[PATCH 2/3][SRU][OEM-5.6] drm/i915/dp: Extract drm_dp_read_dpcd_caps()
Koba Ko
koba.ko at canonical.com
Wed Sep 16 06:51:21 UTC 2020
From: Lyude Paul <lyude at redhat.com>
BugLink: https://bugs.launchpad.net/bugs/1893752
Since DP 1.3, it's been possible for DP receivers to specify an
additional set of DPCD capabilities, which can take precedence over the
capabilities reported at DP_DPCD_REV.
Basically any device supporting DP is going to need to read these in an
identical manner, in particular nouveau, so let's go ahead and just move
this code out of i915 into a shared DRM DP helper that we can use in
other drivers.
v2:
* Remove redundant dpcd[DP_DPCD_REV] == 0 check
* Fix drm_dp_dpcd_read() ret checks
Signed-off-by: Lyude Paul <lyude at redhat.com>
Reviewed-by: Sean Paul <sean at poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-20-lyude@redhat.com
(cherry picked from commit b9936121d95b0127d34fa6c25678994582d1b17c drmtip)
Signed-off-by: Koba Ko <koba.ko at canonical.com>
---
drivers/gpu/drm/drm_dp_helper.c | 187 ++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_dp.c | 56 +-----
drivers/gpu/drm/i915/display/intel_dp.h | 1 -
drivers/gpu/drm/i915/display/intel_lspcon.c | 2 +-
include/drm/drm_dp_helper.h | 3 +
5 files changed, 195 insertions(+), 54 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index aaadc192d9cb..61a336c311e3 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -361,6 +361,193 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
}
EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
+/**
+ * drm_dp_send_real_edid_checksum() - send back real edid checksum value
+ * @aux: DisplayPort AUX channel
+ * @real_edid_checksum: real edid checksum for the last block
+ *
+ * Returns:
+ * True on success
+ */
+bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
+ u8 real_edid_checksum)
+{
+ u8 link_edid_read = 0, auto_test_req = 0, test_resp = 0;
+
+ if (drm_dp_dpcd_read(aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+ &auto_test_req, 1) < 1) {
+ DRM_ERROR("%s: DPCD failed read at register 0x%x\n",
+ aux->name, DP_DEVICE_SERVICE_IRQ_VECTOR);
+ return false;
+ }
+ auto_test_req &= DP_AUTOMATED_TEST_REQUEST;
+
+ if (drm_dp_dpcd_read(aux, DP_TEST_REQUEST, &link_edid_read, 1) < 1) {
+ DRM_ERROR("%s: DPCD failed read at register 0x%x\n",
+ aux->name, DP_TEST_REQUEST);
+ return false;
+ }
+ link_edid_read &= DP_TEST_LINK_EDID_READ;
+
+ if (!auto_test_req || !link_edid_read) {
+ DRM_DEBUG_KMS("%s: Source DUT does not support TEST_EDID_READ\n",
+ aux->name);
+ return false;
+ }
+
+ if (drm_dp_dpcd_write(aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+ &auto_test_req, 1) < 1) {
+ DRM_ERROR("%s: DPCD failed write at register 0x%x\n",
+ aux->name, DP_DEVICE_SERVICE_IRQ_VECTOR);
+ return false;
+ }
+
+ /* send back checksum for the last edid extension block data */
+ if (drm_dp_dpcd_write(aux, DP_TEST_EDID_CHECKSUM,
+ &real_edid_checksum, 1) < 1) {
+ DRM_ERROR("%s: DPCD failed write at register 0x%x\n",
+ aux->name, DP_TEST_EDID_CHECKSUM);
+ return false;
+ }
+
+ test_resp |= DP_TEST_EDID_CHECKSUM_WRITE;
+ if (drm_dp_dpcd_write(aux, DP_TEST_RESPONSE, &test_resp, 1) < 1) {
+ DRM_ERROR("%s: DPCD failed write at register 0x%x\n",
+ aux->name, DP_TEST_RESPONSE);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(drm_dp_send_real_edid_checksum);
+
+static u8 drm_dp_downstream_port_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+ u8 port_count = dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_PORT_COUNT_MASK;
+
+ if (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE && port_count > 4)
+ port_count = 4;
+
+ return port_count;
+}
+
+static int drm_dp_read_extended_dpcd_caps(struct drm_dp_aux *aux,
+ u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+ u8 dpcd_ext[6];
+ int ret;
+
+ /*
+ * Prior to DP1.3 the bit represented by
+ * DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT was reserved.
+ * If it is set DP_DPCD_REV at 0000h could be at a value less than
+ * the true capability of the panel. The only way to check is to
+ * then compare 0000h and 2200h.
+ */
+ if (!(dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
+ DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT))
+ return 0;
+
+ ret = drm_dp_dpcd_read(aux, DP_DP13_DPCD_REV, &dpcd_ext,
+ sizeof(dpcd_ext));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(dpcd_ext))
+ return -EIO;
+
+ if (dpcd[DP_DPCD_REV] > dpcd_ext[DP_DPCD_REV]) {
+ DRM_DEBUG_KMS("%s: Extended DPCD rev less than base DPCD rev (%d > %d)\n",
+ aux->name, dpcd[DP_DPCD_REV],
+ dpcd_ext[DP_DPCD_REV]);
+ return 0;
+ }
+
+ if (!memcmp(dpcd, dpcd_ext, sizeof(dpcd_ext)))
+ return 0;
+
+ DRM_DEBUG_KMS("%s: Base DPCD: %*ph\n",
+ aux->name, DP_RECEIVER_CAP_SIZE, dpcd);
+
+ memcpy(dpcd, dpcd_ext, sizeof(dpcd_ext));
+
+ return 0;
+}
+
+/**
+ * drm_dp_read_dpcd_caps() - read DPCD caps and extended DPCD caps if
+ * available
+ * @aux: DisplayPort AUX channel
+ * @dpcd: Buffer to store the resulting DPCD in
+ *
+ * Attempts to read the base DPCD caps for @aux. Additionally, this function
+ * checks for and reads the extended DPRX caps (%DP_DP13_DPCD_REV) if
+ * present.
+ *
+ * Returns: %0 if the DPCD was read successfully, negative error code
+ * otherwise.
+ */
+int drm_dp_read_dpcd_caps(struct drm_dp_aux *aux,
+ u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+ int ret;
+
+ ret = drm_dp_dpcd_read(aux, DP_DPCD_REV, dpcd, DP_RECEIVER_CAP_SIZE);
+ if (ret < 0)
+ return ret;
+ if (ret != DP_RECEIVER_CAP_SIZE || dpcd[DP_DPCD_REV] == 0)
+ return -EIO;
+
+ ret = drm_dp_read_extended_dpcd_caps(aux, dpcd);
+ if (ret < 0)
+ return ret;
+
+ DRM_DEBUG_KMS("%s: DPCD: %*ph\n",
+ aux->name, DP_RECEIVER_CAP_SIZE, dpcd);
+
+ return ret;
+}
+EXPORT_SYMBOL(drm_dp_read_dpcd_caps);
+
+/**
+ * drm_dp_read_downstream_info() - read DPCD downstream port info if available
+ * @aux: DisplayPort AUX channel
+ * @dpcd: A cached copy of the port's DPCD
+ * @downstream_ports: buffer to store the downstream port info in
+ *
+ * See also:
+ * drm_dp_downstream_max_clock()
+ * drm_dp_downstream_max_bpc()
+ *
+ * Returns: 0 if either the downstream port info was read successfully or
+ * there was no downstream info to read, or a negative error code otherwise.
+ */
+int drm_dp_read_downstream_info(struct drm_dp_aux *aux,
+ const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+ u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS])
+{
+ int ret;
+ u8 len;
+
+ memset(downstream_ports, 0, DP_MAX_DOWNSTREAM_PORTS);
+
+ /* No downstream info to read */
+ if (!drm_dp_is_branch(dpcd) ||
+ dpcd[DP_DPCD_REV] < DP_DPCD_REV_10 ||
+ !(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
+ return 0;
+
+ len = drm_dp_downstream_port_count(dpcd);
+ if (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE)
+ len *= 4;
+
+ ret = drm_dp_dpcd_read(aux, DP_DOWNSTREAM_PORT_0, downstream_ports, len);
+ if (ret < 0)
+ return ret;
+
+ return ret == len ? 0 : -EIO;
+}
+EXPORT_SYMBOL(drm_dp_read_downstream_info);
+
/**
* drm_dp_downstream_max_clock() - extract branch device max
* pixel rate for legacy VGA
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 44273c6509fc..060302a50dc0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4266,56 +4266,6 @@ intel_dp_link_down(struct intel_encoder *encoder,
}
}
-static void
-intel_dp_extended_receiver_capabilities(struct intel_dp *intel_dp)
-{
- u8 dpcd_ext[6];
-
- /*
- * Prior to DP1.3 the bit represented by
- * DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT was reserved.
- * if it is set DP_DPCD_REV at 0000h could be at a value less than
- * the true capability of the panel. The only way to check is to
- * then compare 0000h and 2200h.
- */
- if (!(intel_dp->dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
- DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT))
- return;
-
- if (drm_dp_dpcd_read(&intel_dp->aux, DP_DP13_DPCD_REV,
- &dpcd_ext, sizeof(dpcd_ext)) != sizeof(dpcd_ext)) {
- DRM_ERROR("DPCD failed read at extended capabilities\n");
- return;
- }
-
- if (intel_dp->dpcd[DP_DPCD_REV] > dpcd_ext[DP_DPCD_REV]) {
- DRM_DEBUG_KMS("DPCD extended DPCD rev less than base DPCD rev\n");
- return;
- }
-
- if (!memcmp(intel_dp->dpcd, dpcd_ext, sizeof(dpcd_ext)))
- return;
-
- DRM_DEBUG_KMS("Base DPCD: %*ph\n",
- (int)sizeof(intel_dp->dpcd), intel_dp->dpcd);
-
- memcpy(intel_dp->dpcd, dpcd_ext, sizeof(dpcd_ext));
-}
-
-bool
-intel_dp_read_dpcd(struct intel_dp *intel_dp)
-{
- if (drm_dp_dpcd_read(&intel_dp->aux, 0x000, intel_dp->dpcd,
- sizeof(intel_dp->dpcd)) < 0)
- return false; /* aux transfer failed */
-
- intel_dp_extended_receiver_capabilities(intel_dp);
-
- DRM_DEBUG_KMS("DPCD: %*ph\n", (int) sizeof(intel_dp->dpcd), intel_dp->dpcd);
-
- return intel_dp->dpcd[DP_DPCD_REV] != 0;
-}
-
bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
{
u8 dprx = 0;
@@ -4369,7 +4319,7 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
/* this function is meant to be called only once */
WARN_ON(intel_dp->dpcd[DP_DPCD_REV] != 0);
- if (!intel_dp_read_dpcd(intel_dp))
+ if (drm_dp_read_dpcd_caps(&intel_dp->aux, intel_dp->dpcd) != 0)
return false;
drm_dp_read_desc(&intel_dp->aux, &intel_dp->desc,
@@ -4443,7 +4393,9 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
static bool
intel_dp_get_dpcd(struct intel_dp *intel_dp)
{
- if (!intel_dp_read_dpcd(intel_dp))
+ int ret;
+
+ if (drm_dp_read_dpcd_caps(&intel_dp->aux, intel_dp->dpcd))
return false;
/*
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 3da166054788..a8afddf0ea5a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -104,7 +104,6 @@ bool intel_dp_source_supports_hbr3(struct intel_dp *intel_dp);
bool
intel_dp_get_link_status(struct intel_dp *intel_dp, u8 *link_status);
-bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp);
int intel_dp_link_required(int pixel_clock, int bpp);
int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c
index d807c5648c87..6c7aa8b5f2bb 100644
--- a/drivers/gpu/drm/i915/display/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
@@ -571,7 +571,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
return false;
}
- if (!intel_dp_read_dpcd(dp)) {
+ if (drm_dp_read_dpcd_caps(&dp->aux, dp->dpcd) != 0) {
DRM_ERROR("LSPCON DPCD read failed\n");
return false;
}
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index c5580e988826..98e7fd15cc15 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1456,6 +1456,9 @@ static inline ssize_t drm_dp_dpcd_writeb(struct drm_dp_aux *aux,
return drm_dp_dpcd_write(aux, offset, &value, 1);
}
+int drm_dp_read_dpcd_caps(struct drm_dp_aux *aux,
+ u8 dpcd[DP_RECEIVER_CAP_SIZE]);
+
int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
u8 status[DP_LINK_STATUS_SIZE]);
--
2.25.1
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