Re: [PATCH v3 5/7] i2c: aspeed: Add aspeed_set_slave_busy()

[Quan Nguyen]

On 24/05/2021 17:36, Ryan Chen wrote:
> > -----Original Message-----
> > From: Quan Nguyen <quan@xxxxxxxxxxxxxxxxxxxxxx>
> > Sent: Monday, May 24, 2021 6:20 PM
> > To: Ryan Chen <ryan_chen@xxxxxxxxxxxxxx>; Corey Minyard
> > <minyard@xxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Joel Stanley
> > <joel@xxxxxxxxx>; Andrew Jeffery <andrew@xxxxxxxx>; Brendan Higgins
> > <brendanhiggins@xxxxxxxxxx>; Benjamin Herrenschmidt
> > <benh@xxxxxxxxxxxxxxxxxxx>; Wolfram Sang <wsa@xxxxxxxxxx>; Philipp Zabel
> > <p.zabel@xxxxxxxxxxxxxx>; openipmi-developer@xxxxxxxxxxxxxxxxxxxxx;
> > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > linux-aspeed@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > linux-i2c@xxxxxxxxxxxxxxx
> > Cc: Open Source Submission <patches@xxxxxxxxxxxxxxxxxxx>; Thang Q .
> > Nguyen <thang@xxxxxxxxxxxxxxxxxxxxxx>; Phong Vo
> > <phong@xxxxxxxxxxxxxxxxxxxxxx>; openbmc@xxxxxxxxxxxxxxxx
> > 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@xxxxxxxxxxxxxxxx> On
> > Behalf
> > > > Of Quan Nguyen
> > > > Sent: Wednesday, May 19, 2021 3:50 PM
> > > > To: Corey Minyard <minyard@xxxxxxx>; Rob Herring
> > > > <robh+dt@xxxxxxxxxx>; Joel Stanley <joel@xxxxxxxxx>; Andrew Jeffery
> > > > <andrew@xxxxxxxx>; Brendan Higgins <brendanhiggins@xxxxxxxxxx>;
> > > > Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>; Wolfram Sang
> > > > <wsa@xxxxxxxxxx>; Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>;
> > > > openipmi-developer@xxxxxxxxxxxxxxxxxxxxx;
> > > > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > > > linux-aspeed@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > > linux-i2c@xxxxxxxxxxxxxxx
> > > > Cc: Open Source Submission <patches@xxxxxxxxxxxxxxxxxxx>; Thang Q .
> > > > Nguyen <thang@xxxxxxxxxxxxxxxxxxxxxx>; Phong Vo
> > > > <phong@xxxxxxxxxxxxxxxxxxxxxx>; openbmc@xxxxxxxxxxxxxxxx
> > > > 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@xxxxxxxxxxxxxxxxxxxxxx>
> > > > ---
> > > > 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