Re: [PATCH v3] clk: at91: Add sama5d2 suspend/resume

[Alexandre Belloni]

Hi,

On 11/05/2017 at 09:17:41 +0200, Nicolas Ferre wrote:
> Le 10/05/2017 à 19:09, Alexandre Belloni a écrit :
> > On sama5d2, VDD core maybe be cut while in suspend. This means registers
> > will be lost. Ensure they are saved and restored properly.
> > 
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> 
> Very good, thanks!
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
> 

I've found some issue with this, I'll send v4 soon.

> > ---
> > Changes in v3:
> >  - use regmap_read_poll_timeout to handle the USB PLL
> >  - fix typo
> > 
> > 
> >  drivers/clk/at91/pmc.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 104 insertions(+)
> > 
> > diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> > index 526df5ba042d..7fe1dc8d1829 100644
> > --- a/drivers/clk/at91/pmc.c
> > +++ b/drivers/clk/at91/pmc.c
> > @@ -13,7 +13,9 @@
> >  #include <linux/clk/at91_pmc.h>
> >  #include <linux/of.h>
> >  #include <linux/mfd/syscon.h>
> > +#include <linux/platform_device.h>
> >  #include <linux/regmap.h>
> > +#include <linux/syscore_ops.h>
> >  
> >  #include <asm/proc-fns.h>
> >  
> > @@ -41,3 +43,105 @@ int of_at91_get_clk_range(struct device_node *np, const char *propname,
> >  	return 0;
> >  }
> >  EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
> > +
> > +#ifdef CONFIG_PM
> > +static struct regmap *pmcreg;
> > +
> > +static struct
> > +{
> > +	u32 scsr;
> > +	u32 pcsr0;
> > +	u32 uckr;
> > +	u32 mor;
> > +	u32 mcfr;
> > +	u32 pllar;
> > +	u32 mckr;
> > +	u32 usb;
> > +	u32 imr;
> > +	u32 pcsr1;
> > +	u32 pcr[64];
> > +} pmc_cache;
> > +
> > +static int pmc_suspend(void)
> > +{
> > +	int i;
> > +
> > +	regmap_read(pmcreg, AT91_PMC_IMR, &pmc_cache.scsr);
> > +	regmap_read(pmcreg, AT91_PMC_PCSR, &pmc_cache.pcsr0);
> > +	regmap_read(pmcreg, AT91_CKGR_UCKR, &pmc_cache.uckr);
> > +	regmap_read(pmcreg, AT91_CKGR_MOR, &pmc_cache.mor);
> > +	regmap_read(pmcreg, AT91_CKGR_MCFR, &pmc_cache.mcfr);
> > +	regmap_read(pmcreg, AT91_CKGR_PLLAR, &pmc_cache.pllar);
> > +	regmap_read(pmcreg, AT91_PMC_MCKR, &pmc_cache.mckr);
> > +	regmap_read(pmcreg, AT91_PMC_USB, &pmc_cache.usb);
> > +	regmap_read(pmcreg, AT91_PMC_IMR, &pmc_cache.imr);
> > +	regmap_read(pmcreg, AT91_PMC_PCSR1, &pmc_cache.pcsr1);
> > +
> > +	for (i = 2; i < 64; i++) {
> > +		regmap_write(pmcreg, AT91_PMC_PCR, (i & AT91_PMC_PCR_PID_MASK));
> > +		regmap_read(pmcreg, AT91_PMC_PCR, &pmc_cache.pcr[i]);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void pmc_resume(void)
> > +{
> > +	int i, ret = 0;
> > +	u32 tmp;
> > +
> > +	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
> > +	if (pmc_cache.mckr != tmp)
> > +		pr_warn("MCKR was not configured properly by the firmware\n");
> > +	regmap_read(pmcreg, AT91_CKGR_PLLAR, &tmp);
> > +	if (pmc_cache.pllar != tmp)
> > +		pr_warn("PLLAR was not configured properly by the firmware\n");
> > +
> > +	regmap_write(pmcreg, AT91_PMC_IMR, pmc_cache.scsr);
> > +	regmap_write(pmcreg, AT91_PMC_PCER, pmc_cache.pcsr0);
> > +	regmap_write(pmcreg, AT91_CKGR_UCKR, pmc_cache.uckr);
> > +	regmap_write(pmcreg, AT91_CKGR_MOR, pmc_cache.mor);
> > +	regmap_write(pmcreg, AT91_CKGR_MCFR, pmc_cache.mcfr);
> > +	regmap_write(pmcreg, AT91_PMC_USB, pmc_cache.usb);
> > +	regmap_write(pmcreg, AT91_PMC_IMR, pmc_cache.imr);
> > +	regmap_write(pmcreg, AT91_PMC_PCER1, pmc_cache.pcsr1);
> > +
> > +	for (i = 2; i < 64; i++) {
> > +		regmap_write(pmcreg, AT91_PMC_PCR, (i & AT91_PMC_PCR_PID_MASK));
> > +		regmap_write(pmcreg, AT91_PMC_PCR, pmc_cache.pcr[i]);
> > +	}
> > +
> > +	if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
> > +		ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp, !(tmp & AT91_PMC_LOCKU), 10, 5000);
> > +		if (ret)
> > +			pr_crit("USB PLL didn't lock when resuming\n");
> > +	}
> > +}
> > +
> > +static struct syscore_ops pmc_syscore_ops = {
> > +	.suspend = pmc_suspend,
> > +	.resume = pmc_resume,
> > +};
> > +
> > +static const struct of_device_id sama5d2_pmc_dt_ids[] = {
> > +	{ .compatible = "atmel,sama5d2-pmc" },
> > +	{ /* sentinel */ }
> > +};
> > +
> > +static int __init pmc_register_ops(void)
> > +{
> > +	struct device_node *np;
> > +
> > +	np = of_find_matching_node(NULL, sama5d2_pmc_dt_ids);
> > +
> > +	pmcreg = syscon_node_to_regmap(np);
> > +	if (IS_ERR(pmcreg))
> > +		return PTR_ERR(pmcreg);
> > +
> > +	register_syscore_ops(&pmc_syscore_ops);
> > +
> > +	return 0;
> > +}
> > +/* This has to happen before arch_initcall because of the tcb_clksrc driver */
> > +postcore_initcall(pmc_register_ops);
> > +#endif
> > 
> 
> 
> -- 
> Nicolas Ferre

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