Re: [PATCH] hw/arm/sbsa-ref.c : Add a fake embedded controller

[Graeme Gregory]

On Thu, Aug 20, 2020 at 02:32:01PM +0100, Graeme Gregory wrote:
> A difference between sbsa platform and the virt platform is PSCI is
> handled by ARM-TF in the sbsa platform. This means that the PSCI code
> there needs to communicate some of the platform power changes down
> to the qemu code for things like shutdown/reset control.
> 
> Space has been left to extend the EC if we find other use cases in
> future where ARM-TF and qemu need to communicate.
> 
> Signed-off-by: Graeme Gregory <graeme@nuviainc.com>
> ---
>  hw/arm/sbsa-ref.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 95 insertions(+)
> 
> diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
> index f030a416fd..c8743fc1d0 100644
> --- a/hw/arm/sbsa-ref.c
> +++ b/hw/arm/sbsa-ref.c
> @@ -41,6 +41,7 @@
>  #include "hw/usb.h"
>  #include "hw/char/pl011.h"
>  #include "net/net.h"
> +#include "migration/vmstate.h"
>  
>  #define RAMLIMIT_GB 8192
>  #define RAMLIMIT_BYTES (RAMLIMIT_GB * GiB)
> @@ -62,6 +63,7 @@ enum {
>      SBSA_CPUPERIPHS,
>      SBSA_GIC_DIST,
>      SBSA_GIC_REDIST,
> +    SBSA_SECURE_EC,
>      SBSA_SMMU,
>      SBSA_UART,
>      SBSA_RTC,
> @@ -98,6 +100,14 @@ typedef struct {
>  #define SBSA_MACHINE(obj) \
>      OBJECT_CHECK(SBSAMachineState, (obj), TYPE_SBSA_MACHINE)
>  
> +typedef struct {
> +    SysBusDevice parent_obj;
> +    MemoryRegion iomem;
> +} SECUREECState;
> +
> +#define TYPE_SECURE_EC      "sbsa-secure-ec"
> +#define SECURE_EC(obj) OBJECT_CHECK(SECUREECState, (obj), TYPE_SECURE_EC)
> +
>  static const MemMapEntry sbsa_ref_memmap[] = {
>      /* 512M boot ROM */
>      [SBSA_FLASH] =              {          0, 0x20000000 },
> @@ -107,6 +117,7 @@ static const MemMapEntry sbsa_ref_memmap[] = {
>      [SBSA_CPUPERIPHS] =         { 0x40000000, 0x00040000 },
>      [SBSA_GIC_DIST] =           { 0x40060000, 0x00010000 },
>      [SBSA_GIC_REDIST] =         { 0x40080000, 0x04000000 },
> +    [SBSA_SECURE_EC] =          { 0x50000000, 0x00001000 },
>      [SBSA_UART] =               { 0x60000000, 0x00001000 },
>      [SBSA_RTC] =                { 0x60010000, 0x00001000 },
>      [SBSA_GPIO] =               { 0x60020000, 0x00001000 },
> @@ -585,6 +596,65 @@ static void *sbsa_ref_dtb(const struct arm_boot_info 
> *binfo, int *fdt_size)
>      return board->fdt;
>  }
>  
> +enum sbsa_secure_ec_powerstates {
> +    SBSA_SECURE_EC_CMD_NULL,
> +    SBSA_SECURE_EC_CMD_POWEROFF,
> +    SBSA_SECURE_EC_CMD_REBOOT,
> +};
> +
> +static uint64_t secure_ec_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    /* No use for this currently */
> +    return 0;
> +}
> +
> +static void secure_ec_write(void *opaque, hwaddr offset,
> +                     uint64_t value, unsigned size)
> +{
> +    if (offset == 0) { /* PSCI machine power command register */
> +        switch (value) {
> +        case SBSA_SECURE_EC_CMD_NULL:
> +            break;
> +        case SBSA_SECURE_EC_CMD_POWEROFF:
> +            qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> +            break;
> +        case SBSA_SECURE_EC_CMD_REBOOT:
> +            qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
> +            break;
> +        default:
> +            error_report("sbsa-ref: ERROR Unkown power command");
> +        }
> +    } else {
> +        error_report("sbsa-ref: unknown EC register");
> +    }
> +}
> +
> +static const MemoryRegionOps secure_ec_ops = {
> +    .read = secure_ec_read,
> +    .write = secure_ec_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void secure_ec_init(Object *obj)
> +{
> +    SECUREECState *s = SECURE_EC(obj);
> +    SysBusDevice *dev = SYS_BUS_DEVICE(obj);
> +
> +    memory_region_init_io(&s->iomem, obj, &secure_ec_ops, s, "secure-ec",
> +                            0x1000);
> +    sysbus_init_mmio(dev, &s->iomem);
> +}
> +
> +static void create_secure_ec(MemoryRegion *mem)
> +{
> +    hwaddr base = sbsa_ref_memmap[SBSA_SECURE_EC].base;
> +    DeviceState *dev = qdev_create(NULL, TYPE_SECURE_EC);

I've just discovered the API change here, I tested in an older tree, but
Ill wait for other reviews before re-issuing.

Graeme

> +    SysBusDevice *s = SYS_BUS_DEVICE(dev);
> +
> +    memory_region_add_subregion(mem, base,
> +                                sysbus_mmio_get_region(s, 0));
> +}
> +
>  static void sbsa_ref_init(MachineState *machine)
>  {
>      unsigned int smp_cpus = machine->smp.cpus;
> @@ -708,6 +778,8 @@ static void sbsa_ref_init(MachineState *machine)
>  
>      create_pcie(sms);
>  
> +    create_secure_ec(secure_sysmem);
> +
>      sms->bootinfo.ram_size = machine->ram_size;
>      sms->bootinfo.nb_cpus = smp_cpus;
>      sms->bootinfo.board_id = -1;
> @@ -798,8 +870,31 @@ static const TypeInfo sbsa_ref_info = {
>      .instance_size = sizeof(SBSAMachineState),
>  };
>  
> +static const VMStateDescription vmstate_secure_ec_info = {
> +    .name = "sbsa-secure-ec",
> +    .version_id = 0,
> +    .minimum_version_id = 0,
> +};
> +
> +static void secure_ec_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->vmsd = &vmstate_secure_ec_info;
> +    dc->user_creatable = false;
> +}
> +
> +static const TypeInfo secure_ec_info = {
> +    .name          = TYPE_SECURE_EC,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(SECUREECState),
> +    .instance_init = secure_ec_init,
> +    .class_init    = secure_ec_class_init,
> +};
> +
>  static void sbsa_ref_machine_init(void)
>  {
> +    type_register_static(&secure_ec_info);
>      type_register_static(&sbsa_ref_info);
>  }
>  
> -- 
> 2.25.1
>