The GPU has an idle state register where each bit represents the idle
state of a sub-GPU component like FE or TX. Sample this register
every 10ms and calculate a simple moving average over the sub-GPU
component idle states with a total observation time frame of 1s.

This provides us with a percentage based load of each sub-GPU
component.

Signed-off-by: Christian Gmeiner <christian.gmei...@gmail.com>
---
 drivers/gpu/drm/etnaviv/etnaviv_drv.c | 14 ++++++++++++
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 32 +++++++++++++++++++++++++++
 drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 29 ++++++++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c 
b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index f9afe11c50f0..b31920241c86 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -46,6 +46,19 @@ static void load_gpu(struct drm_device *dev)
        }
 }
 
+static void unload_gpu(struct drm_device *dev)
+{
+       struct etnaviv_drm_private *priv = dev->dev_private;
+       unsigned int i;
+
+       for (i = 0; i < ETNA_MAX_PIPES; i++) {
+               struct etnaviv_gpu *g = priv->gpu[i];
+
+               if (g)
+                       etnaviv_gpu_shutdown(g);
+       }
+}
+
 static int etnaviv_open(struct drm_device *dev, struct drm_file *file)
 {
        struct etnaviv_drm_private *priv = dev->dev_private;
@@ -581,6 +594,7 @@ static void etnaviv_unbind(struct device *dev)
        struct drm_device *drm = dev_get_drvdata(dev);
        struct etnaviv_drm_private *priv = drm->dev_private;
 
+       unload_gpu(drm);
        drm_dev_unregister(drm);
 
        component_unbind_all(dev, drm);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c 
b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index a31eeff2b297..1f0eb7e00657 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -714,6 +714,28 @@ static void etnaviv_gpu_hw_init(struct etnaviv_gpu *gpu)
        gpu_write(gpu, VIVS_HI_INTR_ENBL, ~0U);
 }
 
+static void etnaviv_loadavg_function(struct timer_list *t)
+{
+       struct etnaviv_gpu *gpu = from_timer(gpu, t, loadavg_timer);
+       const u32 idle = gpu_read(gpu, VIVS_HI_IDLE_STATE);
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(etna_idle_module_names); i++)
+               if ((idle & etna_idle_module_names[i].bit))
+                       sma_loadavg_add(&gpu->loadavg_value[i], 0);
+               else
+                       sma_loadavg_add(&gpu->loadavg_value[i], 100);
+
+       spin_lock_bh(&gpu->loadavg_spinlock);
+
+       for (i = 0; i < ARRAY_SIZE(etna_idle_module_names); i++)
+               gpu->loadavg_percentage[i] = 
sma_loadavg_read(&gpu->loadavg_value[i]);
+
+       spin_unlock_bh(&gpu->loadavg_spinlock);
+
+       mod_timer(t, jiffies + msecs_to_jiffies(10));
+}
+
 int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
 {
        struct etnaviv_drm_private *priv = gpu->drm->dev_private;
@@ -804,6 +826,10 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
        for (i = 0; i < ARRAY_SIZE(gpu->event); i++)
                complete(&gpu->event_free);
 
+       /* Setup loadavg timer */
+       timer_setup(&gpu->loadavg_timer, etnaviv_loadavg_function, 0);
+       mod_timer(&gpu->loadavg_timer, jiffies + msecs_to_jiffies(10));
+
        /* Now program the hardware */
        mutex_lock(&gpu->lock);
        etnaviv_gpu_hw_init(gpu);
@@ -824,6 +850,11 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
        return ret;
 }
 
+void etnaviv_gpu_shutdown(struct etnaviv_gpu *gpu)
+{
+       del_timer(&gpu->loadavg_timer);
+}
+
 #ifdef CONFIG_DEBUG_FS
 struct dma_debug {
        u32 address[2];
@@ -1762,6 +1793,7 @@ static int etnaviv_gpu_platform_probe(struct 
platform_device *pdev)
        gpu->dev = &pdev->dev;
        mutex_init(&gpu->lock);
        mutex_init(&gpu->fence_lock);
+       spin_lock_init(&gpu->loadavg_spinlock);
 
        /* Map registers: */
        gpu->mmio = devm_platform_ioremap_resource(pdev, 0);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h 
b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index 8ea48697d132..a5b9c89c6744 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -10,6 +10,8 @@
 #include "etnaviv_gem.h"
 #include "etnaviv_mmu.h"
 #include "etnaviv_drv.h"
+#include "etnaviv_sma.h"
+#include "state_hi.xml.h"
 
 struct etnaviv_gem_submit;
 struct etnaviv_vram_mapping;
@@ -91,6 +93,26 @@ struct clk;
 
 #define ETNA_NR_EVENTS 30
 
+DECLARE_SMA(loadavg, 100)
+
+static const struct {
+    const char *name;
+    u32 bit;
+} etna_idle_module_names[] = {
+    { "FE", VIVS_HI_IDLE_STATE_FE },
+    { "DE", VIVS_HI_IDLE_STATE_DE },
+    { "PE", VIVS_HI_IDLE_STATE_PE },
+    { "SH", VIVS_HI_IDLE_STATE_SH },
+    { "PA", VIVS_HI_IDLE_STATE_PA },
+    { "SE", VIVS_HI_IDLE_STATE_SE },
+    { "RA", VIVS_HI_IDLE_STATE_RA },
+    { "TX", VIVS_HI_IDLE_STATE_TX },
+    { "VG", VIVS_HI_IDLE_STATE_VG },
+    { "IM", VIVS_HI_IDLE_STATE_IM },
+    { "FP", VIVS_HI_IDLE_STATE_FP },
+    { "TS", VIVS_HI_IDLE_STATE_TS },
+};
+
 struct etnaviv_gpu {
        struct drm_device *drm;
        struct thermal_cooling_device *cooling;
@@ -145,6 +167,12 @@ struct etnaviv_gpu {
        unsigned int freq_scale;
        unsigned long base_rate_core;
        unsigned long base_rate_shader;
+
+       /* Loadavg: */
+       struct timer_list loadavg_timer;
+       spinlock_t loadavg_spinlock;
+       struct sma_loadavg loadavg_value[ARRAY_SIZE(etna_idle_module_names)];
+       unsigned int loadavg_percentage[ARRAY_SIZE(etna_idle_module_names)];
 };
 
 static inline void gpu_write(struct etnaviv_gpu *gpu, u32 reg, u32 data)
@@ -160,6 +188,7 @@ static inline u32 gpu_read(struct etnaviv_gpu *gpu, u32 reg)
 int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32 param, u64 *value);
 
 int etnaviv_gpu_init(struct etnaviv_gpu *gpu);
+void etnaviv_gpu_shutdown(struct etnaviv_gpu *gpu);
 bool etnaviv_fill_identity_from_hwdb(struct etnaviv_gpu *gpu);
 
 #ifdef CONFIG_DEBUG_FS
-- 
2.26.2

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