staging: fsl-dpaa2/eth: Fix access to FAS field

Commit 4b2d9fe8 ("staging: fsl-dpaa2/eth: Extra headroom in RX
buffers") removes the software annotation (SWA) area from the RX
buffer layout, as it's not used by anyone, but fails to update the
macros for accessing hardware annotation (HWA) fields, which is
right after the SWA in the buffer headroom.

This may lead to some frame annotation status fields (e.g. indication
if L3/L4 checksum is valid) to be read incorrectly.

Turn the accessor macros into inline functions and add a bool param
to specify if SWA is present or not.

Fixes: 4b2d9fe8 ("staging: fsl-dpaa2/eth: Extra headroom in RX buffers")
Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c

@@ -249,7 +249,7 @@ static void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
 	vaddr = dpaa2_iova_to_virt(priv->iommu_domain, addr);
 	dma_unmap_single(dev, addr, DPAA2_ETH_RX_BUF_SIZE, DMA_FROM_DEVICE);
 
-	fas = dpaa2_get_fas(vaddr);
+	fas = dpaa2_get_fas(vaddr, false);
 	prefetch(fas);
 	buf_data = vaddr + dpaa2_fd_get_offset(fd);
 	prefetch(buf_data);
@@ -385,7 +385,7 @@ static int build_sg_fd(struct dpaa2_eth_priv *priv,
 	 * on TX confirmation. We are clearing FAS (Frame Annotation Status)
 	 * field from the hardware annotation area
 	 */
-	fas = dpaa2_get_fas(sgt_buf);
+	fas = dpaa2_get_fas(sgt_buf, true);
 	memset(fas, 0, DPAA2_FAS_SIZE);
 
 	sgt = (struct dpaa2_sg_entry *)(sgt_buf + priv->tx_data_offset);
@@ -458,7 +458,7 @@ static int build_single_fd(struct dpaa2_eth_priv *priv,
 	 * on TX confirmation. We are clearing FAS (Frame Annotation Status)
 	 * field from the hardware annotation area
 	 */
-	fas = dpaa2_get_fas(buffer_start);
+	fas = dpaa2_get_fas(buffer_start, true);
 	memset(fas, 0, DPAA2_FAS_SIZE);
 
 	/* Store a backpointer to the skb at the beginning of the buffer
@@ -510,7 +510,7 @@ static void free_tx_fd(const struct dpaa2_eth_priv *priv,
 
 	fd_addr = dpaa2_fd_get_addr(fd);
 	skbh = dpaa2_iova_to_virt(priv->iommu_domain, fd_addr);
-	fas = dpaa2_get_fas(skbh);
+	fas = dpaa2_get_fas(skbh, true);
 
 	if (fd_format == dpaa2_fd_single) {
 		skb = *skbh;

drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.h

@@ -153,10 +153,15 @@ struct dpaa2_fas {
 #define DPAA2_FAS_SIZE			(sizeof(struct dpaa2_fas))
 
 /* Accessors for the hardware annotation fields that we use */
-#define dpaa2_get_hwa(buf_addr) \
-	((void *)(buf_addr) + DPAA2_ETH_SWA_SIZE)
-#define dpaa2_get_fas(buf_addr) \
-	(struct dpaa2_fas *)(dpaa2_get_hwa(buf_addr) + DPAA2_FAS_OFFSET)
+static inline void *dpaa2_get_hwa(void *buf_addr, bool swa)
+{
+	return buf_addr + (swa ? DPAA2_ETH_SWA_SIZE : 0);
+}
+
+static inline struct dpaa2_fas *dpaa2_get_fas(void *buf_addr, bool swa)
+{
+	return dpaa2_get_hwa(buf_addr, swa) + DPAA2_FAS_OFFSET;
+}
 
 /* Error and status bits in the frame annotation status word */
 /* Debug frame, otherwise supposed to be discarded */