[PATCH 05/17] drm/msm/a6xx: Fix PDC sleep sequence

[Akhil P Oommen <akhilpo@oss.qualcomm.com>]

Since the PDC resides out of the GPU subsystem and cannot be reset in
case it enters bad state, utmost care must be taken to trigger the PDC
wake/sleep routines in the correct order.

The PDC wake sequence can be exercised only after a PDC sleep sequence.
Additionally, GMU firmware should initialize a few registers before the
KMD can trigger a PDC sleep sequence. So PDC sleep can't be done if the
GMU firmware has not initialized. Track these dependencies using a new
status variable and trigger PDC sleep/wake sequences appropriately.

Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 30 +++++++++++++++++++-----------
 drivers/gpu/drm/msm/adreno/a6xx_gmu.h |  6 ++++++
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 3bebb6dd7059782ceca29f2efd2acee24d3fc930..4d6c70735e0892ed87d6a68d64f24bda844e5e16 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -279,6 +279,8 @@ static int a6xx_gmu_start(struct a6xx_gmu *gmu)
 	if (ret)
 		DRM_DEV_ERROR(gmu->dev, "GMU firmware initialization timed out\n");
 
+	set_bit(GMU_STATUS_FW_START, &gmu->status);
+
 	return ret;
 }
 
@@ -528,6 +530,9 @@ static int a6xx_rpmh_start(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (!test_and_clear_bit(GMU_STATUS_PDC_SLEEP, &gmu->status))
+		return 0;
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, BIT(1));
 
 	ret = gmu_poll_timeout(gmu, REG_A6XX_GMU_RSCC_CONTROL_ACK, val,
@@ -555,6 +560,11 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (test_and_clear_bit(GMU_STATUS_FW_START, &gmu->status))
+		return;
+
+	/* TODO: should we skip if IFPC is not enabled */
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 1);
 
 	ret = gmu_poll_timeout_rscc(gmu, REG_A6XX_GPU_RSCC_RSC_STATUS0_DRV0,
@@ -563,6 +573,8 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 		DRM_DEV_ERROR(gmu->dev, "Unable to power off the GPU RSC\n");
 
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 0);
+
+	set_bit(GMU_STATUS_PDC_SLEEP, &gmu->status);
 }
 
 static inline void pdc_write(void __iomem *ptr, u32 offset, u32 value)
@@ -691,8 +703,6 @@ static void a6xx_gmu_rpmh_init(struct a6xx_gmu *gmu)
 	/* ensure no writes happen before the uCode is fully written */
 	wmb();
 
-	a6xx_rpmh_stop(gmu);
-
 err:
 	if (!IS_ERR_OR_NULL(pdcptr))
 		iounmap(pdcptr);
@@ -852,19 +862,15 @@ static int a6xx_gmu_fw_start(struct a6xx_gmu *gmu, unsigned int state)
 	else
 		gmu_write(gmu, REG_A6XX_GMU_GENERAL_7, 1);
 
-	if (state == GMU_WARM_BOOT) {
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-	} else {
+	ret = a6xx_rpmh_start(gmu);
+	if (ret)
+		return ret;
+
+	if (state == GMU_COLD_BOOT) {
 		if (WARN(!adreno_gpu->fw[ADRENO_FW_GMU],
 			"GMU firmware is not loaded\n"))
 			return -ENOENT;
 
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-
 		ret = a6xx_gmu_fw_load(gmu);
 		if (ret)
 			return ret;
@@ -1046,6 +1052,8 @@ static void a6xx_gmu_force_off(struct a6xx_gmu *gmu)
 
 	/* Reset GPU core blocks */
 	a6xx_gpu_sw_reset(gpu, true);
+
+	a6xx_rpmh_stop(gmu);
 }
 
 static void a6xx_gmu_set_initial_freq(struct msm_gpu *gpu, struct a6xx_gmu *gmu)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index b2d4489b40249b1916ab4a42c89e3f4bdc5c4af9..034f1b4e5a3fb9cd601bfbe6d06d64e5ace3b6e7 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -117,6 +117,12 @@ struct a6xx_gmu {
 
 	struct qmp *qmp;
 	struct a6xx_hfi_msg_bw_table *bw_table;
+
+/* To check if we can trigger sleep seq at PDC. Cleared in a6xx_rpmh_stop() */
+#define GMU_STATUS_FW_START	0
+/* To track if PDC sleep seq was done */
+#define GMU_STATUS_PDC_SLEEP	1
+	unsigned long status;
 };
 
 static inline u32 gmu_read(struct a6xx_gmu *gmu, u32 offset)

-- 
2.50.1