Re: [Qemu-arm] [PATCH v4 05/14] i.MX: Add code to emulate i.MX7 SNVS IP-block

[Philippe Mathieu-Daudé]

On 01/15/2018 10:37 PM, Andrey Smirnov wrote:
> Add code to emulate SNVS IP-block. Currently only the bits needed to
> be able to emulate machine shutdown are implemented.
> 
> Cc: Peter Maydell <address@hidden>
> Cc: Jason Wang <address@hidden>
> Cc: Philippe Mathieu-Daudé <address@hidden>
> Cc: address@hidden
> Cc: address@hidden
> Cc: address@hidden
> Reviewed-by: Peter Maydell <address@hidden>
> Signed-off-by: Andrey Smirnov <address@hidden>
> ---
>  hw/misc/Makefile.objs       |  1 +
>  hw/misc/imx7_snvs.c         | 83 
> +++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/misc/imx7_snvs.h | 35 +++++++++++++++++++
>  3 files changed, 119 insertions(+)
>  create mode 100644 hw/misc/imx7_snvs.c
>  create mode 100644 include/hw/misc/imx7_snvs.h
> 
> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> index 4b2b705a6c..019886912c 100644
> --- a/hw/misc/Makefile.objs
> +++ b/hw/misc/Makefile.objs
> @@ -35,6 +35,7 @@ obj-$(CONFIG_IMX) += imx6_ccm.o
>  obj-$(CONFIG_IMX) += imx6_src.o
>  obj-$(CONFIG_IMX) += imx7_ccm.o
>  obj-$(CONFIG_IMX) += imx2_wdt.o
> +obj-$(CONFIG_IMX) += imx7_snvs.o
>  obj-$(CONFIG_MILKYMIST) += milkymist-hpdmc.o
>  obj-$(CONFIG_MILKYMIST) += milkymist-pfpu.o
>  obj-$(CONFIG_MAINSTONE) += mst_fpga.o
> diff --git a/hw/misc/imx7_snvs.c b/hw/misc/imx7_snvs.c
> new file mode 100644
> index 0000000000..670b9f4639
> --- /dev/null
> +++ b/hw/misc/imx7_snvs.c
> @@ -0,0 +1,83 @@
> +/*
> + * IMX7 Secure Non-Volatile Storage
> + *
> + * Copyright (c) 2017, Impinj, Inc.
> + *
> + * Author: Andrey Smirnov <address@hidden>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + * Bare minimum emulation code needed to support being able to shut
> + * down linux guest gracefully.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/misc/imx7_snvs.h"
> +#include "qemu/log.h"
> +#include "sysemu/sysemu.h"
> +
> +static uint64_t imx7_snvs_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    return 0;
> +}
> +
> +static void imx7_snvs_write(void *opaque, hwaddr offset,
> +                            uint64_t v, unsigned size)
> +{
> +    const uint32_t value = v;
> +    const uint32_t mask  = SNVS_LPCR_TOP | SNVS_LPCR_DP_EN;
> +
> +    if (offset == SNVS_LPCR && ((value & mask) == mask)) {
> +        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> +    }
> +}
> +
> +static const struct MemoryRegionOps imx7_snvs_ops = {
> +    .read = imx7_snvs_read,

Same here, you can remove the imx7_snvs_read() function since
memory_region_dispatch_read() takes care of this and return 0.

> +    .write = imx7_snvs_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +    .impl = {
> +        /*
> +         * Our device would not work correctly if the guest was doing
> +         * unaligned access. This might not be a limitation on the real
> +         * device but in practice there is no reason for a guest to access
> +         * this device unaligned.
> +         */
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +        .unaligned = false,
> +    },
> +};
> +
> +static void imx7_snvs_init(Object *obj)
> +{
> +    SysBusDevice *sd = SYS_BUS_DEVICE(obj);
> +    IMX7SNVSState *s = IMX7_SNVS(obj);
> +
> +    memory_region_init_io(&s->mmio, obj, &imx7_snvs_ops, s,
> +                          TYPE_IMX7_SNVS, 0x1000);
> +
> +    sysbus_init_mmio(sd, &s->mmio);
> +}
> +
> +static void imx7_snvs_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->desc  = "i.MX7 Secure Non-Volatile Storage Module";
> +}
> +
> +static const TypeInfo imx7_snvs_info = {
> +    .name          = TYPE_IMX7_SNVS,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(IMX7SNVSState),
> +    .instance_init = imx7_snvs_init,
> +    .class_init    = imx7_snvs_class_init,
> +};
> +
> +static void imx7_snvs_register_type(void)
> +{
> +    type_register_static(&imx7_snvs_info);
> +}
> +type_init(imx7_snvs_register_type)
> diff --git a/include/hw/misc/imx7_snvs.h b/include/hw/misc/imx7_snvs.h
> new file mode 100644
> index 0000000000..255f8f26f9
> --- /dev/null
> +++ b/include/hw/misc/imx7_snvs.h
> @@ -0,0 +1,35 @@
> +/*
> + * Copyright (c) 2017, Impinj, Inc.
> + *
> + * i.MX7 SNVS block emulation code
> + *
> + * Author: Andrey Smirnov <address@hidden>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef IMX7_SNVS_H
> +#define IMX7_SNVS_H
> +
> +#include "qemu/bitops.h"
> +#include "hw/sysbus.h"
> +
> +
> +enum IMX7SNVSRegisters {
> +    SNVS_LPCR = 0x38,
> +    SNVS_LPCR_TOP   = BIT(6),
> +    SNVS_LPCR_DP_EN = BIT(5)
> +};
> +
> +#define TYPE_IMX7_SNVS "imx7.snvs"
> +#define IMX7_SNVS(obj) OBJECT_CHECK(IMX7SNVSState, (obj), TYPE_IMX7_SNVS)
> +
> +typedef struct IMX7SNVSState {
> +    /* <private> */
> +    SysBusDevice parent_obj;
> +
> +    MemoryRegion mmio;
> +} IMX7SNVSState;
> +
> +#endif /* IMX7_SNVS_H */
>