Hi Mary,
On 19/08/2024 12:25, Mary Guillemard wrote:
Expose timestamp information supported by the GPU with a new device
query.
Mali uses an external timer as GPU system time. On ARM, this is wired to
the generic arch timer so we wire cntfrq_el0 as device frequency.
This new uAPI will be used in Mesa to implement timestamp queries and
VK_KHR_calibrated_timestamps.
Since this extends the uAPI and because userland needs a way to advertise
those features conditionally, this also bumps the driver minor version.
v2:
- Rewrote to use GPU timestamp register
- Added timestamp_offset to drm_panthor_timestamp_info
- Add missing include for arch_timer_get_cntfrq
- Rework commit message
v3:
- Add panthor_gpu_read_64bit_counter
- Change panthor_gpu_read_timestamp to use
panthor_gpu_read_64bit_counter
Signed-off-by: Mary Guillemard <mary.guillemard@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panthor/panthor_drv.c | 43 +++++++++++++++++++++++-
drivers/gpu/drm/panthor/panthor_gpu.c | 47 +++++++++++++++++++++++++++
drivers/gpu/drm/panthor/panthor_gpu.h | 2 ++
include/uapi/drm/panthor_drm.h | 19 +++++++++++
4 files changed, 110 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index b5e7b919f241..444e3bb1cfb5 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -3,6 +3,10 @@
/* Copyright 2019 Linaro, Ltd., Rob Herring <robh@xxxxxxxxxx> */
/* Copyright 2019 Collabora ltd. */
+#ifdef CONFIG_ARM_ARCH_TIMER
+#include <asm/arch_timer.h>
+#endif
+
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of_platform.h>
@@ -164,6 +168,7 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
_Generic(_obj_name, \
PANTHOR_UOBJ_DECL(struct drm_panthor_gpu_info, tiler_present), \
PANTHOR_UOBJ_DECL(struct drm_panthor_csif_info, pad), \
+ PANTHOR_UOBJ_DECL(struct drm_panthor_timestamp_info, current_timestamp), \
PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
@@ -750,10 +755,33 @@ static void panthor_submit_ctx_cleanup(struct panthor_submit_ctx *ctx,
kvfree(ctx->jobs);
}
+static int panthor_query_timestamp_info(struct panthor_device *ptdev,
+ struct drm_panthor_timestamp_info *arg)
+{
+ int ret;
+
+ ret = pm_runtime_resume_and_get(ptdev->base.dev);
+ if (ret)
+ return ret;
+
+#ifdef CONFIG_ARM_ARCH_TIMER
+ arg->timestamp_frequency = arch_timer_get_cntfrq();
+#else
+ arg->timestamp_frequency = 0;
+#endif
+ arg->current_timestamp = panthor_gpu_read_timestamp(ptdev);
+ arg->timestamp_offset = panthor_gpu_read_timestamp_offset(ptdev);
+
+ pm_runtime_put(ptdev->base.dev);
+ return 0;
+}
+
static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct drm_file *file)
{
struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
struct drm_panthor_dev_query *args = data;
+ struct drm_panthor_timestamp_info timestamp_info;
+ int ret;
if (!args->pointer) {
switch (args->type) {
@@ -765,6 +793,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
args->size = sizeof(ptdev->csif_info);
return 0;
+ case DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO:
+ args->size = sizeof(timestamp_info);
+ return 0;
+
default:
return -EINVAL;
}
@@ -777,6 +809,14 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
case DRM_PANTHOR_DEV_QUERY_CSIF_INFO:
return PANTHOR_UOBJ_SET(args->pointer, args->size, ptdev->csif_info);
+ case DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO:
+ ret = panthor_query_timestamp_info(ptdev, ×tamp_info);
+
+ if (ret)
+ return ret;
+
+ return PANTHOR_UOBJ_SET(args->pointer, args->size, timestamp_info);
+
default:
return -EINVAL;
}
@@ -1372,6 +1412,7 @@ static void panthor_debugfs_init(struct drm_minor *minor)
/*
* PanCSF driver version:
* - 1.0 - initial interface
+ * - 1.1 - adds DEV_QUERY_TIMESTAMP_INFO query
*/
static const struct drm_driver panthor_drm_driver = {
.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
@@ -1385,7 +1426,7 @@ static const struct drm_driver panthor_drm_driver = {
.desc = "Panthor DRM driver",
.date = "20230801",
.major = 1,
- .minor = 0,
+ .minor = 1,
.gem_create_object = panthor_gem_create_object,
.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
index 5251d8764e7d..ef66cfea6f1f 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.c
+++ b/drivers/gpu/drm/panthor/panthor_gpu.c
@@ -480,3 +480,50 @@ void panthor_gpu_resume(struct panthor_device *ptdev)
panthor_gpu_irq_resume(&ptdev->gpu->irq, GPU_INTERRUPTS_MASK);
panthor_gpu_l2_power_on(ptdev);
}
+
+/**
+ * panthor_gpu_read_64bit_counter() - Read a 64-bit counter at a given offset.
+ * @ptdev: Device.
+ * @reg: The offset of the register to read.
+ *
+ * Return: The counter value.
+ */
+static unsigned long long
[nit] s/unsigned long long/u64/ ?
+panthor_gpu_read_64bit_counter(struct panthor_device *ptdev, u32 reg)
+{
+ u32 hi, lo;
+
+ do {
+ hi = gpu_read(ptdev, reg + 0x4);
+ lo = gpu_read(ptdev, reg);
+ } while (hi != gpu_read(ptdev, reg + 0x4));
+
+ return ((u64)hi << 32) | lo;
+}
+
+/**
+ * panthor_gpu_read_timestamp() - Read the timstamp register.
[nit] Spelling, `s/timstamp/timestamp/`. Ditto below.
+ * @ptdev: Device.
+ *
+ * Return: The GPU timestamp value.
+ */
+unsigned long long panthor_gpu_read_timestamp(struct panthor_device *ptdev)
+{
+ return panthor_gpu_read_64bit_counter(ptdev, GPU_TIMESTAMP_LO);
+}
+
+/**
+ * panthor_gpu_read_timestamp_offset() - Read the timstamp offset register.
+ * @ptdev: Device.
+ *
+ * Return: The GPU timestamp offset value.
+ */
+unsigned long long panthor_gpu_read_timestamp_offset(struct panthor_device *ptdev)
+{
+ u32 hi, lo;
+
+ hi = gpu_read(ptdev, GPU_TIMESTAMP_OFFSET_HI);
+ lo = gpu_read(ptdev, GPU_TIMESTAMP_OFFSET_LO);
+
+ return ((u64)hi << 32) | lo;
+}
diff --git a/drivers/gpu/drm/panthor/panthor_gpu.h b/drivers/gpu/drm/panthor/panthor_gpu.h
index bba7555dd3c6..73d335859db8 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.h
+++ b/drivers/gpu/drm/panthor/panthor_gpu.h
@@ -48,5 +48,7 @@ int panthor_gpu_l2_power_on(struct panthor_device *ptdev);
int panthor_gpu_flush_caches(struct panthor_device *ptdev,
u32 l2, u32 lsc, u32 other);
int panthor_gpu_soft_reset(struct panthor_device *ptdev);
+unsigned long long panthor_gpu_read_timestamp(struct panthor_device *ptdev);
+unsigned long long panthor_gpu_read_timestamp_offset(struct panthor_device *ptdev);
#endif
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
index 926b1deb1116..944f5618aa05 100644
--- a/include/uapi/drm/panthor_drm.h
+++ b/include/uapi/drm/panthor_drm.h
@@ -260,6 +260,9 @@ enum drm_panthor_dev_query_type {
/** @DRM_PANTHOR_DEV_QUERY_CSIF_INFO: Query command-stream interface information. */
DRM_PANTHOR_DEV_QUERY_CSIF_INFO,
+
+ /** @DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO: Query timestamp information. */
+ DRM_PANTHOR_DEV_QUERY_TIMESTAMP_INFO,
};
/**
@@ -377,6 +380,22 @@ struct drm_panthor_csif_info {
__u32 pad;
};
+/**
+ * struct drm_panthor_timestamp_info - Timestamp information
+ *
+ * Structure grouping all queryable information relating to the GPU timestamp.
+ */
+struct drm_panthor_timestamp_info {
+ /** @timestamp_frequency: The frequency of the timestamp timer. */
+ __u64 timestamp_frequency;
+
+ /** @current_timestamp: The current timestamp. */
+ __u64 current_timestamp;
+
+ /** @timestamp_offset: The offset of the timestamp timer. */
+ __u64 timestamp_offset;
Are you sure you don't want the cntvct_el0 and cntfrq_el0 values here,
too, as separate fields? While they're not values coming from the GPU,
they are related. Getting the lowest delta possible between querying one
timestamp register and the other is quite useful for tooling. Requiring
userspace to do two separate queries, one for CPU time and one for GPU
time, doesn't feel optimal, your max deviation will necessarily be
higher that way.
+};
+
/**
* struct drm_panthor_dev_query - Arguments passed to DRM_PANTHOR_IOCTL_DEV_QUERY
*/
base-commit: 3e828c670b0ac8a9564c69f5c5ecf637b22a58d6
--
Mihail Atanassov <mihail.atanassov@xxxxxxx>
