OMAP: Introduce dependent voltage domain support

There could be dependencies between various voltage domains for
maintaining system performance or hardware limitation reasons
like VDD<X> should be at voltage v1 when VDD<Y> is at voltage v2.
This patch introduce dependent vdd information structures in the
voltage layer which can be used to populate these dependencies
for a voltage domain. This patch also adds support to scale
the dependent vdd and the scalable devices belonging to it
during the scaling of a main vdd through omap_voltage_scale.

As part of this, some of the voltage layer structure definitions are moved from
voltage.c to voltage.h as it needs to be used in the dvfs layer for dependency
voltage handling.

Based on original patch from Thara.

Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Cc: Thara Gopinath <thara@ti.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/dvfs.c b/arch/arm/mach-omap2/dvfs.c
index cefc2be3681..c9d3894df69 100644
--- a/arch/arm/mach-omap2/dvfs.c
+++ b/arch/arm/mach-omap2/dvfs.c
@@ -85,6 +85,7 @@ struct omap_vdd_dvfs_info {
 	struct mutex scaling_mutex; /* dvfs mutex */
 	struct voltagedomain *voltdm;
 	struct list_head dev_list;
+	struct device vdd_device;
 };
 
 static struct omap_vdd_dvfs_info *omap_dvfs_info_list;
@@ -98,6 +99,7 @@ static struct voltagedomain omap3_vdd[] = {
 	.name = "core",
 	},
 };
+static int omap_dvfs_voltage_scale(struct omap_vdd_dvfs_info *dvfs_info);
 
 static int __init omap_dvfs_init(void);
 
@@ -412,6 +414,79 @@ static int omap_dvfs_remove_freq_request(struct omap_vdd_dvfs_info *dvfs_info,
 	return ret;
 }
 
+/* Calculate dependency vdd voltage for given vdd voltage */
+static int calc_dep_vdd_volt(struct device *dev,
+		struct omap_vdd_info *main_vdd, unsigned long main_volt)
+{
+	struct omap_vdd_dep_info *dep_vdds;
+	int i, ret = 0;
+
+	if (!main_vdd->dep_vdd_info) {
+		pr_debug("%s: No dependent VDD's for vdd_%s\n",
+			__func__, main_vdd->voltdm.name);
+		return 0;
+	}
+
+	dep_vdds = main_vdd->dep_vdd_info;
+
+	for (i = 0; i < main_vdd->nr_dep_vdd; i++) {
+		struct omap_vdd_dep_volt *volt_table = dep_vdds[i].dep_table;
+		int nr_volt = 0;
+		unsigned long dep_volt = 0, act_volt = 0;
+
+		while (volt_table[nr_volt].main_vdd_volt != 0) {
+			if (volt_table[nr_volt].main_vdd_volt == main_volt) {
+				dep_volt = volt_table[nr_volt].dep_vdd_volt;
+				break;
+			}
+			nr_volt++;
+		}
+		if (!dep_volt) {
+			pr_warning("%s: Not able to find a matching volt for"
+				"vdd_%s corresponding to vdd_%s %ld volt\n",
+				__func__, dep_vdds[i].name,
+				main_vdd->voltdm.name, main_volt);
+			ret = -EINVAL;
+			continue;
+		}
+
+		if (!dep_vdds[i].voltdm)
+			dep_vdds[i].voltdm =
+				omap_voltage_domain_lookup(dep_vdds[i].name);
+
+		act_volt = dep_volt;
+
+		/* See if dep_volt is possible for the vdd*/
+		ret = omap_dvfs_add_vdd_user(get_dvfs_info(dep_vdds[i].voltdm),
+				dev, act_volt);
+	}
+
+	return ret;
+}
+
+/* Scale dependent VDD */
+static int scale_dep_vdd(struct omap_vdd_dvfs_info *vdd_info)
+{
+	struct omap_vdd_dep_info *dep_vdds;
+	int i;
+	struct omap_vdd_info *main_vdd;
+	struct voltagedomain *voltdm = vdd_info->voltdm;
+	main_vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	if (!main_vdd->dep_vdd_info) {
+		pr_debug("%s: No dependent VDD's for vdd_%s\n",
+			__func__, main_vdd->voltdm.name);
+		return 0;
+	}
+
+	dep_vdds = main_vdd->dep_vdd_info;
+
+	for (i = 0; i < main_vdd->nr_dep_vdd; i++)
+		omap_dvfs_voltage_scale(get_dvfs_info(dep_vdds[i].voltdm));
+
+	return 0;
+}
+
 /**
  * omap_dvfs_voltage_scale() : API to scale the devices associated with a
  *						voltage domain vdd voltage.
@@ -435,6 +510,7 @@ static int omap_dvfs_voltage_scale(struct omap_vdd_dvfs_info *dvfs_info)
 	int ret = 0;
 	struct voltagedomain *voltdm;
 	unsigned long volt;
+	struct omap_vdd_info *vdd;
 
 	if (!dvfs_info || IS_ERR(dvfs_info)) {
 		pr_warning("%s: VDD specified does not exist!\n", __func__);
@@ -442,6 +518,7 @@ static int omap_dvfs_voltage_scale(struct omap_vdd_dvfs_info *dvfs_info)
 	}
 
 	voltdm = dvfs_info->voltdm;
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
 
 	mutex_lock(&dvfs_info->scaling_mutex);
 
@@ -494,6 +571,16 @@ static int omap_dvfs_voltage_scale(struct omap_vdd_dvfs_info *dvfs_info)
 
 	mutex_unlock(&dvfs_info->scaling_mutex);
 
+	/* calculate the voltages for dependent vdd's */
+	if (calc_dep_vdd_volt(&dvfs_info->vdd_device, vdd, volt)) {
+		pr_warning("%s: Error in calculating dependent vdd voltages"
+			"for vdd_%s\n", __func__, voltdm->name);
+		return -EINVAL;
+	}
+
+	/* Scale dependent vdds */
+	scale_dep_vdd(dvfs_info);
+
 	return 0;
 }