Merge branch 'nvram' into next

2 files changed, 209 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c
index 054dfe5b8e77..f803f4b8ab6f 100644
--- a/arch/powerpc/platforms/chrp/time.c
+++ b/arch/powerpc/platforms/chrp/time.c
@@ -29,6 +29,10 @@
 
 extern spinlock_t rtc_lock;
 
+#define NVRAM_AS0  0x74
+#define NVRAM_AS1  0x75
+#define NVRAM_DATA 0x77
+
 static int nvram_as1 = NVRAM_AS1;
 static int nvram_as0 = NVRAM_AS0;
 static int nvram_data = NVRAM_DATA;
diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index bc3c7f2abd79..7e828ba29bc3 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -22,11 +22,25 @@
 #include <asm/prom.h>
 #include <asm/machdep.h>
 
+/* Max bytes to read/write in one go */
+#define NVRW_CNT 0x20
+
 static unsigned int nvram_size;
 static int nvram_fetch, nvram_store;
 static char nvram_buf[NVRW_CNT];	/* assume this is in the first 4GB */
 static DEFINE_SPINLOCK(nvram_lock);
 
+static long nvram_error_log_index = -1;
+static long nvram_error_log_size = 0;
+
+struct err_log_info {
+	int error_type;
+	unsigned int seq_num;
+};
+#define NVRAM_MAX_REQ		2079
+#define NVRAM_MIN_REQ		1055
+
+#define NVRAM_LOG_PART_NAME	"ibm,rtas-log"
 
 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
 {
@@ -119,6 +133,197 @@ static ssize_t pSeries_nvram_get_size(void)
 	return nvram_size ? nvram_size : -ENODEV;
 }
 
+
+/* nvram_write_error_log
+ *
+ * We need to buffer the error logs into nvram to ensure that we have
+ * the failure information to decode.  If we have a severe error there
+ * is no way to guarantee that the OS or the machine is in a state to
+ * get back to user land and write the error to disk.  For example if
+ * the SCSI device driver causes a Machine Check by writing to a bad
+ * IO address, there is no way of guaranteeing that the device driver
+ * is in any state that is would also be able to write the error data
+ * captured to disk, thus we buffer it in NVRAM for analysis on the
+ * next boot.
+ *
+ * In NVRAM the partition containing the error log buffer will looks like:
+ * Header (in bytes):
+ * +-----------+----------+--------+------------+------------------+
+ * | signature | checksum | length | name       | data             |
+ * |0          |1         |2      3|4         15|16        length-1|
+ * +-----------+----------+--------+------------+------------------+
+ *
+ * The 'data' section would look like (in bytes):
+ * +--------------+------------+-----------------------------------+
+ * | event_logged | sequence # | error log                         |
+ * |0            3|4          7|8            nvram_error_log_size-1|
+ * +--------------+------------+-----------------------------------+
+ *
+ * event_logged: 0 if event has not been logged to syslog, 1 if it has
+ * sequence #: The unique sequence # for each event. (until it wraps)
+ * error log: The error log from event_scan
+ */
+int nvram_write_error_log(char * buff, int length,
+                          unsigned int err_type, unsigned int error_log_cnt)
+{
+	int rc;
+	loff_t tmp_index;
+	struct err_log_info info;
+	
+	if (nvram_error_log_index == -1) {
+		return -ESPIPE;
+	}
+
+	if (length > nvram_error_log_size) {
+		length = nvram_error_log_size;
+	}
+
+	info.error_type = err_type;
+	info.seq_num = error_log_cnt;
+
+	tmp_index = nvram_error_log_index;
+
+	rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
+	if (rc <= 0) {
+		printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
+		return rc;
+	}
+
+	rc = ppc_md.nvram_write(buff, length, &tmp_index);
+	if (rc <= 0) {
+		printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
+		return rc;
+	}
+	
+	return 0;
+}
+
+/* nvram_read_error_log
+ *
+ * Reads nvram for error log for at most 'length'
+ */
+int nvram_read_error_log(char * buff, int length,
+                         unsigned int * err_type, unsigned int * error_log_cnt)
+{
+	int rc;
+	loff_t tmp_index;
+	struct err_log_info info;
+	
+	if (nvram_error_log_index == -1)
+		return -1;
+
+	if (length > nvram_error_log_size)
+		length = nvram_error_log_size;
+
+	tmp_index = nvram_error_log_index;
+
+	rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
+	if (rc <= 0) {
+		printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
+		return rc;
+	}
+
+	rc = ppc_md.nvram_read(buff, length, &tmp_index);
+	if (rc <= 0) {
+		printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
+		return rc;
+	}
+
+	*error_log_cnt = info.seq_num;
+	*err_type = info.error_type;
+
+	return 0;
+}
+
+/* This doesn't actually zero anything, but it sets the event_logged
+ * word to tell that this event is safely in syslog.
+ */
+int nvram_clear_error_log(void)
+{
+	loff_t tmp_index;
+	int clear_word = ERR_FLAG_ALREADY_LOGGED;
+	int rc;
+
+	if (nvram_error_log_index == -1)
+		return -1;
+
+	tmp_index = nvram_error_log_index;
+	
+	rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
+	if (rc <= 0) {
+		printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+/* pseries_nvram_init_log_partition
+ *
+ * This will setup the partition we need for buffering the
+ * error logs and cleanup partitions if needed.
+ *
+ * The general strategy is the following:
+ * 1.) If there is log partition large enough then use it.
+ * 2.) If there is none large enough, search
+ * for a free partition that is large enough.
+ * 3.) If there is not a free partition large enough remove 
+ * _all_ OS partitions and consolidate the space.
+ * 4.) Will first try getting a chunk that will satisfy the maximum
+ * error log size (NVRAM_MAX_REQ).
+ * 5.) If the max chunk cannot be allocated then try finding a chunk
+ * that will satisfy the minum needed (NVRAM_MIN_REQ).
+ */
+static int __init pseries_nvram_init_log_partition(void)
+{
+	loff_t p;
+	int size;
+
+	/* Scan nvram for partitions */
+	nvram_scan_partitions();
+
+	/* Lookg for ours */
+	p = nvram_find_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS, &size);
+
+	/* Found one but too small, remove it */
+	if (p && size < NVRAM_MIN_REQ) {
+		pr_info("nvram: Found too small "NVRAM_LOG_PART_NAME" partition"
+			",removing it...");
+		nvram_remove_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS);
+		p = 0;
+	}
+
+	/* Create one if we didn't find */
+	if (!p) {
+		p = nvram_create_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS,
+					   NVRAM_MAX_REQ, NVRAM_MIN_REQ);
+		/* No room for it, try to get rid of any OS partition
+		 * and try again
+		 */
+		if (p == -ENOSPC) {
+			pr_info("nvram: No room to create "NVRAM_LOG_PART_NAME
+				" partition, deleting all OS partitions...");
+			nvram_remove_partition(NULL, NVRAM_SIG_OS);
+			p = nvram_create_partition(NVRAM_LOG_PART_NAME,
+						   NVRAM_SIG_OS, NVRAM_MAX_REQ,
+						   NVRAM_MIN_REQ);
+		}
+	}
+
+	if (p <= 0) {
+		pr_err("nvram: Failed to find or create "NVRAM_LOG_PART_NAME
+		       " partition, err %d\n", (int)p);
+		return 0;
+	}
+
+	nvram_error_log_index = p;
+	nvram_error_log_size = nvram_get_partition_size(p) -
+		sizeof(struct err_log_info);
+	
+	return 0;
+}
+machine_arch_initcall(pseries, pseries_nvram_init_log_partition);
+
 int __init pSeries_nvram_init(void)
 {
 	struct device_node *nvram;