On 1/20/23 03:59, Charles Keepax wrote:
> On Thu, Jan 19, 2023 at 11:12:04AM -0600, Pierre-Louis Bossart wrote:
>> No objection on this addition, just a couple of comments to improve it:
>>
>>> EXPORT_SYMBOL(sdw_bus_master_add);
>>> @@ -158,6 +183,8 @@ static int sdw_delete_slave(struct device *dev, void *data)
>>> mutex_lock(&bus->bus_lock);
>>>
>>> if (slave->dev_num) { /* clear dev_num if assigned */
>>> + irq_dispose_mapping(irq_find_mapping(bus->domain, slave->dev_num));
>>> +
>>
>> could this be done conditionally. e.g.
>>
>> if (slave->prop.irq)
>> irq_dispose_mapping(irq_find_mapping(bus->domain, slave->dev_num));
>>
>>> + slave->irq = irq_create_mapping(bus->domain, dev_num);
>>> + if (!slave->irq) {
>>> + dev_err(bus->dev, "Failed to map IRQ\n");
>>> + return -EINVAL;
>>> + }
>>
>> ...and here....
>>
>> if (slave->prop.irq) {
>> slave->irq = irq_create_mapping(bus->domain, dev_num);
>> if (!slave->irq) {
>> dev_err(bus->dev, "Failed to map IRQ\n");
>> return -EINVAL;
>> }
>> }
>>
>
> Yeah I am happy to make those conditional, I guess it is cleaner
> to not map IRQs if they wont be used.
ok
>
>>> @@ -369,6 +371,7 @@ struct sdw_dpn_prop {
>>> * @clock_reg_supported: the Peripheral implements the clock base and scale
>>> * registers introduced with the SoundWire 1.2 specification. SDCA devices
>>> * do not need to set this boolean property as the registers are required.
>>> + * @irq: call actual IRQ handler on slave, as well as callback
>>> */
>>> struct sdw_slave_prop {
>>> u32 mipi_revision;
>>> @@ -393,6 +396,7 @@ struct sdw_slave_prop {
>>> u8 scp_int1_mask;
>>> u32 quirks;
>>> bool clock_reg_supported;
>>> + bool irq;
>>
>> this can be confused with the 'wake_capable' property.
>>
>> maybe 'out_of_band_irq' ?
>>
>
> Yes I struggle on the name a bit and then just gave up and
> went with plain "irq", hard to know what to call it. Not sure
> out_of_band is quite right since it not really out of band,
> handle_nested_irq pretty much basically boils down to a function
> call really. Maybe something like "map_irq", or "use_domain_irq"?
Naming is hard. I use 'in-band wake' for SoundWire-based notifications,
so I used 'out-of-band' for non-SoundWire stuff.
use_domain_irq sounds goods to me, it's different enough that confusions
are not possible.
>> There should be an explanation and something checking that both are not
>> used concurrently.
>
> I will try to expand the explanation a litte, but I dont see any
> reason to block calling both handlers, no ill effects would come
> for a driver having both and it is useful if any soundwire
> specific steps are needed that arn't on other control buses.
I think it's problematic if the peripheral tries to wake-up the manager
from clock-stop with both an in-band wake (i.e. drive the data line
high) and a separate GPIO-based interrupt. It's asking for trouble IMHO.
We spent hours in the MIPI team to make sure there were no races between
the manager-initiated restarts and peripheral-initiated restarts, adding
a 3rd mechanism in the mix gives me a migraine already.
