riscv: sifive_u: Fix broken GEM support

At present the GEM support in sifive_u machine is seriously broken.
The GEM block register base was set to a weird number (0x100900FC),
which for no way could work with the cadence_gem model in QEMU.

Not like other GEM variants, the FU540-specific GEM has a management
block to control 10/100/1000Mbps link speed changes, that is mapped
to 0x100a0000. We can simply map it into MMIO space without special
handling using create_unimplemented_device().

Update the GEM node compatible string to use the official name used
by the upstream Linux kernel, and add the management block reg base
& size to the <reg> property encoding.

Tested with upstream U-Boot and Linux kernel MACB drivers.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

hw/riscv/Kconfig

@@ -19,6 +19,7 @@ config SIFIVE_U
     select CADENCE
     select HART
     select SIFIVE
+    select UNIMP
 
 config SPIKE
     bool

hw/riscv/sifive_u.c

@@ -3,6 +3,7 @@
  *
  * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
  * Copyright (c) 2017 SiFive, Inc.
+ * Copyright (c) 2019 Bin Meng <bmeng.cn@gmail.com>
  *
  * Provides a board compatible with the SiFive Freedom U SDK:
  *
@@ -11,6 +12,7 @@
  * 2) PLIC (Platform Level Interrupt Controller)
  * 3) PRCI (Power, Reset, Clock, Interrupt)
  * 4) OTP (One-Time Programmable) memory with stored serial number
+ * 5) GEM (Gigabit Ethernet Controller) and management block
  *
  * This board currently generates devicetree dynamically that indicates at least
  * two harts and up to five harts.
@@ -37,6 +39,7 @@
 #include "hw/sysbus.h"
 #include "hw/char/serial.h"
 #include "hw/cpu/cluster.h"
+#include "hw/misc/unimp.h"
 #include "target/riscv/cpu.h"
 #include "hw/riscv/riscv_hart.h"
 #include "hw/riscv/sifive_plic.h"
@@ -45,6 +48,7 @@
 #include "hw/riscv/sifive_u.h"
 #include "hw/riscv/boot.h"
 #include "chardev/char.h"
+#include "net/eth.h"
 #include "sysemu/arch_init.h"
 #include "sysemu/device_tree.h"
 #include "sysemu/sysemu.h"
@@ -67,7 +71,8 @@ static const struct MemmapEntry {
     [SIFIVE_U_UART1] =    { 0x10011000,     0x1000 },
     [SIFIVE_U_OTP] =      { 0x10070000,     0x1000 },
     [SIFIVE_U_DRAM] =     { 0x80000000,        0x0 },
-    [SIFIVE_U_GEM] =      { 0x100900FC,     0x2000 },
+    [SIFIVE_U_GEM] =      { 0x10090000,     0x2000 },
+    [SIFIVE_U_GEM_MGMT] = { 0x100a0000,     0x1000 },
 };
 
 #define OTP_SERIAL          1
@@ -84,7 +89,7 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     char ethclk_names[] = "pclk\0hclk";
     uint32_t plic_phandle, prci_phandle, ethclk_phandle, phandle = 1;
     uint32_t uartclk_phandle;
-    uint32_t hfclk_phandle, rtcclk_phandle;
+    uint32_t hfclk_phandle, rtcclk_phandle, phy_phandle;
 
     fdt = s->fdt = create_device_tree(&s->fdt_size);
     if (!fdt) {
@@ -254,28 +259,36 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     ethclk_phandle = qemu_fdt_get_phandle(fdt, nodename);
     g_free(nodename);
 
+    phy_phandle = phandle++;
     nodename = g_strdup_printf("/soc/ethernet@%lx",
         (long)memmap[SIFIVE_U_GEM].base);
     qemu_fdt_add_subnode(fdt, nodename);
-    qemu_fdt_setprop_string(fdt, nodename, "compatible", "cdns,macb");
+    qemu_fdt_setprop_string(fdt, nodename, "compatible",
+        "sifive,fu540-c000-gem");
     qemu_fdt_setprop_cells(fdt, nodename, "reg",
         0x0, memmap[SIFIVE_U_GEM].base,
-        0x0, memmap[SIFIVE_U_GEM].size);
+        0x0, memmap[SIFIVE_U_GEM].size,
+        0x0, memmap[SIFIVE_U_GEM_MGMT].base,
+        0x0, memmap[SIFIVE_U_GEM_MGMT].size);
     qemu_fdt_setprop_string(fdt, nodename, "reg-names", "control");
     qemu_fdt_setprop_string(fdt, nodename, "phy-mode", "gmii");
+    qemu_fdt_setprop_cell(fdt, nodename, "phy-handle", phy_phandle);
     qemu_fdt_setprop_cell(fdt, nodename, "interrupt-parent", plic_phandle);
     qemu_fdt_setprop_cell(fdt, nodename, "interrupts", SIFIVE_U_GEM_IRQ);
     qemu_fdt_setprop_cells(fdt, nodename, "clocks",
         prci_phandle, PRCI_CLK_GEMGXLPLL, prci_phandle, PRCI_CLK_GEMGXLPLL);
     qemu_fdt_setprop(fdt, nodename, "clock-names", ethclk_names,
         sizeof(ethclk_names));
+    qemu_fdt_setprop(fdt, nodename, "local-mac-address",
+        s->soc.gem.conf.macaddr.a, ETH_ALEN);
     qemu_fdt_setprop_cell(fdt, nodename, "#address-cells", 1);
     qemu_fdt_setprop_cell(fdt, nodename, "#size-cells", 0);
     g_free(nodename);
 
     nodename = g_strdup_printf("/soc/ethernet@%lx/ethernet-phy@0",
         (long)memmap[SIFIVE_U_GEM].base);
     qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cell(fdt, nodename, "phandle", phy_phandle);
     qemu_fdt_setprop_cell(fdt, nodename, "reg", 0x0);
     g_free(nodename);
 
@@ -525,6 +538,9 @@ static void riscv_sifive_u_soc_realize(DeviceState *dev, Error **errp)
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->gem), 0, memmap[SIFIVE_U_GEM].base);
     sysbus_connect_irq(SYS_BUS_DEVICE(&s->gem), 0,
                        plic_gpios[SIFIVE_U_GEM_IRQ]);
+
+    create_unimplemented_device("riscv.sifive.u.gem-mgmt",
+        memmap[SIFIVE_U_GEM_MGMT].base, memmap[SIFIVE_U_GEM_MGMT].size);
 }
 
 static void riscv_sifive_u_machine_init(MachineClass *mc)

include/hw/riscv/sifive_u.h

@@ -64,7 +64,8 @@ enum {
     SIFIVE_U_UART1,
     SIFIVE_U_OTP,
     SIFIVE_U_DRAM,
-    SIFIVE_U_GEM
+    SIFIVE_U_GEM,
+    SIFIVE_U_GEM_MGMT
 };
 
 enum {