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

[Bernhard Beschow]

Am 2. Februar 2025 17:09:06 UTC schrieb "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.

Sure, I'll link your and Zoltan's comments as todos in the next version.

Best regards,
Bernhard

>
>> 
>> 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.
>