powerpc/pseries: Implement indexed-count hotplug memory add

Indexed-count add for memory hotplug guarantees that a contiguous block
of <count> lmbs beginning at a specified <drc index> will be assigned,
any LMBs in this range that are not already assigned will be DLPAR added.
Because of Qemu's per-DIMM memory management, the addition of a contiguous
block of memory currently requires a series of individual calls to add
each LMB in the block. Indexed-count add reduces this series of calls to
a single call for the entire block.

Signed-off-by: Sahil Mehta <sahilmehta17@gmail.com>
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

3 files changed, 147 insertions, 12 deletions

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 076b89247ab5..ec9dd79398ee 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;
+                struct { __be32 count, index; } ic;
                 char    drc_name[1];
         } _drc_u;
 };
@@ -323,6 +324,7 @@ 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 d3a81e746fc4..193e052fa0dd 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.ic.count =
+                                be32_to_cpu(hp_elog->_drc_u.ic.count);
+                hp_elog->_drc_u.ic.index =
+                                be32_to_cpu(hp_elog->_drc_u.ic.index);
         }
 
         switch (hp_elog->resource) {
@@ -467,7 +473,33 @@ static int dlpar_parse_id_type(char **cmd, struct pseries_hp_errorlog *hp_elog)
         if (!arg)
                 return -EINVAL;
 
-        if (sysfs_streq(arg, "index")) {
+        if (sysfs_streq(arg, "indexed-count")) {
+                hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_IC;
+                arg = strsep(cmd, " ");
+                if (!arg) {
+                        pr_err("No DRC count specified.\n");
+                        return -EINVAL;
+                }
+
+                if (kstrtou32(arg, 0, &count)) {
+                        pr_err("Invalid DRC count specified.\n");
+                        return -EINVAL;
+                }
+
+                arg = strsep(cmd, " ");
+                if (!arg) {
+                        pr_err("No DRC Index specified.\n");
+                        return -EINVAL;
+                }
+
+                if (kstrtou32(arg, 0, &index)) {
+                        pr_err("Invalid DRC Index specified.\n");
+                        return -EINVAL;
+                }
+
+                hp_elog->_drc_u.ic.count = cpu_to_be32(count);
+                hp_elog->_drc_u.ic.index = cpu_to_be32(index);
+        } else if (sysfs_streq(arg, "index")) {
                 hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
                 arg = strsep(cmd, " ");
                 if (!arg) {
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index b3b92814ce87..ad8b3a606a8e 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -779,6 +779,97 @@ 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 the LMBs in this range are not reserved */
+        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_acquire_drc(lmbs[i].drc_index);
+                if (rc)
+                        break;
+
+                rc = dlpar_add_lmb(&lmbs[i]);
+                if (rc) {
+                        dlpar_release_drc(lmbs[i].drc_index);
+                        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));
+                        else
+                                dlpar_release_drc(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;
@@ -786,9 +877,6 @@ 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");
@@ -805,22 +893,35 @@ 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.ic.count;
+                        drc_index = hp_elog->_drc_u.ic.index;
+                        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;
         case PSERIES_HP_ELOG_ACTION_READD:
+                drc_index = hp_elog->_drc_u.drc_index;
                 rc = dlpar_memory_readd_by_index(drc_index, prop);
                 break;
         default: