boards: st: stm32h7s78_dk: add Ethernet support

Add Ethernet configuration  to the board's .dtsi file and
add a fallback for sram2 (sram1) which is needed for Ethernet.
Updated the board yaml file to include Ethernet feature and
updated documentation to explain Ethernet usage.

Signed-off-by: Benjamin Klaric <benjamin.klaric01@gmail.com>

Author: bklaric1

boards/st/stm32h7s78_dk/doc/index.rst

@@ -180,6 +180,7 @@ Default Zephyr Peripheral Mapping:
 - USB OTG FS DM/DP : PM12/PM11
 - XSPI1 NCS/DQS0/DQS1/CLK/IO: PO0/PO2/PO3/PO4/PP0..15
 - I2C1 SCL/SDA: PB6/PB9
+- ETH: PA2, PA7, PB0, PB1, PC1, PC4, PC5, PD7, PG11
 
 System Clock
 ------------
@@ -200,6 +201,13 @@ USB
 STM32H7S78-DK Discovery board has 2 USB Type-C connectors. Currently, only
 USB port2 (FS) is supported.
 
+Ethernet
+--------
+
+In order to use Ethernet on STM32H7S78-DK, you need to set the ``JP6`` jumper 
+to PC1 position on the back side of the board.
+
+
 Programming and Debugging
 *************************
 

boards/st/stm32h7s78_dk/stm32h7s78_dk-common.dtsi

@@ -209,6 +209,31 @@
 	};
 };
 
+&mac {
+	pinctrl-0 = <&eth_rmii_ref_clk_pd7
+			&eth_rmii_crs_dv_pa7
+			&eth_rmii_rxd0_pc4
+			&eth_rmii_rxd1_pc5
+			&eth_rmii_tx_en_pg11
+			&eth_rmii_txd0_pb0
+			&eth_rmii_txd1_pb1>;
+	pinctrl-names = "default";
+	phy-connection-type = "rmii";
+	phy-handle = <&eth_phy>;
+	status = "okay";
+};
+
+&mdio {
+	pinctrl-0 = <&eth_mdio_pa2 &eth_mdc_pc1>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	eth_phy: ethernet-phy@0 {
+		compatible = "ethernet-phy";
+		reg = <0x00>;
+	};
+};
+
 &xspi1 {
 	pinctrl-0 = <&xspim_p1_ncs1_po0 &xspim_p1_dqs0_po2
 		     &xspim_p1_dqs1_po3 &xspim_p1_clk_po4

boards/st/stm32h7s78_dk/stm32h7s78_dk.yaml

@@ -16,4 +16,5 @@ supported:
   - octospi
   - usbd
   - memc
+  - netif:eth
 vendor: st

soc/st/stm32/stm32h7rsx/mpu_regions.c

@@ -31,7 +31,13 @@ static const struct arm_mpu_region mpu_regions[] = {
 	MPU_REGION_ENTRY("ID", 0x08FFF800, REGION_FLASH_ATTR(REGION_2K)),
 
 #if DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(mac))
-#define sram_eth_node DT_NODELABEL(sram2)
+
+#if DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(sram2))
+#define sram_eth_node	DT_NODELABEL(sram2)
+#else
+#define sram_eth_node	DT_NODELABEL(sram1)
+#endif
+
 #if DT_NODE_HAS_STATUS_OKAY(sram_eth_node)
 	/* Region 5 - Ethernet DMA buffer RAM */
 	MPU_REGION_ENTRY("SRAM_ETH_BUF", DT_REG_ADDR(sram_eth_node),

soc/st/stm32/stm32h7rsx/sections.ld

@@ -5,7 +5,13 @@
  */
 
 #if DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(mac))
+
+#if DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(sram2))
 #define sram_eth_node	DT_NODELABEL(sram2)
+#else
+#define sram_eth_node	DT_NODELABEL(sram1)
+#endif
+
 #if DT_NODE_HAS_STATUS_OKAY(sram_eth_node)
 SECTION_DATA_PROLOGUE(eth_stm32,(NOLOAD),)
 {