Re: [PATCH v7 05/10] hw/fsi: IBM's On-chip Peripheral Bus

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

Hello Cedric,

On 11/27/23 10:23, Cédric Le Goater wrote:
> On 10/26/23 18:47, Ninad Palsule wrote:
>> This is a part of patchset where IBM's Flexible Service Interface is
>> introduced.
>>
>> The On-Chip Peripheral Bus (OPB): A low-speed bus typically found in
>> POWER processors. This now makes an appearance in the ASPEED SoC due
>> to tight integration of the FSI master IP with the OPB, mainly the
>> existence of an MMIO-mapping of the CFAM address straight onto a
>> sub-region of the OPB address space.
>>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
>> Reviewed-by: Joel Stanley <joel@jms.id.au>
>> ---
>> v2:
>> - Incorporated review comment by Joel.
>> v5:
>> - Incorporated review comments by Cedric.
>> v6:
>> - Incorporated review comments by Cedric & Daniel
>> v7:
>> - Incorporated review comments by Cedric.
>> ---
>>   include/hw/fsi/opb.h | 33 ++++++++++++++++++++
>>   hw/fsi/fsi-master.c  |  3 +-
>>   hw/fsi/opb.c         | 74 ++++++++++++++++++++++++++++++++++++++++++++
>>   hw/fsi/Kconfig       |  4 +++
>>   hw/fsi/meson.build   |  1 +
>>   5 files changed, 113 insertions(+), 2 deletions(-)
>>   create mode 100644 include/hw/fsi/opb.h
>>   create mode 100644 hw/fsi/opb.c
>>
>> diff --git a/include/hw/fsi/opb.h b/include/hw/fsi/opb.h
>> new file mode 100644
>> index 0000000000..8b71bb55c2
>> --- /dev/null
>> +++ b/include/hw/fsi/opb.h
>> @@ -0,0 +1,33 @@
>> +/*
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + * Copyright (C) 2023 IBM Corp.
>> + *
>> + * IBM On-Chip Peripheral Bus
>> + */
>> +#ifndef FSI_OPB_H
>> +#define FSI_OPB_H
>> +
>> +#include "exec/memory.h"
>> +#include "hw/fsi/fsi-master.h"
>> +
>> +#define TYPE_OP_BUS "opb"
>> +OBJECT_DECLARE_SIMPLE_TYPE(OPBus, OP_BUS)
>> +
>> +typedef struct OPBus {
>> +        /*< private >*/
>> +        BusState bus;
>> +
>> +        /*< public >*/
>> +        MemoryRegion mr;
>> +        AddressSpace as;
>> +
>> +        /* Model OPB as dumb enough just to provide an address-space */
>> +        /* TODO: Maybe don't store device state in the bus? */
>> +        FSIMasterState fsi;
>
> Please remove. FSIMasterState should be introduced later.
ok, Thanks for the change. Looks like you moved it from OPBus to 
AspeedAPB2OPBState. I am fine with the change if it is making model cleaner.
>
>> +} OPBus;
>> +
>> +typedef struct OPBusClass {
>> +        BusClass parent_class;
>> +} OPBusClass;
>> +
>> +#endif /* FSI_OPB_H */
>> diff --git a/hw/fsi/fsi-master.c b/hw/fsi/fsi-master.c
>> index bb7a893003..ec092b42ea 100644
>> --- a/hw/fsi/fsi-master.c
>> +++ b/hw/fsi/fsi-master.c
>> @@ -11,8 +11,7 @@
>>   #include "trace.h"
>>     #include "hw/fsi/fsi-master.h"
>> -
>> -#define TYPE_OP_BUS "opb"
>> +#include "hw/fsi/opb.h"
>
> ouch.
>
> This is an ugly hack because the modeling is broken. OPB should be 
> introduced
> before tFSIMasterState.
OK, Thanks for the change.
>
>
>>   #define TO_REG(x)                               ((x) >> 2)
>>   diff --git a/hw/fsi/opb.c b/hw/fsi/opb.c
>> new file mode 100644
>> index 0000000000..04771b4b27
>> --- /dev/null
>> +++ b/hw/fsi/opb.c
>> @@ -0,0 +1,74 @@
>> +/*
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + * Copyright (C) 2023 IBM Corp.
>> + *
>> + * IBM On-chip Peripheral Bus
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +
>> +#include "qapi/error.h"
>> +#include "qemu/log.h"
>> +
>> +#include "hw/fsi/opb.h"
>> +
>> +static void fsi_opb_realize(BusState *bus, Error **errp)
>> +{
>> +    OPBus *opb = OP_BUS(bus);
>> +
>> +    memory_region_init_io(&opb->mr, OBJECT(opb), NULL, opb,
>> +                          NULL, UINT32_MAX);
>> +    address_space_init(&opb->as, &opb->mr, "opb");
>
> Please keep the above and put it in a instance_init handler and remove
> the rest. It should go under AspeedAPB2OPBState.
OK, Thanks for the change.
>
>> +
>> +    if (!object_property_set_bool(OBJECT(&opb->fsi), "realized", 
>> true, errp)) {
>> +        return;
>> +    }
>> +
>> +    memory_region_add_subregion(&opb->mr, 0x80000000, &opb->fsi.iomem);
>> +
>> +    /* OPB2FSI region */
>> +    /*
>> +     * Avoid endianness issues by mapping each slave's memory region 
>> directly.
>> +     * Manually bridging multiple address-spaces causes endian swapping
>> +     * headaches as memory_region_dispatch_read() and
>> +     * memory_region_dispatch_write() correct the endianness based 
>> on the
>> +     * target machine endianness and not relative to the device 
>> endianness on
>> +     * either side of the bridge.
>> +     */
>> +    /*
>> +     * XXX: This is a bit hairy and will need to be fixed when I 
>> sort out the
>> +     * bus/slave relationship and any changes to the CFAM modelling 
>> (multiple
>> +     * slaves, LBUS)
>> +     */
>> +    memory_region_add_subregion(&opb->mr, 0xa0000000, 
>> &opb->fsi.opb2fsi);
>> +}
>> +
>> +static void fsi_opb_init(Object *o)
>> +{
>> +    OPBus *opb = OP_BUS(o);
>> +
>> +    object_initialize_child(o, "fsi-master", &opb->fsi, 
>> TYPE_FSI_MASTER);
>> +    qdev_set_parent_bus(DEVICE(&opb->fsi), BUS(o), &error_abort);
>> +}
>
> Drop all of the above.

OK, Thanks for the review and change.

Regards,

Ninad

>
>
> Thanks,
>
> C.
>
>
>
>> +
>> +static void fsi_opb_class_init(ObjectClass *klass, void *data)
>> +{
>> +    BusClass *bc = BUS_CLASS(klass);
>> +    bc->realize = fsi_opb_realize;
>> +}
>> +
>> +static const TypeInfo opb_info = {
>> +    .name = TYPE_OP_BUS,
>> +    .parent = TYPE_BUS,
>> +    .instance_init = fsi_opb_init,
>> +    .instance_size = sizeof(OPBus),
>> +    .class_init = fsi_opb_class_init,
>> +    .class_size = sizeof(OPBusClass),
>> +};
>> +
>> +static void fsi_opb_register_types(void)
>> +{
>> +    type_register_static(&opb_info);
>> +}
>> +
>> +type_init(fsi_opb_register_types);
>> diff --git a/hw/fsi/Kconfig b/hw/fsi/Kconfig
>> index 8d712e77ed..0f6e6d331a 100644
>> --- a/hw/fsi/Kconfig
>> +++ b/hw/fsi/Kconfig
>> @@ -1,3 +1,7 @@
>> +config FSI_OPB
>> +    bool
>> +    select FSI_CFAM
>> +
>>   config FSI_CFAM
>>       bool
>>       select FSI
>> diff --git a/hw/fsi/meson.build b/hw/fsi/meson.build
>> index f617943b4a..407b8c2775 100644
>> --- a/hw/fsi/meson.build
>> +++ b/hw/fsi/meson.build
>> @@ -2,3 +2,4 @@ system_ss.add(when: 'CONFIG_FSI_LBUS', if_true: 
>> files('lbus.c'))
>>   system_ss.add(when: 'CONFIG_FSI_SCRATCHPAD', if_true: 
>> files('engine-scratchpad.c'))
>>   system_ss.add(when: 'CONFIG_FSI_CFAM', if_true: files('cfam.c'))
>>   system_ss.add(when: 'CONFIG_FSI', if_true: 
>> files('fsi.c','fsi-master.c','fsi-slave.c'))
>> +system_ss.add(when: 'CONFIG_FSI_OPB', if_true: files('opb.c'))
>