[PATCH net-next 07/13] net: macb: move HW IP alignment value to macb_config

@@ -1191,6 +1191,7 @@ struct macb_usrio_config {
 
 struct macb_config {
 	u32			caps;
+	int			hw_ip_align;
 	unsigned int		dma_burst_length;
 	int	(*clk_init)(struct platform_device *pdev, struct clk **pclk,
 			    struct clk **hclk, struct clk **tx_clk,

@@ -1295,6 +1296,7 @@ struct macb {
 
 	u32			caps;
 	unsigned int		dma_burst_length;
+	int			hw_ip_align;
 
 	phy_interface_t		phy_interface;
 

@@ -1352,8 +1352,26 @@ static void gem_rx_refill(struct macb_queue *queue)
 			dma_wmb();
 			macb_set_addr(bp, desc, paddr);
 
-			/* properly align Ethernet header */
-			skb_reserve(skb, NET_IP_ALIGN);
+			/* Properly align Ethernet header.
+			 *
+			 * Here be (small-ish) dragons. 3 features intertwine:
+			 * (1) Hardware adds two dummy bytes. Notice how
+			 *     skb_reserve() is done AFTER dma_map_single().
+			 * (2) The NET_IP_ALIGN value is arch dependent.
+			 * (3) The low 2/3 bits cannot be picked.
+			 *     3 bits if HW_DMA_CAP_PTP.
+			 *
+			 * Notice how (1) and (2) are unrelated (IP-specific
+			 * versus arch-specific) but must agree for a working
+			 * system.
+			 *
+			 * (3) implies we cannot align the IP header (ie respect
+			 * NET_IP_ALIGN) if HW does not add two bytes.
+			 *
+			 * FIXME: migrate away from hw_ip_align == NET_IP_ALIGN
+			 * for all compatibles.
+			 */
+			skb_reserve(skb, bp->hw_ip_align);
 		} else {
 			desc->ctrl = 0;
 			dma_wmb();

@@ -4994,6 +5012,7 @@ static const struct macb_usrio_config sama7g5_usrio = {
 static const struct macb_config fu540_c000_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO |
 		MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = fu540_c000_clk_init,
 	.init = fu540_c000_init,

@@ -5003,6 +5022,7 @@ static const struct macb_config fu540_c000_config = {
 
 static const struct macb_config at91sam9260_config = {
 	.caps = MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII,
+	.hw_ip_align = 2,
 	.clk_init = macb_clk_init,
 	.init = macb_init,
 	.usrio = &macb_default_usrio,

@@ -5011,6 +5031,7 @@ static const struct macb_config at91sam9260_config = {
 static const struct macb_config sama5d3macb_config = {
 	.caps = MACB_CAPS_SG_DISABLED |
 		MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII,
+	.hw_ip_align = 2,
 	.clk_init = macb_clk_init,
 	.init = macb_init,
 	.usrio = &macb_default_usrio,

@@ -5018,6 +5039,7 @@ static const struct macb_config sama5d3macb_config = {
 
 static const struct macb_config pc302gem_config = {
 	.caps = MACB_CAPS_SG_DISABLED | MACB_CAPS_GIGABIT_MODE_AVAILABLE,
+	.hw_ip_align = NET_IP_ALIGN,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5026,6 +5048,7 @@ static const struct macb_config pc302gem_config = {
 
 static const struct macb_config sama5d2_config = {
 	.caps = MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII | MACB_CAPS_JUMBO,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5035,6 +5058,7 @@ static const struct macb_config sama5d2_config = {
 
 static const struct macb_config sama5d29_config = {
 	.caps = MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII | MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5044,6 +5068,7 @@ static const struct macb_config sama5d29_config = {
 static const struct macb_config sama5d3_config = {
 	.caps = MACB_CAPS_SG_DISABLED | MACB_CAPS_GIGABIT_MODE_AVAILABLE |
 		MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII | MACB_CAPS_JUMBO,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5053,6 +5078,7 @@ static const struct macb_config sama5d3_config = {
 
 static const struct macb_config sama5d4_config = {
 	.caps = MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII,
+	.hw_ip_align = 2,
 	.dma_burst_length = 4,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5061,6 +5087,7 @@ static const struct macb_config sama5d4_config = {
 
 static const struct macb_config emac_config = {
 	.caps = MACB_CAPS_NEEDS_RSTONUBR | MACB_CAPS_MACB_IS_EMAC,
+	.hw_ip_align = 2,
 	.clk_init = at91ether_clk_init,
 	.init = at91ether_init,
 	.usrio = &macb_default_usrio,

@@ -5068,6 +5095,7 @@ static const struct macb_config emac_config = {
 
 static const struct macb_config np4_config = {
 	.caps = MACB_CAPS_USRIO_DISABLED,
+	.hw_ip_align = NET_IP_ALIGN,
 	.clk_init = macb_clk_init,
 	.init = macb_init,
 	.usrio = &macb_default_usrio,

@@ -5077,6 +5105,7 @@ static const struct macb_config zynqmp_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
 		MACB_CAPS_JUMBO |
 		MACB_CAPS_GEM_HAS_PTP | MACB_CAPS_BD_RD_PREFETCH,
+	.hw_ip_align = 0,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = init_reset_optional,

@@ -5087,6 +5116,7 @@ static const struct macb_config zynqmp_config = {
 static const struct macb_config zynq_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_NO_GIGABIT_HALF |
 		MACB_CAPS_NEEDS_RSTONUBR,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5097,6 +5127,7 @@ static const struct macb_config mpfs_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
 		MACB_CAPS_JUMBO |
 		MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = init_reset_optional,

@@ -5108,6 +5139,7 @@ static const struct macb_config mpfs_config = {
 static const struct macb_config sama7g5_gem_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_CLK_HW_CHG |
 		MACB_CAPS_MIIONRGMII | MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5118,6 +5150,7 @@ static const struct macb_config sama7g5_emac_config = {
 	.caps = MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII |
 		MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_MIIONRGMII |
 		MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = 2,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5128,6 +5161,7 @@ static const struct macb_config versal_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO |
 		MACB_CAPS_GEM_HAS_PTP | MACB_CAPS_BD_RD_PREFETCH | MACB_CAPS_NEED_TSUCLK |
 		MACB_CAPS_QUEUE_DISABLE,
+	.hw_ip_align = NET_IP_ALIGN,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = init_reset_optional,

@@ -5167,6 +5201,7 @@ static const struct macb_config default_gem_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
 		MACB_CAPS_JUMBO |
 		MACB_CAPS_GEM_HAS_PTP,
+	.hw_ip_align = NET_IP_ALIGN,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,

@@ -5244,6 +5279,7 @@ static int macb_probe(struct platform_device *pdev)
 	bp->tx_clk = tx_clk;
 	bp->rx_clk = rx_clk;
 	bp->tsu_clk = tsu_clk;
+	bp->hw_ip_align = macb_config->hw_ip_align;
 	bp->jumbo_max_len = macb_config->jumbo_max_len;
 
 	if (!hw_is_gem(bp->regs, bp->native_io))