diff options
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 279 | ||||
| -rw-r--r-- | include/drm/drm_dp_mst_helper.h | 25 | ||||
| -rw-r--r-- | include/drm/drm_fixed.h | 53 |
3 files changed, 243 insertions, 114 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 6ed90a2437e5..8ae13de272c4 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -803,6 +803,18 @@ static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad) return mstb; } +static void drm_dp_free_mst_port(struct kref *kref); + +static void drm_dp_free_mst_branch_device(struct kref *kref) +{ + struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref); + if (mstb->port_parent) { + if (list_empty(&mstb->port_parent->next)) + kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port); + } + kfree(mstb); +} + static void drm_dp_destroy_mst_branch_device(struct kref *kref) { struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref); @@ -810,6 +822,15 @@ static void drm_dp_destroy_mst_branch_device(struct kref *kref) bool wake_tx = false; /* + * init kref again to be used by ports to remove mst branch when it is + * not needed anymore + */ + kref_init(kref); + + if (mstb->port_parent && list_empty(&mstb->port_parent->next)) + kref_get(&mstb->port_parent->kref); + + /* * destroy all ports - don't need lock * as there are no more references to the mst branch * device at this point. @@ -835,7 +856,8 @@ static void drm_dp_destroy_mst_branch_device(struct kref *kref) if (wake_tx) wake_up(&mstb->mgr->tx_waitq); - kfree(mstb); + + kref_put(kref, drm_dp_free_mst_branch_device); } static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb) @@ -883,6 +905,7 @@ static void drm_dp_destroy_port(struct kref *kref) * from an EDID retrieval */ mutex_lock(&mgr->destroy_connector_lock); + kref_get(&port->parent->kref); list_add(&port->next, &mgr->destroy_connector_list); mutex_unlock(&mgr->destroy_connector_lock); schedule_work(&mgr->destroy_connector_work); @@ -1018,18 +1041,27 @@ static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port) return send_link; } -static void drm_dp_check_port_guid(struct drm_dp_mst_branch *mstb, - struct drm_dp_mst_port *port) +static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid) { int ret; - if (port->dpcd_rev >= 0x12) { - port->guid_valid = drm_dp_validate_guid(mstb->mgr, port->guid); - if (!port->guid_valid) { - ret = drm_dp_send_dpcd_write(mstb->mgr, - port, - DP_GUID, - 16, port->guid); - port->guid_valid = true; + + memcpy(mstb->guid, guid, 16); + + if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) { + if (mstb->port_parent) { + ret = drm_dp_send_dpcd_write( + mstb->mgr, + mstb->port_parent, + DP_GUID, + 16, + mstb->guid); + } else { + + ret = drm_dp_dpcd_write( + mstb->mgr->aux, + DP_GUID, + mstb->guid, + 16); } } } @@ -1086,7 +1118,6 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb, port->dpcd_rev = port_msg->dpcd_revision; port->num_sdp_streams = port_msg->num_sdp_streams; port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks; - memcpy(port->guid, port_msg->peer_guid, 16); /* manage mstb port lists with mgr lock - take a reference for this list */ @@ -1099,11 +1130,9 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb, if (old_ddps != port->ddps) { if (port->ddps) { - drm_dp_check_port_guid(mstb, port); if (!port->input) drm_dp_send_enum_path_resources(mstb->mgr, mstb, port); } else { - port->guid_valid = false; port->available_pbn = 0; } } @@ -1130,13 +1159,11 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb, drm_dp_put_port(port); goto out; } - if (port->port_num >= DP_MST_LOGICAL_PORT_0) { - port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc); - drm_mode_connector_set_tile_property(port->connector); - } + + drm_mode_connector_set_tile_property(port->connector); + (*mstb->mgr->cbs->register_connector)(port->connector); } - out: /* put reference to this port */ drm_dp_put_port(port); @@ -1161,11 +1188,9 @@ static void drm_dp_update_port(struct drm_dp_mst_branch *mstb, port->ddps = conn_stat->displayport_device_plug_status; if (old_ddps != port->ddps) { + dowork = true; if (port->ddps) { - drm_dp_check_port_guid(mstb, port); - dowork = true; } else { - port->guid_valid = false; port->available_pbn = 0; } } @@ -1222,13 +1247,14 @@ static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper( struct drm_dp_mst_branch *found_mstb; struct drm_dp_mst_port *port; + if (memcmp(mstb->guid, guid, 16) == 0) + return mstb; + + list_for_each_entry(port, &mstb->ports, next) { if (!port->mstb) continue; - if (port->guid_valid && memcmp(port->guid, guid, 16) == 0) - return port->mstb; - found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid); if (found_mstb) @@ -1247,10 +1273,7 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid( /* find the port by iterating down */ mutex_lock(&mgr->lock); - if (mgr->guid_valid && memcmp(mgr->guid, guid, 16) == 0) - mstb = mgr->mst_primary; - else - mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid); + mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid); if (mstb) kref_get(&mstb->kref); @@ -1271,8 +1294,13 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m if (port->input) continue; - if (!port->ddps) + if (!port->ddps) { + if (port->cached_edid) { + kfree(port->cached_edid); + port->cached_edid = NULL; + } continue; + } if (!port->available_pbn) drm_dp_send_enum_path_resources(mgr, mstb, port); @@ -1283,6 +1311,12 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m drm_dp_check_and_send_link_address(mgr, mstb_child); drm_dp_put_mst_branch_device(mstb_child); } + } else if (port->pdt == DP_PEER_DEVICE_SST_SINK || + port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV) { + if (!port->cached_edid) { + port->cached_edid = + drm_get_edid(port->connector, &port->aux.ddc); + } } } } @@ -1302,6 +1336,8 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work) drm_dp_check_and_send_link_address(mgr, mstb); drm_dp_put_mst_branch_device(mstb); } + + (*mgr->cbs->hotplug)(mgr); } static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr, @@ -1555,10 +1591,12 @@ static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr, txmsg->reply.u.link_addr.ports[i].num_sdp_streams, txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks); } + + drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid); + for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) { drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]); } - (*mgr->cbs->hotplug)(mgr); } } else { mstb->link_address_sent = false; @@ -1602,6 +1640,37 @@ static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr, return 0; } +static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb) +{ + if (!mstb->port_parent) + return NULL; + + if (mstb->port_parent->mstb != mstb) + return mstb->port_parent; + + return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent); +} + +static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, + int *port_num) +{ + struct drm_dp_mst_branch *rmstb = NULL; + struct drm_dp_mst_port *found_port; + mutex_lock(&mgr->lock); + if (mgr->mst_primary) { + found_port = drm_dp_get_last_connected_port_to_mstb(mstb); + + if (found_port) { + rmstb = found_port->parent; + kref_get(&rmstb->kref); + *port_num = found_port->port_num; + } + } + mutex_unlock(&mgr->lock); + return rmstb; +} + static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int id, @@ -1609,13 +1678,18 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, { struct drm_dp_sideband_msg_tx *txmsg; struct drm_dp_mst_branch *mstb; - int len, ret; + int len, ret, port_num; u8 sinks[DRM_DP_MAX_SDP_STREAMS]; int i; + port_num = port->port_num; mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent); - if (!mstb) - return -EINVAL; + if (!mstb) { + mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num); + + if (!mstb) + return -EINVAL; + } txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); if (!txmsg) { @@ -1627,7 +1701,7 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, sinks[i] = i; txmsg->dst = mstb; - len = build_allocate_payload(txmsg, port->port_num, + len = build_allocate_payload(txmsg, port_num, id, pbn, port->num_sdp_streams, sinks); @@ -1983,31 +2057,17 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms mgr->mst_primary = mstb; kref_get(&mgr->mst_primary->kref); - { - struct drm_dp_payload reset_pay; - reset_pay.start_slot = 0; - reset_pay.num_slots = 0x3f; - drm_dp_dpcd_write_payload(mgr, 0, &reset_pay); - } - ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, - DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC); + DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC); if (ret < 0) { goto out_unlock; } - - /* sort out guid */ - ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, mgr->guid, 16); - if (ret != 16) { - DRM_DEBUG_KMS("failed to read DP GUID %d\n", ret); - goto out_unlock; - } - - mgr->guid_valid = drm_dp_validate_guid(mgr, mgr->guid); - if (!mgr->guid_valid) { - ret = drm_dp_dpcd_write(mgr->aux, DP_GUID, mgr->guid, 16); - mgr->guid_valid = true; + { + struct drm_dp_payload reset_pay; + reset_pay.start_slot = 0; + reset_pay.num_slots = 0x3f; + drm_dp_dpcd_write_payload(mgr, 0, &reset_pay); } queue_work(system_long_wq, &mgr->work); @@ -2231,9 +2291,8 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr) } drm_dp_update_port(mstb, &msg.u.conn_stat); - DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type); - (*mgr->cbs->hotplug)(mgr); + DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type); } else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) { drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false); if (!mstb) @@ -2320,10 +2379,6 @@ enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector case DP_PEER_DEVICE_SST_SINK: status = connector_status_connected; - /* for logical ports - cache the EDID */ - if (port->port_num >= 8 && !port->cached_edid) { - port->cached_edid = drm_get_edid(connector, &port->aux.ddc); - } break; case DP_PEER_DEVICE_DP_LEGACY_CONV: if (port->ldps) @@ -2378,10 +2433,7 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_ if (port->cached_edid) edid = drm_edid_duplicate(port->cached_edid); - else { - edid = drm_get_edid(connector, &port->aux.ddc); - drm_mode_connector_set_tile_property(connector); - } + port->has_audio = drm_detect_monitor_audio(edid); drm_dp_put_port(port); return edid; @@ -2446,6 +2498,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn); if (pbn == port->vcpi.pbn) { *slots = port->vcpi.num_slots; + drm_dp_put_port(port); return true; } } @@ -2605,32 +2658,31 @@ EXPORT_SYMBOL(drm_dp_check_act_status); */ int drm_dp_calc_pbn_mode(int clock, int bpp) { - fixed20_12 pix_bw; - fixed20_12 fbpp; - fixed20_12 result; - fixed20_12 margin, tmp; - u32 res; - - pix_bw.full = dfixed_const(clock); - fbpp.full = dfixed_const(bpp); - tmp.full = dfixed_const(8); - fbpp.full = dfixed_div(fbpp, tmp); - - result.full = dfixed_mul(pix_bw, fbpp); - margin.full = dfixed_const(54); - tmp.full = dfixed_const(64); - margin.full = dfixed_div(margin, tmp); - result.full = dfixed_div(result, margin); - - margin.full = dfixed_const(1006); - tmp.full = dfixed_const(1000); - margin.full = dfixed_div(margin, tmp); - result.full = dfixed_mul(result, margin); - - result.full = dfixed_div(result, tmp); - result.full = dfixed_ceil(result); - res = dfixed_trunc(result); - return res; + u64 kbps; + s64 peak_kbps; + u32 numerator; + u32 denominator; + + kbps = clock * bpp; + + /* + * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006 + * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on + * common multiplier to render an integer PBN for all link rate/lane + * counts combinations + * calculate + * peak_kbps *= (1006/1000) + * peak_kbps *= (64/54) + * peak_kbps *= 8 convert to bytes + */ + + numerator = 64 * 1006; + denominator = 54 * 8 * 1000 * 1000; + + kbps *= numerator; + peak_kbps = drm_fixp_from_fraction(kbps, denominator); + + return drm_fixp2int_ceil(peak_kbps); } EXPORT_SYMBOL(drm_dp_calc_pbn_mode); @@ -2638,11 +2690,23 @@ static int test_calc_pbn_mode(void) { int ret; ret = drm_dp_calc_pbn_mode(154000, 30); - if (ret != 689) + if (ret != 689) { + DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n", + 154000, 30, 689, ret); return -EINVAL; + } ret = drm_dp_calc_pbn_mode(234000, 30); - if (ret != 1047) + if (ret != 1047) { + DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n", + 234000, 30, 1047, ret); return -EINVAL; + } + ret = drm_dp_calc_pbn_mode(297000, 24); + if (ret != 1063) { + DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n", + 297000, 24, 1063, ret); + return -EINVAL; + } return 0; } @@ -2783,6 +2847,13 @@ static void drm_dp_tx_work(struct work_struct *work) mutex_unlock(&mgr->qlock); } +static void drm_dp_free_mst_port(struct kref *kref) +{ + struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref); + kref_put(&port->parent->kref, drm_dp_free_mst_branch_device); + kfree(port); +} + static void drm_dp_destroy_connector_work(struct work_struct *work) { struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work); @@ -2803,13 +2874,22 @@ static void drm_dp_destroy_connector_work(struct work_struct *work) list_del(&port->next); mutex_unlock(&mgr->destroy_connector_lock); + kref_init(&port->kref); + INIT_LIST_HEAD(&port->next); + mgr->cbs->destroy_connector(mgr, port->connector); drm_dp_port_teardown_pdt(port, port->pdt); - if (!port->input && port->vcpi.vcpi > 0) - drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi); - kfree(port); + if (!port->input && port->vcpi.vcpi > 0) { + if (mgr->mst_state) { + drm_dp_mst_reset_vcpi_slots(mgr, port); + drm_dp_update_payload_part1(mgr); + drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi); + } + } + + kref_put(&port->kref, drm_dp_free_mst_port); send_hotplug = true; } if (send_hotplug) @@ -2847,6 +2927,9 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes; mgr->max_payloads = max_payloads; mgr->conn_base_id = conn_base_id; + if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 || + max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8) + return -EINVAL; mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL); if (!mgr->payloads) return -ENOMEM; @@ -2854,7 +2937,9 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, if (!mgr->proposed_vcpis) return -ENOMEM; set_bit(0, &mgr->payload_mask); - test_calc_pbn_mode(); + if (test_calc_pbn_mode() < 0) + DRM_ERROR("MST PBN self-test failed\n"); + return 0; } EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init); diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 24ab1787b771..fdb47051d549 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -44,8 +44,6 @@ struct drm_dp_vcpi { /** * 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. @@ -70,10 +68,6 @@ struct drm_dp_vcpi { 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; @@ -110,10 +104,12 @@ struct drm_dp_mst_port { * @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. + * @guid: guid for DP 1.2 branch device. port under this branch can be + * identified by port #. * * This structure represents an MST branch device, there is one - * primary branch device at the root, along with any others connected - * to downstream ports + * primary branch device at the root, along with any other branches connected + * to downstream port of parent branches. */ struct drm_dp_mst_branch { struct kref kref; @@ -132,6 +128,9 @@ struct drm_dp_mst_branch { struct drm_dp_sideband_msg_tx *tx_slots[2]; int last_seqno; bool link_address_sent; + + /* global unique identifier to identify branch devices */ + u8 guid[16]; }; @@ -406,11 +405,9 @@ struct drm_dp_payload { * @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. + * @lock: protects mst state, primary, 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. * @@ -432,13 +429,11 @@ struct drm_dp_mst_topology_mgr { 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 */ + struct mutex lock; /* protects mst_state + primary + 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; diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h index d639049a613d..553210c02ee0 100644 --- a/include/drm/drm_fixed.h +++ b/include/drm/drm_fixed.h @@ -73,18 +73,28 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) +#define DRM_FIXED_EPSILON 1LL +#define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON) static inline s64 drm_int2fixp(int a) { return ((s64)a) << DRM_FIXED_POINT; } -static inline int drm_fixp2int(int64_t a) +static inline int drm_fixp2int(s64 a) { return ((s64)a) >> DRM_FIXED_POINT; } -static inline unsigned drm_fixp_msbset(int64_t a) +static inline int drm_fixp2int_ceil(s64 a) +{ + if (a > 0) + return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE); + else + return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE); +} + +static inline unsigned drm_fixp_msbset(s64 a) { unsigned shift, sign = (a >> 63) & 1; @@ -136,6 +146,45 @@ static inline s64 drm_fixp_div(s64 a, s64 b) return result; } +static inline s64 drm_fixp_from_fraction(s64 a, s64 b) +{ + s64 res; + bool a_neg = a < 0; + bool b_neg = b < 0; + u64 a_abs = a_neg ? -a : a; + u64 b_abs = b_neg ? -b : b; + u64 rem; + + /* determine integer part */ + u64 res_abs = div64_u64_rem(a_abs, b_abs, &rem); + + /* determine fractional part */ + { + u32 i = DRM_FIXED_POINT; + + do { + rem <<= 1; + res_abs <<= 1; + if (rem >= b_abs) { + res_abs |= 1; + rem -= b_abs; + } + } while (--i != 0); + } + + /* round up LSB */ + { + u64 summand = (rem << 1) >= b_abs; + + res_abs += summand; + } + + res = (s64) res_abs; + if (a_neg ^ b_neg) + res = -res; + return res; +} + static inline s64 drm_fixp_exp(s64 x) { s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); |