powerpc/pseries: Read rtas partition via pstore

This patch set exploits the pstore subsystem to read details of rtas partition
in NVRAM to a separate file in /dev/pstore. For instance, rtas details will be
stored in a file named [rtas-nvram-4].

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>

1 files changed, 26 insertions, 7 deletions

diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index 9edec8ee02ef..78d72f0175ad 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -131,9 +131,11 @@ static struct z_stream_s stream;
 #ifdef CONFIG_PSTORE
 static enum pstore_type_id nvram_type_ids[] = {
         PSTORE_TYPE_DMESG,
+        PSTORE_TYPE_PPC_RTAS,
         -1
 };
 static int read_type;
+static unsigned long last_rtas_event;
 #endif
 
 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
@@ -297,8 +299,13 @@ int nvram_write_error_log(char * buff, int length,
 {
         int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
                                                 err_type, error_log_cnt);
-        if (!rc)
+        if (!rc) {
                 last_unread_rtas_event = get_seconds();
+#ifdef CONFIG_PSTORE
+                last_rtas_event = get_seconds();
+#endif
+        }
+
         return rc;
 }
 
@@ -506,7 +513,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
 }
 
 /*
- * Reads the oops/panic report.
+ * Reads the oops/panic report and ibm,rtas-log partition.
  * Returns the length of the data we read from each partition.
  * Returns 0 if we've been called before.
  */
@@ -526,6 +533,12 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
                 part = &oops_log_partition;
                 *type = PSTORE_TYPE_DMESG;
                 break;
+        case PSTORE_TYPE_PPC_RTAS:
+                part = &rtas_log_partition;
+                *type = PSTORE_TYPE_PPC_RTAS;
+                time->tv_sec = last_rtas_event;
+                time->tv_nsec = 0;
+                break;
         default:
                 return 0;
         }
@@ -542,11 +555,17 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 
         *count = 0;
         *id = id_no;
-        oops_hdr = (struct oops_log_info *)buff;
-        *buf = buff + sizeof(*oops_hdr);
-        time->tv_sec = oops_hdr->timestamp;
-        time->tv_nsec = 0;
-        return oops_hdr->report_length;
+
+        if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
+                oops_hdr = (struct oops_log_info *)buff;
+                *buf = buff + sizeof(*oops_hdr);
+                time->tv_sec = oops_hdr->timestamp;
+                time->tv_nsec = 0;
+                return oops_hdr->report_length;
+        }
+
+        *buf = buff;
+        return part->size;
 }
 
 static struct pstore_info nvram_pstore_info = {