linux-kernel - Re: [PATCH v3 5/7] i2c: aspeed: Add aspeed_set_slave

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Message-ID: <917237ce-98f8-df5f-32b6-b4145ac47ac9@os.amperecomputing.com>
Date:   Mon, 24 May 2021 17:48:38 +0700
From:   Quan Nguyen <quan@...amperecomputing.com>
To:     Ryan Chen <ryan_chen@...eedtech.com>,
        Corey Minyard <minyard@....org>,
        Rob Herring <robh+dt@...nel.org>,
        Joel Stanley <joel@....id.au>,
        Andrew Jeffery <andrew@...id.au>,
        Brendan Higgins <brendanhiggins@...gle.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Wolfram Sang <wsa@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "openipmi-developer@...ts.sourceforge.net" 
        <openipmi-developer@...ts.sourceforge.net>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-aspeed@...ts.ozlabs.org" <linux-aspeed@...ts.ozlabs.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>
Cc:     Open Source Submission <patches@...erecomputing.com>,
        "Thang Q . Nguyen" <thang@...amperecomputing.com>,
        Phong Vo <phong@...amperecomputing.com>,
        "openbmc@...ts.ozlabs.org" <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH v3 5/7] i2c: aspeed: Add aspeed_set_slave_busy()

On 24/05/2021 17:36, Ryan Chen wrote:
>> -----Original Message-----
>> From: Quan Nguyen <quan@...amperecomputing.com>
>> Sent: Monday, May 24, 2021 6:20 PM
>> To: Ryan Chen <ryan_chen@...eedtech.com>; Corey Minyard
>> <minyard@....org>; Rob Herring <robh+dt@...nel.org>; Joel Stanley
>> <joel@....id.au>; Andrew Jeffery <andrew@...id.au>; Brendan Higgins
>> <brendanhiggins@...gle.com>; Benjamin Herrenschmidt
>> <benh@...nel.crashing.org>; Wolfram Sang <wsa@...nel.org>; Philipp Zabel
>> <p.zabel@...gutronix.de>; openipmi-developer@...ts.sourceforge.net;
>> devicetree@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
>> linux-aspeed@...ts.ozlabs.org; linux-kernel@...r.kernel.org;
>> linux-i2c@...r.kernel.org
>> Cc: Open Source Submission <patches@...erecomputing.com>; Thang Q .
>> Nguyen <thang@...amperecomputing.com>; Phong Vo
>> <phong@...amperecomputing.com>; openbmc@...ts.ozlabs.org
>> Subject: Re: [PATCH v3 5/7] i2c: aspeed: Add aspeed_set_slave_busy()
>>
>> On 24/05/2021 17:06, Ryan Chen wrote:
>>>> -----Original Message-----
>>>> From: openbmc
>>>> <openbmc-bounces+ryan_chen=aspeedtech.com@...ts.ozlabs.org> On
>> Behalf
>>>> Of Quan Nguyen
>>>> Sent: Wednesday, May 19, 2021 3:50 PM
>>>> To: Corey Minyard <minyard@....org>; Rob Herring
>>>> <robh+dt@...nel.org>; Joel Stanley <joel@....id.au>; Andrew Jeffery
>>>> <andrew@...id.au>; Brendan Higgins <brendanhiggins@...gle.com>;
>>>> Benjamin Herrenschmidt <benh@...nel.crashing.org>; Wolfram Sang
>>>> <wsa@...nel.org>; Philipp Zabel <p.zabel@...gutronix.de>;
>>>> openipmi-developer@...ts.sourceforge.net;
>>>> devicetree@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
>>>> linux-aspeed@...ts.ozlabs.org; linux-kernel@...r.kernel.org;
>>>> linux-i2c@...r.kernel.org
>>>> Cc: Open Source Submission <patches@...erecomputing.com>; Thang Q .
>>>> Nguyen <thang@...amperecomputing.com>; Phong Vo
>>>> <phong@...amperecomputing.com>; openbmc@...ts.ozlabs.org
>>>> Subject: [PATCH v3 5/7] i2c: aspeed: Add aspeed_set_slave_busy()
>>>>
>>>> Slave i2c device on AST2500 received a lot of slave irq while it is
>>>> busy processing the response. To handle this case, adds and exports
>>>> aspeed_set_slave_busy() for controller to temporary stop slave irq
>>>> while slave is handling the response, and re-enable them again when the
>> response is ready.
>>>>
>>>> Signed-off-by: Quan Nguyen <quan@...amperecomputing.com>
>>>> ---
>>>> v3:
>>>>     + First introduce in v3 [Quan]
>>>>
>>>>    drivers/i2c/busses/i2c-aspeed.c | 20 ++++++++++++++++++++
>>>>    1 file changed, 20 insertions(+)
>>>>
>>>> diff --git a/drivers/i2c/busses/i2c-aspeed.c
>>>> b/drivers/i2c/busses/i2c-aspeed.c index b2e9c8f0ddf7..9926d04831a2
>>>> 100644
>>>> --- a/drivers/i2c/busses/i2c-aspeed.c
>>>> +++ b/drivers/i2c/busses/i2c-aspeed.c
>>>> @@ -944,6 +944,26 @@ static int aspeed_i2c_init(struct aspeed_i2c_bus
>>>> *bus,
>>>>    	return 0;
>>>>    }
>>>>
>>>> +#if IS_ENABLED(CONFIG_I2C_SLAVE)
>>>> +void aspeed_set_slave_busy(struct i2c_adapter *adap, bool busy) {
>>>> +	struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
>>>> +	unsigned long current_mask, flags;
>>>> +
>>>> +	spin_lock_irqsave(&bus->lock, flags);
>>>> +
>>>> +	current_mask = readl(bus->base + ASPEED_I2C_INTR_CTRL_REG);
>>> Hello
>>> 	Where the bus->base to be remap?
>>>
>>
>> Hi Ryan,
>>
>> In "[PATCH v3 6/7] ipmi: ssif_bmc: Add Aspeed SSIF BMC driver", the
>> ->priv is retrieved by calling i2c_get_adapdata(client->adapter). And in
>> aspeed_set_ssif_bmc_status(), call the exported aspeed_set_slave_busy()
>> using ->priv pointer as code below.
>>
> Yes, I see the probe function " ssif_bmc->priv = i2c_get_adapdata(client->adapter);" to get priv.
> But my question I don’t see the bus->base address be assigned.
> 
Hi Ryan,

In drivers/i2c/busses/i2c-aspeed.c:
struct aspeed_i2c_bus {
         struct i2c_adapter              adap;
         struct device                   *dev;
         void __iomem                    *base;
         struct reset_control            *rst;
         /* Synchronizes I/O mem access to base. */
         spinlock_t                      lock;

So when "struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);", the 
bus->base should point to the base of the aspeed_i2c_bus, which is 
already initialized by the aspeed i2c bus driver.

Do I miss something?

- Quan


>> +extern void aspeed_set_slave_busy(struct i2c_adapter *adap, bool busy);
>> +static void aspeed_set_ssif_bmc_status(struct ssif_bmc_ctx *ssif_bmc,
>> unsigned int status)
>> +{
>> +	if (status & SSIF_BMC_BUSY)
>> +		aspeed_set_slave_busy((struct i2c_adapter *)ssif_bmc->priv, true);
>> +	else if (status & SSIF_BMC_READY)
>> +		aspeed_set_slave_busy((struct i2c_adapter *)ssif_bmc->priv, false); }
>> +
>> +static int ssif_bmc_probe(struct i2c_client *client, const struct
>> i2c_device_id *id)
>> +{
>> +	struct ssif_bmc_ctx *ssif_bmc;
>> +
>> +	ssif_bmc = ssif_bmc_alloc(client, 0);
>> +	if (IS_ERR(ssif_bmc))
>> +		return PTR_ERR(ssif_bmc);
>> +
>> +	ssif_bmc->priv = i2c_get_adapdata(client->adapter);
>> +	ssif_bmc->set_ssif_bmc_status = aspeed_set_ssif_bmc_status;
>> +
>> +	return 0;
>> +}
>>
>> - Quan
>>
>>
>