155 lines
4.5 KiB
C
155 lines
4.5 KiB
C
/*
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* Copyright © 2009 Keith Packard
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting documentation, and
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* that the name of the copyright holders not be used in advertising or
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* publicity pertaining to distribution of the software without specific,
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* written prior permission. The copyright holders make no representations
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* about the suitability of this software for any purpose. It is provided "as
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* is" without express or implied warranty.
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*
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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* OF THIS SOFTWARE.
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*/
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#include <sys/cdefs.h>
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#include <dev/drm2/drmP.h>
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#include <dev/drm2/drm_dp_helper.h>
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/**
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* DOC: dp helpers
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*
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* These functions contain some common logic and helpers at various abstraction
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* levels to deal with Display Port sink devices and related things like DP aux
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* channel transfers, EDID reading over DP aux channels, decoding certain DPCD
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* blocks, ...
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*/
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/* Helpers for DP link training */
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static u8 dp_link_status(u8 link_status[DP_LINK_STATUS_SIZE], int r)
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{
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return link_status[r - DP_LANE0_1_STATUS];
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}
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static u8 dp_get_lane_status(u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_LANE0_1_STATUS + (lane >> 1);
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int s = (lane & 1) * 4;
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u8 l = dp_link_status(link_status, i);
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return (l >> s) & 0xf;
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}
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bool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
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int lane_count)
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{
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u8 lane_align;
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u8 lane_status;
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int lane;
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lane_align = dp_link_status(link_status,
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DP_LANE_ALIGN_STATUS_UPDATED);
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if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
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return false;
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for (lane = 0; lane < lane_count; lane++) {
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lane_status = dp_get_lane_status(link_status, lane);
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if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS)
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return false;
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}
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return true;
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}
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EXPORT_SYMBOL(drm_dp_channel_eq_ok);
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bool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
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int lane_count)
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{
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int lane;
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u8 lane_status;
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for (lane = 0; lane < lane_count; lane++) {
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lane_status = dp_get_lane_status(link_status, lane);
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if ((lane_status & DP_LANE_CR_DONE) == 0)
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return false;
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}
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return true;
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}
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EXPORT_SYMBOL(drm_dp_clock_recovery_ok);
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u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
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int s = ((lane & 1) ?
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DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
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DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
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u8 l = dp_link_status(link_status, i);
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return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
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}
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EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage);
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u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
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int lane)
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{
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int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
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int s = ((lane & 1) ?
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DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
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DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
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u8 l = dp_link_status(link_status, i);
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return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
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}
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EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);
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void drm_dp_link_train_clock_recovery_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) {
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if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)
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udelay(100);
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else
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mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);
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}
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EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay);
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void drm_dp_link_train_channel_eq_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) {
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if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)
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udelay(400);
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else
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mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);
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}
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EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay);
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u8 drm_dp_link_rate_to_bw_code(int link_rate)
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{
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switch (link_rate) {
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case 162000:
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default:
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return DP_LINK_BW_1_62;
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case 270000:
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return DP_LINK_BW_2_7;
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case 540000:
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return DP_LINK_BW_5_4;
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}
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}
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EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code);
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int drm_dp_bw_code_to_link_rate(u8 link_bw)
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{
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switch (link_bw) {
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case DP_LINK_BW_1_62:
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default:
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return 162000;
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case DP_LINK_BW_2_7:
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return 270000;
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case DP_LINK_BW_5_4:
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return 540000;
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}
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}
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EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);
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