Commit 3c6684a1 authored by Frank Li's avatar Frank Li Committed by Alexandre Belloni
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i3c: master: svc: use repeat start when IBI WIN happens



There is a possibility of an IBI WIN occurring when addressing issues, even
when sending CCC commands. Most of the time, returning -EAGAIN is
acceptable, but the case below becomes highly complex.

When a Hotjoin event occurs:
- i3c_master_do_daa()
  - i3c_master_add_i3c_dev_locked()
    - A dynamic address (e.g., 0x9) is already set during DAA.
    - i3c_master_getpid_locked()
      - Another device issues HJ or IBI here. Returning -EAGAIN causes
        failure in adding the new device. However, the dynamic address(0x9)
        has already been assigned to this device. If another device issues
        HJ, it will get this address 0x9 again, causing two devices on the
        bus to use the same dynamic address 0x9.
      - Attempting to send RSTDAA when the first device fails at
        i3c_master_getpid_locked() could also fail when sending RSTDAA for
        the same reason.

According to the I3C spec, address arbitration only happens at START, never
at REPEAT start. Using repeat start when an IBI WIN occurs simplifies this
case, as i3c_master_getpid_locked() will not return an error when another
device tries to send HJ or IBI.

Acked-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20241002-svc-i3c-hj-v6-1-7e6e1d3569ae@nxp.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 851bd21c
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