Adds helpers for starting and stopping capture of frame CRCs through the DPCD. When capture is on, a worker waits for vblanks and retrieves the frame CRC to put it in the queue on the CRTC that is using the eDP connector, so it's passed to userspace.
Signed-off-by: Tomeu Vizoso tomeu.vizoso@collabora.com ---
drivers/gpu/drm/drm_dp_helper.c | 133 ++++++++++++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 7 +++ 2 files changed, 140 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index eae5ef963cb7..bf88ae7deb9a 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -790,6 +790,90 @@ static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags) mutex_unlock(&i2c_to_aux(i2c)->hw_mutex); }
+static int drm_dp_aux_get_crc(struct drm_dp_aux *aux, u8 *crc) +{ + u8 buf, count; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); + if (ret < 0) + return ret; + + WARN_ON(!(buf & DP_TEST_SINK_START)); + + ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK_MISC, &buf); + if (ret < 0) + return ret; + + count = buf & DP_TEST_COUNT_MASK; + if (count == aux->crc_count) + return -EAGAIN; /* No CRC yet */ + + aux->crc_count = count; + + /* At DP_TEST_CRC_R_CR, there's 6 bytes containing CRC data, 2 bytes + * per component (RGB or CrYCb). + */ + ret = drm_dp_dpcd_read(aux, DP_TEST_CRC_R_CR, crc, 6); + if (ret < 0) + return ret; + + return 0; +} + +static void drm_dp_aux_crc_work(struct work_struct *work) +{ + struct drm_dp_aux *aux = container_of(work, struct drm_dp_aux, + crc_work); + struct drm_crtc *crtc; + wait_queue_head_t *wq; + u8 crc_bytes[6]; + uint32_t crcs[3]; + u32 last; + int ret; + + if (WARN_ON(!aux->connector)) + return; + + crtc = aux->connector->state->crtc; + wq = drm_crtc_vblank_waitqueue(crtc); + while (crtc->crc.opened) { + ret = drm_crtc_vblank_get(crtc); + if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", + crtc->index, ret)) + return; + + last = drm_crtc_vblank_count(crtc); + wait_event(*wq, last != drm_crtc_vblank_count(crtc)); + + drm_crtc_vblank_put(crtc); + + if (!crtc->crc.opened) + break; + + ret = drm_dp_aux_get_crc(aux, crc_bytes); + if (ret == -EAGAIN) { + usleep_range(1000, 2000); + ret = drm_dp_aux_get_crc(aux, crc_bytes); + } + + if (ret) { + DRM_DEBUG_KMS("Failed to get a CRC even after retrying: %d\n", + ret); + continue; + } + + spin_lock_irq(&crtc->crc.lock); + crcs[0] = crc_bytes[0] | crc_bytes[1] << 8; + crcs[1] = crc_bytes[2] | crc_bytes[3] << 8; + crcs[2] = crc_bytes[4] | crc_bytes[5] << 8; + ret = drm_crtc_add_crc_entry(crtc, false, 0, crcs); + spin_unlock_irq(&crtc->crc.lock); + if (!ret) + wake_up_interruptible(&crtc->crc.wq); + } +} + /** * drm_dp_aux_init() - minimally initialise an aux channel * @aux: DisplayPort AUX channel @@ -802,6 +886,7 @@ static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags) void drm_dp_aux_init(struct drm_dp_aux *aux) { mutex_init(&aux->hw_mutex); + INIT_WORK(&aux->crc_work, drm_dp_aux_crc_work);
aux->ddc.algo = &drm_dp_i2c_algo; aux->ddc.algo_data = aux; @@ -892,3 +977,51 @@ int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]) EXPORT_SYMBOL(drm_dp_psr_setup_time);
#undef PSR_SETUP_TIME + +/** + * drm_dp_start_crc() - start capture of frame CRCs + * @aux: DisplayPort AUX channel + * + * Returns 0 on success or a negative error code on failure. + */ +int drm_dp_start_crc(struct drm_dp_aux *aux) +{ + u8 buf; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); + if (ret < 0) + return ret; + + ret = drm_dp_dpcd_writeb(aux, DP_TEST_SINK, buf | DP_TEST_SINK_START); + if (ret < 0) + return ret; + + schedule_work(&aux->crc_work); + + return 0; +} +EXPORT_SYMBOL(drm_dp_start_crc); + +/** + * drm_dp_stop_crc() - stop capture of frame CRCs + * @aux: DisplayPort AUX channel + * + * Returns 0 on success or a negative error code on failure. + */ +int drm_dp_stop_crc(struct drm_dp_aux *aux) +{ + u8 buf; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); + if (ret < 0) + return ret; + + ret = drm_dp_dpcd_writeb(aux, DP_TEST_SINK, buf & ~DP_TEST_SINK_START); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(drm_dp_stop_crc); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index f66cc8501d71..c6ddc4edda61 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -712,6 +712,8 @@ struct drm_dp_aux_msg { * @dev: pointer to struct device that is the parent for this AUX channel * @connector: backpointer to connector that uses this AUX channel * @hw_mutex: internal mutex used for locking transfers + * @crc_work: worker that captures CRCs for each frame + * @crc_count: counter of captured frame CRCs * @transfer: transfers a message representing a single AUX transaction * * The .dev field should be set to a pointer to the device that implements @@ -749,6 +751,8 @@ struct drm_dp_aux { struct device *dev; struct drm_connector *connector; struct mutex hw_mutex; + struct work_struct crc_work; + u8 crc_count; ssize_t (*transfer)(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg); /** @@ -820,4 +824,7 @@ void drm_dp_aux_init(struct drm_dp_aux *aux); int drm_dp_aux_register(struct drm_dp_aux *aux); void drm_dp_aux_unregister(struct drm_dp_aux *aux);
+int drm_dp_start_crc(struct drm_dp_aux *aux); +int drm_dp_stop_crc(struct drm_dp_aux *aux); + #endif /* _DRM_DP_HELPER_H_ */