Re: [PATCH v5 3/4] hw/ssi/pnv_spi: Make bus names distinct for each controllers of a socket

[Chalapathi V <chalapathi.v@linux.ibm.com>]

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On 27-02-2025 07:24, Nicholas Piggin wrote:
> On Sat Jan 4, 2025 at 2:18 AM AEST, Chalapathi V wrote:
>> Create a spi buses with distict names on each socket so that responders
>> are attached to correct SPI controllers.
>>
>> QOM tree on a 2 socket machine:
>> (qemu) info qom-tree
>> /machine (powernv10-machine)
>>    /chip[0] (power10_v2.0-pnv-chip)
>>      /pib_spic[0] (pnv-spi)
>>        /chip0.pnv.spi.bus.0 (SSI)
>>        /xscom-spi[0] (memory-region)
>>    /chip[1] (power10_v2.0-pnv-chip)
>>      /pib_spic[0] (pnv-spi)
>>        /chip1.pnv.spi.bus.0 (SSI)
>>        /xscom-spi[0] (memory-region)
> Mechanics of the patch looks fine. I don't know about the name
> though.
>
> I think "pnv-spi-bus" is the right name for the bus. Using dots as
> with chip0. makes it seem like each element is part of a topology.
>
> Would chip0.pnv-spi-bus be better?
Will rename the bus name to chip0.pnv-spi-bus . Thank You
>
> I don't suppose there is a good way to create an alias so existing
> cmdline works and refers to the bus on chip0? Maybe the chip0 bus
> could just not have the chip0. prefix?
>
> Thanks,
> Nick
Would it be best to keep the chip0 prefix to have uniformity?
>> Signed-off-by: Chalapathi V<chalapathi.v@linux.ibm.com>
>> ---
>>   include/hw/ssi/pnv_spi.h           | 3 ++-
>>   hw/ppc/pnv.c                       | 2 ++
>>   hw/ssi/pnv_spi.c                   | 5 +++--
>>   tests/qtest/pnv-spi-seeprom-test.c | 2 +-
>>   4 files changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/hw/ssi/pnv_spi.h b/include/hw/ssi/pnv_spi.h
>> index 9878d9a25f..7fc5da1f84 100644
>> --- a/include/hw/ssi/pnv_spi.h
>> +++ b/include/hw/ssi/pnv_spi.h
>> @@ -31,7 +31,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PnvSpi, PNV_SPI)
>>   #define PNV_SPI_REG_SIZE 8
>>   #define PNV_SPI_REGS 7
>>   
>> -#define TYPE_PNV_SPI_BUS "pnv-spi-bus"
>> +#define TYPE_PNV_SPI_BUS "pnv.spi.bus"
>>   typedef struct PnvSpi {
>>       SysBusDevice parent_obj;
>>   
>> @@ -42,6 +42,7 @@ typedef struct PnvSpi {
>>       Fifo8 rx_fifo;
>>       /* SPI object number */
>>       uint32_t        spic_num;
>> +    uint32_t        chip_id;
>>       uint8_t         transfer_len;
>>       uint8_t         responder_select;
>>       /* To verify if shift_n1 happens prior to shift_n2 */
>> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
>> index 11fd477b71..ce23892fdf 100644
>> --- a/hw/ppc/pnv.c
>> +++ b/hw/ppc/pnv.c
>> @@ -2226,6 +2226,8 @@ static void pnv_chip_power10_realize(DeviceState *dev, Error **errp)
>>           /* pib_spic[2] connected to 25csm04 which implements 1 byte transfer */
>>           object_property_set_int(OBJECT(&chip10->pib_spic[i]), "transfer_len",
>>                                   (i == 2) ? 1 : 4, &error_fatal);
>> +        object_property_set_int(OBJECT(&chip10->pib_spic[i]), "chip-id",
>> +                                chip->chip_id, &error_fatal);
>>           if (!sysbus_realize(SYS_BUS_DEVICE(OBJECT
>>                                           (&chip10->pib_spic[i])), errp)) {
>>               return;
>> diff --git a/hw/ssi/pnv_spi.c b/hw/ssi/pnv_spi.c
>> index 87eac666bb..41beb559c6 100644
>> --- a/hw/ssi/pnv_spi.c
>> +++ b/hw/ssi/pnv_spi.c
>> @@ -1116,14 +1116,15 @@ static const MemoryRegionOps pnv_spi_xscom_ops = {
>>   
>>   static const Property pnv_spi_properties[] = {
>>       DEFINE_PROP_UINT32("spic_num", PnvSpi, spic_num, 0),
>> +    DEFINE_PROP_UINT32("chip-id", PnvSpi, chip_id, 0),
>>       DEFINE_PROP_UINT8("transfer_len", PnvSpi, transfer_len, 4),
>>   };
>>   
>>   static void pnv_spi_realize(DeviceState *dev, Error **errp)
>>   {
>>       PnvSpi *s = PNV_SPI(dev);
>> -    g_autofree char *name = g_strdup_printf(TYPE_PNV_SPI_BUS ".%d",
>> -                    s->spic_num);
>> +    g_autofree char *name = g_strdup_printf("chip%d." TYPE_PNV_SPI_BUS ".%d",
>> +                    s->chip_id, s->spic_num);
>>       s->ssi_bus = ssi_create_bus(dev, name);
>>       s->cs_line = g_new0(qemu_irq, 1);
>>       qdev_init_gpio_out_named(DEVICE(s), s->cs_line, "cs", 1);
>> diff --git a/tests/qtest/pnv-spi-seeprom-test.c b/tests/qtest/pnv-spi-seeprom-test.c
>> index 57f20af76e..ef1005a926 100644
>> --- a/tests/qtest/pnv-spi-seeprom-test.c
>> +++ b/tests/qtest/pnv-spi-seeprom-test.c
>> @@ -92,7 +92,7 @@ static void test_spi_seeprom(const void *data)
>>       qts = qtest_initf("-machine powernv10 -smp 2,cores=2,"
>>                         "threads=1 -accel tcg,thread=single -nographic "
>>                         "-blockdev node-name=pib_spic2,driver=file,"
>> -                      "filename=%s -device 25csm04,bus=pnv-spi-bus.2,cs=0,"
>> +                      "filename=%s -device 25csm04,bus=chip0.pnv.spi.bus.2,cs=0,"
>
>>                         "drive=pib_spic2", tmp_path);
>>       spi_seeprom_transaction(qts, chip);
>>       qtest_quit(qts);

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