[PATCH 4.9 041/103] iwlwifi: mvm: synchronize firmware DMA paging memory

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sara Sharon <sara.sharon@xxxxxxxxx>

commit 4b70f07686d75d1eb5d956812cc810944e0b29b2 upstream.

When driver needs to access the contents of a streaming DMA buffer
without unmapping it it should call dma_sync_single_for_cpu().
Once the call has been made, the CPU "owns" the DMA buffer and can
work with it as needed.
Before the device accesses the buffer, however, ownership should be
transferred back to it with dma_sync_single_for_device().
Both calls weren't performed by the driver, resulting with odd paging
errors on some platforms. Fix it.

Fixes: a6c4fb4441f4 ("iwlwifi: mvm: Add FW paging mechanism for the UMAC on PCI")
Signed-off-by: Sara Sharon <sara.sharon@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c |    4 ++++
 drivers/net/wireless/intel/iwlwifi/mvm/fw.c     |   23 ++++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
@@ -784,12 +784,16 @@ void iwl_mvm_fw_error_dump(struct iwl_mv
 			struct iwl_fw_error_dump_paging *paging;
 			struct page *pages =
 				mvm->fw_paging_db[i].fw_paging_block;
+			dma_addr_t addr = mvm->fw_paging_db[i].fw_paging_phys;
 
 			dump_data->type = cpu_to_le32(IWL_FW_ERROR_DUMP_PAGING);
 			dump_data->len = cpu_to_le32(sizeof(*paging) +
 						     PAGING_BLOCK_SIZE);
 			paging = (void *)dump_data->data;
 			paging->index = cpu_to_le32(i);
+			dma_sync_single_for_cpu(mvm->trans->dev, addr,
+						PAGING_BLOCK_SIZE,
+						DMA_BIDIRECTIONAL);
 			memcpy(paging->data, page_address(pages),
 			       PAGING_BLOCK_SIZE);
 			dump_data = iwl_fw_error_next_data(dump_data);
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -214,6 +214,10 @@ static int iwl_fill_paging_mem(struct iw
 	memcpy(page_address(mvm->fw_paging_db[0].fw_paging_block),
 	       image->sec[sec_idx].data,
 	       mvm->fw_paging_db[0].fw_paging_size);
+	dma_sync_single_for_device(mvm->trans->dev,
+				   mvm->fw_paging_db[0].fw_paging_phys,
+				   mvm->fw_paging_db[0].fw_paging_size,
+				   DMA_BIDIRECTIONAL);
 
 	IWL_DEBUG_FW(mvm,
 		     "Paging: copied %d CSS bytes to first block\n",
@@ -228,9 +232,16 @@ static int iwl_fill_paging_mem(struct iw
 	 * loop stop at num_of_paging_blk since that last block is not full.
 	 */
 	for (idx = 1; idx < mvm->num_of_paging_blk; idx++) {
-		memcpy(page_address(mvm->fw_paging_db[idx].fw_paging_block),
+		struct iwl_fw_paging *block = &mvm->fw_paging_db[idx];
+
+		memcpy(page_address(block->fw_paging_block),
 		       image->sec[sec_idx].data + offset,
-		       mvm->fw_paging_db[idx].fw_paging_size);
+		       block->fw_paging_size);
+		dma_sync_single_for_device(mvm->trans->dev,
+					   block->fw_paging_phys,
+					   block->fw_paging_size,
+					   DMA_BIDIRECTIONAL);
+
 
 		IWL_DEBUG_FW(mvm,
 			     "Paging: copied %d paging bytes to block %d\n",
@@ -242,9 +253,15 @@ static int iwl_fill_paging_mem(struct iw
 
 	/* copy the last paging block */
 	if (mvm->num_of_pages_in_last_blk > 0) {
-		memcpy(page_address(mvm->fw_paging_db[idx].fw_paging_block),
+		struct iwl_fw_paging *block = &mvm->fw_paging_db[idx];
+
+		memcpy(page_address(block->fw_paging_block),
 		       image->sec[sec_idx].data + offset,
 		       FW_PAGING_SIZE * mvm->num_of_pages_in_last_blk);
+		dma_sync_single_for_device(mvm->trans->dev,
+					   block->fw_paging_phys,
+					   block->fw_paging_size,
+					   DMA_BIDIRECTIONAL);
 
 		IWL_DEBUG_FW(mvm,
 			     "Paging: copied %d pages in the last block %d\n",