diff options
| -rw-r--r-- | drivers/i3c/master.c | 65 | ||||
| -rw-r--r-- | include/linux/i3c/master.h | 7 |
2 files changed, 59 insertions, 13 deletions
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index dcf8d23c5941..1bf9cb138f77 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -345,7 +345,7 @@ const struct bus_type i3c_bus_type = { EXPORT_SYMBOL_GPL(i3c_bus_type); static enum i3c_addr_slot_status -i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr) +i3c_bus_get_addr_slot_status_mask(struct i3c_bus *bus, u16 addr, u32 mask) { unsigned long status; int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS; @@ -356,11 +356,17 @@ i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr) status = bus->addrslots[bitpos / BITS_PER_LONG]; status >>= bitpos % BITS_PER_LONG; - return status & I3C_ADDR_SLOT_STATUS_MASK; + return status & mask; } -static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr, - enum i3c_addr_slot_status status) +static enum i3c_addr_slot_status +i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr) +{ + return i3c_bus_get_addr_slot_status_mask(bus, addr, I3C_ADDR_SLOT_STATUS_MASK); +} + +static void i3c_bus_set_addr_slot_status_mask(struct i3c_bus *bus, u16 addr, + enum i3c_addr_slot_status status, u32 mask) { int bitpos = addr * I3C_ADDR_SLOT_STATUS_BITS; unsigned long *ptr; @@ -369,9 +375,14 @@ static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr, return; ptr = bus->addrslots + (bitpos / BITS_PER_LONG); - *ptr &= ~((unsigned long)I3C_ADDR_SLOT_STATUS_MASK << - (bitpos % BITS_PER_LONG)); - *ptr |= (unsigned long)status << (bitpos % BITS_PER_LONG); + *ptr &= ~((unsigned long)mask << (bitpos % BITS_PER_LONG)); + *ptr |= ((unsigned long)status & mask) << (bitpos % BITS_PER_LONG); +} + +static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr, + enum i3c_addr_slot_status status) +{ + i3c_bus_set_addr_slot_status_mask(bus, addr, status, I3C_ADDR_SLOT_STATUS_MASK); } static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr) @@ -383,13 +394,44 @@ static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr) return status == I3C_ADDR_SLOT_FREE; } +/* + * ┌────┬─────────────┬───┬─────────┬───┐ + * │S/Sr│ 7'h7E RnW=0 │ACK│ ENTDAA │ T ├────┐ + * └────┴─────────────┴───┴─────────┴───┘ │ + * ┌─────────────────────────────────────────┘ + * │ ┌──┬─────────────┬───┬─────────────────┬────────────────┬───┬─────────┐ + * └─►│Sr│7'h7E RnW=1 │ACK│48bit UID BCR DCR│Assign 7bit Addr│PAR│ ACK/NACK│ + * └──┴─────────────┴───┴─────────────────┴────────────────┴───┴─────────┘ + * Some master controllers (such as HCI) need to prepare the entire above transaction before + * sending it out to the I3C bus. This means that a 7-bit dynamic address needs to be allocated + * before knowing the target device's UID information. + * + * However, some I3C targets may request specific addresses (called as "init_dyn_addr"), which is + * typically specified by the DT-'s assigned-address property. Lower addresses having higher IBI + * priority. If it is available, i3c_bus_get_free_addr() preferably return a free address that is + * not in the list of desired addresses (called as "init_dyn_addr"). This allows the device with + * the "init_dyn_addr" to switch to its "init_dyn_addr" when it hot-joins the I3C bus. Otherwise, + * if the "init_dyn_addr" is already in use by another I3C device, the target device will not be + * able to switch to its desired address. + * + * If the previous step fails, fallback returning one of the remaining unassigned address, + * regardless of its state in the desired list. + */ static int i3c_bus_get_free_addr(struct i3c_bus *bus, u8 start_addr) { enum i3c_addr_slot_status status; u8 addr; for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) { - status = i3c_bus_get_addr_slot_status(bus, addr); + status = i3c_bus_get_addr_slot_status_mask(bus, addr, + I3C_ADDR_SLOT_EXT_STATUS_MASK); + if (status == I3C_ADDR_SLOT_FREE) + return addr; + } + + for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) { + status = i3c_bus_get_addr_slot_status_mask(bus, addr, + I3C_ADDR_SLOT_STATUS_MASK); if (status == I3C_ADDR_SLOT_FREE) return addr; } @@ -1918,9 +1960,10 @@ 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_mask(&master->bus, + i3cboardinfo->init_dyn_addr, + I3C_ADDR_SLOT_I3C_DEV | I3C_ADDR_SLOT_EXT_DESIRED, + I3C_ADDR_SLOT_EXT_STATUS_MASK); /* * 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 2100547b2d8d..6e5328c6c6af 100644 --- a/include/linux/i3c/master.h +++ b/include/linux/i3c/master.h @@ -298,7 +298,8 @@ enum i3c_open_drain_speed { * @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_DESIRED: the bitmask represents addresses that are preferred by some devices, + * such as the "assigned-address" property in a device tree source. * 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. * @@ -311,9 +312,11 @@ 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_DESIRED = BIT(2), }; -#define I3C_ADDR_SLOT_STATUS_BITS 2 +#define I3C_ADDR_SLOT_STATUS_BITS 4 /** * struct i3c_bus - I3C bus object |