[PATCH v5 1/1] i3c: master: Remove i3c_dev_disable_ibi_locked(olddev) on device hotjoin

* [PATCH v5 1/1] i3c: master: Remove i3c_dev_disable_ibi_locked(olddev) on device hotjoin
@ 2024-10-01 16:22 Frank Li
  2024-10-31 23:00 ` Alexandre Belloni
  0 siblings, 1 reply; 2+ messages in thread
From: Frank Li @ 2024-10-01 16:22 UTC (permalink / raw)
  To: miquel.raynal
  Cc: Frank.li, alexandre.belloni, arnd, bbrezillon, boris.brezillon,
	conor.culhane, gregkh, imx, linux-i3c, linux-kernel, pthombar,
	ravindra.yashvant.shinde, stable

When a new device hotjoins, a new dynamic address is assigned.
i3c_master_add_i3c_dev_locked() identifies that the device was previously
attached to the bus and locates the olddev.

i3c_master_add_i3c_dev_locked()
{
    ...
    olddev = i3c_master_search_i3c_dev_duplicate(newdev);
    ...
    if (olddev) {
        ...
        i3c_dev_disable_ibi_locked(olddev);
        ^^^^^^
        The olddev should not receive any commands on the i3c bus as it
        does not exist and has been assigned a new address. This will
        result in NACK or timeout. So remove it.
    }

    i3c_dev_free_ibi_locked(olddev);
    ^^^^^^^^
    This function internally calls i3c_dev_disable_ibi_locked() function
    causing to send DISEC command with old Address.

    The olddev should not receive any commands on the i3c bus as it
    does not exist and has been assigned a new address. This will
    result in NACK or timeout. So, update the olddev->ibi->enabled
    flag to false to avoid DISEC with OldAddr.
}

Include part of Ravindra Yashvant Shinde's work:
https://lore.kernel.org/linux-i3c/20240820151917.3904956-1-ravindra.yashvant.shinde@nxp.com/T/#u

Fixes: 317bacf960a4 ("i3c: master: add enable(disable) hot join in sys entry")
Co-developed-by: Ravindra Yashvant Shinde <ravindra.yashvant.shinde@nxp.com>
Signed-off-by: Ravindra Yashvant Shinde <ravindra.yashvant.shinde@nxp.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v4 to v5
- none
- just split from big series because need more discussion about dt assign
address.
https://lore.kernel.org/linux-i3c/ZvrAuOBLgi+HtrPD@lizhi-Precision-Tower-5810/T/#t

change from v3 to v4
- merge https://lore.kernel.org/linux-i3c/20240820151917.3904956-1-ravindra.yashvant.shinde@nxp.com/T/#u
- add Miquel Raynal review tag
- add Ravindra Yashvant Shinde 's signed-off
---
 drivers/i3c/master.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 7028f03c2c42e..82f031928e413 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2039,11 +2039,16 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 			ibireq.max_payload_len = olddev->ibi->max_payload_len;
 			ibireq.num_slots = olddev->ibi->num_slots;
 
-			if (olddev->ibi->enabled) {
+			if (olddev->ibi->enabled)
 				enable_ibi = true;
-				i3c_dev_disable_ibi_locked(olddev);
-			}
-
+			/*
+			 * The olddev should not receive any commands on the
+			 * i3c bus as it does not exist and has been assigned
+			 * a new address. This will result in NACK or timeout.
+			 * So, update the olddev->ibi->enabled flag to false
+			 * to avoid DISEC with OldAddr.
+			 */
+			olddev->ibi->enabled = false;
 			i3c_dev_free_ibi_locked(olddev);
 		}
 		mutex_unlock(&olddev->ibi_lock);
-- 
2.34.1


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