[Qemu-devel] [PATCH v1 1/1] sifive_u: Add clock DT node for GEM ethernet

[Alistair Francis <Alistair.Francis@wdc.com>]

From: Anup Patel <anup@brainfault.org>

The GEM ethernet on SiFive unleashed has fixed input clock
of 125MHz as-per SiFive FU540 manual. This patch updates FDT
generation for QEMU sifive_u machine to provide fixed-rate
clock for GEM ethernet.

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 hw/riscv/sifive_u.c         | 18 +++++++++++++++++-
 include/hw/riscv/sifive_u.h |  3 ++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index ef07df2442..5c41ee5017 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -85,7 +85,8 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     int cpu;
     uint32_t *cells;
     char *nodename;
-    uint32_t plic_phandle;
+    char ethclk_names[] = "pclk\0hclk\0tx_clk";
+    uint32_t plic_phandle, ethclk_phandle;
 
     fdt = s->fdt = create_device_tree(&s->fdt_size);
     if (!fdt) {
@@ -197,6 +198,17 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     g_free(cells);
     g_free(nodename);
 
+    nodename = g_strdup_printf("/soc/ethclk");
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "fixed-clock");
+    qemu_fdt_setprop_cell(fdt, nodename, "#clock-cells", 0x0);
+    qemu_fdt_setprop_cell(fdt, nodename, "clock-frequency",
+        SIFIVE_U_GEM_CLOCK_FREQ);
+    qemu_fdt_setprop_cell(fdt, nodename, "phandle", 3);
+    qemu_fdt_setprop_cell(fdt, nodename, "linux,phandle", 3);
+    ethclk_phandle = qemu_fdt_get_phandle(fdt, nodename);
+    g_free(nodename);
+
     nodename = g_strdup_printf("/soc/ethernet@%lx",
         (long)memmap[SIFIVE_U_GEM].base);
     qemu_fdt_add_subnode(fdt, nodename);
@@ -208,6 +220,10 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     qemu_fdt_setprop_string(fdt, nodename, "phy-mode", "gmii");
     qemu_fdt_setprop_cells(fdt, nodename, "interrupt-parent", plic_phandle);
     qemu_fdt_setprop_cells(fdt, nodename, "interrupts", SIFIVE_U_GEM_IRQ);
+    qemu_fdt_setprop_cells(fdt, nodename, "clocks",
+        ethclk_phandle, ethclk_phandle, ethclk_phandle);
+    qemu_fdt_setprop(fdt, nodename, "clocks-names", ethclk_names,
+        sizeof(ethclk_names));
     qemu_fdt_setprop_cells(fdt, nodename, "#address-cells", 1);
     qemu_fdt_setprop_cells(fdt, nodename, "#size-cells", 0);
     g_free(nodename);
diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h
index e8b4d9ffa3..be13cc1304 100644
--- a/include/hw/riscv/sifive_u.h
+++ b/include/hw/riscv/sifive_u.h
@@ -63,7 +63,8 @@ enum {
 };
 
 enum {
-    SIFIVE_U_CLOCK_FREQ = 1000000000
+    SIFIVE_U_CLOCK_FREQ = 1000000000,
+    SIFIVE_U_GEM_CLOCK_FREQ = 125000000
 };
 
 #define SIFIVE_U_PLIC_HART_CONFIG "MS"
-- 
2.19.1