powerpc/pseries: Read of-config partition via pstore

This patch set exploits the pstore subsystem to read details of
of-config partition in NVRAM to a separate file in /dev/pstore.
For instance, of-config partition details will be stored in a
file named [of-nvram-5].

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 50 insertions, 9 deletions

diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index 714ed8ac7d59..f7392f6ea7b3 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -132,9 +132,16 @@ static size_t oops_data_sz;
 static struct z_stream_s stream;
 
 #ifdef CONFIG_PSTORE
+static struct nvram_os_partition of_config_partition = {
+        .name = "of-config",
+        .index = -1,
+        .os_partition = false
+};
+
 static enum pstore_type_id nvram_type_ids[] = {
         PSTORE_TYPE_DMESG,
         PSTORE_TYPE_PPC_RTAS,
+        PSTORE_TYPE_PPC_OF,
         -1
 };
 static int read_type;
@@ -332,10 +339,15 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
 
         tmp_index = part->index;
 
-        rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
-        if (rc <= 0) {
-                pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__, rc);
-                return rc;
+        if (part->os_partition) {
+                rc = ppc_md.nvram_read((char *)&info,
+                                        sizeof(struct err_log_info),
+                                        &tmp_index);
+                if (rc <= 0) {
+                        pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__,
+                                                                        rc);
+                        return rc;
+                }
         }
 
         rc = ppc_md.nvram_read(buff, length, &tmp_index);
@@ -344,8 +356,10 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
                 return rc;
         }
 
-        *error_log_cnt = info.seq_num;
-        *err_type = info.error_type;
+        if (part->os_partition) {
+                *error_log_cnt = info.seq_num;
+                *err_type = info.error_type;
+        }
 
         return 0;
 }
@@ -516,7 +530,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
 }
 
 /*
- * Reads the oops/panic report and ibm,rtas-log partition.
+ * Reads the oops/panic report, rtas and of-config partition.
  * Returns the length of the data we read from each partition.
  * Returns 0 if we've been called before.
  */
@@ -525,9 +539,11 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
                                 struct pstore_info *psi)
 {
         struct oops_log_info *oops_hdr;
-        unsigned int err_type, id_no;
+        unsigned int err_type, id_no, size = 0;
         struct nvram_os_partition *part = NULL;
         char *buff = NULL;
+        int sig = 0;
+        loff_t p;
 
         read_type++;
 
@@ -542,10 +558,29 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
                 time->tv_sec = last_rtas_event;
                 time->tv_nsec = 0;
                 break;
+        case PSTORE_TYPE_PPC_OF:
+                sig = NVRAM_SIG_OF;
+                part = &of_config_partition;
+                *type = PSTORE_TYPE_PPC_OF;
+                *id = PSTORE_TYPE_PPC_OF;
+                time->tv_sec = 0;
+                time->tv_nsec = 0;
+                break;
         default:
                 return 0;
         }
 
+        if (!part->os_partition) {
+                p = nvram_find_partition(part->name, sig, &size);
+                if (p <= 0) {
+                        pr_err("nvram: Failed to find partition %s, "
+                                "err %d\n", part->name, (int)p);
+                        return 0;
+                }
+                part->index = p;
+                part->size = size;
+        }
+
         buff = kmalloc(part->size, GFP_KERNEL);
 
         if (!buff)
@@ -557,7 +592,9 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
         }
 
         *count = 0;
-        *id = id_no;
+
+        if (part->os_partition)
+                *id = id_no;
 
         if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
                 oops_hdr = (struct oops_log_info *)buff;
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index ec24f9ceb5ed..73148aef9e31 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -327,6 +327,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
         case PSTORE_TYPE_PPC_RTAS:
                 sprintf(name, "rtas-%s-%lld", psname, id);
                 break;
+        case PSTORE_TYPE_PPC_OF:
+                sprintf(name, "powerpc-ofw-%s-%lld", psname, id);
+                break;
         case PSTORE_TYPE_UNKNOWN:
                 sprintf(name, "unknown-%s-%lld", psname, id);
                 break;
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index d7a8fe938c0f..615dc18638b8 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -37,6 +37,7 @@ enum pstore_type_id {
         PSTORE_TYPE_FTRACE      = 3,
         /* PPC64 partition types */
         PSTORE_TYPE_PPC_RTAS    = 4,
+        PSTORE_TYPE_PPC_OF      = 5,
         PSTORE_TYPE_UNKNOWN     = 255
 };