mwifiex: DMA alignment for RX packets

This patch adds support for DMA alignment of sk_buffs
allocated for RX.
Patch also adds support to modify skb allocation flags.

Signed-off-by: Marc Yang <yangyang@marvell.com>
Signed-off-by: Qingshui Gao <gaoqs@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mwifiex/decl.h

@@ -33,6 +33,7 @@
 #define MWIFIEX_MAX_BSS_NUM         (3)
 
 #define MWIFIEX_DMA_ALIGN_SZ	    64
+#define MWIFIEX_RX_HEADROOM	    64
 #define MAX_TXPD_SZ		    32
 #define INTF_HDR_ALIGN		     4
 

drivers/net/wireless/mwifiex/main.h

@@ -140,6 +140,9 @@ enum {
 
 #define MWIFIEX_DRV_INFO_SIZE_MAX 0x40000
 
+/* Address alignment */
+#define MWIFIEX_ALIGN_ADDR(p, a) (((long)(p) + (a) - 1) & ~((a) - 1))
+
 struct mwifiex_dbg {
 	u32 num_cmd_host_to_card_failure;
 	u32 num_cmd_sleep_cfm_host_to_card_failure;
@@ -1418,6 +1421,7 @@ u8 mwifiex_adjust_data_rate(struct mwifiex_private *priv,
 			    u8 rx_rate, u8 ht_info);
 
 void mwifiex_dump_drv_info(struct mwifiex_adapter *adapter);
+void *mwifiex_alloc_rx_buf(int rx_len, gfp_t flags);
 
 #ifdef CONFIG_DEBUG_FS
 void mwifiex_debugfs_init(void);

drivers/net/wireless/mwifiex/pcie.c

@@ -498,7 +498,8 @@ static int mwifiex_init_rxq_ring(struct mwifiex_adapter *adapter)
 
 	for (i = 0; i < MWIFIEX_MAX_TXRX_BD; i++) {
 		/* Allocate skb here so that firmware can DMA data from it */
-		skb = dev_alloc_skb(MWIFIEX_RX_DATA_BUF_SIZE);
+		skb = mwifiex_alloc_rx_buf(MWIFIEX_RX_DATA_BUF_SIZE,
+					   GFP_KERNEL | GFP_DMA);
 		if (!skb) {
 			dev_err(adapter->dev,
 				"Unable to allocate skb for RX ring.\n");
@@ -1297,7 +1298,8 @@ static int mwifiex_pcie_process_recv_data(struct mwifiex_adapter *adapter)
 			}
 		}
 
-		skb_tmp = dev_alloc_skb(MWIFIEX_RX_DATA_BUF_SIZE);
+		skb_tmp = mwifiex_alloc_rx_buf(MWIFIEX_RX_DATA_BUF_SIZE,
+					       GFP_KERNEL | GFP_DMA);
 		if (!skb_tmp) {
 			dev_err(adapter->dev,
 				"Unable to allocate skb.\n");

drivers/net/wireless/mwifiex/sdio.c

@@ -1357,7 +1357,7 @@ static int mwifiex_process_int_status(struct mwifiex_adapter *adapter)
 			return -1;
 		rx_len = (u16) (rx_blocks * MWIFIEX_SDIO_BLOCK_SIZE);
 
-		skb = dev_alloc_skb(rx_len);
+		skb = mwifiex_alloc_rx_buf(rx_len, GFP_KERNEL | GFP_DMA);
 		if (!skb)
 			return -1;
 
@@ -1454,7 +1454,8 @@ static int mwifiex_process_int_status(struct mwifiex_adapter *adapter)
 			}
 			rx_len = (u16) (rx_blocks * MWIFIEX_SDIO_BLOCK_SIZE);
 
-			skb = dev_alloc_skb(rx_len);
+			skb = mwifiex_alloc_rx_buf(rx_len,
+						   GFP_KERNEL | GFP_DMA);
 
 			if (!skb) {
 				dev_err(adapter->dev, "%s: failed to alloc skb",

drivers/net/wireless/mwifiex/util.c

@@ -631,3 +631,26 @@ void mwifiex_hist_data_reset(struct mwifiex_private *priv)
 	for (ix = 0; ix < MWIFIEX_MAX_SIG_STRENGTH; ix++)
 		atomic_set(&phist_data->sig_str[ix], 0);
 }
+
+void *mwifiex_alloc_rx_buf(int rx_len, gfp_t flags)
+{
+	struct sk_buff *skb;
+	int buf_len, pad;
+
+	buf_len = rx_len + MWIFIEX_RX_HEADROOM + MWIFIEX_DMA_ALIGN_SZ;
+
+	skb = __dev_alloc_skb(buf_len, flags);
+
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, MWIFIEX_RX_HEADROOM);
+
+	pad = MWIFIEX_ALIGN_ADDR(skb->data, MWIFIEX_DMA_ALIGN_SZ) -
+	      (long)skb->data;
+
+	skb_reserve(skb, pad);
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(mwifiex_alloc_rx_buf);