[Nouveau] [RFC PATCH 06/29] clk: Make pstate a pointer to nvkm_pstate

[Karol Herbst]

We will access the current cstate at least every second and this saves us
some CPU cycles looking them up every second.

v2: Rewording commit message.

Signed-off-by: Karol Herbst <karolherbst at gmail.com>
Reviewed-by: Martin Peres <martin.peres at free.fr>
---
 drm/nouveau/include/nvkm/subdev/clk.h |  4 +++-
 drm/nouveau/nvkm/engine/device/ctrl.c |  5 ++++-
 drm/nouveau/nvkm/subdev/clk/base.c    | 17 ++++++++++++-----
 drm/nouveau/nvkm/subdev/pmu/gk20a.c   | 18 +++++++-----------
 4 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/drm/nouveau/include/nvkm/subdev/clk.h b/drm/nouveau/include/nvkm/subdev/clk.h
index 1340f5b8..ec537e08 100644
--- a/drm/nouveau/include/nvkm/subdev/clk.h
+++ b/drm/nouveau/include/nvkm/subdev/clk.h
@@ -10,6 +10,8 @@ struct nvkm_pll_vals;
 #define NVKM_CLK_CSTATE_BASE    -2 /* pstate base */
 #define NVKM_CLK_CSTATE_HIGHEST -3 /* highest possible */
 
+#define NVKM_CLK_PSTATE_DEFAULT -1
+
 enum nv_clk_src {
 	nv_clk_src_crystal,
 	nv_clk_src_href,
@@ -95,7 +97,7 @@ struct nvkm_clk {
 
 	struct nvkm_notify pwrsrc_ntfy;
 	int pwrsrc;
-	int pstate; /* current */
+	struct nvkm_pstate *pstate; /* current */
 	int ustate_ac; /* user-requested (-1 disabled, -2 perfmon) */
 	int ustate_dc; /* user-requested (-1 disabled, -2 perfmon) */
 	int astate; /* perfmon adjustment (base) */
diff --git a/drm/nouveau/nvkm/engine/device/ctrl.c b/drm/nouveau/nvkm/engine/device/ctrl.c
index b0ece71a..da70626c 100644
--- a/drm/nouveau/nvkm/engine/device/ctrl.c
+++ b/drm/nouveau/nvkm/engine/device/ctrl.c
@@ -52,7 +52,10 @@ nvkm_control_mthd_pstate_info(struct nvkm_control *ctrl, void *data, u32 size)
 		args->v0.ustate_ac = clk->ustate_ac;
 		args->v0.ustate_dc = clk->ustate_dc;
 		args->v0.pwrsrc = clk->pwrsrc;
-		args->v0.pstate = clk->pstate;
+		if (clk->pstate)
+			args->v0.pstate = clk->pstate->pstate;
+		else
+			args->v0.pstate = NVKM_CLK_PSTATE_DEFAULT;
 	} else {
 		args->v0.count = 0;
 		args->v0.ustate_ac = NVIF_CONTROL_PSTATE_INFO_V0_USTATE_DISABLE;
diff --git a/drm/nouveau/nvkm/subdev/clk/base.c b/drm/nouveau/nvkm/subdev/clk/base.c
index 07d530ed..0d4d9fdf 100644
--- a/drm/nouveau/nvkm/subdev/clk/base.c
+++ b/drm/nouveau/nvkm/subdev/clk/base.c
@@ -271,13 +271,16 @@ nvkm_pstate_prog(struct nvkm_clk *clk, int pstatei)
 	struct nvkm_pstate *pstate;
 	int ret, idx = 0;
 
+	if (pstatei == NVKM_CLK_PSTATE_DEFAULT)
+		return 0;
+
 	list_for_each_entry(pstate, &clk->states, head) {
 		if (idx++ == pstatei)
 			break;
 	}
 
 	nvkm_debug(subdev, "setting performance state %d\n", pstatei);
-	clk->pstate = pstatei;
+	clk->pstate = pstate;
 
 	nvkm_pcie_set_link(pci, pstate->pcie_speed, pstate->pcie_width);
 
@@ -306,8 +309,12 @@ nvkm_clk_update_work(struct work_struct *work)
 		return;
 	clk->pwrsrc = power_supply_is_system_supplied();
 
+	if (clk->pstate)
+		pstate = clk->pstate->pstate;
+	else
+		pstate = NVKM_CLK_PSTATE_DEFAULT;
 	nvkm_trace(subdev, "P %d PWR %d U(AC) %d U(DC) %d A %d T %d°C\n",
-		   clk->pstate, clk->pwrsrc, clk->ustate_ac, clk->ustate_dc,
+		   pstate, clk->pwrsrc, clk->ustate_ac, clk->ustate_dc,
 		   clk->astate, clk->temp);
 
 	pstate = clk->pwrsrc ? clk->ustate_ac : clk->ustate_dc;
@@ -315,11 +322,11 @@ nvkm_clk_update_work(struct work_struct *work)
 		pstate = (pstate < 0) ? clk->astate : pstate;
 		pstate = min(pstate, clk->state_nr - 1);
 	} else {
-		pstate = clk->pstate = -1;
+		pstate = NVKM_CLK_PSTATE_DEFAULT;
 	}
 
 	nvkm_trace(subdev, "-> %d\n", pstate);
-	if (pstate != clk->pstate) {
+	if (!clk->pstate || pstate != clk->pstate->pstate) {
 		int ret = nvkm_pstate_prog(clk, pstate);
 		if (ret) {
 			nvkm_error(subdev, "error setting pstate %d: %d\n",
@@ -610,7 +617,7 @@ nvkm_clk_init(struct nvkm_subdev *subdev)
 		return clk->func->init(clk);
 
 	clk->astate = clk->state_nr - 1;
-	clk->pstate = -1;
+	clk->pstate = NULL;
 	clk->temp = 90; /* reasonable default value */
 	nvkm_clk_update(clk, true);
 	return 0;
diff --git a/drm/nouveau/nvkm/subdev/pmu/gk20a.c b/drm/nouveau/nvkm/subdev/pmu/gk20a.c
index 05e81855..de579726 100644
--- a/drm/nouveau/nvkm/subdev/pmu/gk20a.c
+++ b/drm/nouveau/nvkm/subdev/pmu/gk20a.c
@@ -55,24 +55,22 @@ gk20a_pmu_dvfs_target(struct gk20a_pmu *pmu, int *state)
 	return nvkm_clk_astate(clk, *state, 0, false);
 }
 
-static void
-gk20a_pmu_dvfs_get_cur_state(struct gk20a_pmu *pmu, int *state)
-{
-	struct nvkm_clk *clk = pmu->base.subdev.device->clk;
-
-	*state = clk->pstate;
-}
-
 static int
 gk20a_pmu_dvfs_get_target_state(struct gk20a_pmu *pmu,
 				int *state, int load)
 {
 	struct gk20a_pmu_dvfs_data *data = pmu->data;
 	struct nvkm_clk *clk = pmu->base.subdev.device->clk;
+	struct nvkm_pstate *pstate = clk->pstate;
 	int cur_level, level;
 
+	if (!pstate) {
+		*state = 0;
+		return 1;
+	}
+
 	/* For GK20A, the performance level is directly mapped to pstate */
-	level = cur_level = clk->pstate;
+	level = cur_level = clk->pstate->pstate;
 
 	if (load > data->p_load_max) {
 		level = min(clk->state_nr - 1, level + (clk->state_nr / 3));
@@ -142,8 +140,6 @@ gk20a_pmu_dvfs_work(struct nvkm_alarm *alarm)
 	nvkm_trace(subdev, "utilization = %d %%, avg_load = %d %%\n",
 		   utilization, data->avg_load);
 
-	gk20a_pmu_dvfs_get_cur_state(pmu, &state);
-
 	if (gk20a_pmu_dvfs_get_target_state(pmu, &state, data->avg_load)) {
 		nvkm_trace(subdev, "set new state to %d\n", state);
 		gk20a_pmu_dvfs_target(pmu, &state);
-- 
2.14.1