Re: [PATCH 02/19] drm/dp: Add support for DP tunneling

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Jan 23, 2024 at 12:28:33PM +0200, Imre Deak wrote:
> +static char yes_no_chr(int val)
> +{
> +	return val ? 'Y' : 'N';
> +}

We have str_yes_no() already.

v> +
> +#define SKIP_DPRX_CAPS_CHECK		BIT(0)
> +#define ALLOW_ALLOCATED_BW_CHANGE	BIT(1)
> +
> +static bool tunnel_regs_are_valid(struct drm_dp_tunnel_mgr *mgr,
> +				  const struct drm_dp_tunnel_regs *regs,
> +				  unsigned int flags)
> +{
> +	int drv_group_id = tunnel_reg_drv_group_id(regs);
> +	bool check_dprx = !(flags & SKIP_DPRX_CAPS_CHECK);
> +	bool ret = true;
> +
> +	if (!tunnel_reg_bw_alloc_supported(regs)) {
> +		if (tunnel_group_id(drv_group_id)) {
> +			drm_dbg_kms(mgr->dev,
> +				    "DPTUN: A non-zero group ID is only allowed with BWA support\n");
> +			ret = false;
> +		}
> +
> +		if (tunnel_reg(regs, DP_ALLOCATED_BW)) {
> +			drm_dbg_kms(mgr->dev,
> +				    "DPTUN: BW is allocated without BWA support\n");
> +			ret = false;
> +		}
> +
> +		return ret;
> +	}
> +
> +	if (!tunnel_group_id(drv_group_id)) {
> +		drm_dbg_kms(mgr->dev,
> +			    "DPTUN: BWA support requires a non-zero group ID\n");
> +		ret = false;
> +	}
> +
> +	if (check_dprx && hweight8(tunnel_reg_max_dprx_lane_count(regs)) != 1) {
> +		drm_dbg_kms(mgr->dev,
> +			    "DPTUN: Invalid DPRX lane count: %d\n",
> +			    tunnel_reg_max_dprx_lane_count(regs));
> +
> +		ret = false;
> +	}
> +
> +	if (check_dprx && !tunnel_reg_max_dprx_rate(regs)) {
> +		drm_dbg_kms(mgr->dev,
> +			    "DPTUN: DPRX rate is 0\n");
> +
> +		ret = false;
> +	}
> +
> +	if (tunnel_reg(regs, DP_ALLOCATED_BW) > tunnel_reg(regs, DP_ESTIMATED_BW)) {
> +		drm_dbg_kms(mgr->dev,
> +			    "DPTUN: Allocated BW %d > estimated BW %d Mb/s\n",
> +			    DPTUN_BW_ARG(tunnel_reg(regs, DP_ALLOCATED_BW) *
> +					 tunnel_reg_bw_granularity(regs)),
> +			    DPTUN_BW_ARG(tunnel_reg(regs, DP_ESTIMATED_BW) *
> +					 tunnel_reg_bw_granularity(regs)));
> +
> +		ret = false;
> +	}
> +
> +	return ret;
> +}
> +
> +static bool tunnel_info_changes_are_valid(struct drm_dp_tunnel *tunnel,
> +					  const struct drm_dp_tunnel_regs *regs,
> +					  unsigned int flags)
> +{
> +	int new_drv_group_id = tunnel_reg_drv_group_id(regs);
> +	bool ret = true;
> +
> +	if (tunnel->bw_alloc_supported != tunnel_reg_bw_alloc_supported(regs)) {
> +		tun_dbg(tunnel,
> +			"BW alloc support has changed %c -> %c\n",
> +			yes_no_chr(tunnel->bw_alloc_supported),
> +			yes_no_chr(tunnel_reg_bw_alloc_supported(regs)));
> +
> +		ret = false;
> +	}
> +
> +	if (tunnel->group->drv_group_id != new_drv_group_id) {
> +		tun_dbg(tunnel,
> +			"Driver/group ID has changed %d:%d:* -> %d:%d:*\n",
> +			tunnel_group_drv_id(tunnel->group->drv_group_id),
> +			tunnel_group_id(tunnel->group->drv_group_id),
> +			tunnel_group_drv_id(new_drv_group_id),
> +			tunnel_group_id(new_drv_group_id));
> +
> +		ret = false;
> +	}
> +
> +	if (!tunnel->bw_alloc_supported)
> +		return ret;
> +
> +	if (tunnel->bw_granularity != tunnel_reg_bw_granularity(regs)) {
> +		tun_dbg(tunnel,
> +			"BW granularity has changed: %d -> %d Mb/s\n",
> +			DPTUN_BW_ARG(tunnel->bw_granularity),
> +			DPTUN_BW_ARG(tunnel_reg_bw_granularity(regs)));
> +
> +		ret = false;
> +	}
> +
> +	/*
> +	 * On some devices at least the BW alloc mode enabled status is always
> +	 * reported as 0, so skip checking that here.
> +	 */

So it's reported as supported and we enable it, but it's never
reported back as being enabled?

> +
> +	if (!(flags & ALLOW_ALLOCATED_BW_CHANGE) &&
> +	    tunnel->allocated_bw !=
> +	    tunnel_reg(regs, DP_ALLOCATED_BW) * tunnel->bw_granularity) {
> +		tun_dbg(tunnel,
> +			"Allocated BW has changed: %d -> %d Mb/s\n",
> +			DPTUN_BW_ARG(tunnel->allocated_bw),
> +			DPTUN_BW_ARG(tunnel_reg(regs, DP_ALLOCATED_BW) * tunnel->bw_granularity));
> +
> +		ret = false;
> +	}
> +
> +	return ret;
> +}
> +
> +static int
> +read_and_verify_tunnel_regs(struct drm_dp_tunnel *tunnel,
> +			    struct drm_dp_tunnel_regs *regs,
> +			    unsigned int flags)
> +{
> +	int err;
> +
> +	err = read_tunnel_regs(tunnel->aux, regs);
> +	if (err < 0) {
> +		drm_dp_tunnel_set_io_error(tunnel);
> +
> +		return err;
> +	}
> +
> +	if (!tunnel_regs_are_valid(tunnel->group->mgr, regs, flags))
> +		return -EINVAL;
> +
> +	if (!tunnel_info_changes_are_valid(tunnel, regs, flags))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static bool update_dprx_caps(struct drm_dp_tunnel *tunnel, const struct drm_dp_tunnel_regs *regs)
> +{
> +	bool changed = false;
> +
> +	if (tunnel_reg_max_dprx_rate(regs) != tunnel->max_dprx_rate) {
> +		tunnel->max_dprx_rate = tunnel_reg_max_dprx_rate(regs);
> +		changed = true;
> +	}
> +
> +	if (tunnel_reg_max_dprx_lane_count(regs) != tunnel->max_dprx_lane_count) {
> +		tunnel->max_dprx_lane_count = tunnel_reg_max_dprx_lane_count(regs);
> +		changed = true;
> +	}
> +
> +	return changed;
> +}
> +
> +static int dev_id_len(const u8 *dev_id, int max_len)
> +{
> +	while (max_len && dev_id[max_len - 1] == '\0')
> +		max_len--;
> +
> +	return max_len;
> +}
> +
> +static int get_max_dprx_bw(const struct drm_dp_tunnel *tunnel)
> +{
> +	int bw = drm_dp_max_dprx_data_rate(tunnel->max_dprx_rate,
> +					   tunnel->max_dprx_lane_count);
> +
> +	return min(roundup(bw, tunnel->bw_granularity),

Should this round down?

> +		   MAX_DP_REQUEST_BW * tunnel->bw_granularity);
> +}
> +
> +static int get_max_tunnel_bw(const struct drm_dp_tunnel *tunnel)
> +{
> +	return min(get_max_dprx_bw(tunnel), tunnel->group->available_bw);
> +}
> +
> +/**
> + * drm_dp_tunnel_detect - Detect DP tunnel on the link
> + * @mgr: Tunnel manager
> + * @aux: DP AUX on which the tunnel will be detected
> + *
> + * Detect if there is any DP tunnel on the link and add it to the tunnel
> + * group's tunnel list.
> + *
> + * Returns 0 on success, negative error code on failure.
> + */
> +struct drm_dp_tunnel *
> +drm_dp_tunnel_detect(struct drm_dp_tunnel_mgr *mgr,
> +		       struct drm_dp_aux *aux)
> +{
> +	struct drm_dp_tunnel_regs regs;
> +	struct drm_dp_tunnel *tunnel;
> +	int err;
> +
> +	err = read_tunnel_regs(aux, &regs);
> +	if (err)
> +		return ERR_PTR(err);
> +
> +	if (!(tunnel_reg(&regs, DP_TUNNELING_CAPABILITIES) &
> +	      DP_TUNNELING_SUPPORT))
> +		return ERR_PTR(-ENODEV);
> +
> +	/* The DPRX caps are valid only after enabling BW alloc mode. */
> +	if (!tunnel_regs_are_valid(mgr, &regs, SKIP_DPRX_CAPS_CHECK))
> +		return ERR_PTR(-EINVAL);
> +
> +	tunnel = create_tunnel(mgr, aux, &regs);
> +	if (!tunnel)
> +		return ERR_PTR(-ENOMEM);
> +
> +	tun_dbg(tunnel,
> +		"OUI:%*phD DevID:%*pE Rev-HW:%d.%d SW:%d.%d PR-Sup:%c BWA-Sup:%c BWA-En:%c\n",
> +		DP_TUNNELING_OUI_BYTES,
> +			tunnel_reg_ptr(&regs, DP_TUNNELING_OUI),
> +		dev_id_len(tunnel_reg_ptr(&regs, DP_TUNNELING_DEV_ID), DP_TUNNELING_DEV_ID_BYTES),
> +			tunnel_reg_ptr(&regs, DP_TUNNELING_DEV_ID),
> +		(tunnel_reg(&regs, DP_TUNNELING_HW_REV) & DP_TUNNELING_HW_REV_MAJOR_MASK) >>
> +			DP_TUNNELING_HW_REV_MAJOR_SHIFT,
> +		(tunnel_reg(&regs, DP_TUNNELING_HW_REV) & DP_TUNNELING_HW_REV_MINOR_MASK) >>
> +			DP_TUNNELING_HW_REV_MINOR_SHIFT,
> +		tunnel_reg(&regs, DP_TUNNELING_SW_REV_MAJOR),
> +		tunnel_reg(&regs, DP_TUNNELING_SW_REV_MINOR),
> +		yes_no_chr(tunnel_reg(&regs, DP_TUNNELING_CAPABILITIES) &
> +			   DP_PANEL_REPLAY_OPTIMIZATION_SUPPORT),
> +		yes_no_chr(tunnel->bw_alloc_supported),
> +		yes_no_chr(tunnel->bw_alloc_enabled));
> +
> +	return tunnel;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_detect);
> +
> +/**
> + * drm_dp_tunnel_destroy - Destroy tunnel object
> + * @tunnel: Tunnel object
> + *
> + * Remove the tunnel from the tunnel topology and destroy it.
> + */
> +int drm_dp_tunnel_destroy(struct drm_dp_tunnel *tunnel)
> +{
> +	if (drm_WARN_ON(tunnel->group->mgr->dev, tunnel->destroyed))
> +		return -ENODEV;
> +
> +	tun_dbg(tunnel, "destroying\n");
> +
> +	tunnel->destroyed = true;
> +	destroy_tunnel(tunnel);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_destroy);
> +
> +static int check_tunnel(const struct drm_dp_tunnel *tunnel)
> +{
> +	if (tunnel->destroyed)
> +		return -ENODEV;
> +
> +	if (tunnel->has_io_error)
> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +static int group_allocated_bw(struct drm_dp_tunnel_group *group)
> +{
> +	struct drm_dp_tunnel *tunnel;
> +	int group_allocated_bw = 0;
> +
> +	for_each_tunnel_in_group(group, tunnel) {
> +		if (check_tunnel(tunnel) == 0 &&
> +		    tunnel->bw_alloc_enabled)
> +			group_allocated_bw += tunnel->allocated_bw;
> +	}
> +
> +	return group_allocated_bw;
> +}
> +
> +static int calc_group_available_bw(const struct drm_dp_tunnel *tunnel)
> +{
> +	return group_allocated_bw(tunnel->group) -
> +	       tunnel->allocated_bw +
> +	       tunnel->estimated_bw;

Hmm. So the estimated_bw=actually_free_bw + tunnel->allocated_bw?
Ie. how much bw might be available for this tunnel right now?
And here we're trying to deduce the total bandwidth available by
adding in the allocated_bw of all the other tunnels in the group?
Rather weird that we can't just get that number directly...

> +}
> +
> +static int update_group_available_bw(struct drm_dp_tunnel *tunnel,
> +				     const struct drm_dp_tunnel_regs *regs)
> +{
> +	struct drm_dp_tunnel *tunnel_iter;
> +	int group_available_bw;
> +	bool changed;
> +
> +	tunnel->estimated_bw = tunnel_reg(regs, DP_ESTIMATED_BW) * tunnel->bw_granularity;
> +
> +	if (calc_group_available_bw(tunnel) == tunnel->group->available_bw)
> +		return 0;
> +
> +	for_each_tunnel_in_group(tunnel->group, tunnel_iter) {
> +		int err;
> +
> +		if (tunnel_iter == tunnel)
> +			continue;
> +
> +		if (check_tunnel(tunnel_iter) != 0 ||
> +		    !tunnel_iter->bw_alloc_enabled)
> +			continue;
> +
> +		err = drm_dp_dpcd_probe(tunnel_iter->aux, DP_DPCD_REV);
> +		if (err) {
> +			tun_dbg(tunnel_iter,
> +				"Probe failed, assume disconnected (err %pe)\n",
> +				ERR_PTR(err));
> +			drm_dp_tunnel_set_io_error(tunnel_iter);
> +		}
> +	}
> +
> +	group_available_bw = calc_group_available_bw(tunnel);
> +
> +	tun_dbg(tunnel, "Updated group available BW: %d->%d\n",
> +		DPTUN_BW_ARG(tunnel->group->available_bw),
> +		DPTUN_BW_ARG(group_available_bw));
> +
> +	changed = tunnel->group->available_bw != group_available_bw;
> +
> +	tunnel->group->available_bw = group_available_bw;
> +
> +	return changed ? 1 : 0;
> +}
> +
> +static int set_bw_alloc_mode(struct drm_dp_tunnel *tunnel, bool enable)
> +{
> +	u8 mask = DP_DISPLAY_DRIVER_BW_ALLOCATION_MODE_ENABLE | DP_UNMASK_BW_ALLOCATION_IRQ;
> +	u8 val;
> +
> +	if (drm_dp_dpcd_readb(tunnel->aux, DP_DPTX_BW_ALLOCATION_MODE_CONTROL, &val) < 0)
> +		goto out_err;
> +
> +	if (enable)
> +		val |= mask;
> +	else
> +		val &= ~mask;
> +
> +	if (drm_dp_dpcd_writeb(tunnel->aux, DP_DPTX_BW_ALLOCATION_MODE_CONTROL, val) < 0)
> +		goto out_err;
> +
> +	tunnel->bw_alloc_enabled = enable;
> +
> +	return 0;
> +
> +out_err:
> +	drm_dp_tunnel_set_io_error(tunnel);
> +
> +	return -EIO;
> +}
> +
> +/**
> + * drm_dp_tunnel_enable_bw_alloc: Enable DP tunnel BW allocation mode
> + * @tunnel: Tunnel object
> + *
> + * Enable the DP tunnel BW allocation mode on @tunnel if it supports it.
> + *
> + * Returns 0 in case of success, negative error code otherwise.
> + */
> +int drm_dp_tunnel_enable_bw_alloc(struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_regs regs;
> +	int err = check_tunnel(tunnel);
> +
> +	if (err)
> +		return err;
> +
> +	if (!tunnel->bw_alloc_supported)
> +		return -EOPNOTSUPP;
> +
> +	if (!tunnel_group_id(tunnel->group->drv_group_id))
> +		return -EINVAL;
> +
> +	err = set_bw_alloc_mode(tunnel, true);
> +	if (err)
> +		goto out;
> +
> +	err = read_and_verify_tunnel_regs(tunnel, &regs, 0);
> +	if (err) {
> +		set_bw_alloc_mode(tunnel, false);
> +
> +		goto out;
> +	}
> +
> +	if (!tunnel->max_dprx_rate)
> +		update_dprx_caps(tunnel, &regs);
> +
> +	if (tunnel->group->available_bw == -1) {
> +		err = update_group_available_bw(tunnel, &regs);
> +		if (err > 0)
> +			err = 0;
> +	}
> +out:
> +	tun_dbg_stat(tunnel, err,
> +		     "Enabling BW alloc mode: DPRX:%dx%d Group alloc:%d/%d Mb/s",
> +		     tunnel->max_dprx_rate / 100, tunnel->max_dprx_lane_count,
> +		     DPTUN_BW_ARG(group_allocated_bw(tunnel->group)),
> +		     DPTUN_BW_ARG(tunnel->group->available_bw));
> +
> +	return err;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_enable_bw_alloc);
> +
> +/**
> + * drm_dp_tunnel_disable_bw_alloc: Disable DP tunnel BW allocation mode
> + * @tunnel: Tunnel object
> + *
> + * Disable the DP tunnel BW allocation mode on @tunnel.
> + *
> + * Returns 0 in case of success, negative error code otherwise.
> + */
> +int drm_dp_tunnel_disable_bw_alloc(struct drm_dp_tunnel *tunnel)
> +{
> +	int err = check_tunnel(tunnel);
> +
> +	if (err)
> +		return err;
> +
> +	err = set_bw_alloc_mode(tunnel, false);
> +
> +	tun_dbg_stat(tunnel, err, "Disabling BW alloc mode");
> +
> +	return err;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_disable_bw_alloc);
> +
> +bool drm_dp_tunnel_bw_alloc_is_enabled(const struct drm_dp_tunnel *tunnel)
> +{
> +	return tunnel->bw_alloc_enabled;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_bw_alloc_is_enabled);
> +
> +static int bw_req_complete(struct drm_dp_aux *aux, bool *status_changed)
> +{
> +	u8 bw_req_mask = DP_BW_REQUEST_SUCCEEDED | DP_BW_REQUEST_FAILED;
> +	u8 status_change_mask = DP_BW_ALLOCATION_CAPABILITY_CHANGED | DP_ESTIMATED_BW_CHANGED;
> +	u8 val;
> +
> +	if (drm_dp_dpcd_readb(aux, DP_TUNNELING_STATUS, &val) < 0)
> +		return -EIO;
> +
> +	*status_changed = val & status_change_mask;
> +
> +	val &= bw_req_mask;
> +
> +	if (!val)
> +		return -EAGAIN;
> +
> +	if (drm_dp_dpcd_writeb(aux, DP_TUNNELING_STATUS, val) < 0)
> +		return -EIO;
> +
> +	return val == DP_BW_REQUEST_SUCCEEDED ? 0 : -ENOSPC;
> +}
> +
> +static int allocate_tunnel_bw(struct drm_dp_tunnel *tunnel, int bw)
> +{
> +	struct drm_dp_tunnel_mgr *mgr = tunnel->group->mgr;
> +	int request_bw = DIV_ROUND_UP(bw, tunnel->bw_granularity);
> +	unsigned long wait_expires;
> +	DEFINE_WAIT(wait);
> +	int err;
> +
> +	/* Atomic check should prevent the following. */
> +	if (drm_WARN_ON(mgr->dev, request_bw > MAX_DP_REQUEST_BW)) {
> +		err = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (drm_dp_dpcd_writeb(tunnel->aux, DP_REQUEST_BW, request_bw) < 0) {
> +		err = -EIO;
> +		goto out;
> +	}
> +
> +	wait_expires = jiffies + msecs_to_jiffies(3000);
> +
> +	for (;;) {
> +		bool status_changed;
> +
> +		err = bw_req_complete(tunnel->aux, &status_changed);
> +		if (err != -EAGAIN)
> +			break;
> +
> +		if (status_changed) {
> +			struct drm_dp_tunnel_regs regs;
> +
> +			err = read_and_verify_tunnel_regs(tunnel, &regs,
> +							  ALLOW_ALLOCATED_BW_CHANGE);
> +			if (err)
> +				break;
> +		}
> +
> +		if (time_after(jiffies, wait_expires)) {
> +			err = -ETIMEDOUT;
> +			break;
> +		}
> +
> +		prepare_to_wait(&mgr->bw_req_queue, &wait, TASK_UNINTERRUPTIBLE);
> +		schedule_timeout(msecs_to_jiffies(200));
> +	};
> +
> +	finish_wait(&mgr->bw_req_queue, &wait);
> +
> +	if (err)
> +		goto out;
> +
> +	tunnel->allocated_bw = request_bw * tunnel->bw_granularity;
> +
> +out:
> +	tun_dbg_stat(tunnel, err, "Allocating %d/%d Mb/s for tunnel: Group alloc:%d/%d Mb/s",
> +		     DPTUN_BW_ARG(request_bw * tunnel->bw_granularity),
> +		     DPTUN_BW_ARG(get_max_tunnel_bw(tunnel)),
> +		     DPTUN_BW_ARG(group_allocated_bw(tunnel->group)),
> +		     DPTUN_BW_ARG(tunnel->group->available_bw));
> +
> +	if (err == -EIO)
> +		drm_dp_tunnel_set_io_error(tunnel);
> +
> +	return err;
> +}
> +
> +int drm_dp_tunnel_alloc_bw(struct drm_dp_tunnel *tunnel, int bw)
> +{
> +	int err = check_tunnel(tunnel);
> +
> +	if (err)
> +		return err;
> +
> +	return allocate_tunnel_bw(tunnel, bw);
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_alloc_bw);
> +
> +static int check_and_clear_status_change(struct drm_dp_tunnel *tunnel)
> +{
> +	u8 mask = DP_BW_ALLOCATION_CAPABILITY_CHANGED | DP_ESTIMATED_BW_CHANGED;
> +	u8 val;
> +
> +	if (drm_dp_dpcd_readb(tunnel->aux, DP_TUNNELING_STATUS, &val) < 0)
> +		goto out_err;
> +
> +	val &= mask;
> +
> +	if (val) {
> +		if (drm_dp_dpcd_writeb(tunnel->aux, DP_TUNNELING_STATUS, val) < 0)
> +			goto out_err;
> +
> +		return 1;
> +	}
> +
> +	if (!drm_dp_tunnel_bw_alloc_is_enabled(tunnel))
> +		return 0;
> +
> +	/*
> +	 * Check for estimated BW changes explicitly to account for lost
> +	 * BW change notifications.
> +	 */
> +	if (drm_dp_dpcd_readb(tunnel->aux, DP_ESTIMATED_BW, &val) < 0)
> +		goto out_err;
> +
> +	if (val * tunnel->bw_granularity != tunnel->estimated_bw)
> +		return 1;
> +
> +	return 0;
> +
> +out_err:
> +	drm_dp_tunnel_set_io_error(tunnel);
> +
> +	return -EIO;
> +}
> +
> +/**
> + * drm_dp_tunnel_update_state: Update DP tunnel SW state with the HW state
> + * @tunnel: Tunnel object
> + *
> + * Update the SW state of @tunnel with the HW state.
> + *
> + * Returns 0 if the state has not changed, 1 if it has changed and got updated
> + * successfully and a negative error code otherwise.
> + */
> +int drm_dp_tunnel_update_state(struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_regs regs;
> +	bool changed = false;
> +	int ret = check_tunnel(tunnel);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = check_and_clear_status_change(tunnel);
> +	if (ret < 0)
> +		goto out;
> +
> +	if (!ret)
> +		return 0;
> +
> +	ret = read_and_verify_tunnel_regs(tunnel, &regs, 0);
> +	if (ret)
> +		goto out;
> +
> +	if (update_dprx_caps(tunnel, &regs))
> +		changed = true;
> +
> +	ret = update_group_available_bw(tunnel, &regs);
> +	if (ret == 1)
> +		changed = true;
> +
> +out:
> +	tun_dbg_stat(tunnel, ret < 0 ? ret : 0,
> +		     "State update: Changed:%c DPRX:%dx%d Tunnel alloc:%d/%d Group alloc:%d/%d Mb/s",
> +		     yes_no_chr(changed),
> +		     tunnel->max_dprx_rate / 100, tunnel->max_dprx_lane_count,
> +		     DPTUN_BW_ARG(tunnel->allocated_bw),
> +		     DPTUN_BW_ARG(get_max_tunnel_bw(tunnel)),
> +		     DPTUN_BW_ARG(group_allocated_bw(tunnel->group)),
> +		     DPTUN_BW_ARG(tunnel->group->available_bw));
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	if (changed)
> +		return 1;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_update_state);
> +
> +/*
> + * Returns 0 if no re-probe is needed, 1 if a re-probe is needed,
> + * a negative error code otherwise.
> + */
> +int drm_dp_tunnel_handle_irq(struct drm_dp_tunnel_mgr *mgr, struct drm_dp_aux *aux)
> +{
> +	u8 val;
> +
> +	if (drm_dp_dpcd_readb(aux, DP_TUNNELING_STATUS, &val) < 0)
> +		return -EIO;
> +
> +	if (val & (DP_BW_REQUEST_SUCCEEDED | DP_BW_REQUEST_FAILED))
> +		wake_up_all(&mgr->bw_req_queue);
> +
> +	if (val & (DP_BW_ALLOCATION_CAPABILITY_CHANGED | DP_ESTIMATED_BW_CHANGED))
> +		return 1;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_handle_irq);
> +
> +/**
> + * drm_dp_tunnel_max_dprx_rate - Query the maximum rate of the tunnel's DPRX
> + * @tunnel: Tunnel object
> + *
> + * The function is used to query the maximum link rate of the DPRX connected
> + * to @tunnel. Note that this rate will not be limited by the BW limit of the
> + * tunnel, as opposed to the standard and extended DP_MAX_LINK_RATE DPCD
> + * registers.
> + *
> + * Returns the maximum link rate in 10 kbit/s units.
> + */
> +int drm_dp_tunnel_max_dprx_rate(const struct drm_dp_tunnel *tunnel)
> +{
> +	return tunnel->max_dprx_rate;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_max_dprx_rate);
> +
> +/**
> + * drm_dp_tunnel_max_dprx_lane_count - Query the maximum lane count of the tunnel's DPRX
> + * @tunnel: Tunnel object
> + *
> + * The function is used to query the maximum lane count of the DPRX connected
> + * to @tunnel. Note that this lane count will not be limited by the BW limit of
> + * the tunnel, as opposed to the standard and extended DP_MAX_LANE_COUNT DPCD
> + * registers.
> + *
> + * Returns the maximum lane count.
> + */
> +int drm_dp_tunnel_max_dprx_lane_count(const struct drm_dp_tunnel *tunnel)
> +{
> +	return tunnel->max_dprx_lane_count;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_max_dprx_lane_count);
> +
> +/**
> + * drm_dp_tunnel_available_bw - Query the estimated total available BW of the tunnel
> + * @tunnel: Tunnel object
> + *
> + * This function is used to query the estimated total available BW of the
> + * tunnel. This includes the currently allocated and free BW for all the
> + * tunnels in @tunnel's group. The available BW is valid only after the BW
> + * allocation mode has been enabled for the tunnel and its state got updated
> + * calling drm_dp_tunnel_update_state().
> + *
> + * Returns the @tunnel group's estimated total available bandwidth in kB/s
> + * units, or -1 if the available BW isn't valid (the BW allocation mode is
> + * not enabled or the tunnel's state hasn't been updated).
> + */
> +int drm_dp_tunnel_available_bw(const struct drm_dp_tunnel *tunnel)
> +{
> +	return tunnel->group->available_bw;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_available_bw);
> +
> +static struct drm_dp_tunnel_group_state *
> +drm_dp_tunnel_atomic_get_group_state(struct drm_atomic_state *state,
> +				     const struct drm_dp_tunnel *tunnel)
> +{
> +	return (struct drm_dp_tunnel_group_state *)
> +		drm_atomic_get_private_obj_state(state,
> +						 &tunnel->group->base);
> +}
> +
> +static struct drm_dp_tunnel_state *
> +add_tunnel_state(struct drm_dp_tunnel_group_state *group_state,
> +		 struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	tun_dbg_atomic(tunnel,
> +		       "Adding state for tunnel %p to group state %p\n",
> +		       tunnel, group_state);
> +
> +	tunnel_state = kzalloc(sizeof(*tunnel_state), GFP_KERNEL);
> +	if (!tunnel_state)
> +		return NULL;
> +
> +	tunnel_state->group_state = group_state;
> +
> +	drm_dp_tunnel_ref_get(tunnel, &tunnel_state->tunnel_ref);
> +
> +	INIT_LIST_HEAD(&tunnel_state->node);
> +	list_add(&tunnel_state->node, &group_state->tunnel_states);
> +
> +	return tunnel_state;
> +}
> +
> +void drm_dp_tunnel_atomic_clear_state(struct drm_dp_tunnel_state *tunnel_state)
> +{
> +	tun_dbg_atomic(tunnel_state->tunnel_ref.tunnel,
> +		       "Clearing state for tunnel %p\n",
> +		       tunnel_state->tunnel_ref.tunnel);
> +
> +	list_del(&tunnel_state->node);
> +
> +	kfree(tunnel_state->stream_bw);
> +	drm_dp_tunnel_ref_put(&tunnel_state->tunnel_ref);
> +
> +	kfree(tunnel_state);
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_clear_state);
> +
> +static void clear_tunnel_group_state(struct drm_dp_tunnel_group_state *group_state)
> +{
> +	struct drm_dp_tunnel_state *tunnel_state;
> +	struct drm_dp_tunnel_state *tunnel_state_tmp;
> +
> +	for_each_tunnel_state_safe(group_state, tunnel_state, tunnel_state_tmp)
> +		drm_dp_tunnel_atomic_clear_state(tunnel_state);
> +}
> +
> +static struct drm_dp_tunnel_state *
> +get_tunnel_state(struct drm_dp_tunnel_group_state *group_state,
> +		 const struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	for_each_tunnel_state(group_state, tunnel_state)
> +		if (tunnel_state->tunnel_ref.tunnel == tunnel)
> +			return tunnel_state;
> +
> +	return NULL;
> +}
> +
> +static struct drm_dp_tunnel_state *
> +get_or_add_tunnel_state(struct drm_dp_tunnel_group_state *group_state,
> +			struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	tunnel_state = get_tunnel_state(group_state, tunnel);
> +	if (tunnel_state)
> +		return tunnel_state;
> +
> +	return add_tunnel_state(group_state, tunnel);
> +}
> +
> +static struct drm_private_state *
> +tunnel_group_duplicate_state(struct drm_private_obj *obj)
> +{
> +	struct drm_dp_tunnel_group_state *group_state = to_group_state(obj->state);
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	group_state = kzalloc(sizeof(*group_state), GFP_KERNEL);
> +	if (!group_state)
> +		return NULL;
> +
> +	INIT_LIST_HEAD(&group_state->tunnel_states);
> +
> +	__drm_atomic_helper_private_obj_duplicate_state(obj, &group_state->base);
> +
> +	for_each_tunnel_state(to_group_state(obj->state), tunnel_state) {
> +		struct drm_dp_tunnel_state *new_tunnel_state;
> +
> +		new_tunnel_state = get_or_add_tunnel_state(group_state,
> +							   tunnel_state->tunnel_ref.tunnel);
> +		if (!new_tunnel_state)
> +			goto out_free_state;
> +
> +		new_tunnel_state->stream_mask = tunnel_state->stream_mask;
> +		new_tunnel_state->stream_bw = kmemdup(tunnel_state->stream_bw,
> +						      sizeof(*tunnel_state->stream_bw) *
> +							hweight32(tunnel_state->stream_mask),
> +						      GFP_KERNEL);
> +
> +		if (!new_tunnel_state->stream_bw)
> +			goto out_free_state;
> +	}
> +
> +	return &group_state->base;
> +
> +out_free_state:
> +	clear_tunnel_group_state(group_state);
> +	kfree(group_state);
> +
> +	return NULL;
> +}
> +
> +static void tunnel_group_destroy_state(struct drm_private_obj *obj, struct drm_private_state *state)
> +{
> +	struct drm_dp_tunnel_group_state *group_state = to_group_state(state);
> +
> +	clear_tunnel_group_state(group_state);
> +	kfree(group_state);
> +}
> +
> +static const struct drm_private_state_funcs tunnel_group_funcs = {
> +	.atomic_duplicate_state = tunnel_group_duplicate_state,
> +	.atomic_destroy_state = tunnel_group_destroy_state,
> +};
> +
> +struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_state(struct drm_atomic_state *state,
> +			       struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_group_state *group_state =
> +		drm_dp_tunnel_atomic_get_group_state(state, tunnel);
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	if (IS_ERR(group_state))
> +		return ERR_CAST(group_state);
> +
> +	tunnel_state = get_or_add_tunnel_state(group_state, tunnel);
> +	if (!tunnel_state)
> +		return ERR_PTR(-ENOMEM);
> +
> +	return tunnel_state;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_get_state);
> +
> +struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_new_state(struct drm_atomic_state *state,
> +				   const struct drm_dp_tunnel *tunnel)
> +{
> +	struct drm_dp_tunnel_group_state *new_group_state;
> +	int i;
> +
> +	for_each_new_group_in_state(state, new_group_state, i)
> +		if (to_group(new_group_state->base.obj) == tunnel->group)
> +			return get_tunnel_state(new_group_state, tunnel);
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_get_new_state);
> +
> +static bool init_group(struct drm_dp_tunnel_mgr *mgr, struct drm_dp_tunnel_group *group)
> +{
> +	struct drm_dp_tunnel_group_state *group_state = kzalloc(sizeof(*group_state), GFP_KERNEL);
> +
> +	if (!group_state)
> +		return false;
> +
> +	INIT_LIST_HEAD(&group_state->tunnel_states);
> +
> +	group->mgr = mgr;
> +	group->available_bw = -1;
> +	INIT_LIST_HEAD(&group->tunnels);
> +
> +	drm_atomic_private_obj_init(mgr->dev, &group->base, &group_state->base,
> +				    &tunnel_group_funcs);
> +
> +	return true;
> +}
> +
> +static void cleanup_group(struct drm_dp_tunnel_group *group)
> +{
> +	drm_atomic_private_obj_fini(&group->base);
> +}
> +
> +#ifdef CONFIG_DRM_DISPLAY_DEBUG_DP_TUNNEL_STATE
> +static void check_unique_stream_ids(const struct drm_dp_tunnel_group_state *group_state)
> +{
> +	const struct drm_dp_tunnel_state *tunnel_state;
> +	u32 stream_mask = 0;
> +
> +	for_each_tunnel_state(group_state, tunnel_state) {
> +		drm_WARN(to_group(group_state->base.obj)->mgr->dev,
> +			 tunnel_state->stream_mask & stream_mask,
> +			 "[DPTUN %s]: conflicting stream IDs %x (IDs in other tunnels %x)\n",
> +			 tunnel_state->tunnel_ref.tunnel->name,
> +			 tunnel_state->stream_mask,
> +			 stream_mask);
> +
> +		stream_mask |= tunnel_state->stream_mask;
> +	}
> +}
> +#else
> +static void check_unique_stream_ids(const struct drm_dp_tunnel_group_state *group_state)
> +{
> +}
> +#endif
> +
> +static int stream_id_to_idx(u32 stream_mask, u8 stream_id)
> +{
> +	return hweight32(stream_mask & (BIT(stream_id) - 1));
> +}
> +
> +static int resize_bw_array(struct drm_dp_tunnel_state *tunnel_state,
> +			   unsigned long old_mask, unsigned long new_mask)
> +{
> +	unsigned long move_mask = old_mask & new_mask;
> +	int *new_bws = NULL;
> +	int id;
> +
> +	WARN_ON(!new_mask);
> +
> +	if (old_mask == new_mask)
> +		return 0;
> +
> +	new_bws = kcalloc(hweight32(new_mask), sizeof(*new_bws), GFP_KERNEL);
> +	if (!new_bws)
> +		return -ENOMEM;
> +
> +	for_each_set_bit(id, &move_mask, BITS_PER_TYPE(move_mask))
> +		new_bws[stream_id_to_idx(new_mask, id)] =
> +			tunnel_state->stream_bw[stream_id_to_idx(old_mask, id)];
> +
> +	kfree(tunnel_state->stream_bw);
> +	tunnel_state->stream_bw = new_bws;
> +	tunnel_state->stream_mask = new_mask;
> +
> +	return 0;
> +}
> +
> +static int set_stream_bw(struct drm_dp_tunnel_state *tunnel_state,
> +			 u8 stream_id, int bw)
> +{
> +	int err;
> +
> +	err = resize_bw_array(tunnel_state,
> +			      tunnel_state->stream_mask,
> +			      tunnel_state->stream_mask | BIT(stream_id));
> +	if (err)
> +		return err;
> +
> +	tunnel_state->stream_bw[stream_id_to_idx(tunnel_state->stream_mask, stream_id)] = bw;
> +
> +	return 0;
> +}
> +
> +static int clear_stream_bw(struct drm_dp_tunnel_state *tunnel_state,
> +			   u8 stream_id)
> +{
> +	if (!(tunnel_state->stream_mask & ~BIT(stream_id))) {
> +		drm_dp_tunnel_atomic_clear_state(tunnel_state);
> +		return 0;
> +	}
> +
> +	return resize_bw_array(tunnel_state,
> +			       tunnel_state->stream_mask,
> +			       tunnel_state->stream_mask & ~BIT(stream_id));
> +}
> +
> +int drm_dp_tunnel_atomic_set_stream_bw(struct drm_atomic_state *state,
> +					 struct drm_dp_tunnel *tunnel,
> +					 u8 stream_id, int bw)
> +{
> +	struct drm_dp_tunnel_group_state *new_group_state =
> +		drm_dp_tunnel_atomic_get_group_state(state, tunnel);
> +	struct drm_dp_tunnel_state *tunnel_state;
> +	int err;
> +
> +	if (drm_WARN_ON(tunnel->group->mgr->dev,
> +			stream_id > BITS_PER_TYPE(tunnel_state->stream_mask)))
> +		return -EINVAL;
> +
> +	tun_dbg(tunnel,
> +		"Setting %d Mb/s for stream %d\n",
> +		DPTUN_BW_ARG(bw), stream_id);
> +
> +	if (bw == 0) {
> +		tunnel_state = get_tunnel_state(new_group_state, tunnel);
> +		if (!tunnel_state)
> +			return 0;
> +
> +		return clear_stream_bw(tunnel_state, stream_id);
> +	}
> +
> +	tunnel_state = get_or_add_tunnel_state(new_group_state, tunnel);
> +	if (drm_WARN_ON(state->dev, !tunnel_state))
> +		return -EINVAL;
> +
> +	err = set_stream_bw(tunnel_state, stream_id, bw);
> +	if (err)
> +		return err;
> +
> +	check_unique_stream_ids(new_group_state);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_set_stream_bw);
> +
> +int drm_dp_tunnel_atomic_get_tunnel_bw(const struct drm_dp_tunnel_state *tunnel_state)
> +{
> +	int tunnel_bw = 0;
> +	int i;
> +
> +	for (i = 0; i < hweight32(tunnel_state->stream_mask); i++)
> +		tunnel_bw += tunnel_state->stream_bw[i];
> +
> +	return tunnel_bw;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_get_tunnel_bw);
> +
> +int drm_dp_tunnel_atomic_get_group_streams_in_state(struct drm_atomic_state *state,
> +						    const struct drm_dp_tunnel *tunnel,
> +						    u32 *stream_mask)
> +{
> +	struct drm_dp_tunnel_group_state *group_state =
> +		drm_dp_tunnel_atomic_get_group_state(state, tunnel);
> +	struct drm_dp_tunnel_state *tunnel_state;
> +
> +	if (IS_ERR(group_state))
> +		return PTR_ERR(group_state);
> +
> +	*stream_mask = 0;
> +	for_each_tunnel_state(group_state, tunnel_state)
> +		*stream_mask |= tunnel_state->stream_mask;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_get_group_streams_in_state);
> +
> +static int
> +drm_dp_tunnel_atomic_check_group_bw(struct drm_dp_tunnel_group_state *new_group_state,
> +				    u32 *failed_stream_mask)
> +{
> +	struct drm_dp_tunnel_group *group = to_group(new_group_state->base.obj);
> +	struct drm_dp_tunnel_state *new_tunnel_state;
> +	u32 group_stream_mask = 0;
> +	int group_bw = 0;
> +
> +	for_each_tunnel_state(new_group_state, new_tunnel_state) {
> +		struct drm_dp_tunnel *tunnel = new_tunnel_state->tunnel_ref.tunnel;
> +		int max_dprx_bw = get_max_dprx_bw(tunnel);
> +		int tunnel_bw = drm_dp_tunnel_atomic_get_tunnel_bw(new_tunnel_state);
> +
> +		tun_dbg(tunnel,
> +			"%sRequired %d/%d Mb/s total for tunnel.\n",
> +			tunnel_bw > max_dprx_bw ? "Not enough BW: " : "",
> +			DPTUN_BW_ARG(tunnel_bw),
> +			DPTUN_BW_ARG(max_dprx_bw));
> +
> +		if (tunnel_bw > max_dprx_bw) {

I'm a bit confused why we're checking this here. Aren't we already
checking this somewhere else?

> +			*failed_stream_mask = new_tunnel_state->stream_mask;
> +			return -ENOSPC;
> +		}
> +
> +		group_bw += min(roundup(tunnel_bw, tunnel->bw_granularity),
> +				max_dprx_bw);
> +		group_stream_mask |= new_tunnel_state->stream_mask;
> +	}
> +
> +	tun_grp_dbg(group,
> +		    "%sRequired %d/%d Mb/s total for tunnel group.\n",
> +		    group_bw > group->available_bw ? "Not enough BW: " : "",
> +		    DPTUN_BW_ARG(group_bw),
> +		    DPTUN_BW_ARG(group->available_bw));
> +
> +	if (group_bw > group->available_bw) {
> +		*failed_stream_mask = group_stream_mask;
> +		return -ENOSPC;
> +	}
> +
> +	return 0;
> +}
> +
> +int drm_dp_tunnel_atomic_check_stream_bws(struct drm_atomic_state *state,
> +					  u32 *failed_stream_mask)
> +{
> +	struct drm_dp_tunnel_group_state *new_group_state;
> +	int i;
> +
> +	for_each_new_group_in_state(state, new_group_state, i) {
> +		int ret;
> +
> +		ret = drm_dp_tunnel_atomic_check_group_bw(new_group_state,
> +							  failed_stream_mask);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_atomic_check_stream_bws);
> +
> +static void destroy_mgr(struct drm_dp_tunnel_mgr *mgr)
> +{
> +	int i;
> +
> +	for (i = 0; i < mgr->group_count; i++) {
> +		cleanup_group(&mgr->groups[i]);
> +		drm_WARN_ON(mgr->dev, !list_empty(&mgr->groups[i].tunnels));
> +	}
> +
> +#ifdef CONFIG_DRM_DISPLAY_DEBUG_DP_TUNNEL_STATE
> +	ref_tracker_dir_exit(&mgr->ref_tracker);
> +#endif
> +
> +	kfree(mgr->groups);
> +	kfree(mgr);
> +}
> +
> +/**
> + * drm_dp_tunnel_mgr_create - Create a DP tunnel manager
> + * @i915: i915 driver object
> + *
> + * Creates a DP tunnel manager.
> + *
> + * Returns a pointer to the tunnel manager if created successfully or NULL in
> + * case of an error.
> + */
> +struct drm_dp_tunnel_mgr *
> +drm_dp_tunnel_mgr_create(struct drm_device *dev, int max_group_count)
> +{
> +	struct drm_dp_tunnel_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
> +	int i;
> +
> +	if (!mgr)
> +		return NULL;
> +
> +	mgr->dev = dev;
> +	init_waitqueue_head(&mgr->bw_req_queue);
> +
> +	mgr->groups = kcalloc(max_group_count, sizeof(*mgr->groups), GFP_KERNEL);
> +	if (!mgr->groups) {
> +		kfree(mgr);
> +
> +		return NULL;
> +	}
> +
> +#ifdef CONFIG_DRM_DISPLAY_DEBUG_DP_TUNNEL_STATE
> +	ref_tracker_dir_init(&mgr->ref_tracker, 16, "dptun");
> +#endif
> +
> +	for (i = 0; i < max_group_count; i++) {
> +		if (!init_group(mgr, &mgr->groups[i])) {
> +			destroy_mgr(mgr);
> +
> +			return NULL;
> +		}
> +
> +		mgr->group_count++;
> +	}
> +
> +	return mgr;
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_mgr_create);
> +
> +/**
> + * drm_dp_tunnel_mgr_destroy - Destroy DP tunnel manager
> + * @mgr: Tunnel manager object
> + *
> + * Destroy the tunnel manager.
> + */
> +void drm_dp_tunnel_mgr_destroy(struct drm_dp_tunnel_mgr *mgr)
> +{
> +	destroy_mgr(mgr);
> +}
> +EXPORT_SYMBOL(drm_dp_tunnel_mgr_destroy);
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index 281afff6ee4e5..8bfd5d007be8d 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -1382,6 +1382,66 @@
>  #define DP_HDCP_2_2_REG_STREAM_TYPE_OFFSET	0x69494
>  #define DP_HDCP_2_2_REG_DBG_OFFSET		0x69518
>  
> +/* DP-tunneling */
> +#define DP_TUNNELING_OUI				0xe0000
> +#define  DP_TUNNELING_OUI_BYTES				3
> +
> +#define DP_TUNNELING_DEV_ID				0xe0003
> +#define  DP_TUNNELING_DEV_ID_BYTES			6
> +
> +#define DP_TUNNELING_HW_REV				0xe0009
> +#define  DP_TUNNELING_HW_REV_MAJOR_SHIFT		4
> +#define  DP_TUNNELING_HW_REV_MAJOR_MASK			(0xf << DP_TUNNELING_HW_REV_MAJOR_SHIFT)
> +#define  DP_TUNNELING_HW_REV_MINOR_SHIFT		0
> +#define  DP_TUNNELING_HW_REV_MINOR_MASK			(0xf << DP_TUNNELING_HW_REV_MINOR_SHIFT)
> +
> +#define DP_TUNNELING_SW_REV_MAJOR			0xe000a
> +#define DP_TUNNELING_SW_REV_MINOR			0xe000b
> +
> +#define DP_TUNNELING_CAPABILITIES			0xe000d
> +#define  DP_IN_BW_ALLOCATION_MODE_SUPPORT		(1 << 7)
> +#define  DP_PANEL_REPLAY_OPTIMIZATION_SUPPORT		(1 << 6)
> +#define  DP_TUNNELING_SUPPORT				(1 << 0)
> +
> +#define DP_IN_ADAPTER_INFO				0xe000e
> +#define  DP_IN_ADAPTER_NUMBER_BITS			7
> +#define  DP_IN_ADAPTER_NUMBER_MASK			((1 << DP_IN_ADAPTER_NUMBER_BITS) - 1)
> +
> +#define DP_USB4_DRIVER_ID				0xe000f
> +#define  DP_USB4_DRIVER_ID_BITS				4
> +#define  DP_USB4_DRIVER_ID_MASK				((1 << DP_USB4_DRIVER_ID_BITS) - 1)
> +
> +#define DP_USB4_DRIVER_BW_CAPABILITY			0xe0020
> +#define  DP_USB4_DRIVER_BW_ALLOCATION_MODE_SUPPORT	(1 << 7)
> +
> +#define DP_IN_ADAPTER_TUNNEL_INFORMATION		0xe0021
> +#define  DP_GROUP_ID_BITS				3
> +#define  DP_GROUP_ID_MASK				((1 << DP_GROUP_ID_BITS) - 1)
> +
> +#define DP_BW_GRANULARITY				0xe0022
> +#define  DP_BW_GRANULARITY_MASK				0x3
> +
> +#define DP_ESTIMATED_BW					0xe0023
> +#define DP_ALLOCATED_BW					0xe0024
> +
> +#define DP_TUNNELING_STATUS				0xe0025
> +#define  DP_BW_ALLOCATION_CAPABILITY_CHANGED		(1 << 3)
> +#define  DP_ESTIMATED_BW_CHANGED			(1 << 2)
> +#define  DP_BW_REQUEST_SUCCEEDED			(1 << 1)
> +#define  DP_BW_REQUEST_FAILED				(1 << 0)
> +
> +#define DP_TUNNELING_MAX_LINK_RATE			0xe0028
> +
> +#define DP_TUNNELING_MAX_LANE_COUNT			0xe0029
> +#define  DP_TUNNELING_MAX_LANE_COUNT_MASK		0x1f
> +
> +#define DP_DPTX_BW_ALLOCATION_MODE_CONTROL		0xe0030
> +#define  DP_DISPLAY_DRIVER_BW_ALLOCATION_MODE_ENABLE	(1 << 7)
> +#define  DP_UNMASK_BW_ALLOCATION_IRQ			(1 << 6)
> +
> +#define DP_REQUEST_BW					0xe0031
> +#define  MAX_DP_REQUEST_BW				255
> +
>  /* LTTPR: Link Training (LT)-tunable PHY Repeaters */
>  #define DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV 0xf0000 /* 1.3 */
>  #define DP_MAX_LINK_RATE_PHY_REPEATER			    0xf0001 /* 1.4a */
> diff --git a/include/drm/display/drm_dp_tunnel.h b/include/drm/display/drm_dp_tunnel.h
> new file mode 100644
> index 0000000000000..f6449b1b4e6e9
> --- /dev/null
> +++ b/include/drm/display/drm_dp_tunnel.h
> @@ -0,0 +1,270 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef __DRM_DP_TUNNEL_H__
> +#define __DRM_DP_TUNNEL_H__
> +
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +
> +struct drm_dp_aux;
> +
> +struct drm_device;
> +
> +struct drm_atomic_state;
> +struct drm_dp_tunnel_mgr;
> +struct drm_dp_tunnel_state;
> +
> +struct ref_tracker;
> +
> +struct drm_dp_tunnel_ref {
> +	struct drm_dp_tunnel *tunnel;
> +#ifdef CONFIG_DRM_DISPLAY_DEBUG_DP_TUNNEL_STATE
> +	struct ref_tracker *tracker;
> +#endif
> +};
> +
> +#ifdef CONFIG_DRM_DISPLAY_DP_TUNNEL
> +
> +struct drm_dp_tunnel *
> +drm_dp_tunnel_get_untracked(struct drm_dp_tunnel *tunnel);
> +void drm_dp_tunnel_put_untracked(struct drm_dp_tunnel *tunnel);
> +
> +#ifdef CONFIG_DRM_DISPLAY_DEBUG_DP_TUNNEL_STATE
> +struct drm_dp_tunnel *
> +drm_dp_tunnel_get(struct drm_dp_tunnel *tunnel, struct ref_tracker **tracker);
> +
> +void
> +drm_dp_tunnel_put(struct drm_dp_tunnel *tunnel, struct ref_tracker **tracker);
> +#else
> +#define drm_dp_tunnel_get(tunnel, tracker) \
> +	drm_dp_tunnel_get_untracked(tunnel)
> +
> +#define drm_dp_tunnel_put(tunnel, tracker) \
> +	drm_dp_tunnel_put_untracked(tunnel)
> +
> +#endif
> +
> +static inline void drm_dp_tunnel_ref_get(struct drm_dp_tunnel *tunnel,
> +					   struct drm_dp_tunnel_ref *tunnel_ref)
> +{
> +	tunnel_ref->tunnel = drm_dp_tunnel_get(tunnel, &tunnel_ref->tracker);
> +}
> +
> +static inline void drm_dp_tunnel_ref_put(struct drm_dp_tunnel_ref *tunnel_ref)
> +{
> +	drm_dp_tunnel_put(tunnel_ref->tunnel, &tunnel_ref->tracker);
> +}
> +
> +struct drm_dp_tunnel *
> +drm_dp_tunnel_detect(struct drm_dp_tunnel_mgr *mgr,
> +		     struct drm_dp_aux *aux);
> +int drm_dp_tunnel_destroy(struct drm_dp_tunnel *tunnel);
> +
> +int drm_dp_tunnel_enable_bw_alloc(struct drm_dp_tunnel *tunnel);
> +int drm_dp_tunnel_disable_bw_alloc(struct drm_dp_tunnel *tunnel);
> +bool drm_dp_tunnel_bw_alloc_is_enabled(const struct drm_dp_tunnel *tunnel);
> +int drm_dp_tunnel_alloc_bw(struct drm_dp_tunnel *tunnel, int bw);
> +int drm_dp_tunnel_check_state(struct drm_dp_tunnel *tunnel);
> +int drm_dp_tunnel_update_state(struct drm_dp_tunnel *tunnel);
> +
> +void drm_dp_tunnel_set_io_error(struct drm_dp_tunnel *tunnel);
> +
> +int drm_dp_tunnel_handle_irq(struct drm_dp_tunnel_mgr *mgr,
> +			     struct drm_dp_aux *aux);
> +
> +int drm_dp_tunnel_max_dprx_rate(const struct drm_dp_tunnel *tunnel);
> +int drm_dp_tunnel_max_dprx_lane_count(const struct drm_dp_tunnel *tunnel);
> +int drm_dp_tunnel_available_bw(const struct drm_dp_tunnel *tunnel);
> +
> +const char *drm_dp_tunnel_name(const struct drm_dp_tunnel *tunnel);
> +
> +struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_state(struct drm_atomic_state *state,
> +			       struct drm_dp_tunnel *tunnel);
> +struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_new_state(struct drm_atomic_state *state,
> +				   const struct drm_dp_tunnel *tunnel);
> +
> +void drm_dp_tunnel_atomic_clear_state(struct drm_dp_tunnel_state *tunnel_state);
> +
> +int drm_dp_tunnel_atomic_set_stream_bw(struct drm_atomic_state *state,
> +				       struct drm_dp_tunnel *tunnel,
> +				       u8 stream_id, int bw);
> +int drm_dp_tunnel_atomic_get_group_streams_in_state(struct drm_atomic_state *state,
> +						    const struct drm_dp_tunnel *tunnel,
> +						    u32 *stream_mask);
> +
> +int drm_dp_tunnel_atomic_check_stream_bws(struct drm_atomic_state *state,
> +					  u32 *failed_stream_mask);
> +
> +int drm_dp_tunnel_atomic_get_tunnel_bw(const struct drm_dp_tunnel_state *tunnel_state);
> +
> +struct drm_dp_tunnel_mgr *
> +drm_dp_tunnel_mgr_create(struct drm_device *dev, int max_group_count);
> +void drm_dp_tunnel_mgr_destroy(struct drm_dp_tunnel_mgr *mgr);
> +
> +#else
> +
> +static inline struct drm_dp_tunnel *
> +drm_dp_tunnel_get_untracked(struct drm_dp_tunnel *tunnel)
> +{
> +	return NULL;
> +}
> +
> +static inline void
> +drm_dp_tunnel_put_untracked(struct drm_dp_tunnel *tunnel) {}
> +
> +static inline struct drm_dp_tunnel *
> +drm_dp_tunnel_get(struct drm_dp_tunnel *tunnel, struct ref_tracker **tracker)
> +{
> +	return NULL;
> +}
> +
> +static inline void
> +drm_dp_tunnel_put(struct drm_dp_tunnel *tunnel, struct ref_tracker **tracker) {}
> +
> +static inline void drm_dp_tunnel_ref_get(struct drm_dp_tunnel *tunnel,
> +					   struct drm_dp_tunnel_ref *tunnel_ref) {}
> +static inline void drm_dp_tunnel_ref_put(struct drm_dp_tunnel_ref *tunnel_ref) {}
> +
> +static inline struct drm_dp_tunnel *
> +drm_dp_tunnel_detect(struct drm_dp_tunnel_mgr *mgr,
> +		     struct drm_dp_aux *aux)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline int
> +drm_dp_tunnel_destroy(struct drm_dp_tunnel *tunnel)
> +{
> +	return 0;
> +}
> +
> +static inline int drm_dp_tunnel_enable_bw_alloc(struct drm_dp_tunnel *tunnel)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int drm_dp_tunnel_disable_bw_alloc(struct drm_dp_tunnel *tunnel)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline bool drm_dp_tunnel_bw_alloc_is_enabled(const struct drm_dp_tunnel *tunnel)
> +{
> +	return false;
> +}
> +
> +static inline int
> +drm_dp_tunnel_alloc_bw(struct drm_dp_tunnel *tunnel, int bw)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_check_state(struct drm_dp_tunnel *tunnel)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_update_state(struct drm_dp_tunnel *tunnel)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline void drm_dp_tunnel_set_io_error(struct drm_dp_tunnel *tunnel) {}
> +static inline int
> +drm_dp_tunnel_handle_irq(struct drm_dp_tunnel_mgr *mgr,
> +			 struct drm_dp_aux *aux)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_max_dprx_rate(const struct drm_dp_tunnel *tunnel)
> +{
> +	return 0;
> +}
> +
> +static inline int
> +drm_dp_tunnel_max_dprx_lane_count(const struct drm_dp_tunnel *tunnel)
> +{
> +	return 0;
> +}
> +
> +static inline int
> +drm_dp_tunnel_available_bw(const struct drm_dp_tunnel *tunnel)
> +{
> +	return -1;
> +}
> +
> +static inline const char *
> +drm_dp_tunnel_name(const struct drm_dp_tunnel *tunnel)
> +{
> +	return NULL;
> +}
> +
> +static inline struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_state(struct drm_atomic_state *state,
> +			       struct drm_dp_tunnel *tunnel)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline struct drm_dp_tunnel_state *
> +drm_dp_tunnel_atomic_get_new_state(struct drm_atomic_state *state,
> +				   const struct drm_dp_tunnel *tunnel)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline void
> +drm_dp_tunnel_atomic_clear_state(struct drm_dp_tunnel_state *tunnel_state) {}
> +
> +static inline int
> +drm_dp_tunnel_atomic_set_stream_bw(struct drm_atomic_state *state,
> +				   struct drm_dp_tunnel *tunnel,
> +				   u8 stream_id, int bw)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_atomic_get_group_streams_in_state(struct drm_atomic_state *state,
> +						const struct drm_dp_tunnel *tunnel,
> +						u32 *stream_mask)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_atomic_check_stream_bws(struct drm_atomic_state *state,
> +				      u32 *failed_stream_mask)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int
> +drm_dp_tunnel_atomic_get_tunnel_bw(const struct drm_dp_tunnel_state *tunnel_state)
> +{
> +	return 0;
> +}
> +
> +static inline struct drm_dp_tunnel_mgr *
> +drm_dp_tunnel_mgr_create(struct drm_device *dev, int max_group_count)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline
> +void drm_dp_tunnel_mgr_destroy(struct drm_dp_tunnel_mgr *mgr) {}
> +
> +
> +#endif /* CONFIG_DRM_DISPLAY_DP_TUNNEL */
> +
> +#endif /* __DRM_DP_TUNNEL_H__ */
> -- 
> 2.39.2

-- 
Ville Syrjälä
Intel