iwlwifi: DMA fixes

A few issues wrt DMA were uncovered when using the driver with swiotlb.
- driver should not use memory after it has been mapped
- iwl3945's RX queue management cannot use all of iwlagn because
  the size of the RX buffer is different. Revert back to using
  iwl3945 specific routines that map/unmap memory.
- no need to "dma_syn_single_range_for_cpu" followed by pci_unmap_single,
  we can just call pci_unmap_single initially
- only map the memory area that will be used by device. this is especially
  relevant to the mapping of iwl_cmd. we should not map the entire
  structure because the meta data at the beginning of structure contains
  the address to be used later for unmapping. If the address to be used for
  unmapping is stored in mapped data it creates a problem.
- ensure that _if_ memory needs to be modified after it is mapped that we
  call _sync_single_for_cpu first, and then release it back to device with
  _sync_single_for_device
- we mapped the wrong length of data for host commands, with mapped length
  differing with length provided to device, fix that.

Thanks to Jason Andryuk <jandryuk@gmail.com> for significant bisecting
help to find these issues.

This fixes http://www.intellinuxwireless.org/bugzilla/show_bug.cgi?id=1964

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Tested-by: Ben Gamari <bgamari@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index ec9a13846ed..cf7f0db58fc 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -360,12 +360,16 @@ struct iwl_host_cmd {
 
 /**
  * struct iwl_rx_queue - Rx queue
+ * @bd: driver's pointer to buffer of receive buffer descriptors (rbd)
+ * @dma_addr: bus address of buffer of receive buffer descriptors (rbd)
  * @read: Shared index to newest available Rx buffer
  * @write: Shared index to oldest written Rx packet
  * @free_count: Number of pre-allocated buffers in rx_free
  * @rx_free: list of free SKBs for use
  * @rx_used: List of Rx buffers with no SKB
  * @need_update: flag to indicate we need to update read/write index
+ * @rb_stts: driver's pointer to receive buffer status
+ * @rb_stts_dma: bus address of receive buffer status
  *
  * NOTE:  rx_free and rx_used are used as a FIFO for iwl_rx_mem_buffers
  */