Re: [PATCH v3 03/11] i3c: master: Extend address status bit to 4 and add I3C_ADDR_SLOT_EXT_INIT

Miquel Raynal
2024-08-23T16:04:55Z

Hi Frank,

> static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr)
> {
> enum i3c_addr_slot_status status;
> @@ -388,6 +405,14 @@ static int i3c_bus_get_free_addr(struct i3c_bus *bus, u8 start_addr)
> enum i3c_addr_slot_status status;
> u8 addr;
>
> + /* try find an address, which have not pre-allocated by assigned-address */

Try to find has been

pre-allocated?

> + for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
> + status = i3c_bus_get_addr_slot_status_ext(bus, addr);
> + if (status == I3C_ADDR_SLOT_FREE)
> + return addr;
> + }
> +
> + /* use pre-allocoated by assigned-address because such device was removed at bus*/

Use allocated

pre-allocated or assigned?

I guess the logic should be:
- try the assigned-address
- look for a free slot
- look for an already in use slot that must concern a disconnected
device

But the comments are not precise enough IMHO. Can you rephrase them?

> for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
> status = i3c_bus_get_addr_slot_status(bus, addr);
> if (status == I3C_ADDR_SLOT_FREE)
> @@ -1906,9 +1931,9 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> goto err_rstdaa;
> }
>
> - i3c_bus_set_addr_slot_status(&master->bus,
> - i3cboardinfo->init_dyn_addr,
> - I3C_ADDR_SLOT_I3C_DEV);
> + i3c_bus_set_addr_slot_status_ext(&master->bus,
> + i3cboardinfo->init_dyn_addr,
> + I3C_ADDR_SLOT_I3C_DEV | I3C_ADDR_SLOT_EXT_INIT);
>
> /*
> * Only try to create/attach devices that have a static
> diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> index 4601b6957f799..c923b76bbc321 100644
> --- a/include/linux/i3c/master.h
> +++ b/include/linux/i3c/master.h
> @@ -284,6 +284,8 @@ enum i3c_bus_mode {
> * @I3C_ADDR_SLOT_I2C_DEV: address is assigned to an I2C device
> * @I3C_ADDR_SLOT_I3C_DEV: address is assigned to an I3C device
> * @I3C_ADDR_SLOT_STATUS_MASK: address slot mask
> + * @I3C_ADDR_SLOT_EXT_INIT: the bit mask display of addresses is preferred by some devices,

I'm sorry, but I don't understand what "bit mask display of addresses"
means.

> + * such as the "assigned-address" in device tree source (dts).
> *
> * On an I3C bus, addresses are assigned dynamically, and we need to know which
> * addresses are free to use and which ones are already assigned.
> @@ -297,9 +299,11 @@ enum i3c_addr_slot_status {
> I3C_ADDR_SLOT_I2C_DEV,
> I3C_ADDR_SLOT_I3C_DEV,
> I3C_ADDR_SLOT_STATUS_MASK = 3,
> + I3C_ADDR_SLOT_EXT_STATUS_MASK = 7,
> + I3C_ADDR_SLOT_EXT_INIT = BIT(2),
> };
>
> -#define I3C_ADDR_SLOT_BITS 2
> +#define I3C_ADDR_SLOT_BITS 4
>
> /**
> * struct i3c_bus - I3C bus object
>

Thanks,
Miquèl