From 79c1da7c3bf74be9b1dae9450ef79f32dd22def6 Mon Sep 17 00:00:00 2001 From: Tomeu Vizoso Date: Fri, 3 Mar 2017 14:39:34 +0100 Subject: [PATCH] drm/dp: add helpers for capture of frame CRCs 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. v2: Reuse drm_crtc_wait_one_vblank Update locking, as drm_crtc_add_crc_entry now takes the lock v3: Don't call wake_up_interruptible directly, that's now done in drm_crtc_add_crc_entry. v4: Style fixes (Sean Paul) Reworked retry of CRC reads (Sean Paul) Flush worker after stopping CRC generationa (Sean Paul) v5: Move back to make the retry explicitly once v6: Set and use the drm_crtc backpointer (Sean Paul) Signed-off-by: Tomeu Vizoso Signed-off-by: Sean Paul Link: http://patchwork.freedesktop.org/patch/msgid/20170303133936.14964-3-tomeu.vizoso@collabora.com --- drivers/gpu/drm/drm_dp_helper.c | 126 ++++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 7 ++ 2 files changed, 133 insertions(+) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 68908c1d5ca1..c40cfe2e63ab 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -981,6 +981,78 @@ static const struct i2c_lock_operations drm_dp_i2c_lock_ops = { .unlock_bus = unlock_bus, }; +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; + u8 crc_bytes[6]; + uint32_t crcs[3]; + int ret; + + if (WARN_ON(!aux->crtc)) + return; + + crtc = aux->crtc; + while (crtc->crc.opened) { + drm_crtc_wait_one_vblank(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 == -EAGAIN) { + DRM_DEBUG_KMS("Get CRC failed after retrying: %d\n", + ret); + continue; + } else if (ret) { + DRM_DEBUG_KMS("Failed to get a CRC: %d\n", ret); + continue; + } + + 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; + drm_crtc_add_crc_entry(crtc, false, 0, crcs); + } +} + /** * drm_dp_aux_init() - minimally initialise an aux channel * @aux: DisplayPort AUX channel @@ -993,6 +1065,7 @@ static const struct i2c_lock_operations drm_dp_i2c_lock_ops = { 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; @@ -1081,3 +1154,56 @@ 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, struct drm_crtc *crtc) +{ + 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; + + aux->crc_count = 0; + aux->crtc = crtc; + 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; + + flush_work(&aux->crc_work); + aux->crtc = NULL; + + 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 afe515855f0a..c34984c8d5d0 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -734,6 +734,8 @@ struct drm_dp_aux_msg { * @dev: pointer to struct device that is the parent for this AUX channel * @crtc: backpointer to the crtc that is currently using 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 @@ -771,6 +773,8 @@ struct drm_dp_aux { struct device *dev; struct drm_crtc *crtc; 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); /** @@ -849,4 +853,7 @@ 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, struct drm_crtc *crtc); +int drm_dp_stop_crc(struct drm_dp_aux *aux); + #endif /* _DRM_DP_HELPER_H_ */ -- 2.20.1