drm/nouveau/volt: Add min_id parameter to nvkm_volt_set_id

Each pstate has its own voltage map entry like each cstate has.

The voltages of those entries act as a floor value for the currently
selected pstate and nvidia never sets a voltage below them.
Signed-off-by: Karol Herbst <karolherbst@gmail.com>
Reviewed-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/subdev/volt.h

@@ -29,7 +29,7 @@ struct nvkm_volt {
 
 int nvkm_volt_map_min(struct nvkm_volt *volt, u8 id);
 int nvkm_volt_get(struct nvkm_volt *);
-int nvkm_volt_set_id(struct nvkm_volt *, u8 id, int condition);
+int nvkm_volt_set_id(struct nvkm_volt *, u8 id, u8 min_id, int condition);
 
 int nv40_volt_new(struct nvkm_device *, int, struct nvkm_volt **);
 int gk104_volt_new(struct nvkm_device *, int, struct nvkm_volt **);

drivers/gpu/drm/nouveau/nvkm/subdev/clk/base.c

@@ -99,7 +99,8 @@ nvkm_cstate_prog(struct nvkm_clk *clk, struct nvkm_pstate *pstate, int cstatei)
 	}
 
 	if (volt) {
-		ret = nvkm_volt_set_id(volt, cstate->voltage, +1);
+		ret = nvkm_volt_set_id(volt, cstate->voltage,
+				       pstate->base.voltage, +1);
 		if (ret && ret != -ENODEV) {
 			nvkm_error(subdev, "failed to raise voltage: %d\n", ret);
 			return ret;
@@ -113,7 +114,8 @@ nvkm_cstate_prog(struct nvkm_clk *clk, struct nvkm_pstate *pstate, int cstatei)
 	}
 
 	if (volt) {
-		ret = nvkm_volt_set_id(volt, cstate->voltage, -1);
+		ret = nvkm_volt_set_id(volt, cstate->voltage,
+				       pstate->base.voltage, -1);
 		if (ret && ret != -ENODEV)
 			nvkm_error(subdev, "failed to lower voltage: %d\n", ret);
 	}

drivers/gpu/drm/nouveau/nvkm/subdev/volt/base.c

@@ -110,7 +110,7 @@ nvkm_volt_map(struct nvkm_volt *volt, u8 id)
 }
 
 int
-nvkm_volt_set_id(struct nvkm_volt *volt, u8 id, int condition)
+nvkm_volt_set_id(struct nvkm_volt *volt, u8 id, u8 min_id, int condition)
 {
 	int ret;
 
@@ -123,6 +123,9 @@ nvkm_volt_set_id(struct nvkm_volt *volt, u8 id, int condition)
 		if (!condition || prev < 0 ||
 		    (condition < 0 && ret < prev) ||
 		    (condition > 0 && ret > prev)) {
+			int min = nvkm_volt_map(volt, min_id);
+			if (min >= 0)
+				ret = max(min, ret);
 			ret = nvkm_volt_set(volt, ret);
 		} else {
 			ret = 0;