Re: [PATCH v4 02/10] hw/fsi: Introduce IBM's scratchpad

[Ninad Palsule <ninad@linux.ibm.com>]

Hello Cedric,

On 9/11/23 07:19, Cédric Le Goater wrote:
> On 9/9/23 00:28, Ninad Palsule wrote:
>> This is a part of patchset where IBM's Flexible Service Interface is
>> introduced.
>>
>> The LBUS device is embeded inside the scratchpad. The scratchpad
>> provides a non-functional registers. There is a 1-1 relation between
>> scratchpad and LBUS devices. Each LBUS device has 1K memory mapped in
>> the LBUS.
>
>
> The commit log is a bit confusing.

I have improved it in my next patch. Please check and let me know.

Thanks for the review.

~Ninad

>
> C.
>
>
>>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
>> ---
>> v2:
>> - Incorporated Joel's review comments.
>> ---
>>   hw/fsi/Kconfig                     |   4 ++
>>   hw/fsi/engine-scratchpad.c         | 100 +++++++++++++++++++++++++++++
>>   hw/fsi/meson.build                 |   1 +
>>   include/hw/fsi/engine-scratchpad.h |  33 ++++++++++
>>   4 files changed, 138 insertions(+)
>>   create mode 100644 hw/fsi/engine-scratchpad.c
>>   create mode 100644 include/hw/fsi/engine-scratchpad.h
>>
>> diff --git a/hw/fsi/Kconfig b/hw/fsi/Kconfig
>> index 687449e14e..2a9c49f2c9 100644
>> --- a/hw/fsi/Kconfig
>> +++ b/hw/fsi/Kconfig
>> @@ -1,2 +1,6 @@
>> +config SCRATCHPAD
>> +    bool
>> +    select LBUS
>> +
>>   config LBUS
>>       bool
>> diff --git a/hw/fsi/engine-scratchpad.c b/hw/fsi/engine-scratchpad.c
>> new file mode 100644
>> index 0000000000..15a8f8cc66
>> --- /dev/null
>> +++ b/hw/fsi/engine-scratchpad.c
>> @@ -0,0 +1,100 @@
>> +/*
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + * Copyright (C) 2023 IBM Corp.
>> + *
>> + * IBM scratchpad engine
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +
>> +#include "qapi/error.h"
>> +#include "qemu/log.h"
>> +
>> +#include "hw/fsi/engine-scratchpad.h"
>> +
>> +static uint64_t scratchpad_read(void *opaque, hwaddr addr, unsigned 
>> size)
>> +{
>> +    ScratchPad *s = SCRATCHPAD(opaque);
>> +
>> +    qemu_log_mask(LOG_UNIMP, "%s: read @0x%" HWADDR_PRIx " size=%d\n",
>> +                  __func__, addr, size);
>> +
>> +    if (addr) {
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "%s: Out of bounds read: 0x%"HWADDR_PRIx" for 
>> %u\n",
>> +                      __func__, addr, size);
>> +        return 0;
>> +    }
>> +
>> +    return s->reg;
>> +}
>> +
>> +static void scratchpad_write(void *opaque, hwaddr addr, uint64_t data,
>> +                                 unsigned size)
>> +{
>> +    ScratchPad *s = SCRATCHPAD(opaque);
>> +
>> +    qemu_log_mask(LOG_UNIMP, "%s: write @0x%" HWADDR_PRIx " size=%d "
>> +                  "value=%"PRIx64"\n", __func__, addr, size, data);
>> +
>> +    if (addr) {
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "%s: Out of bounds write: 0x%"HWADDR_PRIx" for 
>> %u\n",
>> +                      __func__, addr, size);
>> +        return;
>> +    }
>> +
>> +    s->reg = data;
>> +}
>> +
>> +static const struct MemoryRegionOps scratchpad_ops = {
>> +    .read = scratchpad_read,
>> +    .write = scratchpad_write,
>> +    .endianness = DEVICE_BIG_ENDIAN,
>> +};
>> +
>> +static void scratchpad_realize(DeviceState *dev, Error **errp)
>> +{
>> +    LBusDevice *ldev = LBUS_DEVICE(dev);
>> +
>> +    memory_region_init_io(&ldev->iomem, OBJECT(ldev), &scratchpad_ops,
>> +                          ldev, TYPE_SCRATCHPAD, 0x400);
>> +}
>> +
>> +static void scratchpad_reset(DeviceState *dev)
>> +{
>> +    ScratchPad *s = SCRATCHPAD(dev);
>> +
>> +    s->reg = 0;
>> +}
>> +
>> +static void scratchpad_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +    LBusDeviceClass *ldc = LBUS_DEVICE_CLASS(klass);
>> +
>> +    dc->realize = scratchpad_realize;
>> +    dc->reset = scratchpad_reset;
>> +
>> +    ldc->config =
>> +          ENGINE_CONFIG_NEXT            /* valid */
>> +        | 0x00010000                    /* slots */
>> +        | 0x00001000                    /* version */
>> +        | ENGINE_CONFIG_TYPE_SCRATCHPAD /* type */
>> +        | 0x00000007;                   /* crc */
>> +}
>> +
>> +static const TypeInfo scratchpad_info = {
>> +    .name = TYPE_SCRATCHPAD,
>> +    .parent = TYPE_LBUS_DEVICE,
>> +    .instance_size = sizeof(ScratchPad),
>> +    .class_init = scratchpad_class_init,
>> +    .class_size = sizeof(LBusDeviceClass),
>> +};
>> +
>> +static void scratchpad_register_types(void)
>> +{
>> +    type_register_static(&scratchpad_info);
>> +}
>> +
>> +type_init(scratchpad_register_types);
>> diff --git a/hw/fsi/meson.build b/hw/fsi/meson.build
>> index e1007d5fea..f90e09ddab 100644
>> --- a/hw/fsi/meson.build
>> +++ b/hw/fsi/meson.build
>> @@ -1 +1,2 @@
>>   system_ss.add(when: 'CONFIG_LBUS', if_true: files('lbus.c'))
>> +system_ss.add(when: 'CONFIG_SCRATCHPAD', if_true: 
>> files('engine-scratchpad.c'))
>> diff --git a/include/hw/fsi/engine-scratchpad.h 
>> b/include/hw/fsi/engine-scratchpad.h
>> new file mode 100644
>> index 0000000000..63bf89ac5a
>> --- /dev/null
>> +++ b/include/hw/fsi/engine-scratchpad.h
>> @@ -0,0 +1,33 @@
>> +/*
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + * Copyright (C) 2023 IBM Corp.
>> + *
>> + * IBM scratchpad engne
>> + */
>> +#ifndef FSI_ENGINE_SCRATCHPAD_H
>> +#define FSI_ENGINE_SCRATCHPAD_H
>> +
>> +#include "qemu/bitops.h"
>> +
>> +#include "hw/fsi/lbus.h"
>> +
>> +#define ENGINE_CONFIG_NEXT              BE_BIT(0)
>> +#define ENGINE_CONFIG_VPD               BE_BIT(1)
>> +#define ENGINE_CONFIG_SLOTS             BE_GENMASK(8, 15)
>> +#define ENGINE_CONFIG_VERSION           BE_GENMASK(16, 19)
>> +#define ENGINE_CONFIG_TYPE              BE_GENMASK(20, 27)
>> +#define   ENGINE_CONFIG_TYPE_PEEK       (0x02 << 4)
>> +#define   ENGINE_CONFIG_TYPE_FSI        (0x03 << 4)
>> +#define   ENGINE_CONFIG_TYPE_SCRATCHPAD (0x06 << 4)
>> +#define ENGINE_CONFIG_CRC              BE_GENMASK(28, 31)
>> +
>> +#define TYPE_SCRATCHPAD "scratchpad"
>> +#define SCRATCHPAD(obj) OBJECT_CHECK(ScratchPad, (obj), 
>> TYPE_SCRATCHPAD)
>> +
>> +typedef struct ScratchPad {
>> +        LBusDevice parent;
>> +
>> +        uint32_t reg;
>> +} ScratchPad;
>> +
>> +#endif /* FSI_ENGINE_SCRATCHPAD_H */
>