drm/helper: add Displayport multi-stream helper (v0.6)

This is the initial import of the helper for displayport multistream.

It consists of a topology manager, init/destroy/set mst state

It supports DP 1.2 MST sideband msg protocol handler - via hpd irqs

connector detect and edid retrieval interface.

It supports i2c device over DP 1.2 sideband msg protocol (EDID reads only)

bandwidth manager API via vcpi allocation and payload updating,
along with a helper to check the ACT status.

Objects:
MST topology manager - one per toplevel MST capable GPU port - not sure if this should be higher level again
MST branch unit - one instance per plugged branching unit - one at top of hierarchy - others hanging from ports
MST port - one port per port reported by branching units, can have MST units hanging from them as well.

Changes since initial posting:
a) add a mutex responsbile for the queues, it locks the sideband and msg slots, and msgs to transmit state
b) add worker to handle connection state change events, for MST device chaining and hotplug
c) add a payload spinlock
d) add path sideband msg support
e) fixup enum path resources transmit
f) reduce max dpcd msg to 16, as per DP1.2 spec.
g) separate tx queue kicking from irq processing and move irq acking back to drivers.

Changes since v0.2:
a) reorganise code,
b) drop ACT forcing code
c) add connector naming interface using path property
d) add topology dumper helper
e) proper reference counting and lookup for ports and mstbs.
f) move tx kicking into a workq
g) add aux locking - this should be redone
h) split teardown into two parts
i) start working on documentation on interface.

Changes since v0.3:
a) vc payload locking and tracking fixes
b) add hotplug callback into driver - replaces crazy return 1 scheme
c) txmsg + mst branch device refcount fixes
d) don't bail on mst shutdown if device is gone
e) change irq handler to take all 4 bytes of SINK_COUNT + ESI vectors
f) make DP payload updates timeout longer - observed on docking station redock
g) add more info to debugfs dumper

Changes since v0.4:
a) suspend/resume support
b) more debugging in debugfs

Changes since v0.5:
a) use byte * to avoid unnecessary stack usage
b) fix num_sdp_streams interpretation.
c) init payload state for unplug events
d) remove lenovo dock sink count hack
e) drop aux lock - post rebase
f) call hotplug on port destroy

TODO:
misc features

Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 509 insertions, 0 deletions

diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
new file mode 100644
index 000000000000..9b446ada2532
--- /dev/null
+++ b/include/drm/drm_dp_mst_helper.h
@@ -0,0 +1,509 @@
+/*
+ * Copyright © 2014 Red Hat.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+#ifndef _DRM_DP_MST_HELPER_H_
+#define _DRM_DP_MST_HELPER_H_
+
+#include <linux/types.h>
+#include <drm/drm_dp_helper.h>
+
+struct drm_dp_mst_branch;
+
+/**
+ * struct drm_dp_vcpi - Virtual Channel Payload Identifer
+ * @vcpi: Virtual channel ID.
+ * @pbn: Payload Bandwidth Number for this channel
+ * @aligned_pbn: PBN aligned with slot size
+ * @num_slots: number of slots for this PBN
+ */
+struct drm_dp_vcpi {
+	int vcpi;
+	int pbn;
+	int aligned_pbn;
+	int num_slots;
+};
+
+/**
+ * struct drm_dp_mst_port - MST port
+ * @kref: reference count for this port.
+ * @guid_valid: for DP 1.2 devices if we have validated the GUID.
+ * @guid: guid for DP 1.2 device on this port.
+ * @port_num: port number
+ * @input: if this port is an input port.
+ * @mcs: message capability status - DP 1.2 spec.
+ * @ddps: DisplayPort Device Plug Status - DP 1.2
+ * @pdt: Peer Device Type
+ * @ldps: Legacy Device Plug Status
+ * @dpcd_rev: DPCD revision of device on this port
+ * @num_sdp_streams: Number of simultaneous streams
+ * @num_sdp_stream_sinks: Number of stream sinks
+ * @available_pbn: Available bandwidth for this port.
+ * @next: link to next port on this branch device
+ * @mstb: branch device attach below this port
+ * @aux: i2c aux transport to talk to device connected to this port.
+ * @parent: branch device parent of this port
+ * @vcpi: Virtual Channel Payload info for this port.
+ * @connector: DRM connector this port is connected to.
+ * @mgr: topology manager this port lives under.
+ *
+ * This structure represents an MST port endpoint on a device somewhere
+ * in the MST topology.
+ */
+struct drm_dp_mst_port {
+	struct kref kref;
+
+	/* if dpcd 1.2 device is on this port - its GUID info */
+	bool guid_valid;
+	u8 guid[16];
+
+	u8 port_num;
+	bool input;
+	bool mcs;
+	bool ddps;
+	u8 pdt;
+	bool ldps;
+	u8 dpcd_rev;
+	u8 num_sdp_streams;
+	u8 num_sdp_stream_sinks;
+	uint16_t available_pbn;
+	struct list_head next;
+	struct drm_dp_mst_branch *mstb; /* pointer to an mstb if this port has one */
+	struct drm_dp_aux aux; /* i2c bus for this port? */
+	struct drm_dp_mst_branch *parent;
+
+	struct drm_dp_vcpi vcpi;
+	struct drm_connector *connector;
+	struct drm_dp_mst_topology_mgr *mgr;
+};
+
+/**
+ * struct drm_dp_mst_branch - MST branch device.
+ * @kref: reference count for this port.
+ * @rad: Relative Address to talk to this branch device.
+ * @lct: Link count total to talk to this branch device.
+ * @num_ports: number of ports on the branch.
+ * @msg_slots: one bit per transmitted msg slot.
+ * @ports: linked list of ports on this branch.
+ * @port_parent: pointer to the port parent, NULL if toplevel.
+ * @mgr: topology manager for this branch device.
+ * @tx_slots: transmission slots for this device.
+ * @last_seqno: last sequence number used to talk to this.
+ * @link_address_sent: if a link address message has been sent to this device yet.
+ *
+ * This structure represents an MST branch device, there is one
+ * primary branch device at the root, along with any others connected
+ * to downstream ports
+ */
+struct drm_dp_mst_branch {
+	struct kref kref;
+	u8 rad[8];
+	u8 lct;
+	int num_ports;
+
+	int msg_slots;
+	struct list_head ports;
+
+	/* list of tx ops queue for this port */
+	struct drm_dp_mst_port *port_parent;
+	struct drm_dp_mst_topology_mgr *mgr;
+
+	/* slots are protected by mstb->mgr->qlock */
+	struct drm_dp_sideband_msg_tx *tx_slots[2];
+	int last_seqno;
+	bool link_address_sent;
+};
+
+
+/* sideband msg header - not bit struct */
+struct drm_dp_sideband_msg_hdr {
+	u8 lct;
+	u8 lcr;
+	u8 rad[8];
+	bool broadcast;
+	bool path_msg;
+	u8 msg_len;
+	bool somt;
+	bool eomt;
+	bool seqno;
+};
+
+struct drm_dp_nak_reply {
+	u8 guid[16];
+	u8 reason;
+	u8 nak_data;
+};
+
+struct drm_dp_link_address_ack_reply {
+	u8 guid[16];
+	u8 nports;
+	struct drm_dp_link_addr_reply_port {
+		bool input_port;
+		u8 peer_device_type;
+		u8 port_number;
+		bool mcs;
+		bool ddps;
+		bool legacy_device_plug_status;
+		u8 dpcd_revision;
+		u8 peer_guid[16];
+		u8 num_sdp_streams;
+		u8 num_sdp_stream_sinks;
+	} ports[16];
+};
+
+struct drm_dp_remote_dpcd_read_ack_reply {
+	u8 port_number;
+	u8 num_bytes;
+	u8 bytes[255];
+};
+
+struct drm_dp_remote_dpcd_write_ack_reply {
+	u8 port_number;
+};
+
+struct drm_dp_remote_dpcd_write_nak_reply {
+	u8 port_number;
+	u8 reason;
+	u8 bytes_written_before_failure;
+};
+
+struct drm_dp_remote_i2c_read_ack_reply {
+	u8 port_number;
+	u8 num_bytes;
+	u8 bytes[255];
+};
+
+struct drm_dp_remote_i2c_read_nak_reply {
+	u8 port_number;
+	u8 nak_reason;
+	u8 i2c_nak_transaction;
+};
+
+struct drm_dp_remote_i2c_write_ack_reply {
+	u8 port_number;
+};
+
+
+struct drm_dp_sideband_msg_rx {
+	u8 chunk[48];
+	u8 msg[256];
+	u8 curchunk_len;
+	u8 curchunk_idx; /* chunk we are parsing now */
+	u8 curchunk_hdrlen;
+	u8 curlen; /* total length of the msg */
+	bool have_somt;
+	bool have_eomt;
+	struct drm_dp_sideband_msg_hdr initial_hdr;
+};
+
+
+struct drm_dp_allocate_payload {
+	u8 port_number;
+	u8 number_sdp_streams;
+	u8 vcpi;
+	u16 pbn;
+	u8 sdp_stream_sink[8];
+};
+
+struct drm_dp_allocate_payload_ack_reply {
+	u8 port_number;
+	u8 vcpi;
+	u16 allocated_pbn;
+};
+
+struct drm_dp_connection_status_notify {
+	u8 guid[16];
+	u8 port_number;
+	bool legacy_device_plug_status;
+	bool displayport_device_plug_status;
+	bool message_capability_status;
+	bool input_port;
+	u8 peer_device_type;
+};
+
+struct drm_dp_remote_dpcd_read {
+	u8 port_number;
+	u32 dpcd_address;
+	u8 num_bytes;
+};
+
+struct drm_dp_remote_dpcd_write {
+	u8 port_number;
+	u32 dpcd_address;
+	u8 num_bytes;
+	u8 *bytes;
+};
+
+struct drm_dp_remote_i2c_read {
+	u8 num_transactions;
+	u8 port_number;
+	struct {
+		u8 i2c_dev_id;
+		u8 num_bytes;
+		u8 *bytes;
+		u8 no_stop_bit;
+		u8 i2c_transaction_delay;
+	} transactions[4];
+	u8 read_i2c_device_id;
+	u8 num_bytes_read;
+};
+
+struct drm_dp_remote_i2c_write {
+	u8 port_number;
+	u8 write_i2c_device_id;
+	u8 num_bytes;
+	u8 *bytes;
+};
+
+/* this covers ENUM_RESOURCES, POWER_DOWN_PHY, POWER_UP_PHY */
+struct drm_dp_port_number_req {
+	u8 port_number;
+};
+
+struct drm_dp_enum_path_resources_ack_reply {
+	u8 port_number;
+	u16 full_payload_bw_number;
+	u16 avail_payload_bw_number;
+};
+
+/* covers POWER_DOWN_PHY, POWER_UP_PHY */
+struct drm_dp_port_number_rep {
+	u8 port_number;
+};
+
+struct drm_dp_query_payload {
+	u8 port_number;
+	u8 vcpi;
+};
+
+struct drm_dp_resource_status_notify {
+	u8 port_number;
+	u8 guid[16];
+	u16 available_pbn;
+};
+
+struct drm_dp_query_payload_ack_reply {
+	u8 port_number;
+	u8 allocated_pbn;
+};
+
+struct drm_dp_sideband_msg_req_body {
+	u8 req_type;
+	union ack_req {
+		struct drm_dp_connection_status_notify conn_stat;
+		struct drm_dp_port_number_req port_num;
+		struct drm_dp_resource_status_notify resource_stat;
+
+		struct drm_dp_query_payload query_payload;
+		struct drm_dp_allocate_payload allocate_payload;
+
+		struct drm_dp_remote_dpcd_read dpcd_read;
+		struct drm_dp_remote_dpcd_write dpcd_write;
+
+		struct drm_dp_remote_i2c_read i2c_read;
+		struct drm_dp_remote_i2c_write i2c_write;
+	} u;
+};
+
+struct drm_dp_sideband_msg_reply_body {
+	u8 reply_type;
+	u8 req_type;
+	union ack_replies {
+		struct drm_dp_nak_reply nak;
+		struct drm_dp_link_address_ack_reply link_addr;
+		struct drm_dp_port_number_rep port_number;
+
+		struct drm_dp_enum_path_resources_ack_reply path_resources;
+		struct drm_dp_allocate_payload_ack_reply allocate_payload;
+		struct drm_dp_query_payload_ack_reply query_payload;
+
+		struct drm_dp_remote_dpcd_read_ack_reply remote_dpcd_read_ack;
+		struct drm_dp_remote_dpcd_write_ack_reply remote_dpcd_write_ack;
+		struct drm_dp_remote_dpcd_write_nak_reply remote_dpcd_write_nack;
+
+		struct drm_dp_remote_i2c_read_ack_reply remote_i2c_read_ack;
+		struct drm_dp_remote_i2c_read_nak_reply remote_i2c_read_nack;
+		struct drm_dp_remote_i2c_write_ack_reply remote_i2c_write_ack;
+	} u;
+};
+
+/* msg is queued to be put into a slot */
+#define DRM_DP_SIDEBAND_TX_QUEUED 0
+/* msg has started transmitting on a slot - still on msgq */
+#define DRM_DP_SIDEBAND_TX_START_SEND 1
+/* msg has finished transmitting on a slot - removed from msgq only in slot */
+#define DRM_DP_SIDEBAND_TX_SENT 2
+/* msg has received a response - removed from slot */
+#define DRM_DP_SIDEBAND_TX_RX 3
+#define DRM_DP_SIDEBAND_TX_TIMEOUT 4
+
+struct drm_dp_sideband_msg_tx {
+	u8 msg[256];
+	u8 chunk[48];
+	u8 cur_offset;
+	u8 cur_len;
+	struct drm_dp_mst_branch *dst;
+	struct list_head next;
+	int seqno;
+	int state;
+	bool path_msg;
+	struct drm_dp_sideband_msg_reply_body reply;
+};
+
+/* sideband msg handler */
+struct drm_dp_mst_topology_mgr;
+struct drm_dp_mst_topology_cbs {
+	/* create a connector for a port */
+	struct drm_connector *(*add_connector)(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, char *path);
+	void (*destroy_connector)(struct drm_dp_mst_topology_mgr *mgr,
+				  struct drm_connector *connector);
+	void (*hotplug)(struct drm_dp_mst_topology_mgr *mgr);
+
+};
+
+#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
+
+#define DP_PAYLOAD_LOCAL 1
+#define DP_PAYLOAD_REMOTE 2
+#define DP_PAYLOAD_DELETE_LOCAL 3
+
+struct drm_dp_payload {
+	int payload_state;
+	int start_slot;
+	int num_slots;
+};
+
+/**
+ * struct drm_dp_mst_topology_mgr - DisplayPort MST manager
+ * @dev: device pointer for adding i2c devices etc.
+ * @cbs: callbacks for connector addition and destruction.
+ * @max_dpcd_transaction_bytes - maximum number of bytes to read/write in one go.
+ * @aux: aux channel for the DP connector.
+ * @max_payloads: maximum number of payloads the GPU can generate.
+ * @conn_base_id: DRM connector ID this mgr is connected to.
+ * @down_rep_recv: msg receiver state for down replies.
+ * @up_req_recv: msg receiver state for up requests.
+ * @lock: protects mst state, primary, guid, dpcd.
+ * @mst_state: if this manager is enabled for an MST capable port.
+ * @mst_primary: pointer to the primary branch device.
+ * @guid_valid: GUID valid for the primary branch device.
+ * @guid: GUID for primary port.
+ * @dpcd: cache of DPCD for primary port.
+ * @pbn_div: PBN to slots divisor.
+ *
+ * This struct represents the toplevel displayport MST topology manager.
+ * There should be one instance of this for every MST capable DP connector
+ * on the GPU.
+ */
+struct drm_dp_mst_topology_mgr {
+
+	struct device *dev;
+	struct drm_dp_mst_topology_cbs *cbs;
+	int max_dpcd_transaction_bytes;
+	struct drm_dp_aux *aux; /* auxch for this topology mgr to use */
+	int max_payloads;
+	int conn_base_id;
+
+	/* only ever accessed from the workqueue - which should be serialised */
+	struct drm_dp_sideband_msg_rx down_rep_recv;
+	struct drm_dp_sideband_msg_rx up_req_recv;
+
+	/* pointer to info about the initial MST device */
+	struct mutex lock; /* protects mst_state + primary + guid + dpcd */
+
+	bool mst_state;
+	struct drm_dp_mst_branch *mst_primary;
+	/* primary MST device GUID */
+	bool guid_valid;
+	u8 guid[16];
+	u8 dpcd[DP_RECEIVER_CAP_SIZE];
+	u8 sink_count;
+	int pbn_div;
+	int total_slots;
+	int avail_slots;
+	int total_pbn;
+
+	/* messages to be transmitted */
+	/* qlock protects the upq/downq and in_progress,
+	   the mstb tx_slots and txmsg->state once they are queued */
+	struct mutex qlock;
+	struct list_head tx_msg_downq;
+	struct list_head tx_msg_upq;
+	bool tx_down_in_progress;
+	bool tx_up_in_progress;
+
+	/* payload info + lock for it */
+	struct mutex payload_lock;
+	struct drm_dp_vcpi **proposed_vcpis;
+	struct drm_dp_payload *payloads;
+	unsigned long payload_mask;
+
+	wait_queue_head_t tx_waitq;
+	struct work_struct work;
+
+	struct work_struct tx_work;
+};
+
+int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, struct device *dev, struct drm_dp_aux *aux, int max_dpcd_transaction_bytes, int max_payloads, int conn_base_id);
+
+void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
+
+
+int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state);
+
+
+int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled);
+
+
+enum drm_connector_status drm_dp_mst_detect_port(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
+
+struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
+
+
+int drm_dp_calc_pbn_mode(int clock, int bpp);
+
+
+bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots);
+
+
+void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
+
+
+void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
+				struct drm_dp_mst_port *port);
+
+
+int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
+			   int pbn);
+
+
+int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr);
+
+
+int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr);
+
+int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
+
+void drm_dp_mst_dump_topology(struct seq_file *m,
+			      struct drm_dp_mst_topology_mgr *mgr);
+
+void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
+int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
+#endif