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SubjectRe: [PATCH i2c-next v6] i2c: aspeed: Handle master/slave combined irq events properly
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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",
>>
>
>

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