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 <akhi...@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

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