ethernet: stmmac: dwmac-rk: generate the mac address from the system serial number

Added the feature of generating MAC addresses from serial numbers for dwmac-rk
and added the necessary fallback strategies.

Signed-off-by: meilimao <meilimao@meilimao.org>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -168,11 +168,21 @@ config DWMAC_ROCKCHIP
 	depends on OF && (ARCH_ROCKCHIP || COMPILE_TEST)
 	select MFD_SYSCON
 	help
-	  Support for Ethernet controller on Rockchip RK3288 SoC.
+	  Support for Ethernet controller on Rockchip SoC.
 
-	  This selects the Rockchip RK3288 SoC glue layer support for
+	  This selects the Rockchip SoC glue layer support for
 	  the stmmac device driver.
 
+config DWMAC_ROCKCHIP_SERIAL_MAC
+	bool "Generate static ethernet mac address from system serial number"
+	depends on DWMAC_ROCKCHIP
+	default n
+	help
+	  Generate consistent MAC address from system serial number.
+
+	  This selects uses the system serial number to generate a 
+	  fixed Ethernet Mac address instead of a random one.
+
 config DWMAC_ROCKCHIP_TOOL
 	bool "Rockchip dwmac tool support"
 	depends on DWMAC_ROCKCHIP

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -27,9 +27,8 @@ obj-$(CONFIG_DWMAC_MEDIATEK)	+= dwmac-mediatek.o
 obj-$(CONFIG_DWMAC_MESON)	+= dwmac-meson.o dwmac-meson8b.o
 obj-$(CONFIG_DWMAC_OXNAS)	+= dwmac-oxnas.o
 obj-$(CONFIG_DWMAC_QCOM_ETHQOS)	+= dwmac-qcom-ethqos.o
-obj-$(CONFIG_DWMAC_ROCKCHIP)	+= dwmac-rockchip.o
-dwmac-rockchip-objs := dwmac-rk.o
-dwmac-rockchip-$(CONFIG_DWMAC_ROCKCHIP_TOOL) += dwmac-rk-tool.o
+obj-$(CONFIG_DWMAC_ROCKCHIP)	+= dwmac-rk.o
+obj-$(CONFIG_DWMAC_ROCKCHIP_TOOL) += dwmac-rk-tool.o
 obj-$(CONFIG_STMMAC_UIO) += stmmac_uio.o
 obj-$(CONFIG_DWMAC_SOCFPGA)	+= dwmac-altr-socfpga.o
 obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
@@ -48,3 +47,5 @@ obj-$(CONFIG_STMMAC_PCI)	+= stmmac-pci.o
 obj-$(CONFIG_DWMAC_INTEL)	+= dwmac-intel.o
 obj-$(CONFIG_DWMAC_LOONGSON)	+= dwmac-loongson.o
 stmmac-pci-objs:= stmmac_pci.o
+
+ccflags-$(CONFIG_DWMAC_ROCKCHIP_SERIAL_MAC) += -DDWMAC_ROCKCHIP_SERIAL_MAC

drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /**
- * DOC: dwmac-rk.c - Rockchip RK3288 DWMAC specific glue layer
+ * DOC: dwmac-rk.c - Rockchip DWMAC specific glue layer
  *
  * Copyright (C) 2014 Chen-Zhi (Roger Chen)
  *
@@ -28,6 +28,9 @@
 #include <soc/rockchip/rockchip_csu.h>
 #include "stmmac_platform.h"
 #include "dwmac-rk-tool.h"
+#ifdef DWMAC_ROCKCHIP_SERIAL_MAC
+#include <asm/system_info.h>
+#endif
 
 #define MAX_ETH		2
 
@@ -3254,6 +3257,102 @@ int dwmac_rk_get_phy_interface(struct stmmac_priv *priv)
 }
 EXPORT_SYMBOL(dwmac_rk_get_phy_interface);
 
+/**
+ * rk_generate_fallback_mac - Generate a fallback MAC address
+ * @addr: Buffer to store the MAC address (6 bytes)
+ * @iface_id: Interface identifier
+ *
+ * Generate a random MAC address with a local-admin OUI as fallback.
+ * Always returns a valid MAC address.
+ */
+static void rk_generate_fallback_mac(u8 *addr, int iface_id)
+{
+    /* Generate a random MAC address */
+    eth_random_addr(addr);
+    
+    /* Ensure the address is valid */
+    if (!is_valid_ether_addr(addr)) {
+        eth_zero_addr(addr);
+        /* Set a fallback locally administered address */
+        addr[0] = 0x02;    /* Locally administered bit is set */
+        addr[1] = 0x00;
+        addr[2] = 0xa4;
+        addr[3] = 0xff;
+        addr[4] = iface_id & 0xff;
+        addr[5] = 0xfe;
+    }
+}
+
+#ifdef DWMAC_ROCKCHIP_SERIAL_MAC
+/* 
+ * rk_get_mac_from_serial - Generate MAC address from system serial number
+ * @addr: Buffer to store the MAC address (6 bytes)
+ * @iface_id: Interface identifier
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int rk_get_mac_from_serial(u8 *addr, int iface_id)
+{
+    unsigned long long serial;
+    
+    /* Check the validity of the serial number */
+    if (system_serial_low == 0 && system_serial_high == 0)
+        return -ENODEV;
+    
+    /* Combine the 64-bit serial number */
+    serial = ((unsigned long long)system_serial_high << 32) | system_serial_low;
+    
+    /* Validate the serial number (optional but recommended) */
+    if (serial == 0 || serial == 0xFFFFFFFFFFFFFFFFULL)
+        return -EINVAL;
+    
+    /* Generate OUI: 02:00:a4 (locally administered address) */
+    addr[0] = 0x02;    /* Locally administered bit is set */
+    addr[1] = 0x00;
+    addr[2] = 0xa4;
+    
+    /* Use parts of the serial number */
+    addr[3] = 0x10 + ((serial >> 40) & 0xff);
+    addr[4] = (serial >> 32) & 0xff;
+    addr[5] = ((serial >> 24) & 0xff) + iface_id;
+    
+    return 0;
+}
+#endif /* DWMAC_ROCKCHIP_SERIAL_MAC */
+
+/* 
+ * rk_set_mac_address - Set up MAC address for an interface
+ * @addr: Buffer to store the MAC address (6 bytes)
+ * @iface_id: Interface identifier
+ *
+ * This function attempts to generate a deterministic MAC address from the
+ * system serial number if DWMAC_ROCKCHIP_SERIAL_MAC is enabled. If that fails
+ * or the feature is disabled, it falls back to a random MAC address.
+ *
+ * Return: Always returns 0 (success), as we guarantee a valid address.
+ */
+static int rk_set_mac_address(u8 *addr, int iface_id)
+{
+#ifdef DWMAC_ROCKCHIP_SERIAL_MAC
+    int ret;
+    
+    /* Attempt to generate MAC from serial number */
+    ret = rk_get_mac_from_serial(addr, iface_id);
+    if (ret == 0 && is_valid_ether_addr(addr)) {
+        return 0;  /* Success, return immediately */
+    }
+    
+    /* Fall back to a random address on failure */
+    printk_once(KERN_WARNING "dwc-rockchip: Serial MAC generation failed, using random for interface %d\n",
+                iface_id);
+#endif
+    
+    /* Generate fallback MAC address */
+    rk_generate_fallback_mac(addr, iface_id);
+    
+    return 0;
+}
+
 static void rk_get_eth_addr(void *priv, unsigned char *addr)
 {
     struct rk_priv_data *bsp_priv = priv;
@@ -3261,38 +3360,81 @@ static void rk_get_eth_addr(void *priv, unsigned char *addr)
     unsigned char ethaddr[ETH_ALEN * MAX_ETH] = {0};
     int ret, id = bsp_priv->id;
 
-	if (is_valid_ether_addr(addr))
-		goto out;
-
-	if (id < 0 || id >= MAX_ETH) {
-		dev_err(dev, "%s: Invalid ethernet bus id %d\n", __func__, id);
+    /* Check if the address is already valid */
+    if (is_valid_ether_addr(addr)) {
+        dev_info(dev, "%s: MAC address already set: %pM\n", __func__, addr);
         return;
     }
 
-	ret = rk_vendor_read(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
-	if (ret <= 0 ||
-	    !is_valid_ether_addr(&ethaddr[id * ETH_ALEN])) {
-		dev_err(dev, "%s: rk_vendor_read eth mac address failed (%d)\n",
-			__func__, ret);
-		eth_random_addr(&ethaddr[id * ETH_ALEN]);
-		memcpy(addr, &ethaddr[id * ETH_ALEN], ETH_ALEN);
-		dev_err(dev, "%s: generate random eth mac address: %pM\n", __func__, addr);
-
-		ret = rk_vendor_write(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
-		if (ret != 0)
-			dev_err(dev, "%s: rk_vendor_write eth mac address failed (%d)\n",
-				__func__, ret);
-
-		ret = rk_vendor_read(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
-		if (ret != ETH_ALEN * MAX_ETH)
-			dev_err(dev, "%s: id: %d rk_vendor_read eth mac address failed (%d)\n",
-				__func__, id, ret);
-	} else {
-		memcpy(addr, &ethaddr[id * ETH_ALEN], ETH_ALEN);
+    if (id < 0 || id >= MAX_ETH) {
+        dev_err(dev, "%s: Invalid ethernet bus id %d\n", __func__, id);
+        /* Still try to set a MAC address even with invalid ID */
+        id = 0;
     }
 
-out:
-	dev_err(dev, "%s: mac address: %pM\n", __func__, addr);
+#ifdef DWMAC_ROCKCHIP_SERIAL_MAC
+    /* Try to generate MAC from system serial number first */
+    dev_info(dev, "%s: Attempting to generate MAC from system serial number for interface %d\n",
+             __func__, id);
+    
+    if (rk_set_mac_address(addr, id) == 0 && is_valid_ether_addr(addr)) {
+        dev_info(dev, "%s: Generated MAC from serial: %pM\n", __func__, addr);
+        
+        /* Store the generated MAC address to vendor storage for persistence */
+        ret = rk_vendor_read(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
+        if (ret < 0) {
+            /* Initialize the buffer if read failed */
+            memset(ethaddr, 0, ETH_ALEN * MAX_ETH);
+        }
+        
+        /* Copy our generated MAC to the appropriate position */
+        memcpy(&ethaddr[id * ETH_ALEN], addr, ETH_ALEN);
+        
+        /* Write back to vendor storage */
+        ret = rk_vendor_write(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
+        if (ret != 0) {
+            dev_warn(dev, "%s: Failed to store MAC to vendor storage (%d)\n",
+                     __func__, ret);
+        } else {
+            dev_info(dev, "%s: Stored generated MAC to vendor storage\n", __func__);
+        }
+        return;
+    }
+    
+    dev_warn(dev, "%s: Serial-based MAC generation failed for interface %d, falling back to vendor storage\n",
+             __func__, id);
+#endif /* DWMAC_ROCKCHIP_SERIAL_MAC */
+
+    /* Fallback: try to read from vendor storage */
+    ret = rk_vendor_read(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
+    if (ret > 0 && is_valid_ether_addr(&ethaddr[id * ETH_ALEN])) {
+        memcpy(addr, &ethaddr[id * ETH_ALEN], ETH_ALEN);
+        dev_info(dev, "%s: Retrieved MAC from vendor storage: %pM\n",
+                 __func__, addr);
+        return;
+    }
+
+    /* Last resort: generate fallback MAC */
+    dev_warn(dev, "%s: No valid MAC found, generating fallback for interface %d\n",
+             __func__, id);
+    
+    rk_generate_fallback_mac(addr, id);
+    
+    /* Store the fallback MAC to vendor storage */
+    if (ret < 0) {
+        /* Initialize the buffer if read failed */
+        memset(ethaddr, 0, ETH_ALEN * MAX_ETH);
+    }
+    memcpy(&ethaddr[id * ETH_ALEN], addr, ETH_ALEN);
+    
+    ret = rk_vendor_write(LAN_MAC_ID, ethaddr, ETH_ALEN * MAX_ETH);
+    if (ret != 0) {
+        dev_err(dev, "%s: Failed to store fallback MAC to vendor storage (%d)\n",
+                __func__, ret);
+    } else {
+        dev_info(dev, "%s: Stored fallback MAC to vendor storage: %pM\n",
+                 __func__, addr);
+    }
 }
 
 static int rk_gmac_probe(struct platform_device *pdev)
@@ -3483,5 +3625,5 @@ static struct platform_driver rk_gmac_dwmac_driver = {
 module_platform_driver(rk_gmac_dwmac_driver);
 
 MODULE_AUTHOR("Chen-Zhi (Roger Chen) <roger.chen@rock-chips.com>");
-MODULE_DESCRIPTION("Rockchip RK3288 DWMAC specific glue layer");
+MODULE_DESCRIPTION("Rockchip DWMAC specific glue layer");
 MODULE_LICENSE("GPL");