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drm/bridge: ti-sn65dsi86: Avoid invalid rates
Based on work by Bjorn Andersson <bjorn.andersson@linaro.org>, Jeffrey Hugo <jeffrey.l.hugo@gmail.com>, and Rob Clark <robdclark@chromium.org>. Let's read the SUPPORTED_LINK_RATES and/or MAX_LINK_RATE (depending on the eDP version of the sink) to figure out what eDP rates are supported and pick the ideal one. NOTE: I have only personally tested this code on eDP panels that are 1.3 or older. Code reading SUPPORTED_LINK_RATES for DP 1.4+ was tested by hacking the code to pretend that a table was there. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191218143416.v3.9.Ib59207b66db377380d13748752d6fce5596462c5@changeid
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1 changed files with 75 additions and 25 deletions
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@ -475,39 +475,85 @@ static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn_bridge *pdata)
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return i;
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return i;
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}
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}
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static int ti_sn_bridge_get_max_dp_rate_idx(struct ti_sn_bridge *pdata)
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static void ti_sn_bridge_read_valid_rates(struct ti_sn_bridge *pdata,
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bool rate_valid[])
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{
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{
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u8 data;
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unsigned int rate_per_200khz;
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unsigned int rate_mhz;
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u8 dpcd_val;
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int ret;
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int ret;
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int i, j;
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ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &data);
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ret = drm_dp_dpcd_readb(&pdata->aux, DP_EDP_DPCD_REV, &dpcd_val);
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if (ret != 1) {
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DRM_DEV_ERROR(pdata->dev,
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"Can't read eDP rev (%d), assuming 1.1\n", ret);
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dpcd_val = DP_EDP_11;
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}
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if (dpcd_val >= DP_EDP_14) {
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/* eDP 1.4 devices must provide a custom table */
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__le16 sink_rates[DP_MAX_SUPPORTED_RATES];
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ret = drm_dp_dpcd_read(&pdata->aux, DP_SUPPORTED_LINK_RATES,
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sink_rates, sizeof(sink_rates));
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if (ret != sizeof(sink_rates)) {
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DRM_DEV_ERROR(pdata->dev,
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"Can't read supported rate table (%d)\n", ret);
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/* By zeroing we'll fall back to DP_MAX_LINK_RATE. */
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memset(sink_rates, 0, sizeof(sink_rates));
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}
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for (i = 0; i < ARRAY_SIZE(sink_rates); i++) {
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rate_per_200khz = le16_to_cpu(sink_rates[i]);
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if (!rate_per_200khz)
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break;
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rate_mhz = rate_per_200khz * 200 / 1000;
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for (j = 0;
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j < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
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j++) {
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if (ti_sn_bridge_dp_rate_lut[j] == rate_mhz)
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rate_valid[j] = true;
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}
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}
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for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut); i++) {
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if (rate_valid[i])
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return;
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}
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DRM_DEV_ERROR(pdata->dev,
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"No matching eDP rates in table; falling back\n");
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}
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/* On older versions best we can do is use DP_MAX_LINK_RATE */
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ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &dpcd_val);
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if (ret != 1) {
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if (ret != 1) {
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DRM_DEV_ERROR(pdata->dev,
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DRM_DEV_ERROR(pdata->dev,
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"Can't read max rate (%d); assuming 5.4 GHz\n",
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"Can't read max rate (%d); assuming 5.4 GHz\n",
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ret);
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ret);
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return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1;
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dpcd_val = DP_LINK_BW_5_4;
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}
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}
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/*
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switch (dpcd_val) {
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* Return an index into ti_sn_bridge_dp_rate_lut. Just hardcode
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default:
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* these indicies since it's not like the register spec is ever going
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DRM_DEV_ERROR(pdata->dev,
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* to change and a loop would just be more complicated. Apparently
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"Unexpected max rate (%#x); assuming 5.4 GHz\n",
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* the DP sink can only return these few rates as supported even
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(int)dpcd_val);
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* though the bridge allows some rates in between.
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/* fall through */
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*/
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switch (data) {
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case DP_LINK_BW_1_62:
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return 1;
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case DP_LINK_BW_2_7:
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return 4;
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case DP_LINK_BW_5_4:
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case DP_LINK_BW_5_4:
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return 7;
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rate_valid[7] = 1;
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/* fall through */
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case DP_LINK_BW_2_7:
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rate_valid[4] = 1;
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/* fall through */
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case DP_LINK_BW_1_62:
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rate_valid[1] = 1;
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break;
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}
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}
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DRM_DEV_ERROR(pdata->dev,
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"Unexpected max data rate (%#x); assuming 5.4 GHz\n",
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(int)data);
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return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1;
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}
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}
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static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
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static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
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@ -609,9 +655,9 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata, int dp_rate_idx,
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static void ti_sn_bridge_enable(struct drm_bridge *bridge)
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static void ti_sn_bridge_enable(struct drm_bridge *bridge)
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{
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{
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struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
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struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
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bool rate_valid[ARRAY_SIZE(ti_sn_bridge_dp_rate_lut)] = { };
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const char *last_err_str = "No supported DP rate";
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const char *last_err_str = "No supported DP rate";
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int dp_rate_idx;
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int dp_rate_idx;
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int max_dp_rate_idx;
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unsigned int val;
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unsigned int val;
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int ret = -EINVAL;
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int ret = -EINVAL;
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@ -655,11 +701,15 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge)
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regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
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regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
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val);
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val);
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ti_sn_bridge_read_valid_rates(pdata, rate_valid);
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/* Train until we run out of rates */
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/* Train until we run out of rates */
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max_dp_rate_idx = ti_sn_bridge_get_max_dp_rate_idx(pdata);
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for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata);
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for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata);
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dp_rate_idx <= max_dp_rate_idx;
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dp_rate_idx < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
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dp_rate_idx++) {
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dp_rate_idx++) {
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if (!rate_valid[dp_rate_idx])
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continue;
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ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str);
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ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str);
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if (!ret)
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if (!ret)
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break;
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break;
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