On 05/15/2013 12:24 PM, Ulf Hansson wrote:
On 1 May 2013 06:42, Saravana Kannan <skannan@xxxxxxxxxxxxxx> wrote:
<snip>
- /* migrate prepare */
- if (clk->prepare_count)
+ /*
+ * Migrate prepare state between parents and prevent race with
+ * clk_enable().
+ *
+ * If the clock is not prepared, then a race with
+ * clk_enable/disable() is impossible since we already have the
+ * prepare lock (future calls to clk_enable() need to be preceded by
+ * a clk_prepare()).
+ *
+ * If the clock is prepared, migrate the prepared state to the new
+ * parent and also protect against a race with clk_enable() by
+ * forcing the clock and the new parent on. This ensures that all
+ * future calls to clk_enable() are practically NOPs with respect to
+ * hardware and software states.
+ */
Maybe an additional note about that since CLK_SET_PARENT_GATE is a
prerequisite for doing migration of "prepare", we also interpreted
this flags as it is acceptable to enable the clock(s) in this context.
Done. Sent v2 patch.
<snip>
Looks good! Thanks for having another round to fixup this kind of
tricky code. :-)
Thanks :-)
Acked-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Thanks again.
-Saravana
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