diff mbox series

[3/8] hw/misc: add a toy i2c echo device

Message ID 20230214171830.681594-4-clg@kaod.org
State New
Headers show
Series aspeed: I2C fixes, -drive removal (first step) | expand

Commit Message

Cédric Le Goater Feb. 14, 2023, 5:18 p.m. UTC
From: Klaus Jensen <k.jensen@samsung.com>

Add an example I2C device to demonstrate how a slave may master the bus
and send data asynchronously to another slave.

The device will echo whatever it is sent to the device identified by the
first byte received.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
[ clg: - Changed to build to use CONFIG_ASPEED_SOC since only supported
         on such SoCs
       - folded in these fixes :
       	 https://lore.kernel.org/qemu-devel/Y3yMKAhOkYGtnkOp@cormorant.local/
]
Message-Id: <20220601210831.67259-7-its@irrelevant.dk>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/misc/i2c-echo.c  | 156 ++++++++++++++++++++++++++++++++++++++++++++
 hw/misc/meson.build |   2 +
 2 files changed, 158 insertions(+)
 create mode 100644 hw/misc/i2c-echo.c

Comments

Philippe Mathieu-Daudé Feb. 15, 2023, 10:55 a.m. UTC | #1
On 14/2/23 18:18, Cédric Le Goater wrote:
> From: Klaus Jensen <k.jensen@samsung.com>
> 
> Add an example I2C device to demonstrate how a slave may master the bus
> and send data asynchronously to another slave.

What a rebellion...

> The device will echo whatever it is sent to the device identified by the
> first byte received.
> 
> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> [ clg: - Changed to build to use CONFIG_ASPEED_SOC since only supported
>           on such SoCs
>         - folded in these fixes :
>         	 https://lore.kernel.org/qemu-devel/Y3yMKAhOkYGtnkOp@cormorant.local/
> ]
> Message-Id: <20220601210831.67259-7-its@irrelevant.dk>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>   hw/misc/i2c-echo.c  | 156 ++++++++++++++++++++++++++++++++++++++++++++
>   hw/misc/meson.build |   2 +
>   2 files changed, 158 insertions(+)
>   create mode 100644 hw/misc/i2c-echo.c


> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
> index 448e14b531..3eb1bda710 100644
> --- a/hw/misc/meson.build
> +++ b/hw/misc/meson.build
> @@ -129,6 +129,8 @@ softmmu_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_rng.c'))
>   
>   softmmu_ss.add(when: 'CONFIG_GRLIB', if_true: files('grlib_ahb_apb_pnp.c'))
>   
> +softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('i2c-echo.c'))

s/CONFIG_ASPEED_SOC/CONFIG_I2C/ since this is a generic device.

>   specific_ss.add(when: 'CONFIG_AVR_POWER', if_true: files('avr_power.c'))
>   
>   specific_ss.add(when: 'CONFIG_MAC_VIA', if_true: files('mac_via.c'))
Cédric Le Goater Feb. 15, 2023, 11:09 a.m. UTC | #2
On 2/15/23 11:55, Philippe Mathieu-Daudé wrote:
> On 14/2/23 18:18, Cédric Le Goater wrote:
>> From: Klaus Jensen <k.jensen@samsung.com>
>>
>> Add an example I2C device to demonstrate how a slave may master the bus
>> and send data asynchronously to another slave.
> 
> What a rebellion...
> 
>> The device will echo whatever it is sent to the device identified by the
>> first byte received.
>>
>> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
>> [ clg: - Changed to build to use CONFIG_ASPEED_SOC since only supported
>>           on such SoCs
>>         - folded in these fixes :
>>              https://lore.kernel.org/qemu-devel/Y3yMKAhOkYGtnkOp@cormorant.local/
>> ]
>> Message-Id: <20220601210831.67259-7-its@irrelevant.dk>
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> ---
>>   hw/misc/i2c-echo.c  | 156 ++++++++++++++++++++++++++++++++++++++++++++
>>   hw/misc/meson.build |   2 +
>>   2 files changed, 158 insertions(+)
>>   create mode 100644 hw/misc/i2c-echo.c
> 
> 
>> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
>> index 448e14b531..3eb1bda710 100644
>> --- a/hw/misc/meson.build
>> +++ b/hw/misc/meson.build
>> @@ -129,6 +129,8 @@ softmmu_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_rng.c'))
>>   softmmu_ss.add(when: 'CONFIG_GRLIB', if_true: files('grlib_ahb_apb_pnp.c'))
>> +softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('i2c-echo.c'))
> 
> s/CONFIG_ASPEED_SOC/CONFIG_I2C/ since this is a generic device.

even if only supported by the Aspeed SoC ? I am OK with both.


> 
>>   specific_ss.add(when: 'CONFIG_AVR_POWER', if_true: files('avr_power.c'))
>>   specific_ss.add(when: 'CONFIG_MAC_VIA', if_true: files('mac_via.c'))
>
Philippe Mathieu-Daudé Feb. 15, 2023, 12:26 p.m. UTC | #3
On 15/2/23 12:09, Cédric Le Goater wrote:
> On 2/15/23 11:55, Philippe Mathieu-Daudé wrote:
>> On 14/2/23 18:18, Cédric Le Goater wrote:
>>> From: Klaus Jensen <k.jensen@samsung.com>
>>>
>>> Add an example I2C device to demonstrate how a slave may master the bus
>>> and send data asynchronously to another slave.
>>
>> What a rebellion...
>>
>>> The device will echo whatever it is sent to the device identified by the
>>> first byte received.
>>>
>>> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
>>> [ clg: - Changed to build to use CONFIG_ASPEED_SOC since only supported
>>>           on such SoCs
>>>         - folded in these fixes :
>>>              
>>> https://lore.kernel.org/qemu-devel/Y3yMKAhOkYGtnkOp@cormorant.local/
>>> ]
>>> Message-Id: <20220601210831.67259-7-its@irrelevant.dk>
>>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>>> ---
>>>   hw/misc/i2c-echo.c  | 156 ++++++++++++++++++++++++++++++++++++++++++++
>>>   hw/misc/meson.build |   2 +
>>>   2 files changed, 158 insertions(+)
>>>   create mode 100644 hw/misc/i2c-echo.c
>>
>>
>>> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
>>> index 448e14b531..3eb1bda710 100644
>>> --- a/hw/misc/meson.build
>>> +++ b/hw/misc/meson.build
>>> @@ -129,6 +129,8 @@ softmmu_ss.add(when: 'CONFIG_NRF51_SOC', if_true: 
>>> files('nrf51_rng.c'))
>>>   softmmu_ss.add(when: 'CONFIG_GRLIB', if_true: 
>>> files('grlib_ahb_apb_pnp.c'))
>>> +softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('i2c-echo.c'))
>>
>> s/CONFIG_ASPEED_SOC/CONFIG_I2C/ since this is a generic device.
> 
> even if only supported by the Aspeed SoC ? I am OK with both.

Any machine exposing an i2c bus can use this device, isn't it?

   -device i2c-echo,bus=bus69,address=0x42 ...
Cédric Le Goater Feb. 17, 2023, 8:24 a.m. UTC | #4
On 2/15/23 13:26, Philippe Mathieu-Daudé wrote:
> On 15/2/23 12:09, Cédric Le Goater wrote:
>> On 2/15/23 11:55, Philippe Mathieu-Daudé wrote:
>>> On 14/2/23 18:18, Cédric Le Goater wrote:
>>>> From: Klaus Jensen <k.jensen@samsung.com>
>>>>
>>>> Add an example I2C device to demonstrate how a slave may master the bus
>>>> and send data asynchronously to another slave.
>>>
>>> What a rebellion...
>>>
>>>> The device will echo whatever it is sent to the device identified by the
>>>> first byte received.
>>>>
>>>> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
>>>> [ clg: - Changed to build to use CONFIG_ASPEED_SOC since only supported
>>>>           on such SoCs
>>>>         - folded in these fixes :
>>>> https://lore.kernel.org/qemu-devel/Y3yMKAhOkYGtnkOp@cormorant.local/
>>>> ]
>>>> Message-Id: <20220601210831.67259-7-its@irrelevant.dk>
>>>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>>>> ---
>>>>   hw/misc/i2c-echo.c  | 156 ++++++++++++++++++++++++++++++++++++++++++++
>>>>   hw/misc/meson.build |   2 +
>>>>   2 files changed, 158 insertions(+)
>>>>   create mode 100644 hw/misc/i2c-echo.c
>>>
>>>
>>>> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
>>>> index 448e14b531..3eb1bda710 100644
>>>> --- a/hw/misc/meson.build
>>>> +++ b/hw/misc/meson.build
>>>> @@ -129,6 +129,8 @@ softmmu_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_rng.c'))
>>>>   softmmu_ss.add(when: 'CONFIG_GRLIB', if_true: files('grlib_ahb_apb_pnp.c'))
>>>> +softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('i2c-echo.c'))
>>>
>>> s/CONFIG_ASPEED_SOC/CONFIG_I2C/ since this is a generic device.
>>
>> even if only supported by the Aspeed SoC ? I am OK with both.
> 
> Any machine exposing an i2c bus can use this device, isn't it?
> 
>    -device i2c-echo,bus=bus69,address=0x42 ...

Would you have a machine with I2C buses and image to try that on ?
Not an aspeed one obvioulsy

Thanks,

C.
diff mbox series

Patch

diff --git a/hw/misc/i2c-echo.c b/hw/misc/i2c-echo.c
new file mode 100644
index 0000000000..5705ab5d73
--- /dev/null
+++ b/hw/misc/i2c-echo.c
@@ -0,0 +1,156 @@ 
+#include "qemu/osdep.h"
+#include "qemu/timer.h"
+#include "qemu/main-loop.h"
+#include "block/aio.h"
+#include "hw/i2c/i2c.h"
+
+#define TYPE_I2C_ECHO "i2c-echo"
+OBJECT_DECLARE_SIMPLE_TYPE(I2CEchoState, I2C_ECHO)
+
+enum i2c_echo_state {
+    I2C_ECHO_STATE_IDLE,
+    I2C_ECHO_STATE_START_SEND,
+    I2C_ECHO_STATE_ACK,
+};
+
+typedef struct I2CEchoState {
+    I2CSlave parent_obj;
+
+    I2CBus *bus;
+
+    enum i2c_echo_state state;
+    QEMUBH *bh;
+
+    unsigned int pos;
+    uint8_t data[3];
+} I2CEchoState;
+
+static void i2c_echo_bh(void *opaque)
+{
+    I2CEchoState *state = opaque;
+
+    switch (state->state) {
+    case I2C_ECHO_STATE_IDLE:
+        return;
+
+    case I2C_ECHO_STATE_START_SEND:
+        if (i2c_start_send_async(state->bus, state->data[0])) {
+            goto release_bus;
+        }
+
+        state->pos++;
+        state->state = I2C_ECHO_STATE_ACK;
+        return;
+
+    case I2C_ECHO_STATE_ACK:
+        if (state->pos > 2) {
+            break;
+        }
+
+        if (i2c_send_async(state->bus, state->data[state->pos++])) {
+            break;
+        }
+
+        return;
+    }
+
+
+    i2c_end_transfer(state->bus);
+release_bus:
+    i2c_bus_release(state->bus);
+
+    state->state = I2C_ECHO_STATE_IDLE;
+}
+
+static int i2c_echo_event(I2CSlave *s, enum i2c_event event)
+{
+    I2CEchoState *state = I2C_ECHO(s);
+
+    switch (event) {
+    case I2C_START_RECV:
+        state->pos = 0;
+
+        break;
+
+    case I2C_START_SEND:
+        state->pos = 0;
+
+        break;
+
+    case I2C_FINISH:
+        state->pos = 0;
+        state->state = I2C_ECHO_STATE_START_SEND;
+        i2c_bus_master(state->bus, state->bh);
+
+        break;
+
+    case I2C_NACK:
+        break;
+
+    default:
+        return -1;
+    }
+
+    return 0;
+}
+
+static uint8_t i2c_echo_recv(I2CSlave *s)
+{
+    I2CEchoState *state = I2C_ECHO(s);
+
+    if (state->pos > 2) {
+        return 0xff;
+    }
+
+    return state->data[state->pos++];
+}
+
+static int i2c_echo_send(I2CSlave *s, uint8_t data)
+{
+    I2CEchoState *state = I2C_ECHO(s);
+
+    if (state->pos > 2) {
+        return -1;
+    }
+
+    state->data[state->pos++] = data;
+
+    return 0;
+}
+
+static void i2c_echo_realize(DeviceState *dev, Error **errp)
+{
+    I2CEchoState *state = I2C_ECHO(dev);
+    BusState *bus = qdev_get_parent_bus(dev);
+
+    state->bus = I2C_BUS(bus);
+    state->bh = qemu_bh_new(i2c_echo_bh, state);
+
+    return;
+}
+
+static void i2c_echo_class_init(ObjectClass *oc, void *data)
+{
+    I2CSlaveClass *sc = I2C_SLAVE_CLASS(oc);
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = i2c_echo_realize;
+
+    sc->event = i2c_echo_event;
+    sc->recv = i2c_echo_recv;
+    sc->send = i2c_echo_send;
+}
+
+static const TypeInfo i2c_echo = {
+    .name = TYPE_I2C_ECHO,
+    .parent = TYPE_I2C_SLAVE,
+    .instance_size = sizeof(I2CEchoState),
+    .class_init = i2c_echo_class_init,
+};
+
+static void register_types(void)
+{
+    type_register_static(&i2c_echo);
+}
+
+type_init(register_types);
diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index 448e14b531..3eb1bda710 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -129,6 +129,8 @@  softmmu_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_rng.c'))
 
 softmmu_ss.add(when: 'CONFIG_GRLIB', if_true: files('grlib_ahb_apb_pnp.c'))
 
+softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('i2c-echo.c'))
+
 specific_ss.add(when: 'CONFIG_AVR_POWER', if_true: files('avr_power.c'))
 
 specific_ss.add(when: 'CONFIG_MAC_VIA', if_true: files('mac_via.c'))