From 44e6dcd30a10e5b5d70cbf1bc248b146eabcec03 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Fri, 19 Jul 2019 06:40:44 -0700 Subject: [PATCH] riscv: sivive_u: Add dummy serial clock and aliases entry for uart The riscv uart needs valid clocks. This requires a refereence to the clock node. Since the SOC clock is not emulated by qemu, add a reference to a fixed clock instead. The clock-frequency entry in the uart node does not seem to be necessary, so drop it. In addition to a reference to the clock, the driver also needs an aliases entry for the serial node. Add it as well. Without this patch, the serial driver fails to instantiate with the following error message. sifive-serial 10013000.uart: unable to find controller clock sifive-serial: probe of 10013000.uart failed with error -2 when trying to boot Linux. Signed-off-by: Guenter Roeck Reviewed-by: Alistair Francis Signed-off-by: Palmer Dabbelt --- hw/riscv/sifive_u.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c index 32167d05a1..8313f2605e 100644 --- a/hw/riscv/sifive_u.c +++ b/hw/riscv/sifive_u.c @@ -76,6 +76,7 @@ static void *create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap, char *nodename; char ethclk_names[] = "pclk\0hclk\0tx_clk"; uint32_t plic_phandle, ethclk_phandle, phandle = 1; + uint32_t uartclk_phandle; fdt = s->fdt = create_device_tree(&s->fdt_size); if (!fdt) { @@ -226,6 +227,17 @@ static void *create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap, qemu_fdt_setprop_cells(fdt, nodename, "reg", 0x0); g_free(nodename); + uartclk_phandle = phandle++; + nodename = g_strdup_printf("/soc/uartclk"); + 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", 3686400); + qemu_fdt_setprop_cell(fdt, nodename, "phandle", uartclk_phandle); + qemu_fdt_setprop_cell(fdt, nodename, "linux,phandle", uartclk_phandle); + uartclk_phandle = qemu_fdt_get_phandle(fdt, nodename); + g_free(nodename); + nodename = g_strdup_printf("/soc/uart@%lx", (long)memmap[SIFIVE_U_UART0].base); qemu_fdt_add_subnode(fdt, nodename); @@ -233,8 +245,7 @@ static void *create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap, qemu_fdt_setprop_cells(fdt, nodename, "reg", 0x0, memmap[SIFIVE_U_UART0].base, 0x0, memmap[SIFIVE_U_UART0].size); - qemu_fdt_setprop_cell(fdt, nodename, "clock-frequency", - SIFIVE_U_CLOCK_FREQ / 2); + qemu_fdt_setprop_cells(fdt, nodename, "clocks", uartclk_phandle); qemu_fdt_setprop_cells(fdt, nodename, "interrupt-parent", plic_phandle); qemu_fdt_setprop_cells(fdt, nodename, "interrupts", SIFIVE_U_UART0_IRQ); @@ -243,6 +254,10 @@ static void *create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap, if (cmdline) { qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline); } + + qemu_fdt_add_subnode(fdt, "/aliases"); + qemu_fdt_setprop_string(fdt, "/aliases", "serial0", nodename); + g_free(nodename); return fdt;