Re: [PATCH V2 04/12] clk: tegra: add support for peripheral clock suspend and resume

[Sowjanya Komatineni]

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On 5/29/19 4:30 PM, Stephen Boyd wrote:
> Quoting Sowjanya Komatineni (2019-05-28 16:08:48)
> > This patch implements peripheral clock context save and restore
> > to support system suspend and resume operation.
> Again, why?
Will add more in commit in next version of this series.
> > diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c
> > index 6f2862eddad7..08b788766564 100644
> > --- a/drivers/clk/tegra/clk.c
> > +++ b/drivers/clk/tegra/clk.c
> > @@ -81,6 +81,10 @@ static struct clk **clks;
> >   static int clk_num;
> >   static struct clk_onecell_data clk_data;
> >   
> > +#ifdef CONFIG_PM_SLEEP
> > +static u32 *periph_ctx;
> > +#endif
> Please move this into the ifdef below.
WIll fix in V3
> > +
> >   /* Handlers for SoC-specific reset lines */
> >   static int (*special_reset_assert)(unsigned long);
> >   static int (*special_reset_deassert)(unsigned long);
> > @@ -210,6 +214,65 @@ const struct tegra_clk_periph_regs *get_reg_bank(int clkid)
> >          }
> >   }
> >   
> > +#ifdef CONFIG_PM_SLEEP
> > +void tegra_clk_periph_suspend(void __iomem *clk_base)
> > +{
> > +       int i, idx;
> > +
> > +       idx = 0;
> > +       for (i = 0; i < periph_banks; i++, idx++)
> > +               periph_ctx[idx] =
> > +                       readl_relaxed(clk_base + periph_regs[i].rst_reg);
> > +
> > +       for (i = 0; i < periph_banks; i++, idx++)
> > +               periph_ctx[idx] =
> > +                       readl_relaxed(clk_base + periph_regs[i].enb_reg);
> > +}
> > +
> > +void tegra_clk_periph_force_on(u32 *clks_on, int count, void __iomem *clk_base)
> > +{
> > +       int i;
> > +
> > +       WARN_ON(count != periph_banks);
> > +
> > +       for (i = 0; i < count; i++)
> > +               writel_relaxed(clks_on[i], clk_base + periph_regs[i].enb_reg);
> > +}
> > +
> > +void tegra_clk_periph_resume(void __iomem *clk_base)
> > +{
> > +       int i, idx;
> > +
> > +       idx = 0;
> > +       for (i = 0; i < periph_banks; i++, idx++)
> > +               writel_relaxed(periph_ctx[idx],
> > +                              clk_base + periph_regs[i].rst_reg);
> > +
> > +       /* ensure all resets have propagated */
> > +       fence_udelay(2, clk_base);
> > +       tegra_read_chipid();
> > +
> > +       for (i = 0; i < periph_banks; i++, idx++)
> > +               writel_relaxed(periph_ctx[idx],
> > +                              clk_base + periph_regs[i].enb_reg);
> > +
> > +       /* ensure all enables have propagated */
> > +       fence_udelay(2, clk_base);
> > +       tegra_read_chipid();
> > +}
> > +
> > +static int tegra_clk_suspend_ctx_init(int banks)
> > +{
> > +       int err = 0;
> > +
> > +       periph_ctx = kzalloc(2 * banks * sizeof(*periph_ctx), GFP_KERNEL);
> Is this kcalloc(2 * banks, sizeof(*periph_ctx)... ?
Will fix in V3
> > +       if (!periph_ctx)
> > +               err = -ENOMEM;
> > +
> > +       return err;
> > +}
> > +#endif
> > +
> >   struct clk ** __init tegra_clk_init(void __iomem *regs, int num, int banks)
> >   {
> >          clk_base = regs;
> > @@ -226,11 +289,20 @@ struct clk ** __init tegra_clk_init(void __iomem *regs, int num, int banks)
> >          periph_banks = banks;
> >   
> >          clks = kcalloc(num, sizeof(struct clk *), GFP_KERNEL);
> > -       if (!clks)
> > +       if (!clks) {
> >                  kfree(periph_clk_enb_refcnt);
> > +               return NULL;
> > +       }
> >   
> >          clk_num = num;
> >   
> > +#ifdef CONFIG_PM_SLEEP
> Can you use if (IS_ENABLED(CONFIG_PM_SLEEP)) here?
Will fix in V3
> > +       if (tegra_clk_suspend_ctx_init(banks)) {
> > +               kfree(periph_clk_enb_refcnt);
> > +               kfree(clks);
> > +               return NULL;
> > +       }
> > +#endif
> >          return clks;
> >   }
> >