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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 <linux@roeck-us.net>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This commit is contained in:
Guenter Roeck 2019-07-19 06:40:44 -07:00 committed by Palmer Dabbelt
parent 0f8d446249
commit 44e6dcd30a
No known key found for this signature in database
GPG Key ID: EF4CA1502CCBAB41
1 changed files with 17 additions and 2 deletions
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19
hw/riscv/sifive_u.c
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@ -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;