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From: Guenter Roeck <linux@roeck-us.net>
To: "Cédric Le Goater" <clg@kaod.org>,
	"Jae Hyun Yoo" <jae.hyun.yoo@linux.intel.com>
Cc: Joel Stanley <joel@jms.id.au>,
	linux-aspeed@lists.ozlabs.org,
	Vernon Mauery <vernon.mauery@linux.intel.com>,
	OpenBMC Maillist <openbmc@lists.ozlabs.org>,
	Brendan Higgins <brendanhiggins@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-i2c@vger.kernel.org, jarkko.nikula@linux.intel.com,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	James Feist <james.feist@linux.intel.com>
Subject: Re: [PATCH i2c-next v6] i2c: aspeed: Handle master/slave combined irq events properly
Date: Thu, 13 Sep 2018 06:33:29 -0700	[thread overview]
Message-ID: <3f86e75f-1502-eae8-0633-d087937111c8@roeck-us.net> (raw)
In-Reply-To: <fb185839-3ae0-01dc-09e8-f22db55ecb04@kaod.org>

On 09/12/2018 10:45 PM, Cédric Le Goater wrote

[ ... ]

>> ---
>> qemu:
>>
>> diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c
>> index c762c73..0d4aa08 100644
>> --- a/hw/i2c/aspeed_i2c.c
>> +++ b/hw/i2c/aspeed_i2c.c
>> @@ -180,6 +180,33 @@ static uint8_t aspeed_i2c_get_state(AspeedI2CBus *bus)
>>       return (bus->cmd >> I2CD_TX_STATE_SHIFT) & I2CD_TX_STATE_MASK;
>>   }
>>   
>> +static void aspeed_i2c_handle_rx_cmd(AspeedI2CBus *bus)
>> +{
>> +    int ret;
>> +
>> +    if (!(bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST))) {
>> +        return;
>> +    }
> 
> it deserves a comment to understand which scenario we are trying to handle.
> 
>> +    if (bus->intr_status & I2CD_INTR_RX_DONE) {
>> +        return;
>> +    }
> 
> should be handled in aspeed_i2c_bus_handle_cmd() I think
> 

I moved those two checks into the calling code.


>> +    aspeed_i2c_set_state(bus, I2CD_MRXD);
>> +    ret = i2c_recv(bus->bus);
>> +    if (ret < 0) {
>> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
>> +        ret = 0xff;
>> +    } else {
>> +        bus->intr_status |= I2CD_INTR_RX_DONE;
>> +    }
>> +    bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
>> +    if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
>> +        i2c_nack(bus->bus);
>> +    }
>> +    bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST);
>> +    aspeed_i2c_set_state(bus, I2CD_MACTIVE);
>> +}
>> +
>>   /*
>>    * The state machine needs some refinement. It is only used to track
>>    * invalid STOP commands for the moment.
>> @@ -188,7 +215,7 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
>>   {
>>       bus->cmd &= ~0xFFFF;
>>       bus->cmd |= value & 0xFFFF;
>> -    bus->intr_status = 0;> +    bus->intr_status &= I2CD_INTR_RX_DONE;
> 
> it deserves a comment to understand which scenario we are trying to handle.
>    

Ok. FWIW, I wonder if intr_status should be touched here in the first place,
but I neither have the hardware nor a datasheet, so I don't know if any bits
are auto-cleared.

>>       if (bus->cmd & I2CD_M_START_CMD) {
>>           uint8_t state = aspeed_i2c_get_state(bus) & I2CD_MACTIVE ?
>> @@ -227,22 +254,7 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
>>       }
>>   
>>       if (bus->cmd & (I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST)) {
>> -        int ret;
>> -
>> -        aspeed_i2c_set_state(bus, I2CD_MRXD);
>> -        ret = i2c_recv(bus->bus);
>> -        if (ret < 0) {
>> -            qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
>> -            ret = 0xff;
>> -        } else {
>> -            bus->intr_status |= I2CD_INTR_RX_DONE;
>> -        }
>> -        bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
>> -        if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
>> -            i2c_nack(bus->bus);
>> -        }
>> -        bus->cmd &= ~(I2CD_M_RX_CMD | I2CD_M_S_RX_CMD_LAST);
>> -        aspeed_i2c_set_state(bus, I2CD_MACTIVE);
>> +        aspeed_i2c_handle_rx_cmd(bus);
>>       }
>>   
>>       if (bus->cmd & I2CD_M_STOP_CMD) {
>> @@ -263,6 +275,7 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset,
>>                                    uint64_t value, unsigned size)
>>   {
>>       AspeedI2CBus *bus = opaque;
>> +    int status;
>>   
>>       switch (offset) {
>>       case I2CD_FUN_CTRL_REG:
>> @@ -283,9 +296,16 @@ static void aspeed_i2c_bus_write(void *opaque, hwaddr offset,
>>           bus->intr_ctrl = value & 0x7FFF;
>>           break;
>>       case I2CD_INTR_STS_REG:
>> +        status = bus->intr_status;
>>           bus->intr_status &= ~(value & 0x7FFF);
>> -        bus->controller->intr_status &= ~(1 << bus->id);
>> -        qemu_irq_lower(bus->controller->irq);
>> +        if (!bus->intr_status) {
>> +            bus->controller->intr_status &= ~(1 << bus->id);
>> +            qemu_irq_lower(bus->controller->irq);
>> +        }
> 
> That part below is indeed something to fix. I had a similar patch.
> 

Should I split it out as separate patch ? Alternatively, if you submitted
your patch already, I'll be happy to use it as base for mine.

Thanks,
Guenter

> 
>> +        if ((status & I2CD_INTR_RX_DONE) && !(bus->intr_status & I2CD_INTR_RX_DONE)) {
>> +            aspeed_i2c_handle_rx_cmd(bus);
>> +            aspeed_i2c_bus_raise_interrupt(bus);
>> +        }
> 
> ok.
> 
> Thanks for looking into this.
> 
> C.
> 
>>           break;
>>       case I2CD_DEV_ADDR_REG:
>>           qemu_log_mask(LOG_UNIMP, "%s: slave mode not implemented\n",
>>
> 
> 


  reply	other threads:[~2018-09-13 13:33 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-23 22:57 [PATCH i2c-next v6] i2c: aspeed: Handle master/slave combined irq events properly Jae Hyun Yoo
2018-09-06 17:26 ` Brendan Higgins
2018-09-06 17:32   ` Jae Hyun Yoo
2018-09-06 18:08     ` Wolfram Sang
2018-09-06 18:33       ` Jae Hyun Yoo
2018-09-06 18:40 ` Wolfram Sang
2018-09-11 18:37 ` Guenter Roeck
2018-09-11 18:45   ` Cédric Le Goater
2018-09-11 20:30   ` Jae Hyun Yoo
2018-09-11 20:41     ` Guenter Roeck
2018-09-11 22:18       ` Jae Hyun Yoo
2018-09-11 22:53         ` Joel Stanley
2018-09-11 23:33           ` Guenter Roeck
2018-09-11 23:58             ` Jae Hyun Yoo
2018-09-12  1:34               ` Guenter Roeck
2018-09-12 16:54                 ` Jae Hyun Yoo
2018-09-12 19:58                   ` Guenter Roeck
2018-09-12 20:10                     ` Jae Hyun Yoo
2018-09-12 20:30                       ` Guenter Roeck
2018-09-12 22:31                         ` Jae Hyun Yoo
2018-09-12 23:30                           ` Guenter Roeck
2018-09-13  5:45                         ` Cédric Le Goater
2018-09-13 13:33                           ` Guenter Roeck [this message]
2018-09-13 15:48                             ` Cédric Le Goater
2018-09-13 15:57                               ` Guenter Roeck
2018-09-13 16:35                                 ` Cédric Le Goater
2018-09-14  3:48                                   ` Guenter Roeck
2018-09-14  5:38                                     ` Cédric Le Goater
2018-09-14 13:23                                       ` Guenter Roeck
2018-09-14 16:52                                         ` Jae Hyun Yoo
2018-09-13  5:47                   ` Cédric Le Goater
2018-09-13 16:31                     ` Jae Hyun Yoo
2018-09-13 16:51                       ` Cédric Le Goater
2018-09-13 17:01                         ` Jae Hyun Yoo
2018-09-12  5:57             ` Cédric Le Goater

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