iwlwifi: fix TX cmd dma unmapping

This patch:
1. fixes command DMA unmapping, this might be visible only
	on platforms where DMA unmapping is no noop such as PPC64 (not tested)
2. attaches correctly high memory part of the host command buffer
3. changes structure of TFD TB
	instead of describing transmit buffer (TB) tuple it describes single
	TB and makes code more readable on price of one unaligned access
4. eliminates using of IWL_GET/SET_BITs for TFD handling
5. renames TFD structures to mach the HW spec
6. reduces iwl_tx_info size by reserving first TB to the host command

This patch should not have any visible effect on x86 32

This patch is rework of
iwlwifi: fix DMA code and bugs from
Johannes Berg <johannes@sipsolutions.net>

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 0f57bf4..1f42e90 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -112,11 +112,9 @@
 				* space less than this */
 } __attribute__ ((packed));
 
-#define MAX_NUM_OF_TBS          (20)
-
 /* One for each TFD */
 struct iwl_tx_info {
-	struct sk_buff *skb[MAX_NUM_OF_TBS];
+	struct sk_buff *skb[IWL_NUM_OF_TBS - 1];
 };
 
 /**
@@ -134,7 +132,7 @@
  */
 struct iwl_tx_queue {
 	struct iwl_queue q;
-	struct iwl_tfd_frame *bd;
+	struct iwl_tfd *tfds;
 	struct iwl_cmd *cmd[TFD_TX_CMD_SLOTS];
 	struct iwl_tx_info *txb;
 	int need_update;
@@ -252,7 +250,8 @@
 	/* The CMD_SIZE_HUGE flag bit indicates that the command
 	 * structure is stored at the end of the shared queue memory. */
 	u32 flags;
-
+	DECLARE_PCI_UNMAP_ADDR(mapping)
+	DECLARE_PCI_UNMAP_LEN(len)
 } __attribute__ ((packed));
 
 #define IWL_CMD_MAX_PAYLOAD 320