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Re: [Qemu-devel] [PATCH v2 1/6] arm: Uniquely name imx25 I2C buses.
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/6] arm: Uniquely name imx25 I2C buses. |
Date: |
Sat, 3 Dec 2016 18:16:06 +1100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
On 02/12/16 18:55, Cédric Le Goater wrote:
> On 12/02/2016 12:34 AM, Alexey Kardashevskiy wrote:
>> On 01/12/16 23:31, Cédric Le Goater wrote:
>>> On 12/01/2016 01:42 AM, Alastair D'Silva wrote:
>>>> On Wed, 2016-11-30 at 09:18 +0100, Cédric Le Goater wrote:
>>>>> On 11/30/2016 06:36 AM, Alastair D'Silva wrote:
>>>>>> From: Alastair D'Silva <address@hidden>
>>>>>>
>>>>>> The imx25 chip provides 3 i2c buses, but they have all been named
>>>>>> "i2c", which makes it difficult to predict which bus a device will
>>>>>> be connected to when specified on the command line.
>>>>>>
>>>>>> This patch addresses the issue by naming the buses uniquely:
>>>>>> i2c.0 i2c.1 i2c.2
>>>>>>
>>>>>> Signed-off-by: Alastair D'Silva <address@hidden>
>>>>>> ---
>>>>>> hw/arm/imx25_pdk.c | 4 +---
>>>>>> hw/i2c/imx_i2c.c | 6 +++++-
>>>>>> 2 files changed, 6 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> diff --git a/hw/arm/imx25_pdk.c b/hw/arm/imx25_pdk.c
>>>>>> index 025b608..c6f04d3 100644
>>>>>> --- a/hw/arm/imx25_pdk.c
>>>>>> +++ b/hw/arm/imx25_pdk.c
>>>>>> @@ -138,9 +138,7 @@ static void imx25_pdk_init(MachineState
>>>>>> *machine)
>>>>>> * We add it here (only on qtest usage) to be able to do a
>>>>>> bit
>>>>>> * of simple qtest. See "make check" for details.
>>>>>> */
>>>>>> - i2c_create_slave((I2CBus *)qdev_get_child_bus(DEVICE(&s-
>>>>>>> soc.i2c[0]),
>>>>>> - "i2c"),
>>>>>> - "ds1338", 0x68);
>>>>>> + i2c_create_slave(s->soc.i2c[0].bus, "ds1338", 0x68);
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> diff --git a/hw/i2c/imx_i2c.c b/hw/i2c/imx_i2c.c
>>>>>> index 37e5a62..7be10fb 100644
>>>>>> --- a/hw/i2c/imx_i2c.c
>>>>>> +++ b/hw/i2c/imx_i2c.c
>>>>>> @@ -305,12 +305,16 @@ static const VMStateDescription
>>>>>> imx_i2c_vmstate = {
>>>>>> static void imx_i2c_realize(DeviceState *dev, Error **errp)
>>>>>> {
>>>>>> IMXI2CState *s = IMX_I2C(dev);
>>>>>> + static int bus_count;
>>>>>
>>>>> hmm, the static is ugly :/
>>>>>
>>>>> Isn't there other ways to achieve this naming ?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> C.
>>>>>
>>>>
>>>> I'm not seeing an obvious way around it. The busses are realized
>>>> independently (so I can't implement what we do with the aspeed i2c
>>>> busses), and it is named before fsl-imx25:fsl_imx25_realize() can apply
>>>> specific properties to the bus.
>>>>
>>>> If you have any suggestions, I'm all ears.
>>>
>>> What about that ?
>>>
>>> @@ -310,7 +310,7 @@ static void imx_i2c_realize(DeviceState
>>> IMX_I2C_MEM_SIZE);
>>> sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
>>> sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
>>> - s->bus = i2c_init_bus(DEVICE(dev), "i2c");
>>> + s->bus = i2c_init_bus(DEVICE(dev), NULL);
>>> }
>>>
>>> static void imx_i2c_class_init(ObjectClass *klass, void *data)
>>>
>>> Which should name automatically the I2C objects :
>>
>>
>> If you ever do migration, you'll have to specify "id" in the command line
>> anyway. Even in the example below the buses are numbered in messed order,
>> is that desired effect (may be it is, just asking :) )?
>
> That's how it comes out with qom-tree. I haven't dug deeper to see
> how this was implemented.
That's fine, your approach will give unique names, it is just hard to
predict what i2c device will end up connected to which i2c bus, and I
usually want to control this instead of guessing (which will work till some
nonobvious change in QOM :) ).
>
> C.
>
>>>
>>> (qemu) info qom-tree
>>> /machine (imx25-pdk-machine)
>>> /peripheral (container)
>>> /soc (fsl,imx25)
>>> /peripheral-anon (container)
>>> /unattached (container)
>>> /device[0] (arm926-arm-cpu)
>>> /unnamed-gpio-in[1] (irq)
>>> /unnamed-gpio-in[3] (irq)
>>> /unnamed-gpio-in[2] (irq)
>>> /unnamed-gpio-in[0] (irq)
>>>
>>> /device[15] (imx.i2c)
>>> /imx.i2c[0] (qemu:memory-region)
>>> /i2c-bus.0 (i2c-bus)
>>> /device[17] (imx.i2c)
>>> /imx.i2c[0] (qemu:memory-region)
>>> /i2c-bus.2 (i2c-bus)
>>> /device[16] (imx.i2c)
>>> /imx.i2c[0] (qemu:memory-region)
>>> /i2c-bus.1 (i2c-bus)
>>> ....
>>>
>>>
>>> Cheers,
>>>
>>> C.
>>>
>>
>>
>
--
Alexey