[PATCH v3 4/4] drm/v3d: Introduce Runtime Power Management
Maíra Canal
mcanal at igalia.com
Fri Jan 16 12:19:25 PST 2026
Commit 90a64adb0876 ("drm/v3d: Get rid of pm code") removed the last
bits of power management code that V3D had, which were actually never
hooked. Therefore, currently, the GPU clock is enabled during probe
and only disabled when removing the driver.
Implement proper power management using the kernel's Runtime PM
framework.
Signed-off-by: Maíra Canal <mcanal at igalia.com>
---
drivers/gpu/drm/v3d/Makefile | 3 +-
drivers/gpu/drm/v3d/v3d_debugfs.c | 23 +++++++++-
drivers/gpu/drm/v3d/v3d_drv.c | 86 +++++++++++++++++------------------
drivers/gpu/drm/v3d/v3d_drv.h | 20 ++++++++
drivers/gpu/drm/v3d/v3d_gem.c | 9 +++-
drivers/gpu/drm/v3d/v3d_mmu.c | 12 ++++-
drivers/gpu/drm/v3d/v3d_power.c | 96 +++++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/v3d/v3d_submit.c | 19 ++++++--
8 files changed, 213 insertions(+), 55 deletions(-)
diff --git a/drivers/gpu/drm/v3d/Makefile b/drivers/gpu/drm/v3d/Makefile
index b7d673f1153bef16db3800e50b2bfaf36bf8871b..9cb1fd4e4091dbb56e6a73e2b8a51fa0d242698b 100644
--- a/drivers/gpu/drm/v3d/Makefile
+++ b/drivers/gpu/drm/v3d/Makefile
@@ -13,7 +13,8 @@ v3d-y := \
v3d_trace_points.o \
v3d_sched.o \
v3d_sysfs.o \
- v3d_submit.o
+ v3d_submit.o \
+ v3d_power.o
v3d-$(CONFIG_DEBUG_FS) += v3d_debugfs.o
diff --git a/drivers/gpu/drm/v3d/v3d_debugfs.c b/drivers/gpu/drm/v3d/v3d_debugfs.c
index 89f24eec62a74ec49b28f0b22dbf626ba7a35206..634cc796ba2324dc497694c070f2cfffcc4424c9 100644
--- a/drivers/gpu/drm/v3d/v3d_debugfs.c
+++ b/drivers/gpu/drm/v3d/v3d_debugfs.c
@@ -97,7 +97,11 @@ static int v3d_v3d_debugfs_regs(struct seq_file *m, void *unused)
struct drm_debugfs_entry *entry = m->private;
struct drm_device *dev = entry->dev;
struct v3d_dev *v3d = to_v3d_dev(dev);
- int i, core;
+ int i, core, ret;
+
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ return ret;
for (i = 0; i < ARRAY_SIZE(v3d_hub_reg_defs); i++) {
const struct v3d_reg_def *def = &v3d_hub_reg_defs[i];
@@ -139,6 +143,8 @@ static int v3d_v3d_debugfs_regs(struct seq_file *m, void *unused)
}
}
+ v3d_pm_runtime_put(v3d);
+
return 0;
}
@@ -148,7 +154,11 @@ static int v3d_v3d_debugfs_ident(struct seq_file *m, void *unused)
struct drm_device *dev = entry->dev;
struct v3d_dev *v3d = to_v3d_dev(dev);
u32 ident0, ident1, ident2, ident3, cores;
- int core;
+ int core, ret;
+
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ return ret;
ident0 = V3D_READ(V3D_HUB_IDENT0);
ident1 = V3D_READ(V3D_HUB_IDENT1);
@@ -207,6 +217,8 @@ static int v3d_v3d_debugfs_ident(struct seq_file *m, void *unused)
}
}
+ v3d_pm_runtime_put(v3d);
+
return 0;
}
@@ -234,6 +246,11 @@ static int v3d_measure_clock(struct seq_file *m, void *unused)
uint32_t cycles;
int core = 0;
int measure_ms = 1000;
+ int ret;
+
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ return ret;
if (v3d->ver >= V3D_GEN_41) {
int cycle_count_reg = V3D_PCTR_CYCLE_COUNT(v3d->ver);
@@ -253,6 +270,8 @@ static int v3d_measure_clock(struct seq_file *m, void *unused)
msleep(measure_ms);
cycles = V3D_CORE_READ(core, V3D_PCTR_0_PCTR0);
+ v3d_pm_runtime_put(v3d);
+
seq_printf(m, "cycles: %d (%d.%d Mhz)\n",
cycles,
cycles / (measure_ms * 1000),
diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
index cb12d17cce2bf9e49432e3d3dddef1afdc4d93a0..022fbdff4ab973c60c29e2aa6c4e449da0cfaaf3 100644
--- a/drivers/gpu/drm/v3d/v3d_drv.c
+++ b/drivers/gpu/drm/v3d/v3d_drv.c
@@ -59,6 +59,7 @@ static int v3d_get_param_ioctl(struct drm_device *dev, void *data,
[DRM_V3D_PARAM_V3D_CORE0_IDENT1] = V3D_CTL_IDENT1,
[DRM_V3D_PARAM_V3D_CORE0_IDENT2] = V3D_CTL_IDENT2,
};
+ int ret;
if (args->pad != 0)
return -EINVAL;
@@ -75,12 +76,19 @@ static int v3d_get_param_ioctl(struct drm_device *dev, void *data,
if (args->value != 0)
return -EINVAL;
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ return ret;
+
if (args->param >= DRM_V3D_PARAM_V3D_CORE0_IDENT0 &&
args->param <= DRM_V3D_PARAM_V3D_CORE0_IDENT2) {
args->value = V3D_CORE_READ(0, offset);
} else {
args->value = V3D_READ(offset);
}
+
+ v3d_pm_runtime_put(v3d);
+
return 0;
}
@@ -287,36 +295,6 @@ static const struct of_device_id v3d_of_match[] = {
};
MODULE_DEVICE_TABLE(of, v3d_of_match);
-static void
-v3d_idle_sms(struct v3d_dev *v3d)
-{
- if (v3d->ver < V3D_GEN_71)
- return;
-
- V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_CLEAR_POWER_OFF);
-
- if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
- V3D_SMS_STATE) == V3D_SMS_IDLE), 100)) {
- DRM_ERROR("Failed to power up SMS\n");
- }
-
- v3d_reset_sms(v3d);
-}
-
-static void
-v3d_power_off_sms(struct v3d_dev *v3d)
-{
- if (v3d->ver < V3D_GEN_71)
- return;
-
- V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_POWER_OFF);
-
- if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
- V3D_SMS_STATE) == V3D_SMS_POWER_OFF_STATE), 100)) {
- DRM_ERROR("Failed to power off SMS\n");
- }
-}
-
static int
map_regs(struct v3d_dev *v3d, void __iomem **regs, const char *name)
{
@@ -383,6 +361,9 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
if (IS_ERR(v3d->clk))
return dev_err_probe(dev, PTR_ERR(v3d->clk), "Failed to get V3D clock\n");
+ if (v3d->clk)
+ v3d->max_clk_rate = clk_round_rate(v3d->clk, ULONG_MAX);
+
ret = v3d_irq_init(v3d);
if (ret)
return ret;
@@ -400,19 +381,26 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
if (ret)
goto dma_free;
- ret = clk_prepare_enable(v3d->clk);
- if (ret) {
- dev_err(&pdev->dev, "Couldn't enable the V3D clock\n");
+ ret = devm_pm_runtime_enable(dev);
+ if (ret)
goto gem_destroy;
- }
- v3d_idle_sms(v3d);
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret)
+ goto gem_destroy;
+
+ /* If PM is disabled, we need to call v3d_power_resume() manually. */
+ if (!IS_ENABLED(CONFIG_PM)) {
+ ret = v3d_power_resume(dev);
+ if (ret)
+ goto gem_destroy;
+ }
mmu_debug = V3D_READ(V3D_MMU_DEBUG_INFO);
mask = DMA_BIT_MASK(30 + V3D_GET_FIELD(mmu_debug, V3D_MMU_PA_WIDTH));
ret = dma_set_mask_and_coherent(dev, mask);
if (ret)
- goto clk_disable;
+ goto runtime_pm_put;
dma_set_max_seg_size(&pdev->dev, UINT_MAX);
@@ -433,25 +421,27 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
v3d->rev = V3D_GET_FIELD(ident3, V3D_HUB_IDENT3_IPREV);
v3d_gem_init(drm);
- v3d_irq_enable(v3d);
+
+ pm_runtime_set_autosuspend_delay(dev, 50);
+ pm_runtime_use_autosuspend(dev);
ret = drm_dev_register(drm, 0);
if (ret)
- goto irq_disable;
+ goto runtime_pm_put;
ret = v3d_sysfs_init(dev);
if (ret)
goto drm_unregister;
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+
return 0;
drm_unregister:
drm_dev_unregister(drm);
-irq_disable:
- v3d_irq_disable(v3d);
-clk_disable:
- v3d_power_off_sms(v3d);
- clk_disable_unprepare(v3d->clk);
+runtime_pm_put:
+ pm_runtime_put_sync_suspend(dev);
gem_destroy:
v3d_gem_destroy(drm);
dma_free:
@@ -469,21 +459,27 @@ static void v3d_platform_drm_remove(struct platform_device *pdev)
drm_dev_unregister(drm);
- v3d_power_off_sms(v3d);
+ pm_runtime_suspend(dev);
- clk_disable_unprepare(v3d->clk);
+ /* If PM is disabled, we need to call v3d_power_suspend() manually. */
+ if (!IS_ENABLED(CONFIG_PM))
+ v3d_power_suspend(dev);
v3d_gem_destroy(drm);
dma_free_wc(dev, 4096, v3d->mmu_scratch, v3d->mmu_scratch_paddr);
}
+static DEFINE_RUNTIME_DEV_PM_OPS(v3d_pm_ops, v3d_power_suspend,
+ v3d_power_resume, NULL);
+
static struct platform_driver v3d_platform_driver = {
.probe = v3d_platform_drm_probe,
.remove = v3d_platform_drm_remove,
.driver = {
.name = "v3d",
.of_match_table = v3d_of_match,
+ .pm = pm_ptr(&v3d_pm_ops),
},
};
diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
index 738a09351c306db33078db1e053cd133d55d2138..32835b83caf0309a9e316d6882f63685f58bb6e3 100644
--- a/drivers/gpu/drm/v3d/v3d_drv.h
+++ b/drivers/gpu/drm/v3d/v3d_drv.h
@@ -3,6 +3,7 @@
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/pm_runtime.h>
#include <linux/spinlock_types.h>
#include <linux/workqueue.h>
@@ -134,6 +135,8 @@ struct v3d_dev {
void __iomem *gca_regs;
void __iomem *sms_regs;
struct clk *clk;
+ unsigned long max_clk_rate;
+
struct reset_control *reset;
/* Virtual and DMA addresses of the single shared page table. */
@@ -324,6 +327,8 @@ struct v3d_job {
/* Callback for the freeing of the job on refcount going to 0. */
void (*free)(struct kref *ref);
+
+ bool has_pm_ref;
};
struct v3d_bin_job {
@@ -597,6 +602,21 @@ int v3d_mmu_set_page_table(struct v3d_dev *v3d);
void v3d_mmu_insert_ptes(struct v3d_bo *bo);
void v3d_mmu_remove_ptes(struct v3d_bo *bo);
+/* v3d_power.c */
+int v3d_power_suspend(struct device *dev);
+int v3d_power_resume(struct device *dev);
+
+static __always_inline int v3d_pm_runtime_get(struct v3d_dev *v3d)
+{
+ return pm_runtime_resume_and_get(v3d->drm.dev);
+}
+
+static __always_inline int v3d_pm_runtime_put(struct v3d_dev *v3d)
+{
+ pm_runtime_mark_last_busy(v3d->drm.dev);
+ return pm_runtime_put_autosuspend(v3d->drm.dev);
+}
+
/* v3d_sched.c */
void v3d_timestamp_query_info_free(struct v3d_timestamp_query_info *query_info,
unsigned int count);
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 1f532030c3883257810877c75da38636bf25f58e..70e488180c4684db3415201f19586099914afb15 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -125,10 +125,16 @@ void
v3d_reset(struct v3d_dev *v3d)
{
struct drm_device *dev = &v3d->drm;
+ int ret;
+
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ return;
DRM_DEV_ERROR(dev->dev, "Resetting GPU for hang.\n");
DRM_DEV_ERROR(dev->dev, "V3D_ERR_STAT: 0x%08x\n",
V3D_CORE_READ(0, V3D_ERR_STAT));
+
trace_v3d_reset_begin(dev);
/* XXX: only needed for safe powerdown, not reset. */
@@ -147,6 +153,8 @@ v3d_reset(struct v3d_dev *v3d)
v3d_perfmon_stop(v3d, v3d->active_perfmon, false);
trace_v3d_reset_end(dev);
+
+ v3d_pm_runtime_put(v3d);
}
static void
@@ -344,7 +352,6 @@ v3d_gem_init(struct drm_device *dev)
struct v3d_dev *v3d = to_v3d_dev(dev);
v3d_init_hw_state(v3d);
- v3d_mmu_set_page_table(v3d);
}
void
diff --git a/drivers/gpu/drm/v3d/v3d_mmu.c b/drivers/gpu/drm/v3d/v3d_mmu.c
index a25d25a8ae617bf68e133e1793cd0bb930bb07f6..1699819756aadfc40f7d41ff19847d42ddf10dce 100644
--- a/drivers/gpu/drm/v3d/v3d_mmu.c
+++ b/drivers/gpu/drm/v3d/v3d_mmu.c
@@ -37,7 +37,13 @@ static bool v3d_mmu_is_aligned(u32 page, u32 page_address, size_t alignment)
int v3d_mmu_flush_all(struct v3d_dev *v3d)
{
- int ret;
+ int ret = 0;
+
+ pm_runtime_get_noresume(v3d->drm.dev);
+
+ /* Flush the PTs only if we're already awake */
+ if (!pm_runtime_active(v3d->drm.dev))
+ goto pm_put;
V3D_WRITE(V3D_MMUC_CONTROL, V3D_MMUC_CONTROL_FLUSH |
V3D_MMUC_CONTROL_ENABLE);
@@ -46,7 +52,7 @@ int v3d_mmu_flush_all(struct v3d_dev *v3d)
V3D_MMUC_CONTROL_FLUSHING), 100);
if (ret) {
dev_err(v3d->drm.dev, "MMUC flush wait idle failed\n");
- return ret;
+ goto pm_put;
}
V3D_WRITE(V3D_MMU_CTL, V3D_READ(V3D_MMU_CTL) |
@@ -57,6 +63,8 @@ int v3d_mmu_flush_all(struct v3d_dev *v3d)
if (ret)
dev_err(v3d->drm.dev, "MMU TLB clear wait idle failed\n");
+pm_put:
+ pm_runtime_put_autosuspend(v3d->drm.dev);
return ret;
}
diff --git a/drivers/gpu/drm/v3d/v3d_power.c b/drivers/gpu/drm/v3d/v3d_power.c
new file mode 100644
index 0000000000000000000000000000000000000000..285f56acf544bbfd3d9848253e788a138aacf2af
--- /dev/null
+++ b/drivers/gpu/drm/v3d/v3d_power.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2026 Raspberry Pi */
+
+#include <linux/clk.h>
+#include <linux/reset.h>
+
+#include <drm/drm_print.h>
+
+#include "v3d_drv.h"
+#include "v3d_regs.h"
+
+static void
+v3d_resume_sms(struct v3d_dev *v3d)
+{
+ if (v3d->ver < V3D_GEN_71)
+ return;
+
+ V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_CLEAR_POWER_OFF);
+
+ if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
+ V3D_SMS_STATE) == V3D_SMS_IDLE), 100)) {
+ drm_err(&v3d->drm, "Failed to power up SMS\n");
+ }
+
+ v3d_reset_sms(v3d);
+}
+
+static void
+v3d_suspend_sms(struct v3d_dev *v3d)
+{
+ if (v3d->ver < V3D_GEN_71)
+ return;
+
+ V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_POWER_OFF);
+
+ if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
+ V3D_SMS_STATE) == V3D_SMS_POWER_OFF_STATE), 100)) {
+ drm_err(&v3d->drm, "Failed to power off SMS\n");
+ }
+}
+
+int v3d_power_suspend(struct device *dev)
+{
+ struct drm_device *drm = dev_get_drvdata(dev);
+ struct v3d_dev *v3d = to_v3d_dev(drm);
+
+ v3d_irq_disable(v3d);
+ v3d_suspend_sms(v3d);
+
+ if (v3d->reset)
+ reset_control_assert(v3d->reset);
+
+ /* Some firmware versions might not actually power off the clock
+ * when we set the clock state to off. Therefore, set the clock
+ * rate to 0 to ensure it is running in the minimum rate.
+ */
+ if (v3d->clk)
+ clk_set_rate(v3d->clk, 0);
+
+ clk_disable_unprepare(v3d->clk);
+
+ return 0;
+}
+
+int v3d_power_resume(struct device *dev)
+{
+ struct drm_device *drm = dev_get_drvdata(dev);
+ struct v3d_dev *v3d = to_v3d_dev(drm);
+ int ret;
+
+ ret = clk_prepare_enable(v3d->clk);
+ if (ret)
+ return ret;
+
+ /* Set the clock to the maximum rate and let the firmware decide
+ * if we can actually keep it.
+ */
+ if (v3d->clk)
+ clk_set_rate(v3d->clk, v3d->max_clk_rate);
+
+ if (v3d->reset) {
+ ret = reset_control_deassert(v3d->reset);
+ if (ret)
+ goto clk_disable;
+ }
+
+ v3d_resume_sms(v3d);
+ v3d_mmu_set_page_table(v3d);
+ v3d_irq_enable(v3d);
+
+ return 0;
+
+clk_disable:
+ clk_disable_unprepare(v3d->clk);
+ return ret;
+}
diff --git a/drivers/gpu/drm/v3d/v3d_submit.c b/drivers/gpu/drm/v3d/v3d_submit.c
index 7de5a95ee7ca92d480af1f2996c12f2cefa56f34..7487aff499f4587b2887a886c366d735952cee95 100644
--- a/drivers/gpu/drm/v3d/v3d_submit.c
+++ b/drivers/gpu/drm/v3d/v3d_submit.c
@@ -103,6 +103,9 @@ v3d_job_free(struct kref *ref)
if (job->perfmon)
v3d_perfmon_put(job->perfmon);
+ if (job->has_pm_ref)
+ v3d_pm_runtime_put(job->v3d);
+
kfree(job);
}
@@ -184,13 +187,13 @@ v3d_job_init(struct v3d_dev *v3d, struct drm_file *file_priv,
if (copy_from_user(&in, handle++, sizeof(in))) {
ret = -EFAULT;
DRM_DEBUG("Failed to copy wait dep handle.\n");
- goto fail_deps;
+ goto fail_job_init;
}
ret = drm_sched_job_add_syncobj_dependency(&job->base, file_priv, in.handle, 0);
// TODO: Investigate why this was filtered out for the IOCTL.
if (ret && ret != -ENOENT)
- goto fail_deps;
+ goto fail_job_init;
}
}
} else {
@@ -198,14 +201,22 @@ v3d_job_init(struct v3d_dev *v3d, struct drm_file *file_priv,
// TODO: Investigate why this was filtered out for the IOCTL.
if (ret && ret != -ENOENT)
- goto fail_deps;
+ goto fail_job_init;
+ }
+
+ /* CPU jobs don't require hardware resources */
+ if (queue != V3D_CPU) {
+ ret = v3d_pm_runtime_get(v3d);
+ if (ret)
+ goto fail_job_init;
+ job->has_pm_ref = true;
}
kref_init(&job->refcount);
return 0;
-fail_deps:
+fail_job_init:
drm_sched_job_cleanup(&job->base);
return ret;
}
--
2.52.0
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