[v2] clk: at91: Add sama5d2 suspend/resume
diff mbox

Message ID 20170426112148.25256-1-alexandre.belloni@free-electrons.com
State Superseded
Headers show

Commit Message

Alexandre Belloni April 26, 2017, 11:21 a.m. UTC
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@free-electrons.com>
---

Changes in v2:
 - don't set MCKR or PLLAR and expect them to be properly set by the
   firmware/bootloader.

 drivers/clk/at91/pmc.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

Comments

Nicolas Ferre April 27, 2017, 10:13 a.m. UTC | #1
Le 26/04/2017 à 13:21, 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@free-electrons.com>
> ---
> 
> Changes in v2:
>  - don't set MCKR or PLLAR and expect them to be properly set by the
>    firmware/bootloader.
> 
>  drivers/clk/at91/pmc.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 114 insertions(+)
> 
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 526df5ba042d..338cd293b356 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 +43,115 @@ 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 bool pmc_ready(unsigned int mask)
> +{
> +	unsigned int status;
> +
> +	regmap_read(pmcreg, AT91_PMC_SR, &status);
> +
> +	return ((status & mask) == mask) ? 1 : 0;
> +}
> +
> +static void pmc_resume(void)
> +{
> +	int i;
> +	unsigned int mask = 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)
> +		mask |= AT91_PMC_LOCKU;

I understand the use of mask to be generic... but this one ^ is now the
only one used: we can simplify (and even remove the use of a function).

> +
> +	while (!pmc_ready(mask))
> +		cpu_relax();

I would prefer to have a timeout + printk(KERN_CRIT ...) here

> +}
> +
> +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 becaues of the tcb_clksrc driver */

NIT: typo ^ (because)

> +postcore_initcall(pmc_register_ops);
> +#endif
>

Patch
diff mbox

diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 526df5ba042d..338cd293b356 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 +43,115 @@  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 bool pmc_ready(unsigned int mask)
+{
+	unsigned int status;
+
+	regmap_read(pmcreg, AT91_PMC_SR, &status);
+
+	return ((status & mask) == mask) ? 1 : 0;
+}
+
+static void pmc_resume(void)
+{
+	int i;
+	unsigned int mask = 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)
+		mask |= AT91_PMC_LOCKU;
+
+	while (!pmc_ready(mask))
+		cpu_relax();
+}
+
+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 becaues of the tcb_clksrc driver */
+postcore_initcall(pmc_register_ops);
+#endif