i3c: master: Avoid sending DISEC command with old device address.

[PATCH] i3c: master: Avoid sending DISEC command with old device address.

Posted by nxf24178 1 year, 5 months ago

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) {
        enable_ibi = true;
        ...
    }
    i3c_dev_free_ibi_locked(olddev);
    ^^^^^^^^
    This function internally calls i3c_dev_disable_ibi_locked(addr)
    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.
    ...
}

Signed-off-by: Ravindra Yashvant Shinde <ravindra.yashvant.shinde@nxp.com>
---
 drivers/i3c/master.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 7028f03c2c42..07ccb2c00074 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2042,6 +2042,7 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
 			if (olddev->ibi->enabled) {
 				enable_ibi = true;
 				i3c_dev_disable_ibi_locked(olddev);
+				olddev->ibi->enabled = false;
 			}
 
 			i3c_dev_free_ibi_locked(olddev);
-- 
2.46.0

Re: [PATCH] i3c: master: Avoid sending DISEC command with old device address.

Posted by Frank Li 1 year, 5 months ago

On Tue, Aug 20, 2024 at 10:08:17AM +0530, nxf24178 wrote:

Avoid use nxp nxf24178 as your name, please update it with your real name.

> 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) {
>         enable_ibi = true;
>         ...
>     }
>     i3c_dev_free_ibi_locked(olddev);
>     ^^^^^^^^
>     This function internally calls i3c_dev_disable_ibi_locked(addr)
>     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.
>     ...
> }
>
> Signed-off-by: Ravindra Yashvant Shinde <ravindra.yashvant.shinde@nxp.com>
> ---
>  drivers/i3c/master.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 7028f03c2c42..07ccb2c00074 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -2042,6 +2042,7 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
>  			if (olddev->ibi->enabled) {
>  				enable_ibi = true;
>  				i3c_dev_disable_ibi_locked(olddev);
> +				olddev->ibi->enabled = false;
>  			}

you can set olddev->ibi->enable = false unconditional. and add comments
about why set it to false here.

Frank

>
>  			i3c_dev_free_ibi_locked(olddev);
> --
> 2.46.0
>