Re: [PATCH v5 03/10] hw/fsi: Introduce IBM's cfam,fsi-slave

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Oct 11, 2023 at 10:13:32AM -0500, Ninad Palsule wrote:
> This is a part of patchset where IBM's Flexible Service Interface is
> introduced.
> 
> The Common FRU Access Macro (CFAM), an address space containing
> various "engines" that drive accesses on busses internal and external
> to the POWER chip. Examples include the SBEFIFO and I2C masters. The
> engines hang off of an internal Local Bus (LBUS) which is described
> by the CFAM configuration block.
> 
> The FSI slave: The slave is the terminal point of the FSI bus for
> FSI symbols addressed to it. Slaves can be cascaded off of one
> another. The slave's configuration registers appear in address space
> of the CFAM to which it is attached.
> 
> 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.
> v3:
> - Incorporated Thomas Huth's review comments.
> v5:
> - Incorporated review comments by Cedric.


> +static void cfam_realize(DeviceState *dev, Error **errp)
> +{
> +    CFAMState *cfam = CFAM(dev);
> +    FSISlaveState *slave = FSI_SLAVE(dev);
> +    Error *err = NULL;
> +
> +    /* Each slave has a 2MiB address space */
> +    memory_region_init_io(&cfam->mr, OBJECT(cfam), &cfam_unimplemented_ops,
> +                          cfam, TYPE_CFAM, 2 * 1024 * 1024);
> +    address_space_init(&cfam->as, &cfam->mr, TYPE_CFAM);
> +
> +    qbus_init(&cfam->lbus, sizeof(cfam->lbus), TYPE_FSI_LBUS,
> +                        DEVICE(cfam), NULL);
> +
> +    lbus_create_device(&cfam->lbus, TYPE_SCRATCHPAD, 0);
> +
> +    object_property_set_bool(OBJECT(&cfam->config), "realized", true, &err);
> +    if (err) {
> +        error_propagate(errp, err);
> +        return;
> +    }

object_property_set_bool returns false on error so this use of a local
Error object is redundant.

   if (!object_property_set_bool(..., &errp)) {
       return;
   }


If a local Error had been required though, this code should have instead
been using ERRP_GUARD - see include/qapi/error.h docs for illustration
for future work.

> +    qdev_set_parent_bus(DEVICE(&cfam->config), BUS(&cfam->lbus), &error_abort);
> +
> +    object_property_set_bool(OBJECT(&cfam->lbus), "realized", true, &err);
> +    if (err) {
> +        error_propagate(errp, err);
> +        return;
> +    }

Likewise

> +
> +    memory_region_add_subregion(&cfam->mr, 0, &cfam->config.iomem);
> +    /* memory_region_add_subregion(&cfam->mr, 0x800, &cfam->lbus.peek.iomem); */
> +    memory_region_add_subregion(&cfam->mr, 0x800, &slave->iomem);
> +    memory_region_add_subregion(&cfam->mr, 0xc00, &cfam->lbus.mr);
> +}
> +
> +static void cfam_init(Object *o)
> +{
> +    CFAMState *s = CFAM(o);
> +
> +    object_initialize_child(o, TYPE_CFAM_CONFIG, &s->config, TYPE_CFAM_CONFIG);
> +}
> +
> +static void cfam_finalize(Object *o)
> +{
> +    CFAMState *s = CFAM(o);
> +
> +    address_space_destroy(&s->as);
> +}
> +
> +static void cfam_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    dc->bus_type = TYPE_FSI_BUS;
> +    dc->realize = cfam_realize;
> +}
> +
> +static const TypeInfo cfam_info = {
> +    .name = TYPE_CFAM,
> +    .parent = TYPE_FSI_SLAVE,
> +    .instance_init = cfam_init,
> +    .instance_finalize = cfam_finalize,
> +    .instance_size = sizeof(CFAMState),
> +    .class_init = cfam_class_init,
> +};
> +
> +static void cfam_register_types(void)
> +{
> +    type_register_static(&cfam_config_info);
> +    type_register_static(&cfam_info);
> +}
> +
> +type_init(cfam_register_types);
> diff --git a/hw/fsi/fsi-slave.c b/hw/fsi/fsi-slave.c
> new file mode 100644
> index 0000000000..127fdd8a4f
> --- /dev/null
> +++ b/hw/fsi/fsi-slave.c
> @@ -0,0 +1,96 @@
> +/*
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + * Copyright (C) 2023 IBM Corp.
> + *
> + * IBM Flexible Service Interface slave
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "qemu/bitops.h"
> +#include "qapi/error.h"
> +#include "qemu/log.h"
> +#include "trace.h"
> +
> +#include "hw/fsi/fsi-slave.h"
> +
> +#define TO_REG(x)                               ((x) >> 2)
> +
> +#define FSI_SMODE               TO_REG(0x00)
> +#define   FSI_SMODE_WSTART      BE_BIT(0)
> +#define   FSI_SMODE_AUX_EN      BE_BIT(1)
> +#define   FSI_SMODE_SLAVE_ID    BE_GENMASK(6, 7)
> +#define   FSI_SMODE_ECHO_DELAY  BE_GENMASK(8, 11)
> +#define   FSI_SMODE_SEND_DELAY  BE_GENMASK(12, 15)
> +#define   FSI_SMODE_LBUS_DIV    BE_GENMASK(20, 23)
> +#define   FSI_SMODE_BRIEF_LEFT  BE_GENMASK(24, 27)
> +#define   FSI_SMODE_BRIEF_RIGHT BE_GENMASK(28, 31)
> +
> +#define FSI_SDMA                TO_REG(0x04)
> +#define FSI_SISC                TO_REG(0x08)
> +#define FSI_SCISC               TO_REG(0x08)
> +#define FSI_SISM                TO_REG(0x0c)
> +#define FSI_SISS                TO_REG(0x10)
> +#define FSI_SSISM               TO_REG(0x10)
> +#define FSI_SCISM               TO_REG(0x14)
> +
> +static uint64_t fsi_slave_read(void *opaque, hwaddr addr, unsigned size)
> +{
> +    FSISlaveState *s = FSI_SLAVE(opaque);
> +
> +    trace_fsi_slave_read(addr, size);
> +
> +    if (addr + size > sizeof(s->regs)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: Out of bounds read: 0x%"HWADDR_PRIx" for %u\n",
> +                      __func__, addr, size);
> +        return 0;
> +    }
> +
> +    return s->regs[TO_REG(addr)];
> +}
> +
> +static void fsi_slave_write(void *opaque, hwaddr addr, uint64_t data,
> +                                 unsigned size)
> +{
> +    FSISlaveState *s = FSI_SLAVE(opaque);
> +
> +    trace_fsi_slave_write(addr, size, data);
> +
> +    if (addr + size > sizeof(s->regs)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: Out of bounds write: 0x%"HWADDR_PRIx" for %u\n",
> +                      __func__, addr, size);
> +        return;
> +    }
> +
> +    s->regs[TO_REG(addr)] = data;
> +}
> +
> +static const struct MemoryRegionOps fsi_slave_ops = {
> +    .read = fsi_slave_read,
> +    .write = fsi_slave_write,
> +    .endianness = DEVICE_BIG_ENDIAN,
> +};
> +
> +static void fsi_slave_init(Object *o)
> +{
> +    FSISlaveState *s = FSI_SLAVE(o);
> +
> +    memory_region_init_io(&s->iomem, OBJECT(s), &fsi_slave_ops,
> +                          s, TYPE_FSI_SLAVE, 0x400);
> +}
> +
> +static const TypeInfo fsi_slave_info = {
> +    .name = TYPE_FSI_SLAVE,
> +    .parent = TYPE_DEVICE,
> +    .instance_init = fsi_slave_init,
> +    .instance_size = sizeof(FSISlaveState),
> +};
> +
> +static void fsi_slave_register_types(void)
> +{
> +    type_register_static(&fsi_slave_info);
> +}
> +
> +type_init(fsi_slave_register_types);
> diff --git a/hw/fsi/Kconfig b/hw/fsi/Kconfig
> index f7c7fd1b28..8d712e77ed 100644
> --- a/hw/fsi/Kconfig
> +++ b/hw/fsi/Kconfig
> @@ -1,3 +1,12 @@
> +config FSI_CFAM
> +    bool
> +    select FSI
> +    select FSI_SCRATCHPAD
> +    select FSI_LBUS
> +
> +config FSI
> +    bool
> +
>  config FSI_SCRATCHPAD
>      bool
>      select FSI_LBUS
> diff --git a/hw/fsi/meson.build b/hw/fsi/meson.build
> index d45a98c223..a9e7cd4099 100644
> --- a/hw/fsi/meson.build
> +++ b/hw/fsi/meson.build
> @@ -1,2 +1,4 @@
>  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-slave.c'))
> diff --git a/hw/fsi/trace-events b/hw/fsi/trace-events
> index 97fd070354..752a5683a0 100644
> --- a/hw/fsi/trace-events
> +++ b/hw/fsi/trace-events
> @@ -1,2 +1,9 @@
>  scratchpad_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
>  scratchpad_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
> +cfam_config_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
> +cfam_config_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
> +cfam_unimplemented_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
> +cfam_unimplemented_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
> +cfam_config_write_noaddr(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
> +fsi_slave_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
> +fsi_slave_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
> -- 
> 2.39.2
> 

With regards,
Daniel
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