ARM: OMAP2+: Add functions to save and restore powerdomain context

The powerdomain control registers are stored in the WKUP powerdomain on
AM33XX/AM43XX, which is lost on RTC-only suspend and also hibernate. This
adds context save and restore functions for those registers.
Sometimes the powerdomain state does not need to change,
perhaps we only need to change memory retention states, so make
sure the restored state is different from the current state before we wait
for a transition.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/prm44xx.c b/arch/arm/mach-omap2/prm44xx.c
index acb95936dfe7..47b657ceba8f 100644
--- a/arch/arm/mach-omap2/prm44xx.c
+++ b/arch/arm/mach-omap2/prm44xx.c
@@ -667,6 +667,54 @@ static int omap4_check_vcvp(void)
 	return 0;
 }
 
+/**
+ * omap4_pwrdm_save_context - Saves the powerdomain state
+ * @pwrdm: pointer to individual powerdomain
+ *
+ * The function saves the powerdomain state control information.
+ * This is needed in rtc+ddr modes where we lose powerdomain context.
+ */
+static void omap4_pwrdm_save_context(struct powerdomain *pwrdm)
+{
+	pwrdm->context = omap4_prminst_read_inst_reg(pwrdm->prcm_partition,
+						     pwrdm->prcm_offs,
+						     pwrdm->pwrstctrl_offs);
+
+	/*
+	 * Do not save LOWPOWERSTATECHANGE, writing a 1 indicates a request,
+	 * reading back a 1 indicates a request in progress.
+	 */
+	pwrdm->context &= ~OMAP4430_LOWPOWERSTATECHANGE_MASK;
+}
+
+/**
+ * omap4_pwrdm_restore_context - Restores the powerdomain state
+ * @pwrdm: pointer to individual powerdomain
+ *
+ * The function restores the powerdomain state control information.
+ * This is needed in rtc+ddr modes where we lose powerdomain context.
+ */
+static void omap4_pwrdm_restore_context(struct powerdomain *pwrdm)
+{
+	int st, ctrl;
+
+	st = omap4_prminst_read_inst_reg(pwrdm->prcm_partition,
+					 pwrdm->prcm_offs,
+					 pwrdm->pwrstctrl_offs);
+
+	omap4_prminst_write_inst_reg(pwrdm->context,
+				     pwrdm->prcm_partition,
+				     pwrdm->prcm_offs,
+				     pwrdm->pwrstctrl_offs);
+
+	/* Make sure we only wait for a transition if there is one */
+	st &= OMAP_POWERSTATEST_MASK;
+	ctrl = OMAP_POWERSTATEST_MASK & pwrdm->context;
+
+	if (st != ctrl)
+		omap4_pwrdm_wait_transition(pwrdm);
+}
+
 struct pwrdm_ops omap4_pwrdm_operations = {
 	.pwrdm_set_next_pwrst	= omap4_pwrdm_set_next_pwrst,
 	.pwrdm_read_next_pwrst	= omap4_pwrdm_read_next_pwrst,
@@ -685,6 +733,8 @@ struct pwrdm_ops omap4_pwrdm_operations = {
 	.pwrdm_set_mem_retst	= omap4_pwrdm_set_mem_retst,
 	.pwrdm_wait_transition	= omap4_pwrdm_wait_transition,
 	.pwrdm_has_voltdm	= omap4_check_vcvp,
+	.pwrdm_save_context	= omap4_pwrdm_save_context,
+	.pwrdm_restore_context	= omap4_pwrdm_restore_context,
 };
 
 static int omap44xx_prm_late_init(void);