Re: [PATCH v1] clk: Export __clk_lookup()

[elaine.zhang]

å 2020/7/23 äå9:42, elaine.zhang åé:
> å 2020/7/23 äå8:51, Stephen Boyd åé:
> > Quoting Heiko Stuebner (2020-07-22 11:26:50)
> > > Hi Elaine,
> > >
> > > Am Mittwoch, 22. Juli 2020, 04:32:30 CEST schrieb Elaine Zhang:
> > > > Export __clk_lookup() to support user built as module.
> > > >
> > > > ERROR:
> > > > drivers/clk/rockchip/clk.ko: In function
> > > > `rockchip_clk_protect_critical':
> > > > drivers/clk/rockchip/clk.c:741:
> > > > undefined reference to `__clk_lookup'
> > > can you elaborate a bit more on why this would be needed?
> > >
> > > Because right now the Rockchip clocks are of course built into
> > > the main kernel image (especially due to them being needed during early
> > > boot) and __clk_lookup actually is a pretty deep part of the clock-
> > > framework itself, as probably also denoted by the "__" in the function
> > > name.
> > Can you stop using __clk_lookup()? The plan is to remove it.
>
> Rk use __clk_lookup() as:
>
> drivers/clk/rockchip/clk.c
>
> void __init rockchip_clk_protect_critical(const char *const clocks[],
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int nclocks)
> {
> ÂÂÂÂÂÂÂ int i;
>
> ÂÂÂÂÂÂÂ /* Protect the clocks that needs to stay on */
> ÂÂÂÂÂÂÂ for (i = 0; i < nclocks; i++) {
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct clk *clk = __clk_lookup(clocks[i]);
>
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if (clk)
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ clk_prepare_enable(clk);
> ÂÂÂÂÂÂÂ }
> }
> e.g:
>
> drivers/clk/rockchip/clk-rk3328.c
>
> static const char *const rk3328_critical_clocks[] __initconst = {
> ÂÂÂÂÂÂÂ "aclk_bus",
> ÂÂÂÂÂÂÂ "aclk_bus_niu",
> ÂÂÂÂÂÂÂ "pclk_bus",
> ÂÂÂÂÂÂÂ "pclk_bus_niu",
> ÂÂÂÂÂÂÂ "hclk_bus",
> ÂÂÂÂÂÂÂ "hclk_bus_niu",
> ÂÂÂÂÂÂÂ "aclk_peri",
> ............
>
> };
>
> If have plan to remove the __clk_lookup, I need to replace the 
> rockchip_clk_protect_critical, and use the flag CLK_IS_CRITICAL.(but 
> use flag CLK_IS_CRITICAL, the enable count is always "0")
Use the CLK_IS_CRITICAL, there is no guarantee that the parent clk is 
enabled, So the flag CLK_IS_CRITICAL need to be added to all special 
clks according to the clk tree.
> >