Re: [PATCH 09/15] hw/riscv: sifive_u: Add reset functionality

[Alistair Francis]

On Mon, Jun 8, 2020 at 7:23 AM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> From: Bin Meng <bin.meng@windriver.com>
>
> The HiFive Unleashed board wires GPIO pin#10 to the input of the
> system reset signal. Let's set up the GPIO pin#10 and insert a
> "gpio-restart" device tree node so that reboot is now functional
> with QEMU 'sifive_u' machine.
>
> Signed-off-by: Bin Meng <bin.meng@windriver.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>
>  hw/riscv/sifive_u.c | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
> index 881949b..ef51874 100644
> --- a/hw/riscv/sifive_u.c
> +++ b/hw/riscv/sifive_u.c
> @@ -37,6 +37,7 @@
>  #include "qapi/error.h"
>  #include "qapi/visitor.h"
>  #include "hw/boards.h"
> +#include "hw/irq.h"
>  #include "hw/loader.h"
>  #include "hw/sysbus.h"
>  #include "hw/char/serial.h"
> @@ -53,6 +54,7 @@
>  #include "net/eth.h"
>  #include "sysemu/arch_init.h"
>  #include "sysemu/device_tree.h"
> +#include "sysemu/runstate.h"
>  #include "sysemu/sysemu.h"
>  #include "exec/address-spaces.h"
>
> @@ -96,7 +98,7 @@ static void create_fdt(SiFiveUState *s, const struct 
> MemmapEntry *memmap,
>      uint32_t *cells;
>      char *nodename;
>      char ethclk_names[] = "pclk\0hclk";
> -    uint32_t plic_phandle, prci_phandle, phandle = 1;
> +    uint32_t plic_phandle, prci_phandle, gpio_phandle, phandle = 1;
>      uint32_t hfclk_phandle, rtcclk_phandle, phy_phandle;
>
>      fdt = s->fdt = create_device_tree(&s->fdt_size);
> @@ -270,9 +272,11 @@ static void create_fdt(SiFiveUState *s, const struct 
> MemmapEntry *memmap,
>      g_free(cells);
>      g_free(nodename);
>
> +    gpio_phandle = phandle++;
>      nodename = g_strdup_printf("/soc/gpio@%lx",
>          (long)memmap[SIFIVE_U_GPIO].base);
>      qemu_fdt_add_subnode(fdt, nodename);
> +    qemu_fdt_setprop_cell(fdt, nodename, "phandle", gpio_phandle);
>      qemu_fdt_setprop_cells(fdt, nodename, "clocks",
>          prci_phandle, PRCI_CLK_TLCLK);
>      qemu_fdt_setprop_cell(fdt, nodename, "#interrupt-cells", 2);
> @@ -292,6 +296,12 @@ static void create_fdt(SiFiveUState *s, const struct 
> MemmapEntry *memmap,
>      qemu_fdt_setprop_string(fdt, nodename, "compatible", "sifive,gpio0");
>      g_free(nodename);
>
> +    nodename = g_strdup_printf("/gpio-restart");
> +    qemu_fdt_add_subnode(fdt, nodename);
> +    qemu_fdt_setprop_cells(fdt, nodename, "gpios", gpio_phandle, 10, 1);
> +    qemu_fdt_setprop_string(fdt, nodename, "compatible", "gpio-restart");
> +    g_free(nodename);
> +
>      phy_phandle = phandle++;
>      nodename = g_strdup_printf("/soc/ethernet@%lx",
>          (long)memmap[SIFIVE_U_GEM].base);
> @@ -352,6 +362,14 @@ static void create_fdt(SiFiveUState *s, const struct 
> MemmapEntry *memmap,
>      g_free(nodename);
>  }
>
> +static void sifive_u_machine_reset(void *opaque, int n, int level)
> +{
> +    /* gpio pin active low triggers reset */
> +    if (!level) {
> +        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
> +    }
> +}
> +
>  static void sifive_u_machine_init(MachineState *machine)
>  {
>      const struct MemmapEntry *memmap = sifive_u_memmap;
> @@ -383,6 +401,10 @@ static void sifive_u_machine_init(MachineState *machine)
>      memory_region_add_subregion(system_memory, memmap[SIFIVE_U_FLASH0].base,
>                                  flash0);
>
> +    /* register gpio-restart */
> +    qdev_connect_gpio_out(DEVICE(&(s->soc.gpio)), 10,
> +                          qemu_allocate_irq(sifive_u_machine_reset, NULL, 
> 0));
> +
>      /* create device tree */
>      create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline);
>
> --
> 2.7.4
>
>