1 /* 2 * Copyright © 2009 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 #include <linux/export.h> 24 #include <drm/drmP.h> 25 #include <drm/drm_dp_helper.h> 26 27 28 /* Helpers for DP link training */ 29 static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r) 30 { 31 return link_status[r - DP_LANE0_1_STATUS]; 32 } 33 34 static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE], 35 int lane) 36 { 37 int i = DP_LANE0_1_STATUS + (lane >> 1); 38 int s = (lane & 1) * 4; 39 u8 l = dp_link_status(link_status, i); 40 return (l >> s) & 0xf; 41 } 42 43 bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE], 44 int lane_count) 45 { 46 u8 lane_align; 47 u8 lane_status; 48 int lane; 49 50 lane_align = dp_link_status(link_status, 51 DP_LANE_ALIGN_STATUS_UPDATED); 52 if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) 53 return false; 54 for (lane = 0; lane < lane_count; lane++) { 55 lane_status = dp_get_lane_status(link_status, lane); 56 if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) 57 return false; 58 } 59 return true; 60 } 61 EXPORT_SYMBOL(drm_dp_channel_eq_ok); 62 63 bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE], 64 int lane_count) 65 { 66 int lane; 67 u8 lane_status; 68 69 for (lane = 0; lane < lane_count; lane++) { 70 lane_status = dp_get_lane_status(link_status, lane); 71 if ((lane_status & DP_LANE_CR_DONE) == 0) 72 return false; 73 } 74 return true; 75 } 76 EXPORT_SYMBOL(drm_dp_clock_recovery_ok); 77 78 u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE], 79 int lane) 80 { 81 int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); 82 int s = ((lane & 1) ? 83 DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : 84 DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); 85 u8 l = dp_link_status(link_status, i); 86 87 return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT; 88 } 89 EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage); 90 91 u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE], 92 int lane) 93 { 94 int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); 95 int s = ((lane & 1) ? 96 DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : 97 DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); 98 u8 l = dp_link_status(link_status, i); 99 100 return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT; 101 } 102 EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); 103 104 void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { 105 if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) 106 udelay(100); 107 else 108 mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); 109 } 110 EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); 111 112 void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { 113 if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) 114 udelay(400); 115 else 116 mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); 117 } 118 EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); 119 120 u8 drm_dp_link_rate_to_bw_code(int link_rate) 121 { 122 switch (link_rate) { 123 case 162000: 124 default: 125 return DP_LINK_BW_1_62; 126 case 270000: 127 return DP_LINK_BW_2_7; 128 case 540000: 129 return DP_LINK_BW_5_4; 130 } 131 } 132 EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code); 133 134 int drm_dp_bw_code_to_link_rate(u8 link_bw) 135 { 136 switch (link_bw) { 137 case DP_LINK_BW_1_62: 138 default: 139 return 162000; 140 case DP_LINK_BW_2_7: 141 return 270000; 142 case DP_LINK_BW_5_4: 143 return 540000; 144 } 145 } 146 EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); 147