465,41 @@ static ssize_t dlpar_store(struct class *class, struct 
class_attribute *attr,
                goto dlpar_store_out;
        }
 
-       if (!strncmp(arg, "index", 5)) {
+       if (!strncmp(arg, "indexed-count", 13)) {
+               u32 index, count;
+               char *cstr, *istr;
+
+               hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_IC;
+               arg += strlen("indexed-count ");
+
+               cstr = kstrdup(arg, GFP_KERNEL);
+               if (!cstr) {
+                       rc = -EINVAL;
+                       pr_err("kstrudup failed before parse : \"%s\"\n", buf);
+                       goto dlpar_store_out;
+               }
+
+               istr = strchr(cstr, ' ');
+               if (!istr) {
+                       rc = -EINVAL;
+                       pr_err("Invalid indexed-count command : \"%s\"\n", buf);
+                       goto dlpar_store_out;
+               }
+
+               *istr++ = '\0';
+
+               if (kstrtou32(cstr, 0, &count) || kstrtou32(istr, 0, &index)) {
+                       rc = -EINVAL;
+                       pr_err("Invalid index or count : \"%s\"\n", buf);
+                       kfree(cstr);
+                       goto dlpar_store_out;
+               }
+
+               kfree(cstr);
+
+               hp_elog->_drc_u.indexed_count[0] = cpu_to_be32(count);
+               hp_elog->_drc_u.indexed_count[1] = cpu_to_be32(index);
+       } else if (!strncmp(arg, "index", 5)) {
                u32 index;
 
                hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c 
b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 76ec104..badc66d 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -725,6 +725,89 @@ static int dlpar_memory_add_by_index(u32 drc_index, struct 
property *prop)
        return rc;
 }
 
+static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index,
+                                 struct property *prop)
+{
+       struct of_drconf_cell *lmbs;
+       u32 num_lmbs, *p;
+       int i, rc, start_lmb_found;
+       int lmbs_available = 0, start_index = 0, end_index;
+
+       pr_info("Attempting to hot-add %u LMB(s) at index %x\n",
+               lmbs_to_add, drc_index);
+
+       if (lmbs_to_add == 0)
+               return -EINVAL;
+
+       p = prop->value;
+       num_lmbs = *p++;
+       lmbs = (struct of_drconf_cell *)p;
+       start_lmb_found = 0;
+
+       /* Navigate to drc_index */
+       while (start_index < num_lmbs) {
+               if (lmbs[start_index].drc_index == drc_index) {
+                       start_lmb_found = 1;
+                       break;
+               }
+
+               start_index++;
+       }
+
+       if (!start_lmb_found)
+               return -EINVAL;
+
+       end_index = start_index + lmbs_to_add;
+
+       /* Validate that there are enough LMBs to satisfy the request */
+       for (i = start_index; i < end_index; i++) {
+               if (lmbs[i].flags & DRCONF_MEM_RESERVED)
+                       break;
+
+               lmbs_available++;
+       }
+
+       if (lmbs_available < lmbs_to_add)
+               return -EINVAL;
+
+       for (i = start_index; i < end_index; i++) {
+               if (lmbs[i].flags & DRCONF_MEM_ASSIGNED)
+                       continue;
+
+               rc = dlpar_add_lmb(&lmbs[i]);
+               if (rc)
+                       break;
+
+               lmbs[i].reserved = 1;
+       }
+
+       if (rc) {
+               pr_err("Memory indexed-count-add failed, removing any added 
LMBs\n");
+
+               for (i = start_index; i < end_index; i++) {
+                       if (!lmbs[i].reserved)
+                               continue;
+
+                       rc = dlpar_remove_lmb(&lmbs[i]);
+                       if (rc)
+                               pr_err("Failed to remove LMB, drc index %x\n",
+                                      be32_to_cpu(lmbs[i].drc_index));
+               }
+               rc = -EINVAL;
+       } else {
+               for (i = start_index; i < end_index; i++) {
+                       if (!lmbs[i].reserved)
+                               continue;
+
+                       pr_info("Memory at %llx (drc index %x) was hot-added\n",
+                               lmbs[i].base_addr, lmbs[i].drc_index);
+                       lmbs[i].reserved = 0;
+               }
+       }
+
+       return rc;
+}
+
 int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
 {
        struct device_node *dn;
@@ -732,9 +815,6 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
        u32 count, drc_index;
        int rc;
 
-       count = hp_elog->_drc_u.drc_count;
-       drc_index = hp_elog->_drc_u.drc_index;
-
        lock_device_hotplug();
 
        dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
@@ -751,20 +831,32 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
 
        switch (hp_elog->action) {
        case PSERIES_HP_ELOG_ACTION_ADD:
-               if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
+               if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) {
+                       count = hp_elog->_drc_u.drc_count;
                        rc = dlpar_memory_add_by_count(count, prop);
-               else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
+               } else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
+                       drc_index = hp_elog->_drc_u.drc_index;
                        rc = dlpar_memory_add_by_index(drc_index, prop);
-               else
+               } else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_IC) {
+                       count = hp_elog->_drc_u.indexed_count[0];
+                       drc_index = hp_elog->_drc_u.indexed_count[1];
+                       rc = dlpar_memory_add_by_ic(count, drc_index, prop);
+               } else {
                        rc = -EINVAL;
+               }
+
                break;
        case PSERIES_HP_ELOG_ACTION_REMOVE:
-               if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
+               if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) {
+                       count = hp_elog->_drc_u.drc_count;
                        rc = dlpar_memory_remove_by_count(count, prop);
-               else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
+               } else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
+                       drc_index = hp_elog->_drc_u.drc_index;
                        rc = dlpar_memory_remove_by_index(drc_index, prop);
-               else
+               } else {
                        rc = -EINVAL;
+               }
+
                break;
        default:
                pr_err("Invalid action (%d) specified\n", hp_elog->action);

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