[PATCH v5 1/3] drm/dp_mst: Add self-tests for up requests

From: Sam McNally
Date: Mon May 24 2021 - 21:00:17 EST


Up requests are decoded by drm_dp_sideband_parse_req(), which operates
on a drm_dp_sideband_msg_rx, unlike down requests. Expand the existing
self-test helper sideband_msg_req_encode_decode() to copy the message
contents and length from a drm_dp_sideband_msg_tx to
drm_dp_sideband_msg_rx and use the parse function under test in place of
decode. Add an additional helper for testing clearly-invalid up
messages, verifying that parse rejects them.

Add support for currently-supported up requests to
drm_dp_dump_sideband_msg_req_body(); add support to
drm_dp_encode_sideband_req() to allow encoding for the self-tests.

Add self-tests for CONNECTION_STATUS_NOTIFY and RESOURCE_STATUS_NOTIFY.

Signed-off-by: Sam McNally <sammc@xxxxxxxxxxxx>
---

Changes in v5:
- Set mock device name to more clearly attribute error/debug logging to
the self-test, in particular for cases where failures are expected

Changes in v4:
- New in v4

drivers/gpu/drm/drm_dp_mst_topology.c | 54 ++++++-
.../gpu/drm/drm_dp_mst_topology_internal.h | 4 +
.../drm/selftests/test-drm_dp_mst_helper.c | 149 ++++++++++++++++--
3 files changed, 192 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 54604633e65c..573f39a3dc16 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -442,6 +442,37 @@ drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
idx++;
}
break;
+ case DP_CONNECTION_STATUS_NOTIFY: {
+ const struct drm_dp_connection_status_notify *msg;
+
+ msg = &req->u.conn_stat;
+ buf[idx] = (msg->port_number & 0xf) << 4;
+ idx++;
+ memcpy(&raw->msg[idx], msg->guid, 16);
+ idx += 16;
+ raw->msg[idx] = 0;
+ raw->msg[idx] |= msg->legacy_device_plug_status ? BIT(6) : 0;
+ raw->msg[idx] |= msg->displayport_device_plug_status ? BIT(5) : 0;
+ raw->msg[idx] |= msg->message_capability_status ? BIT(4) : 0;
+ raw->msg[idx] |= msg->input_port ? BIT(3) : 0;
+ raw->msg[idx] |= FIELD_PREP(GENMASK(2, 0), msg->peer_device_type);
+ idx++;
+ break;
+ }
+ case DP_RESOURCE_STATUS_NOTIFY: {
+ const struct drm_dp_resource_status_notify *msg;
+
+ msg = &req->u.resource_stat;
+ buf[idx] = (msg->port_number & 0xf) << 4;
+ idx++;
+ memcpy(&raw->msg[idx], msg->guid, 16);
+ idx += 16;
+ buf[idx] = (msg->available_pbn & 0xff00) >> 8;
+ idx++;
+ buf[idx] = (msg->available_pbn & 0xff);
+ idx++;
+ break;
+ }
}
raw->cur_len = idx;
}
@@ -672,6 +703,22 @@ drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req
req->u.enc_status.stream_behavior,
req->u.enc_status.valid_stream_behavior);
break;
+ case DP_CONNECTION_STATUS_NOTIFY:
+ P("port=%d guid=%*ph legacy=%d displayport=%d messaging=%d input=%d peer_type=%d",
+ req->u.conn_stat.port_number,
+ (int)ARRAY_SIZE(req->u.conn_stat.guid), req->u.conn_stat.guid,
+ req->u.conn_stat.legacy_device_plug_status,
+ req->u.conn_stat.displayport_device_plug_status,
+ req->u.conn_stat.message_capability_status,
+ req->u.conn_stat.input_port,
+ req->u.conn_stat.peer_device_type);
+ break;
+ case DP_RESOURCE_STATUS_NOTIFY:
+ P("port=%d guid=%*ph pbn=%d",
+ req->u.resource_stat.port_number,
+ (int)ARRAY_SIZE(req->u.resource_stat.guid), req->u.resource_stat.guid,
+ req->u.resource_stat.available_pbn);
+ break;
default:
P("???\n");
break;
@@ -1116,9 +1163,9 @@ static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst
return false;
}

-static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
- struct drm_dp_sideband_msg_rx *raw,
- struct drm_dp_sideband_msg_req_body *msg)
+bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
+ struct drm_dp_sideband_msg_rx *raw,
+ struct drm_dp_sideband_msg_req_body *msg)
{
memset(msg, 0, sizeof(*msg));
msg->req_type = (raw->msg[0] & 0x7f);
@@ -1134,6 +1181,7 @@ static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
return false;
}
}
+EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_sideband_parse_req);

static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology_internal.h b/drivers/gpu/drm/drm_dp_mst_topology_internal.h
index eeda9a61c657..0356a2e0dba1 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology_internal.h
+++ b/drivers/gpu/drm/drm_dp_mst_topology_internal.h
@@ -21,4 +21,8 @@ void
drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
int indent, struct drm_printer *printer);

+bool
+drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
+ struct drm_dp_sideband_msg_rx *raw,
+ struct drm_dp_sideband_msg_req_body *msg);
#endif /* !_DRM_DP_MST_HELPER_INTERNAL_H_ */
diff --git a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
index 6b4759ed6bfd..7bbeb1e5bc97 100644
--- a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
+++ b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
@@ -13,6 +13,10 @@
#include "../drm_dp_mst_topology_internal.h"
#include "test-drm_modeset_common.h"

+static void mock_release(struct device *dev)
+{
+}
+
int igt_dp_mst_calc_pbn_mode(void *ignored)
{
int pbn, i;
@@ -120,27 +124,60 @@ sideband_msg_req_equal(const struct drm_dp_sideband_msg_req_body *in,
static bool
sideband_msg_req_encode_decode(struct drm_dp_sideband_msg_req_body *in)
{
- struct drm_dp_sideband_msg_req_body *out;
+ struct drm_dp_sideband_msg_req_body *out = NULL;
struct drm_printer p = drm_err_printer(PREFIX_STR);
- struct drm_dp_sideband_msg_tx *txmsg;
+ struct drm_dp_sideband_msg_tx *txmsg = NULL;
+ struct drm_dp_sideband_msg_rx *rxmsg = NULL;
+ struct drm_dp_mst_topology_mgr *mgr = NULL;
int i, ret;
- bool result = true;
+ bool result = false;

out = kzalloc(sizeof(*out), GFP_KERNEL);
if (!out)
- return false;
+ goto out;

txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
if (!txmsg)
- return false;
+ goto out;

- drm_dp_encode_sideband_req(in, txmsg);
- ret = drm_dp_decode_sideband_req(txmsg, out);
- if (ret < 0) {
- drm_printf(&p, "Failed to decode sideband request: %d\n",
- ret);
- result = false;
+ rxmsg = kzalloc(sizeof(*rxmsg), GFP_KERNEL);
+ if (!rxmsg)
goto out;
+
+ mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
+ if (!mgr)
+ goto out;
+
+ mgr->dev = kzalloc(sizeof(*mgr->dev), GFP_KERNEL);
+ if (!mgr->dev)
+ goto out;
+
+ mgr->dev->dev = kzalloc(sizeof(*mgr->dev->dev), GFP_KERNEL);
+ if (!mgr->dev->dev)
+ goto out;
+
+ mgr->dev->dev->release = mock_release;
+ mgr->dev->dev->init_name = PREFIX_STR;
+ device_initialize(mgr->dev->dev);
+
+ drm_dp_encode_sideband_req(in, txmsg);
+ switch (in->req_type) {
+ case DP_CONNECTION_STATUS_NOTIFY:
+ case DP_RESOURCE_STATUS_NOTIFY:
+ memcpy(&rxmsg->msg, txmsg->msg, ARRAY_SIZE(rxmsg->msg));
+ rxmsg->curlen = txmsg->cur_len;
+ if (!drm_dp_sideband_parse_req(mgr, rxmsg, out)) {
+ drm_printf(&p, "Failed to decode sideband request\n");
+ goto out;
+ }
+ break;
+ default:
+ ret = drm_dp_decode_sideband_req(txmsg, out);
+ if (ret < 0) {
+ drm_printf(&p, "Failed to decode sideband request: %d\n", ret);
+ goto out;
+ }
+ break;
}

if (!sideband_msg_req_equal(in, out)) {
@@ -148,9 +185,9 @@ sideband_msg_req_encode_decode(struct drm_dp_sideband_msg_req_body *in)
drm_dp_dump_sideband_msg_req_body(in, 1, &p);
drm_printf(&p, "Got:\n");
drm_dp_dump_sideband_msg_req_body(out, 1, &p);
- result = false;
goto out;
}
+ result = true;

switch (in->req_type) {
case DP_REMOTE_DPCD_WRITE:
@@ -171,6 +208,66 @@ sideband_msg_req_encode_decode(struct drm_dp_sideband_msg_req_body *in)
out:
kfree(out);
kfree(txmsg);
+ kfree(rxmsg);
+ if (mgr) {
+ if (mgr->dev) {
+ put_device(mgr->dev->dev);
+ kfree(mgr->dev);
+ }
+ kfree(mgr);
+ }
+ return result;
+}
+
+static bool
+sideband_msg_req_parse(int req_type)
+{
+ struct drm_dp_sideband_msg_req_body *out = NULL;
+ struct drm_printer p = drm_err_printer(PREFIX_STR);
+ struct drm_dp_sideband_msg_rx *rxmsg = NULL;
+ struct drm_dp_mst_topology_mgr *mgr = NULL;
+ bool result = false;
+
+ out = kzalloc(sizeof(*out), GFP_KERNEL);
+ if (!out)
+ goto out;
+
+ rxmsg = kzalloc(sizeof(*rxmsg), GFP_KERNEL);
+ if (!rxmsg)
+ goto out;
+
+ mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
+ if (!mgr)
+ goto out;
+
+ mgr->dev = kzalloc(sizeof(*mgr->dev), GFP_KERNEL);
+ if (!mgr->dev)
+ goto out;
+
+ mgr->dev->dev = kzalloc(sizeof(*mgr->dev->dev), GFP_KERNEL);
+ if (!mgr->dev->dev)
+ goto out;
+
+ mgr->dev->dev->release = mock_release;
+ mgr->dev->dev->init_name = PREFIX_STR " expected parse failure";
+ device_initialize(mgr->dev->dev);
+
+ rxmsg->curlen = 1;
+ rxmsg->msg[0] = req_type & 0x7f;
+ if (drm_dp_sideband_parse_req(mgr, rxmsg, out))
+ drm_printf(&p, "Unexpectedly decoded invalid sideband request\n");
+ else
+ result = true;
+out:
+ kfree(out);
+ kfree(rxmsg);
+ if (mgr) {
+ if (mgr->dev) {
+ put_device(mgr->dev->dev);
+ kfree(mgr->dev);
+ }
+ kfree(mgr);
+ }
return result;
}

@@ -268,6 +365,34 @@ int igt_dp_mst_sideband_msg_req_decode(void *unused)
in.u.enc_status.valid_stream_behavior = 1;
DO_TEST();

+ in.req_type = DP_CONNECTION_STATUS_NOTIFY;
+ in.u.conn_stat.port_number = 0xf;
+ get_random_bytes(in.u.conn_stat.guid, sizeof(in.u.conn_stat.guid));
+ in.u.conn_stat.legacy_device_plug_status = 1;
+ in.u.conn_stat.displayport_device_plug_status = 0;
+ in.u.conn_stat.message_capability_status = 0;
+ in.u.conn_stat.input_port = 0;
+ in.u.conn_stat.peer_device_type = 7;
+ DO_TEST();
+ in.u.conn_stat.displayport_device_plug_status = 1;
+ DO_TEST();
+ in.u.conn_stat.message_capability_status = 1;
+ DO_TEST();
+ in.u.conn_stat.input_port = 1;
+ DO_TEST();
+
+ in.req_type = DP_RESOURCE_STATUS_NOTIFY;
+ in.u.resource_stat.port_number = 0xf;
+ get_random_bytes(in.u.resource_stat.guid, sizeof(in.u.resource_stat.guid));
+ in.u.resource_stat.available_pbn = 0xcdef;
+ DO_TEST();
+
+#undef DO_TEST
+#define DO_TEST(req_type) FAIL_ON(!sideband_msg_req_parse(req_type))
+ DO_TEST(DP_CONNECTION_STATUS_NOTIFY);
+ DO_TEST(DP_RESOURCE_STATUS_NOTIFY);
+
+ DO_TEST(DP_REMOTE_I2C_WRITE);
#undef DO_TEST
return 0;
}
--
2.31.1.818.g46aad6cb9e-goog