[U-Boot] [PATCH v4 09/11] sun5/7i: add an implementation of the psci suspend function

[Maxime Ripard]

On Tue, May 02, 2017 at 09:04:18AM +0200, Antoine Tenart wrote:
> Hi Maxime,
> 
> On Mon, May 01, 2017 at 11:13:27PM +0200, Maxime Ripard wrote:
> > On Sun, Apr 30, 2017 at 03:29:54PM +0200, Antoine Tenart wrote:
> > > +
> > > +static void __secure sunxi_clock_enter_idle(struct sunxi_ccm_reg *ccm)
> > > +{
> > > +	/* switch cpuclk to osc24m */
> > > +	clrsetbits_le32(&ccm->cpu_ahb_apb0_cfg, 0x3 << CPU_CLK_SRC_SHIFT,
> > > +			CPU_CLK_SRC_OSC24M << CPU_CLK_SRC_SHIFT);
> > > +
> > > +	/* disable pll1 */
> > > +	clrbits_le32(&ccm->pll1_cfg, CCM_PLL1_CTRL_EN);
> > > +
> > > +#ifndef CONFIG_MACH_SUN7I
> > > +	/*
> > > +	 * Switch cpuclk to losc. Based on my experience this didn't worked for
> > > +	 * sun7i, hence the ifndef.
> > > +	 */
> > > +	clrbits_le32(&ccm->cpu_ahb_apb0_cfg, 0x3 << CPU_CLK_SRC_SHIFT);
> > > +#endif
> > 
> > Do we enter idle per-core, or is it a cluster-wide state?
> 
> This is cluster-wise, as sunxi_clock_enter_idle() is only called when
> all CPU are in IDLE state (called the PSCI suspend function). See
> psci_cpu_suspend().

Hmm, ok. That's still a bit weird. The clock documentation says that
you should wait 8 cycles when you reparent, which is something you're
not doing. Maybe that can be the issue.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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