1  /*
2   * Copyright © 2008 Keith Packard
3   *
4   * Permission to use, copy, modify, distribute, and sell this software and its
5   * documentation for any purpose is hereby granted without fee, provided that
6   * the above copyright notice appear in all copies and that both that copyright
7   * notice and this permission notice appear in supporting documentation, and
8   * that the name of the copyright holders not be used in advertising or
9   * publicity pertaining to distribution of the software without specific,
10   * written prior permission.  The copyright holders make no representations
11   * about the suitability of this software for any purpose.  It is provided "as
12   * is" without express or implied warranty.
13   *
14   * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15   * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16   * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17   * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18   * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19   * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20   * OF THIS SOFTWARE.
21   */
22  
23  #ifndef _DRM_DP_HELPER_H_
24  #define _DRM_DP_HELPER_H_
25  
26  #include <linux/delay.h>
27  #include <linux/i2c.h>
28  
29  #include <drm/display/drm_dp.h>
30  #include <drm/drm_connector.h>
31  
32  struct drm_device;
33  struct drm_dp_aux;
34  struct drm_panel;
35  
36  bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
37  			  int lane_count);
38  bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
39  			      int lane_count);
40  u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],
41  				     int lane);
42  u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE],
43  					  int lane);
44  u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE],
45  				   int lane);
46  
47  int drm_dp_read_clock_recovery_delay(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE],
48  				     enum drm_dp_phy dp_phy, bool uhbr);
49  int drm_dp_read_channel_eq_delay(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE],
50  				 enum drm_dp_phy dp_phy, bool uhbr);
51  
52  void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux,
53  					    const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
54  void drm_dp_lttpr_link_train_clock_recovery_delay(void);
55  void drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
56  					const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
57  void drm_dp_lttpr_link_train_channel_eq_delay(const struct drm_dp_aux *aux,
58  					      const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
59  
60  int drm_dp_128b132b_read_aux_rd_interval(struct drm_dp_aux *aux);
61  bool drm_dp_128b132b_lane_channel_eq_done(const u8 link_status[DP_LINK_STATUS_SIZE],
62  					  int lane_count);
63  bool drm_dp_128b132b_lane_symbol_locked(const u8 link_status[DP_LINK_STATUS_SIZE],
64  					int lane_count);
65  bool drm_dp_128b132b_eq_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE]);
66  bool drm_dp_128b132b_cds_interlane_align_done(const u8 link_status[DP_LINK_STATUS_SIZE]);
67  bool drm_dp_128b132b_link_training_failed(const u8 link_status[DP_LINK_STATUS_SIZE]);
68  
69  u8 drm_dp_link_rate_to_bw_code(int link_rate);
70  int drm_dp_bw_code_to_link_rate(u8 link_bw);
71  
72  const char *drm_dp_phy_name(enum drm_dp_phy dp_phy);
73  
74  /**
75   * struct drm_dp_vsc_sdp - drm DP VSC SDP
76   *
77   * This structure represents a DP VSC SDP of drm
78   * It is based on DP 1.4 spec [Table 2-116: VSC SDP Header Bytes] and
79   * [Table 2-117: VSC SDP Payload for DB16 through DB18]
80   *
81   * @sdp_type: secondary-data packet type
82   * @revision: revision number
83   * @length: number of valid data bytes
84   * @pixelformat: pixel encoding format
85   * @colorimetry: colorimetry format
86   * @bpc: bit per color
87   * @dynamic_range: dynamic range information
88   * @content_type: CTA-861-G defines content types and expected processing by a sink device
89   */
90  struct drm_dp_vsc_sdp {
91  	unsigned char sdp_type;
92  	unsigned char revision;
93  	unsigned char length;
94  	enum dp_pixelformat pixelformat;
95  	enum dp_colorimetry colorimetry;
96  	int bpc;
97  	enum dp_dynamic_range dynamic_range;
98  	enum dp_content_type content_type;
99  };
100  
101  /**
102   * struct drm_dp_as_sdp - drm DP Adaptive Sync SDP
103   *
104   * This structure represents a DP AS SDP of drm
105   * It is based on DP 2.1 spec [Table 2-126:  Adaptive-Sync SDP Header Bytes] and
106   * [Table 2-127: Adaptive-Sync SDP Payload for DB0 through DB8]
107   *
108   * @sdp_type: Secondary-data packet type
109   * @revision: Revision Number
110   * @length: Number of valid data bytes
111   * @vtotal: Minimum Vertical Vtotal
112   * @target_rr: Target Refresh
113   * @duration_incr_ms: Successive frame duration increase
114   * @duration_decr_ms: Successive frame duration decrease
115   * @target_rr_divider: Target refresh rate divider
116   * @mode: Adaptive Sync Operation Mode
117   */
118  struct drm_dp_as_sdp {
119  	unsigned char sdp_type;
120  	unsigned char revision;
121  	unsigned char length;
122  	int vtotal;
123  	int target_rr;
124  	int duration_incr_ms;
125  	int duration_decr_ms;
126  	bool target_rr_divider;
127  	enum operation_mode mode;
128  };
129  
130  void drm_dp_as_sdp_log(struct drm_printer *p,
131  		       const struct drm_dp_as_sdp *as_sdp);
132  void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc);
133  
134  bool drm_dp_vsc_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
135  bool drm_dp_as_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
136  
137  int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]);
138  
139  static inline int
drm_dp_max_link_rate(const u8 dpcd[DP_RECEIVER_CAP_SIZE])140  drm_dp_max_link_rate(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
141  {
142  	return drm_dp_bw_code_to_link_rate(dpcd[DP_MAX_LINK_RATE]);
143  }
144  
145  static inline u8
drm_dp_max_lane_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE])146  drm_dp_max_lane_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
147  {
148  	return dpcd[DP_MAX_LANE_COUNT] & DP_MAX_LANE_COUNT_MASK;
149  }
150  
151  static inline bool
drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])152  drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
153  {
154  	return dpcd[DP_DPCD_REV] >= 0x11 &&
155  		(dpcd[DP_MAX_LANE_COUNT] & DP_ENHANCED_FRAME_CAP);
156  }
157  
158  static inline bool
drm_dp_fast_training_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])159  drm_dp_fast_training_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
160  {
161  	return dpcd[DP_DPCD_REV] >= 0x11 &&
162  		(dpcd[DP_MAX_DOWNSPREAD] & DP_NO_AUX_HANDSHAKE_LINK_TRAINING);
163  }
164  
165  static inline bool
drm_dp_tps3_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])166  drm_dp_tps3_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
167  {
168  	return dpcd[DP_DPCD_REV] >= 0x12 &&
169  		dpcd[DP_MAX_LANE_COUNT] & DP_TPS3_SUPPORTED;
170  }
171  
172  static inline bool
drm_dp_max_downspread(const u8 dpcd[DP_RECEIVER_CAP_SIZE])173  drm_dp_max_downspread(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
174  {
175  	return dpcd[DP_DPCD_REV] >= 0x11 ||
176  		dpcd[DP_MAX_DOWNSPREAD] & DP_MAX_DOWNSPREAD_0_5;
177  }
178  
179  static inline bool
drm_dp_tps4_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])180  drm_dp_tps4_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
181  {
182  	return dpcd[DP_DPCD_REV] >= 0x14 &&
183  		dpcd[DP_MAX_DOWNSPREAD] & DP_TPS4_SUPPORTED;
184  }
185  
186  static inline u8
drm_dp_training_pattern_mask(const u8 dpcd[DP_RECEIVER_CAP_SIZE])187  drm_dp_training_pattern_mask(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
188  {
189  	return (dpcd[DP_DPCD_REV] >= 0x14) ? DP_TRAINING_PATTERN_MASK_1_4 :
190  		DP_TRAINING_PATTERN_MASK;
191  }
192  
193  static inline bool
drm_dp_is_branch(const u8 dpcd[DP_RECEIVER_CAP_SIZE])194  drm_dp_is_branch(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
195  {
196  	return dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT;
197  }
198  
199  /* DP/eDP DSC support */
200  u8 drm_dp_dsc_sink_bpp_incr(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]);
201  u8 drm_dp_dsc_sink_max_slice_count(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE],
202  				   bool is_edp);
203  u8 drm_dp_dsc_sink_line_buf_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]);
204  int drm_dp_dsc_sink_supported_input_bpcs(const u8 dsc_dpc[DP_DSC_RECEIVER_CAP_SIZE],
205  					 u8 dsc_bpc[3]);
206  
207  static inline bool
drm_dp_sink_supports_dsc(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])208  drm_dp_sink_supports_dsc(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
209  {
210  	return dsc_dpcd[DP_DSC_SUPPORT - DP_DSC_SUPPORT] &
211  		DP_DSC_DECOMPRESSION_IS_SUPPORTED;
212  }
213  
214  static inline u16
drm_edp_dsc_sink_output_bpp(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])215  drm_edp_dsc_sink_output_bpp(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
216  {
217  	return dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
218  		((dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
219  		  DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK) << 8);
220  }
221  
222  static inline u32
drm_dp_dsc_sink_max_slice_width(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])223  drm_dp_dsc_sink_max_slice_width(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
224  {
225  	/* Max Slicewidth = Number of Pixels * 320 */
226  	return dsc_dpcd[DP_DSC_MAX_SLICE_WIDTH - DP_DSC_SUPPORT] *
227  		DP_DSC_SLICE_WIDTH_MULTIPLIER;
228  }
229  
230  /**
231   * drm_dp_dsc_sink_supports_format() - check if sink supports DSC with given output format
232   * @dsc_dpcd : DSC-capability DPCDs of the sink
233   * @output_format: output_format which is to be checked
234   *
235   * Returns true if the sink supports DSC with the given output_format, false otherwise.
236   */
237  static inline bool
drm_dp_dsc_sink_supports_format(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE],u8 output_format)238  drm_dp_dsc_sink_supports_format(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE], u8 output_format)
239  {
240  	return dsc_dpcd[DP_DSC_DEC_COLOR_FORMAT_CAP - DP_DSC_SUPPORT] & output_format;
241  }
242  
243  /* Forward Error Correction Support on DP 1.4 */
244  static inline bool
drm_dp_sink_supports_fec(const u8 fec_capable)245  drm_dp_sink_supports_fec(const u8 fec_capable)
246  {
247  	return fec_capable & DP_FEC_CAPABLE;
248  }
249  
250  static inline bool
drm_dp_channel_coding_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])251  drm_dp_channel_coding_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
252  {
253  	return dpcd[DP_MAIN_LINK_CHANNEL_CODING] & DP_CAP_ANSI_8B10B;
254  }
255  
256  static inline bool
drm_dp_128b132b_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])257  drm_dp_128b132b_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
258  {
259  	return dpcd[DP_MAIN_LINK_CHANNEL_CODING] & DP_CAP_ANSI_128B132B;
260  }
261  
262  static inline bool
drm_dp_alternate_scrambler_reset_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])263  drm_dp_alternate_scrambler_reset_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
264  {
265  	return dpcd[DP_EDP_CONFIGURATION_CAP] &
266  			DP_ALTERNATE_SCRAMBLER_RESET_CAP;
267  }
268  
269  /* Ignore MSA timing for Adaptive Sync support on DP 1.4 */
270  static inline bool
drm_dp_sink_can_do_video_without_timing_msa(const u8 dpcd[DP_RECEIVER_CAP_SIZE])271  drm_dp_sink_can_do_video_without_timing_msa(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
272  {
273  	return dpcd[DP_DOWN_STREAM_PORT_COUNT] &
274  		DP_MSA_TIMING_PAR_IGNORED;
275  }
276  
277  /**
278   * drm_edp_backlight_supported() - Check an eDP DPCD for VESA backlight support
279   * @edp_dpcd: The DPCD to check
280   *
281   * Note that currently this function will return %false for panels which support various DPCD
282   * backlight features but which require the brightness be set through PWM, and don't support setting
283   * the brightness level via the DPCD.
284   *
285   * Returns: %True if @edp_dpcd indicates that VESA backlight controls are supported, %false
286   * otherwise
287   */
288  static inline bool
drm_edp_backlight_supported(const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE])289  drm_edp_backlight_supported(const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE])
290  {
291  	return !!(edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP);
292  }
293  
294  /**
295   * drm_dp_is_uhbr_rate - Determine if a link rate is UHBR
296   * @link_rate: link rate in 10kbits/s units
297   *
298   * Determine if the provided link rate is an UHBR rate.
299   *
300   * Returns: %True if @link_rate is an UHBR rate.
301   */
drm_dp_is_uhbr_rate(int link_rate)302  static inline bool drm_dp_is_uhbr_rate(int link_rate)
303  {
304  	return link_rate >= 1000000;
305  }
306  
307  /*
308   * DisplayPort AUX channel
309   */
310  
311  /**
312   * struct drm_dp_aux_msg - DisplayPort AUX channel transaction
313   * @address: address of the (first) register to access
314   * @request: contains the type of transaction (see DP_AUX_* macros)
315   * @reply: upon completion, contains the reply type of the transaction
316   * @buffer: pointer to a transmission or reception buffer
317   * @size: size of @buffer
318   */
319  struct drm_dp_aux_msg {
320  	unsigned int address;
321  	u8 request;
322  	u8 reply;
323  	void *buffer;
324  	size_t size;
325  };
326  
327  struct cec_adapter;
328  struct drm_connector;
329  struct drm_edid;
330  
331  /**
332   * struct drm_dp_aux_cec - DisplayPort CEC-Tunneling-over-AUX
333   * @lock: mutex protecting this struct
334   * @adap: the CEC adapter for CEC-Tunneling-over-AUX support.
335   * @connector: the connector this CEC adapter is associated with
336   * @unregister_work: unregister the CEC adapter
337   */
338  struct drm_dp_aux_cec {
339  	struct mutex lock;
340  	struct cec_adapter *adap;
341  	struct drm_connector *connector;
342  	struct delayed_work unregister_work;
343  };
344  
345  /**
346   * struct drm_dp_aux - DisplayPort AUX channel
347   *
348   * An AUX channel can also be used to transport I2C messages to a sink. A
349   * typical application of that is to access an EDID that's present in the sink
350   * device. The @transfer() function can also be used to execute such
351   * transactions. The drm_dp_aux_register() function registers an I2C adapter
352   * that can be passed to drm_probe_ddc(). Upon removal, drivers should call
353   * drm_dp_aux_unregister() to remove the I2C adapter. The I2C adapter uses long
354   * transfers by default; if a partial response is received, the adapter will
355   * drop down to the size given by the partial response for this transaction
356   * only.
357   */
358  struct drm_dp_aux {
359  	/**
360  	 * @name: user-visible name of this AUX channel and the
361  	 * I2C-over-AUX adapter.
362  	 *
363  	 * It's also used to specify the name of the I2C adapter. If set
364  	 * to %NULL, dev_name() of @dev will be used.
365  	 */
366  	const char *name;
367  
368  	/**
369  	 * @ddc: I2C adapter that can be used for I2C-over-AUX
370  	 * communication
371  	 */
372  	struct i2c_adapter ddc;
373  
374  	/**
375  	 * @dev: pointer to struct device that is the parent for this
376  	 * AUX channel.
377  	 */
378  	struct device *dev;
379  
380  	/**
381  	 * @drm_dev: pointer to the &drm_device that owns this AUX channel.
382  	 * Beware, this may be %NULL before drm_dp_aux_register() has been
383  	 * called.
384  	 *
385  	 * It should be set to the &drm_device that will be using this AUX
386  	 * channel as early as possible. For many graphics drivers this should
387  	 * happen before drm_dp_aux_init(), however it's perfectly fine to set
388  	 * this field later so long as it's assigned before calling
389  	 * drm_dp_aux_register().
390  	 */
391  	struct drm_device *drm_dev;
392  
393  	/**
394  	 * @crtc: backpointer to the crtc that is currently using this
395  	 * AUX channel
396  	 */
397  	struct drm_crtc *crtc;
398  
399  	/**
400  	 * @hw_mutex: internal mutex used for locking transfers.
401  	 *
402  	 * Note that if the underlying hardware is shared among multiple
403  	 * channels, the driver needs to do additional locking to
404  	 * prevent concurrent access.
405  	 */
406  	struct mutex hw_mutex;
407  
408  	/**
409  	 * @crc_work: worker that captures CRCs for each frame
410  	 */
411  	struct work_struct crc_work;
412  
413  	/**
414  	 * @crc_count: counter of captured frame CRCs
415  	 */
416  	u8 crc_count;
417  
418  	/**
419  	 * @transfer: transfers a message representing a single AUX
420  	 * transaction.
421  	 *
422  	 * This is a hardware-specific implementation of how
423  	 * transactions are executed that the drivers must provide.
424  	 *
425  	 * A pointer to a &drm_dp_aux_msg structure describing the
426  	 * transaction is passed into this function. Upon success, the
427  	 * implementation should return the number of payload bytes that
428  	 * were transferred, or a negative error-code on failure.
429  	 *
430  	 * Helpers will propagate these errors, with the exception of
431  	 * the %-EBUSY error, which causes a transaction to be retried.
432  	 * On a short, helpers will return %-EPROTO to make it simpler
433  	 * to check for failure.
434  	 *
435  	 * The @transfer() function must only modify the reply field of
436  	 * the &drm_dp_aux_msg structure. The retry logic and i2c
437  	 * helpers assume this is the case.
438  	 *
439  	 * Also note that this callback can be called no matter the
440  	 * state @dev is in and also no matter what state the panel is
441  	 * in. It's expected:
442  	 *
443  	 * - If the @dev providing the AUX bus is currently unpowered then
444  	 *   it will power itself up for the transfer.
445  	 *
446  	 * - If we're on eDP (using a drm_panel) and the panel is not in a
447  	 *   state where it can respond (it's not powered or it's in a
448  	 *   low power state) then this function may return an error, but
449  	 *   not crash. It's up to the caller of this code to make sure that
450  	 *   the panel is powered on if getting an error back is not OK. If a
451  	 *   drm_panel driver is initiating a DP AUX transfer it may power
452  	 *   itself up however it wants. All other code should ensure that
453  	 *   the pre_enable() bridge chain (which eventually calls the
454  	 *   drm_panel prepare function) has powered the panel.
455  	 */
456  	ssize_t (*transfer)(struct drm_dp_aux *aux,
457  			    struct drm_dp_aux_msg *msg);
458  
459  	/**
460  	 * @wait_hpd_asserted: wait for HPD to be asserted
461  	 *
462  	 * This is mainly useful for eDP panels drivers to wait for an eDP
463  	 * panel to finish powering on. It is optional for DP AUX controllers
464  	 * to implement this function. It is required for DP AUX endpoints
465  	 * (panel drivers) to call this function after powering up but before
466  	 * doing AUX transfers unless the DP AUX endpoint driver knows that
467  	 * we're not using the AUX controller's HPD. One example of the panel
468  	 * driver not needing to call this is if HPD is hooked up to a GPIO
469  	 * that the panel driver can read directly.
470  	 *
471  	 * If a DP AUX controller does not implement this function then it
472  	 * may still support eDP panels that use the AUX controller's built-in
473  	 * HPD signal by implementing a long wait for HPD in the transfer()
474  	 * callback, though this is deprecated.
475  	 *
476  	 * This function will efficiently wait for the HPD signal to be
477  	 * asserted. The `wait_us` parameter that is passed in says that we
478  	 * know that the HPD signal is expected to be asserted within `wait_us`
479  	 * microseconds. This function could wait for longer than `wait_us` if
480  	 * the logic in the DP controller has a long debouncing time. The
481  	 * important thing is that if this function returns success that the
482  	 * DP controller is ready to send AUX transactions.
483  	 *
484  	 * This function returns 0 if HPD was asserted or -ETIMEDOUT if time
485  	 * expired and HPD wasn't asserted. This function should not print
486  	 * timeout errors to the log.
487  	 *
488  	 * The semantics of this function are designed to match the
489  	 * readx_poll_timeout() function. That means a `wait_us` of 0 means
490  	 * to wait forever. Like readx_poll_timeout(), this function may sleep.
491  	 *
492  	 * NOTE: this function specifically reports the state of the HPD pin
493  	 * that's associated with the DP AUX channel. This is different from
494  	 * the HPD concept in much of the rest of DRM which is more about
495  	 * physical presence of a display. For eDP, for instance, a display is
496  	 * assumed always present even if the HPD pin is deasserted.
497  	 */
498  	int (*wait_hpd_asserted)(struct drm_dp_aux *aux, unsigned long wait_us);
499  
500  	/**
501  	 * @i2c_nack_count: Counts I2C NACKs, used for DP validation.
502  	 */
503  	unsigned i2c_nack_count;
504  	/**
505  	 * @i2c_defer_count: Counts I2C DEFERs, used for DP validation.
506  	 */
507  	unsigned i2c_defer_count;
508  	/**
509  	 * @cec: struct containing fields used for CEC-Tunneling-over-AUX.
510  	 */
511  	struct drm_dp_aux_cec cec;
512  	/**
513  	 * @is_remote: Is this AUX CH actually using sideband messaging.
514  	 */
515  	bool is_remote;
516  
517  	/**
518  	 * @powered_down: If true then the remote endpoint is powered down.
519  	 */
520  	bool powered_down;
521  };
522  
523  int drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset);
524  void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered);
525  ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
526  			 void *buffer, size_t size);
527  ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset,
528  			  void *buffer, size_t size);
529  
530  /**
531   * drm_dp_dpcd_readb() - read a single byte from the DPCD
532   * @aux: DisplayPort AUX channel
533   * @offset: address of the register to read
534   * @valuep: location where the value of the register will be stored
535   *
536   * Returns the number of bytes transferred (1) on success, or a negative
537   * error code on failure.
538   */
drm_dp_dpcd_readb(struct drm_dp_aux * aux,unsigned int offset,u8 * valuep)539  static inline ssize_t drm_dp_dpcd_readb(struct drm_dp_aux *aux,
540  					unsigned int offset, u8 *valuep)
541  {
542  	return drm_dp_dpcd_read(aux, offset, valuep, 1);
543  }
544  
545  /**
546   * drm_dp_dpcd_writeb() - write a single byte to the DPCD
547   * @aux: DisplayPort AUX channel
548   * @offset: address of the register to write
549   * @value: value to write to the register
550   *
551   * Returns the number of bytes transferred (1) on success, or a negative
552   * error code on failure.
553   */
drm_dp_dpcd_writeb(struct drm_dp_aux * aux,unsigned int offset,u8 value)554  static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux,
555  					 unsigned int offset, u8 value)
556  {
557  	return drm_dp_dpcd_write(aux, offset, &value, 1);
558  }
559  
560  int drm_dp_read_dpcd_caps(struct drm_dp_aux *aux,
561  			  u8 dpcd[DP_RECEIVER_CAP_SIZE]);
562  
563  int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
564  				 u8 status[DP_LINK_STATUS_SIZE]);
565  
566  int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
567  				     enum drm_dp_phy dp_phy,
568  				     u8 link_status[DP_LINK_STATUS_SIZE]);
569  
570  bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
571  				    u8 real_edid_checksum);
572  
573  int drm_dp_read_downstream_info(struct drm_dp_aux *aux,
574  				const u8 dpcd[DP_RECEIVER_CAP_SIZE],
575  				u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS]);
576  bool drm_dp_downstream_is_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
577  			       const u8 port_cap[4], u8 type);
578  bool drm_dp_downstream_is_tmds(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
579  			       const u8 port_cap[4],
580  			       const struct drm_edid *drm_edid);
581  int drm_dp_downstream_max_dotclock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
582  				   const u8 port_cap[4]);
583  int drm_dp_downstream_max_tmds_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
584  				     const u8 port_cap[4],
585  				     const struct drm_edid *drm_edid);
586  int drm_dp_downstream_min_tmds_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
587  				     const u8 port_cap[4],
588  				     const struct drm_edid *drm_edid);
589  int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
590  			      const u8 port_cap[4],
591  			      const struct drm_edid *drm_edid);
592  bool drm_dp_downstream_420_passthrough(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
593  				       const u8 port_cap[4]);
594  bool drm_dp_downstream_444_to_420_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
595  					     const u8 port_cap[4]);
596  struct drm_display_mode *drm_dp_downstream_mode(struct drm_device *dev,
597  						const u8 dpcd[DP_RECEIVER_CAP_SIZE],
598  						const u8 port_cap[4]);
599  int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);
600  void drm_dp_downstream_debug(struct seq_file *m,
601  			     const u8 dpcd[DP_RECEIVER_CAP_SIZE],
602  			     const u8 port_cap[4],
603  			     const struct drm_edid *drm_edid,
604  			     struct drm_dp_aux *aux);
605  enum drm_mode_subconnector
606  drm_dp_subconnector_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
607  			 const u8 port_cap[4]);
608  void drm_dp_set_subconnector_property(struct drm_connector *connector,
609  				      enum drm_connector_status status,
610  				      const u8 *dpcd,
611  				      const u8 port_cap[4]);
612  
613  struct drm_dp_desc;
614  bool drm_dp_read_sink_count_cap(struct drm_connector *connector,
615  				const u8 dpcd[DP_RECEIVER_CAP_SIZE],
616  				const struct drm_dp_desc *desc);
617  int drm_dp_read_sink_count(struct drm_dp_aux *aux);
618  
619  int drm_dp_read_lttpr_common_caps(struct drm_dp_aux *aux,
620  				  const u8 dpcd[DP_RECEIVER_CAP_SIZE],
621  				  u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
622  int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux,
623  			       const u8 dpcd[DP_RECEIVER_CAP_SIZE],
624  			       enum drm_dp_phy dp_phy,
625  			       u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
626  int drm_dp_lttpr_count(const u8 cap[DP_LTTPR_COMMON_CAP_SIZE]);
627  int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
628  int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
629  bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
630  bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
631  
632  void drm_dp_remote_aux_init(struct drm_dp_aux *aux);
633  void drm_dp_aux_init(struct drm_dp_aux *aux);
634  int drm_dp_aux_register(struct drm_dp_aux *aux);
635  void drm_dp_aux_unregister(struct drm_dp_aux *aux);
636  
637  int drm_dp_start_crc(struct drm_dp_aux *aux, struct drm_crtc *crtc);
638  int drm_dp_stop_crc(struct drm_dp_aux *aux);
639  
640  struct drm_dp_dpcd_ident {
641  	u8 oui[3];
642  	u8 device_id[6];
643  	u8 hw_rev;
644  	u8 sw_major_rev;
645  	u8 sw_minor_rev;
646  } __packed;
647  
648  /**
649   * struct drm_dp_desc - DP branch/sink device descriptor
650   * @ident: DP device identification from DPCD 0x400 (sink) or 0x500 (branch).
651   * @quirks: Quirks; use drm_dp_has_quirk() to query for the quirks.
652   */
653  struct drm_dp_desc {
654  	struct drm_dp_dpcd_ident ident;
655  	u32 quirks;
656  };
657  
658  int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
659  		     bool is_branch);
660  
661  int drm_dp_dump_lttpr_desc(struct drm_dp_aux *aux, enum drm_dp_phy dp_phy);
662  
663  /**
664   * enum drm_dp_quirk - Display Port sink/branch device specific quirks
665   *
666   * Display Port sink and branch devices in the wild have a variety of bugs, try
667   * to collect them here. The quirks are shared, but it's up to the drivers to
668   * implement workarounds for them.
669   */
670  enum drm_dp_quirk {
671  	/**
672  	 * @DP_DPCD_QUIRK_CONSTANT_N:
673  	 *
674  	 * The device requires main link attributes Mvid and Nvid to be limited
675  	 * to 16 bits. So will give a constant value (0x8000) for compatability.
676  	 */
677  	DP_DPCD_QUIRK_CONSTANT_N,
678  	/**
679  	 * @DP_DPCD_QUIRK_NO_PSR:
680  	 *
681  	 * The device does not support PSR even if reports that it supports or
682  	 * driver still need to implement proper handling for such device.
683  	 */
684  	DP_DPCD_QUIRK_NO_PSR,
685  	/**
686  	 * @DP_DPCD_QUIRK_NO_SINK_COUNT:
687  	 *
688  	 * The device does not set SINK_COUNT to a non-zero value.
689  	 * The driver should ignore SINK_COUNT during detection. Note that
690  	 * drm_dp_read_sink_count_cap() automatically checks for this quirk.
691  	 */
692  	DP_DPCD_QUIRK_NO_SINK_COUNT,
693  	/**
694  	 * @DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD:
695  	 *
696  	 * The device supports MST DSC despite not supporting Virtual DPCD.
697  	 * The DSC caps can be read from the physical aux instead.
698  	 */
699  	DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
700  	/**
701  	 * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS:
702  	 *
703  	 * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite
704  	 * the DP_MAX_LINK_RATE register reporting a lower max multiplier.
705  	 */
706  	DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS,
707  	/**
708  	 * @DP_DPCD_QUIRK_HBLANK_EXPANSION_REQUIRES_DSC:
709  	 *
710  	 * The device applies HBLANK expansion for some modes, but this
711  	 * requires enabling DSC.
712  	 */
713  	DP_DPCD_QUIRK_HBLANK_EXPANSION_REQUIRES_DSC,
714  };
715  
716  /**
717   * drm_dp_has_quirk() - does the DP device have a specific quirk
718   * @desc: Device descriptor filled by drm_dp_read_desc()
719   * @quirk: Quirk to query for
720   *
721   * Return true if DP device identified by @desc has @quirk.
722   */
723  static inline bool
drm_dp_has_quirk(const struct drm_dp_desc * desc,enum drm_dp_quirk quirk)724  drm_dp_has_quirk(const struct drm_dp_desc *desc, enum drm_dp_quirk quirk)
725  {
726  	return desc->quirks & BIT(quirk);
727  }
728  
729  /**
730   * struct drm_edp_backlight_info - Probed eDP backlight info struct
731   * @pwmgen_bit_count: The pwmgen bit count
732   * @pwm_freq_pre_divider: The PWM frequency pre-divider value being used for this backlight, if any
733   * @max: The maximum backlight level that may be set
734   * @lsb_reg_used: Do we also write values to the DP_EDP_BACKLIGHT_BRIGHTNESS_LSB register?
735   * @aux_enable: Does the panel support the AUX enable cap?
736   * @aux_set: Does the panel support setting the brightness through AUX?
737   *
738   * This structure contains various data about an eDP backlight, which can be populated by using
739   * drm_edp_backlight_init().
740   */
741  struct drm_edp_backlight_info {
742  	u8 pwmgen_bit_count;
743  	u8 pwm_freq_pre_divider;
744  	u16 max;
745  
746  	bool lsb_reg_used : 1;
747  	bool aux_enable : 1;
748  	bool aux_set : 1;
749  };
750  
751  int
752  drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl,
753  		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
754  		       u16 *current_level, u8 *current_mode);
755  int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl,
756  				u16 level);
757  int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl,
758  			     u16 level);
759  int drm_edp_backlight_disable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl);
760  
761  #if IS_ENABLED(CONFIG_DRM_KMS_HELPER) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
762  	(IS_MODULE(CONFIG_DRM_KMS_HELPER) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
763  
764  int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);
765  
766  #else
767  
drm_panel_dp_aux_backlight(struct drm_panel * panel,struct drm_dp_aux * aux)768  static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,
769  					     struct drm_dp_aux *aux)
770  {
771  	return 0;
772  }
773  
774  #endif
775  
776  #ifdef CONFIG_DRM_DISPLAY_DP_AUX_CEC
777  void drm_dp_cec_irq(struct drm_dp_aux *aux);
778  void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
779  				   struct drm_connector *connector);
780  void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux);
781  void drm_dp_cec_attach(struct drm_dp_aux *aux, u16 source_physical_address);
782  void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid);
783  void drm_dp_cec_unset_edid(struct drm_dp_aux *aux);
784  #else
drm_dp_cec_irq(struct drm_dp_aux * aux)785  static inline void drm_dp_cec_irq(struct drm_dp_aux *aux)
786  {
787  }
788  
789  static inline void
drm_dp_cec_register_connector(struct drm_dp_aux * aux,struct drm_connector * connector)790  drm_dp_cec_register_connector(struct drm_dp_aux *aux,
791  			      struct drm_connector *connector)
792  {
793  }
794  
drm_dp_cec_unregister_connector(struct drm_dp_aux * aux)795  static inline void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux)
796  {
797  }
798  
drm_dp_cec_attach(struct drm_dp_aux * aux,u16 source_physical_address)799  static inline void drm_dp_cec_attach(struct drm_dp_aux *aux,
800  				     u16 source_physical_address)
801  {
802  }
803  
drm_dp_cec_set_edid(struct drm_dp_aux * aux,const struct edid * edid)804  static inline void drm_dp_cec_set_edid(struct drm_dp_aux *aux,
805  				       const struct edid *edid)
806  {
807  }
808  
drm_dp_cec_unset_edid(struct drm_dp_aux * aux)809  static inline void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
810  {
811  }
812  
813  #endif
814  
815  /**
816   * struct drm_dp_phy_test_params - DP Phy Compliance parameters
817   * @link_rate: Requested Link rate from DPCD 0x219
818   * @num_lanes: Number of lanes requested by sing through DPCD 0x220
819   * @phy_pattern: DP Phy test pattern from DPCD 0x248
820   * @hbr2_reset: DP HBR2_COMPLIANCE_SCRAMBLER_RESET from DCPD 0x24A and 0x24B
821   * @custom80: DP Test_80BIT_CUSTOM_PATTERN from DPCDs 0x250 through 0x259
822   * @enhanced_frame_cap: flag for enhanced frame capability.
823   */
824  struct drm_dp_phy_test_params {
825  	int link_rate;
826  	u8 num_lanes;
827  	u8 phy_pattern;
828  	u8 hbr2_reset[2];
829  	u8 custom80[10];
830  	bool enhanced_frame_cap;
831  };
832  
833  int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
834  				struct drm_dp_phy_test_params *data);
835  int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
836  				struct drm_dp_phy_test_params *data, u8 dp_rev);
837  int drm_dp_get_pcon_max_frl_bw(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
838  			       const u8 port_cap[4]);
839  int drm_dp_pcon_frl_prepare(struct drm_dp_aux *aux, bool enable_frl_ready_hpd);
840  bool drm_dp_pcon_is_frl_ready(struct drm_dp_aux *aux);
841  int drm_dp_pcon_frl_configure_1(struct drm_dp_aux *aux, int max_frl_gbps,
842  				u8 frl_mode);
843  int drm_dp_pcon_frl_configure_2(struct drm_dp_aux *aux, int max_frl_mask,
844  				u8 frl_type);
845  int drm_dp_pcon_reset_frl_config(struct drm_dp_aux *aux);
846  int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux);
847  
848  bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux);
849  int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask);
850  void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux,
851  					   struct drm_connector *connector);
852  bool drm_dp_pcon_enc_is_dsc_1_2(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
853  int drm_dp_pcon_dsc_max_slices(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
854  int drm_dp_pcon_dsc_max_slice_width(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
855  int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]);
856  int drm_dp_pcon_pps_default(struct drm_dp_aux *aux);
857  int drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128]);
858  int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]);
859  bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
860  					       const u8 port_cap[4], u8 color_spc);
861  int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8 color_spc);
862  
863  #define DRM_DP_BW_OVERHEAD_MST		BIT(0)
864  #define DRM_DP_BW_OVERHEAD_UHBR		BIT(1)
865  #define DRM_DP_BW_OVERHEAD_SSC_REF_CLK	BIT(2)
866  #define DRM_DP_BW_OVERHEAD_FEC		BIT(3)
867  #define DRM_DP_BW_OVERHEAD_DSC		BIT(4)
868  
869  int drm_dp_bw_overhead(int lane_count, int hactive,
870  		       int dsc_slice_count,
871  		       int bpp_x16, unsigned long flags);
872  int drm_dp_bw_channel_coding_efficiency(bool is_uhbr);
873  int drm_dp_max_dprx_data_rate(int max_link_rate, int max_lanes);
874  
875  ssize_t drm_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc, struct dp_sdp *sdp);
876  
877  #endif /* _DRM_DP_HELPER_H_ */
878