iwlwifi: speed up event log dumps

Take advantage of device's auto-increment for SRAM reads to eliminate extra
write address accesses.

Grab/release NIC access before/after entire read sequence, rather than for
each read individually.

After a quick check of dmesg logs, this seems to double Event Log dump speed,
reducing from about 20 milliseconds to about 10 milliseconds for 512 entries
using 3945.

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 9c40742727a2..2abd1f5b5eea 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -1666,6 +1666,7 @@ static void iwl_print_event_log(struct iwl_priv *priv, u32 start_idx,
         u32 event_size; /* 2 u32s, or 3 u32s if timestamp recorded */
         u32 ptr;        /* SRAM byte address of log data */
         u32 ev, time, data; /* event log data */
+        unsigned long reg_flags;
 
         if (num_events == 0)
                 return;
@@ -1681,25 +1682,34 @@ static void iwl_print_event_log(struct iwl_priv *priv, u32 start_idx,
 
         ptr = base + EVENT_START_OFFSET + (start_idx * event_size);
 
+        /* Make sure device is powered up for SRAM reads */
+        spin_lock_irqsave(&priv->reg_lock, reg_flags);
+        iwl_grab_nic_access(priv);
+
+        /* Set starting address; reads will auto-increment */
+        _iwl_write_direct32(priv, HBUS_TARG_MEM_RADDR, ptr);
+        rmb();
+
         /* "time" is actually "data" for mode 0 (no timestamp).
         * place event id # at far right for easier visual parsing. */
         for (i = 0; i < num_events; i++) {
-                ev = iwl_read_targ_mem(priv, ptr);
-                ptr += sizeof(u32);
-                time = iwl_read_targ_mem(priv, ptr);
-                ptr += sizeof(u32);
+                ev = _iwl_read_direct32(priv, HBUS_TARG_MEM_RDAT);
+                time = _iwl_read_direct32(priv, HBUS_TARG_MEM_RDAT);
                 if (mode == 0) {
                         /* data, ev */
                         trace_iwlwifi_dev_ucode_event(priv, 0, time, ev);
                         IWL_ERR(priv, "EVT_LOG:0x%08x:%04u\n", time, ev);
                 } else {
-                        data = iwl_read_targ_mem(priv, ptr);
-                        ptr += sizeof(u32);
+                        data = _iwl_read_direct32(priv, HBUS_TARG_MEM_RDAT);
                         IWL_ERR(priv, "EVT_LOGT:%010u:0x%08x:%04u\n",
                                         time, data, ev);
                         trace_iwlwifi_dev_ucode_event(priv, time, data, ev);
                 }
         }
+
+        /* Allow device to power down */
+        iwl_release_nic_access(priv);
+        spin_unlock_irqrestore(&priv->reg_lock, reg_flags);
 }
 
 /* For sanity check only.  Actual size is determined by uCode, typ. 512 */