Add a helper to dump the DPCD descriptor for an LTTPR PHY. This is based
on [1] and [2] moving the helper to DRM core as suggested by Ville.
[1] https://lore.kernel.org/all/20240703155937.1674856-5-imre.deak@xxxxxxxxx
[2] https://lore.kernel.org/all/20240703155937.1674856-6-imre.deak@xxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/display/drm_dp_helper.c | 66 +++++++++++++++++++++----
include/drm/display/drm_dp.h | 4 ++
include/drm/display/drm_dp_helper.h | 2 +
3 files changed, 62 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index d4c34f3641400..6ee51003de3ce 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -2328,6 +2328,31 @@ drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch)
#undef DEVICE_ID_ANY
#undef DEVICE_ID
+static int drm_dp_read_ident(struct drm_dp_aux *aux, unsigned int offset,
+ struct drm_dp_dpcd_ident *ident)
+{
+ int ret;
+
+ ret = drm_dp_dpcd_read(aux, offset, ident, sizeof(*ident));
+
+ return ret < 0 ? ret : 0;
+}
+
+static void drm_dp_dump_desc(struct drm_dp_aux *aux,
+ const char *device_name, const struct drm_dp_desc *desc)
+{
+ const struct drm_dp_dpcd_ident *ident = &desc->ident;
+
+ drm_dbg_kms(aux->drm_dev,
+ "%s: %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d quirks 0x%04x\n",
+ aux->name, device_name,
+ (int)sizeof(ident->oui), ident->oui,
+ (int)strnlen(ident->device_id, sizeof(ident->device_id)), ident->device_id,
+ ident->hw_rev >> 4, ident->hw_rev & 0xf,
+ ident->sw_major_rev, ident->sw_minor_rev,
+ desc->quirks);
+}
+
/**
* drm_dp_read_desc - read sink/branch descriptor from DPCD
* @aux: DisplayPort AUX channel
@@ -2344,27 +2369,48 @@ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
{
struct drm_dp_dpcd_ident *ident = &desc->ident;
unsigned int offset = is_branch ? DP_BRANCH_OUI : DP_SINK_OUI;
- int ret, dev_id_len;
+ int ret;
- ret = drm_dp_dpcd_read(aux, offset, ident, sizeof(*ident));
+ ret = drm_dp_read_ident(aux, offset, ident);
if (ret < 0)
return ret;
desc->quirks = drm_dp_get_quirks(ident, is_branch);
- dev_id_len = strnlen(ident->device_id, sizeof(ident->device_id));
-
- drm_dbg_kms(aux->drm_dev,
- "%s: DP %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d quirks 0x%04x\n",
- aux->name, is_branch ? "branch" : "sink",
- (int)sizeof(ident->oui), ident->oui, dev_id_len,
- ident->device_id, ident->hw_rev >> 4, ident->hw_rev & 0xf,
- ident->sw_major_rev, ident->sw_minor_rev, desc->quirks);
+ drm_dp_dump_desc(aux, is_branch ? "DP branch" : "DP sink", desc);
return 0;
}
EXPORT_SYMBOL(drm_dp_read_desc);
+/**
+ * drm_dp_dump_lttpr_desc - read and dump the DPCD descriptor for an LTTPR PHY
+ * @aux: DisplayPort AUX channel
+ * @dp_phy: LTTPR PHY instance
+ *
+ * Read the DPCD LTTPR PHY descriptor for @dp_phy and print a debug message
+ * with its details to dmesg.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int drm_dp_dump_lttpr_desc(struct drm_dp_aux *aux, enum drm_dp_phy dp_phy)
+{
+ struct drm_dp_desc desc = {};
+ int ret;
+
+ if (drm_WARN_ON(aux->drm_dev, dp_phy < DP_PHY_LTTPR1 || dp_phy > DP_MAX_LTTPR_COUNT))
+ return -EINVAL;
+
+ ret = drm_dp_read_ident(aux, DP_OUI_PHY_REPEATER(dp_phy), &desc.ident);
+ if (ret < 0)
+ return ret;
+
+ drm_dp_dump_desc(aux, drm_dp_phy_name(dp_phy), &desc);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_dp_dump_lttpr_desc);
+
/**
* drm_dp_dsc_sink_bpp_incr() - Get bits per pixel increment
* @dsc_dpcd: DSC capabilities from DPCD
diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
index 173548c6473a9..a6f8b098c56f1 100644
--- a/include/drm/display/drm_dp.h
+++ b/include/drm/display/drm_dp.h
@@ -1543,6 +1543,10 @@ enum drm_dp_phy {
#define DP_SYMBOL_ERROR_COUNT_LANE2_PHY_REPEATER1 0xf0039 /* 1.3 */
#define DP_SYMBOL_ERROR_COUNT_LANE3_PHY_REPEATER1 0xf003b /* 1.3 */
+#define DP_OUI_PHY_REPEATER1 0xf003d /* 1.3 */
+#define DP_OUI_PHY_REPEATER(dp_phy) \
+ DP_LTTPR_REG(dp_phy, DP_OUI_PHY_REPEATER1)
+
#define __DP_FEC1_BASE 0xf0290 /* 1.4 */
#define __DP_FEC2_BASE 0xf0298 /* 1.4 */
#define DP_FEC_BASE(dp_phy) \
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index ea03e1dd26ba7..bbb1cdc4fc68d 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -657,6 +657,8 @@ struct drm_dp_desc {
int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
bool is_branch);
+int drm_dp_dump_lttpr_desc(struct drm_dp_aux *aux, enum drm_dp_phy dp_phy);
+
/**
* enum drm_dp_quirk - Display Port sink/branch device specific quirks
*
