On 10/8/19 3:45 PM, Jae Hyun Yoo wrote:
> Hi Tao,
>
> On 10/8/2019 3:00 PM, Tao Ren wrote:
>> On 10/7/19 4:13 PM, Jae Hyun Yoo wrote:
>>> In case of master pending state, it should not trigger the master
>>> command because this H/W is sharing the same data buffer for slave
>>> and master operations, so this commit fixes the issue with making
>>> the master command triggering happen when the state goes to active
>>> state.
>>>
>>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
>>> ---
>>> drivers/i2c/busses/i2c-aspeed.c | 9 +++++----
>>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
>>> index fa66951b05d0..40f6cf98d32e 100644
>>> --- a/drivers/i2c/busses/i2c-aspeed.c
>>> +++ b/drivers/i2c/busses/i2c-aspeed.c
>>> @@ -336,18 +336,19 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
>>> struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
>>> u8 slave_addr = i2c_8bit_addr_from_msg(msg);
>>> - bus->master_state = ASPEED_I2C_MASTER_START;
>>> -
>>> #if IS_ENABLED(CONFIG_I2C_SLAVE)
>>> /*
>>> * If it's requested in the middle of a slave session, set the master
>>> * state to 'pending' then H/W will continue handling this master
>>> * command when the bus comes back to the idle state.
>>> */
>>> - if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE)
>>> + if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) {
>>> bus->master_state = ASPEED_I2C_MASTER_PENDING;
>>> + return;
>>> + }
>>> #endif /* CONFIG_I2C_SLAVE */
>>> + bus->master_state = ASPEED_I2C_MASTER_START;
>>> bus->buf_index = 0;
>>> if (msg->flags & I2C_M_RD) {
>>> @@ -432,7 +433,7 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
>>> if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE)
>>> goto out_no_complete;
>>> - bus->master_state = ASPEED_I2C_MASTER_START;
>>> + aspeed_i2c_do_start(bus);
>>> }
>>
>> Shall we move the restart-master logic from master_irq to bus_irq? The reason being:
>> master transaction cannot be restarted when aspeed-i2c is running in slave state and
>> receives STOP interrupt, because aspeed_i2c_master_irq won't be called in this case.
>
> Even in that case, master can be restarted properly because slave_irq
> will be called first because master is in MASTER_PENDING state, so the
> slave_irq handles the STOP interrupt as well, and then master_irq will
> be called with SLAVE_INACTIVE state so the aspeed_i2c_do_start can be
> called eventually.
I mean master_irq cannot be called when irq_remaining becomes 0 after slave_irq.
Cheers,
Tao
