Thread (3 messages) 3 messages, 3 authors, 2025-06-20

Re: [PATCH v3] clk: scmi: Handle case where child clocks are initialized before their parents

From: Sudeep Holla <hidden>
Date: 2025-06-13 13:43:40
Also in: arm-scmi, linux-clk, lkml

On Thu, Jun 12, 2025 at 02:56:57PM +0200, Sascha Hauer wrote:
The SCMI clock driver currently assumes that parent clocks are always
initialized before their children. However, this assumption can fail if
a child clock is encountered before its parent during probe.

This leads to an issue during initialization of the parent_data array:

    sclk->parent_data[i].hw = hws[sclk->info->parents[i]];

If the parent clock's hardware structure has not been initialized yet,
this assignment results in invalid data.

To resolve this, allocate all struct scmi_clk instances as a contiguous
array at the beginning of the probe and populate the hws[] array
upfront. This ensures that any parent referenced later is already
initialized, regardless of the order in which clocks are processed.

Note that we can no longer free individual scmi_clk instances if
scmi_clk_ops_init() fails which shouldn't be a problem if the SCMI
platform has proper per-agent clock discovery.

Fixes: 65a8a3dd3b95f ("clk: scmi: Add support for clock {set,get}_parent")
Reviewed-by: peng.fan@nxp.com
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Reviewed-by: Sudeep Holla <redacted>
Mike/Stephen,

Please pick this up in your next round of fixes.

-- 
Regards,
Sudeep
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