/* * Copyright © 2008 Intel Corporation * Copyright © 2016 Collabora Ltd * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. * * Based on code from the i915 driver. * Original author: Damien Lespiau <[email protected]> * */ #include <linux/circ_buf.h> #include <linux/ctype.h> #include <linux/debugfs.h> #include <linux/poll.h> #include <linux/uaccess.h> #include <drm/drm_crtc.h> #include <drm/drm_debugfs_crc.h> #include <drm/drm_drv.h> #include <drm/drm_print.h> #include "drm_internal.h" /** * DOC: CRC ABI * * DRM device drivers can provide to userspace CRC information of each frame as * it reached a given hardware component (a CRC sampling "source"). * * Userspace can control generation of CRCs in a given CRTC by writing to the * file dri/0/crtc-N/crc/control in debugfs, with N being the :ref:`index of * the CRTC<crtc_index>`. Accepted values are source names (which are * driver-specific) and the "auto" keyword, which will let the driver select a * default source of frame CRCs for this CRTC. * * Once frame CRC generation is enabled, userspace can capture them by reading * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame * number in the first field and then a number of unsigned integer fields * containing the CRC data. Fields are separated by a single space and the number * of CRC fields is source-specific. * * Note that though in some cases the CRC is computed in a specified way and on * the frame contents as supplied by userspace (eDP 1.3), in general the CRC * computation is performed in an unspecified way and on frame contents that have * been already processed in also an unspecified way and thus userspace cannot * rely on being able to generate matching CRC values for the frame contents that * it submits. In this general case, the maximum userspace can do is to compare * the reported CRCs of frames that should have the same contents. * * On the driver side the implementation effort is minimal, drivers only need to * implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source. * The debugfs files are automatically set up if those vfuncs are set. CRC samples * need to be captured in the driver by calling drm_crtc_add_crc_entry(). * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source * may result in a commit (even a full modeset). * * CRC results must be reliable across non-full-modeset atomic commits, so if a * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with * CRC generation, then the driver must mark that commit as a full modeset * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure * consistent results, generic userspace must re-setup CRC generation after a * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET. */ static int crc_control_show(struct seq_file *m, void *data) { … } static int crc_control_open(struct inode *inode, struct file *file) { … } static ssize_t crc_control_write(struct file *file, const char __user *ubuf, size_t len, loff_t *offp) { … } static const struct file_operations drm_crtc_crc_control_fops = …; static int crtc_crc_data_count(struct drm_crtc_crc *crc) { … } static void crtc_crc_cleanup(struct drm_crtc_crc *crc) { … } static int crtc_crc_open(struct inode *inode, struct file *filep) { … } static int crtc_crc_release(struct inode *inode, struct file *filep) { … } /* * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space * separated, with a newline at the end and null-terminated. */ #define LINE_LEN(values_cnt) … #define MAX_LINE_LEN … static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, size_t count, loff_t *pos) { … } static __poll_t crtc_crc_poll(struct file *file, poll_table *wait) { … } static const struct file_operations drm_crtc_crc_data_fops = …; void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) { … } /** * drm_crtc_add_crc_entry - Add entry with CRC information for a frame * @crtc: CRTC to which the frame belongs * @has_frame: whether this entry has a frame number to go with * @frame: number of the frame these CRCs are about * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt * * For each frame, the driver polls the source of CRCs for new data and calls * this function to add them to the buffer from where userspace reads. */ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, uint32_t frame, uint32_t *crcs) { … } EXPORT_SYMBOL_GPL(…);
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