Re: [PATCH 20/21] hw/i2c: Import TCA6416 emulation from Xilinx

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 1/2/25 16:28, Bernhard Beschow wrote:
> 
> 
> Am 30. Januar 2025 23:05:53 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>> Cc'ing AMD folks
>>
>> Hi Bernhard,
>>
>> TL;DR; can't you use the PCF8574 which is a more complete model of I/O
>> expander? (See hw/gpio/pcf8574.c)
> 
> If it is software-compatible then I could use it. I'm modeling a real board whose device tree I'd like to use unchanged, so I don't have much choice. The only reason I need it is because its absence clogs the i2c bus.

No clue about compatibility. If you unfortunately need to add it,
then please address my comments in the next version.

> 
> Best regards,
> Bernhard
> 
>>
>> On 20/1/25 21:37, Bernhard Beschow wrote:
>>> Xilinx QEMU implements a TCA6416 device model which may be useful for the
>>> broader QEMU community, so upstream it. In the Xilinx fork, the device model
>>> gets compiled whenever CONFIG_CADENCE is true, so have it maintained by the
>>> "hw/*/cadence_*" maintainers.
>>>
>>> The code is based on Xilinx QEMU version xilinx_v2024.2 plus the following
>>> modifications:
>>> * Use OBJECT_DECLARE_SIMPLE_TYPE()
>>> * Port from DPRINTF() to trace events
>>> * Follow QEMU conventions for naming of state struct
>>> * Rename type to not contain a ','
>>> * Use DEFINE_TYPES() macro
>>> * Implement under hw/gpio since device is i2c client and gpio provider
>>> * Have dedicated Kconfig switch
>>>
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>>
>>> --
>>> I have a use for TCA6416 emulation. Question: Are Xilinx Zynq maintainers
>>> willing to maintain this device model?
>>> ---
>>>    MAINTAINERS          |   1 +
>>>    hw/gpio/tca6416.c    | 122 +++++++++++++++++++++++++++++++++++++++++++
>>>    hw/gpio/Kconfig      |   5 ++
>>>    hw/gpio/meson.build  |   1 +
>>>    hw/gpio/trace-events |   4 ++
>>>    5 files changed, 133 insertions(+)
>>>    create mode 100644 hw/gpio/tca6416.c
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 7531d65429..0cac9c90bc 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -1030,6 +1030,7 @@ S: Maintained
>>>    F: hw/*/xilinx_*
>>>    F: hw/*/cadence_*
>>>    F: hw/misc/zynq_slcr.c
>>> +F: hw/gpio/tca6416.c
>>>    F: hw/adc/zynq-xadc.c
>>>    F: include/hw/misc/zynq_slcr.h
>>>    F: include/hw/adc/zynq-xadc.h
>>> diff --git a/hw/gpio/tca6416.c b/hw/gpio/tca6416.c
>>> new file mode 100644
>>> index 0000000000..81ed7a654d
>>> --- /dev/null
>>> +++ b/hw/gpio/tca6416.c
>>> @@ -0,0 +1,122 @@
>>> +/*
>>> + * QEMU model of TCA6416 16-Bit I/O Expander
>>
>> Please add datasheet reference.
>>
>>> + *
>>> + * Copyright (c) 2018 Xilinx Inc.
>>> + *
>>> + * Written by Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>
>>> + *
>>> + * Permission is hereby granted, free of charge, to any person obtaining a copy
>>> + * of this software and associated documentation files (the "Software"), to deal
>>> + * in the Software without restriction, including without limitation the rights
>>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>>> + * copies of the Software, and to permit persons to whom the Software is
>>> + * furnished to do so, subject to the following conditions:
>>> + *
>>> + * The above copyright notice and this permission notice shall be included in
>>> + * all copies or substantial portions of the Software.
>>> + *
>>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
>>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
>>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>>> + * THE SOFTWARE.
>>
>> Sai/Edgar/Francisco, should we update to AMD here? Remove or update the
>> email address? Also, can you Ack the replacement of this license by a
>> SPDX tag?
>>
>>> + */
>>> +#include "qemu/osdep.h"
>>> +#include "hw/i2c/i2c.h"
>>> +#include "trace.h"
>>> +
>>> +#define TYPE_TCA6416 "tca6416"
>>> +OBJECT_DECLARE_SIMPLE_TYPE(Tca6416State, TCA6416)
>>> +
>>> +#define IN_PORT0    0
>>> +#define IN_PORT1    1
>>> +#define OUT_PORT0   2
>>> +#define OUT_PORT1   3
>>> +#define POL_INV0    4
>>> +#define POL_INV1    5
>>> +#define CONF_PORT0  6
>>> +#define CONF_PORT1  7
>>
>> enum up to here?
>>
>>> +#define RMAX (CONF_PORT1 + 1)
>>> +
>>> +enum tca6416_events {
>>> +     ADDR_DONE,
>>> +     ADDRESSING,
>>> +};
>>> +
>>> +struct Tca6416State {
>>> +     I2CSlave i2c;
>>> +
>>> +     uint8_t addr;
>>> +     uint8_t state;
>>> +     uint8_t regs[RMAX];
>>> +};
>>> +
>>> +static uint8_t tca6416_read(I2CSlave *i2c)
>>> +{
>>> +    Tca6416State *s = TCA6416(i2c);
>>> +    uint8_t ret;
>>> +
>>> +    ret = s->regs[s->addr];
>>> +    trace_tca6416_read(ret);
>>> +    return ret;
>>> +}
>>> +
>>> +static int tca6416_write(I2CSlave *i2c, uint8_t data)
>>> +{
>>> +    Tca6416State *s = TCA6416(i2c);
>>> +
>>> +    trace_tca6416_write(data);
>>> +    if (s->state == ADDRESSING) {
>>> +        s->addr = data;
>>
>> I suppose HW masks here.
>>
>>           s->addr = data & 0xf;
>>
>>> +    } else {
>>> +        s->regs[s->addr] = data;
>>
>> (otherwise this could overflow).
>>
>> So this device isn't doing anything actually (I'd have
>> expected 1 IRQ and 16 GPIO lines). What is the point,
>> at least in this state?
>>
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void tca6416_realize(DeviceState *dev, Error **errp)
>>> +{
>>> +    Tca6416State *s = TCA6416(dev);
>>> +
>>
>> Missing:
>>
>>        s->regs[OUT_PORT0] = 0xff;
>>        s->regs[OUT_PORT1] = 0xff;
>>        s->regs[POL_INV0] = 0x00;
>>        s->regs[POL_INV1] = 0x00;
>>
>>> +    s->regs[CONF_PORT0] = 0xFF;
>>> +    s->regs[CONF_PORT1] = 0xFF;
>>
>> Style is 0xff.
>>
>> That said, this is not a REALIZE but RESET handler.
>>
>>> +}
>>> +
>>> +static int tca6416_event(I2CSlave *i2c, enum i2c_event event)
>>> +{
>>> +    Tca6416State *s = TCA6416(i2c);
>>> +
>>> +    switch (event) {
>>> +    case I2C_START_SEND:
>>> +        s->state = ADDRESSING;
>>> +        break;
>>> +    default:
>>> +         s->state = ADDR_DONE;
>>> +    };
>>> +    return 0;
>>> +}
>>> +
>>> +static void tca6416_class_init(ObjectClass *klass, void *data)
>>> +{
>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>> +    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
>>> +
>>> +    dc->realize = tca6416_realize;
>>
>> (tca6416_realize is a reset handler).
>>
>> Please complete:
>>
>>        dc->desc = "TCA6416 I/O Expander";
>>        set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>>
>> No migration state?
>>
>>> +    k->recv = tca6416_read;
>>> +    k->send = tca6416_write;
>>> +    k->event = tca6416_event;
>>> +}> +
>>> +static const TypeInfo tca6416_types[] = {
>>> +    {
>>> +        .name = TYPE_TCA6416,
>>> +        .parent = TYPE_I2C_SLAVE,
>>> +        .class_init = tca6416_class_init,
>>> +        .instance_size = sizeof(Tca6416State),
>>> +    }
>>> +};
>>> +
>>> +DEFINE_TYPES(tca6416_types)
>>> diff --git a/hw/gpio/Kconfig b/hw/gpio/Kconfig
>>> index c423e10f59..a240cf2de2 100644
>>> --- a/hw/gpio/Kconfig
>>> +++ b/hw/gpio/Kconfig
>>> @@ -20,5 +20,10 @@ config PCF8574
>>>        bool
>>>        depends on I2C
>>>    +config TCA6416
>>> +    bool
>>> +    depends on I2C
>>> +    default y if I2C_DEVICES
>>> +
>>>    config ZAURUS_SCOOP
>>>        bool
>>> diff --git a/hw/gpio/meson.build b/hw/gpio/meson.build
>>> index 74840619c0..b3ff7c7460 100644
>>> --- a/hw/gpio/meson.build
>>> +++ b/hw/gpio/meson.build
>>> @@ -18,3 +18,4 @@ system_ss.add(when: 'CONFIG_STM32L4X5_SOC', if_true: files('stm32l4x5_gpio.c'))
>>>    system_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('aspeed_gpio.c'))
>>>    system_ss.add(when: 'CONFIG_SIFIVE_GPIO', if_true: files('sifive_gpio.c'))
>>>    system_ss.add(when: 'CONFIG_PCF8574', if_true: files('pcf8574.c'))
>>> +system_ss.add(when: 'CONFIG_TCA6416', if_true: files('tca6416.c'))
>>> diff --git a/hw/gpio/trace-events b/hw/gpio/trace-events
>>> index cea896b28f..6724f2efb8 100644
>>> --- a/hw/gpio/trace-events
>>> +++ b/hw/gpio/trace-events
>>> @@ -46,3 +46,7 @@ stm32l4x5_gpio_read(char *gpio, uint64_t addr) "GPIO%s addr: 0x%" PRIx64 " "
>>>    stm32l4x5_gpio_write(char *gpio, uint64_t addr, uint64_t data) "GPIO%s addr: 0x%" PRIx64 " val: 0x%" PRIx64 ""
>>>    stm32l4x5_gpio_update_idr(char *gpio, uint32_t old_idr, uint32_t new_idr) "GPIO%s from: 0x%x to: 0x%x"
>>>    stm32l4x5_gpio_pins(char *gpio, uint16_t disconnected, uint16_t high) "GPIO%s disconnected pins: 0x%x levels: 0x%x"
>>> +
>>> +# tca6416.c
>>> +tca6416_write(uint8_t value) "0x%02x"
>>
>> "wr 0x%02x"
>>
>>> +tca6416_read(uint8_t value) "0x%02x"
>>
>> "rd ..."
>>
>> Regards,
>>
>> Phil.