iwlwifi: pcie: use partial pages if applicable

If we have only 2k RBs like on the latest (AX210) hardware, then
even on x86 where PAGE_SIZE is 4k we currently waste half of the
memory.

If this is the case, return partial pages from the allocator and
track the offset in each RBD (to be able to find the data in them
and remap them later.)

This might also address other platforms with larger PAGE_SIZE by
putting more RBs into a single large page.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
index c7d094cf1e4e..2ac730859eac 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
@@ -106,6 +106,8 @@ struct iwl_host_cmd;
  * @page: driver's pointer to the rxb page
  * @invalid: rxb is in driver ownership - not owned by HW
  * @vid: index of this rxb in the global table
+ * @offset: indicates which offset of the page (in bytes)
+ *	this buffer uses (if multiple RBs fit into one page)
  */
 struct iwl_rx_mem_buffer {
 	dma_addr_t page_dma;
@@ -113,6 +115,7 @@ struct iwl_rx_mem_buffer {
 	u16 vid;
 	bool invalid;
 	struct list_head list;
+	u32 offset;
 };
 
 /**
@@ -511,6 +514,11 @@ struct cont_rec {
  * @in_rescan: true if we have triggered a device rescan
  * @base_rb_stts: base virtual address of receive buffer status for all queues
  * @base_rb_stts_dma: base physical address of receive buffer status
+ * @supported_dma_mask: DMA mask to validate the actual address against,
+ *	will be DMA_BIT_MASK(11) or DMA_BIT_MASK(12) depending on the device
+ * @alloc_page_lock: spinlock for the page allocator
+ * @alloc_page: allocated page to still use parts of
+ * @alloc_page_used: how much of the allocated page was already used (bytes)
  */
 struct iwl_trans_pcie {
 	struct iwl_rxq *rxq;
@@ -583,6 +591,12 @@ struct iwl_trans_pcie {
 	bool pcie_dbg_dumped_once;
 	u32 rx_page_order;
 	u32 rx_buf_bytes;
+	u32 supported_dma_mask;
+
+	/* allocator lock for the two values below */
+	spinlock_t alloc_page_lock;
+	struct page *alloc_page;
+	u32 alloc_page_used;
 
 	/*protect hw register */
 	spinlock_t reg_lock;