diff options
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_link_bw.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_link_bw.c | 497 |
1 files changed, 497 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_link_bw.c b/drivers/gpu/drm/i915/display/intel_link_bw.c new file mode 100644 index 000000000000..d2862de894fa --- /dev/null +++ b/drivers/gpu/drm/i915/display/intel_link_bw.c @@ -0,0 +1,497 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright © 2023 Intel Corporation + */ + +#include <linux/ctype.h> +#include <linux/debugfs.h> +#include <linux/int_log.h> +#include <linux/math.h> + +#include <drm/drm_fixed.h> +#include <drm/drm_print.h> + +#include "intel_atomic.h" +#include "intel_crtc.h" +#include "intel_display_core.h" +#include "intel_display_types.h" +#include "intel_dp.h" +#include "intel_dp_mst.h" +#include "intel_dp_tunnel.h" +#include "intel_fdi.h" +#include "intel_link_bw.h" +#include "intel_vdsc.h" + +static int get_forced_link_bpp_x16(struct intel_atomic_state *state, + const struct intel_crtc *crtc) +{ + struct intel_digital_connector_state *conn_state; + struct intel_connector *connector; + int force_bpp_x16 = INT_MAX; + int i; + + for_each_new_intel_connector_in_state(state, connector, conn_state, i) { + if (conn_state->base.crtc != &crtc->base) + continue; + + if (!connector->link.force_bpp_x16) + continue; + + force_bpp_x16 = min(force_bpp_x16, connector->link.force_bpp_x16); + } + + return force_bpp_x16 < INT_MAX ? force_bpp_x16 : 0; +} + +/** + * intel_link_bw_init_limits - initialize BW limits + * @state: Atomic state + * @limits: link BW limits + * + * Initialize @limits. + */ +void intel_link_bw_init_limits(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits) +{ + struct intel_display *display = to_intel_display(state); + enum pipe pipe; + + limits->link_dsc_pipes = 0; + limits->bpp_limit_reached_pipes = 0; + for_each_pipe(display, pipe) { + struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe); + const struct intel_crtc_state *crtc_state = + intel_atomic_get_new_crtc_state(state, crtc); + int forced_bpp_x16 = get_forced_link_bpp_x16(state, crtc); + + if (state->base.duplicated && crtc_state) { + limits->max_bpp_x16[pipe] = crtc_state->max_link_bpp_x16; + if (intel_dsc_enabled_on_link(crtc_state)) + limits->link_dsc_pipes |= BIT(pipe); + } else { + limits->max_bpp_x16[pipe] = INT_MAX; + } + + if (forced_bpp_x16) + limits->max_bpp_x16[pipe] = min(limits->max_bpp_x16[pipe], forced_bpp_x16); + } +} + +/** + * __intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe + * @state: atomic state + * @limits: link BW limits + * @pipe_mask: mask of pipes to select from + * @reason: explanation of why bpp reduction is needed + * @reduce_forced_bpp: allow reducing bpps below their forced link bpp + * + * Select the pipe from @pipe_mask with the biggest link bpp value and set the + * maximum of link bpp in @limits below this value. Modeset the selected pipe, + * so that its state will get recomputed. + * + * This function can be called to resolve a link's BW overallocation by reducing + * the link bpp of one pipe on the link and hence reducing the total link BW. + * + * Returns + * - 0 in case of success + * - %-ENOSPC if no pipe can further reduce its link bpp + * - Other negative error, if modesetting the selected pipe failed + */ +static int __intel_link_bw_reduce_bpp(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits, + u8 pipe_mask, + const char *reason, + bool reduce_forced_bpp) +{ + struct intel_display *display = to_intel_display(state); + enum pipe max_bpp_pipe = INVALID_PIPE; + struct intel_crtc *crtc; + int max_bpp_x16 = 0; + + for_each_intel_crtc_in_pipe_mask(display->drm, crtc, pipe_mask) { + struct intel_crtc_state *crtc_state; + int link_bpp_x16; + + if (limits->bpp_limit_reached_pipes & BIT(crtc->pipe)) + continue; + + crtc_state = intel_atomic_get_crtc_state(&state->base, + crtc); + if (IS_ERR(crtc_state)) + return PTR_ERR(crtc_state); + + if (crtc_state->dsc.compression_enable) + link_bpp_x16 = crtc_state->dsc.compressed_bpp_x16; + else + /* + * TODO: for YUV420 the actual link bpp is only half + * of the pipe bpp value. The MST encoder's BW allocation + * is based on the pipe bpp value, set the actual link bpp + * limit here once the MST BW allocation is fixed. + */ + link_bpp_x16 = fxp_q4_from_int(crtc_state->pipe_bpp); + + if (!reduce_forced_bpp && + link_bpp_x16 <= get_forced_link_bpp_x16(state, crtc)) + continue; + + if (link_bpp_x16 > max_bpp_x16) { + max_bpp_x16 = link_bpp_x16; + max_bpp_pipe = crtc->pipe; + } + } + + if (max_bpp_pipe == INVALID_PIPE) + return -ENOSPC; + + limits->max_bpp_x16[max_bpp_pipe] = max_bpp_x16 - 1; + + return intel_modeset_pipes_in_mask_early(state, reason, + BIT(max_bpp_pipe)); +} + +int intel_link_bw_reduce_bpp(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits, + u8 pipe_mask, + const char *reason) +{ + int ret; + + /* Try to keep any forced link BPP. */ + ret = __intel_link_bw_reduce_bpp(state, limits, pipe_mask, reason, false); + if (ret == -ENOSPC) + ret = __intel_link_bw_reduce_bpp(state, limits, pipe_mask, reason, true); + + return ret; +} + +/** + * intel_link_bw_compute_pipe_bpp - compute pipe bpp limited by max link bpp + * @crtc_state: the crtc state + * + * Compute the pipe bpp limited by the CRTC's maximum link bpp. Encoders can + * call this function during state computation in the simple case where the + * link bpp will always match the pipe bpp. This is the case for all non-DP + * encoders, while DP encoders will use a link bpp lower than pipe bpp in case + * of DSC compression. + * + * Returns %true in case of success, %false if pipe bpp would need to be + * reduced below its valid range. + */ +bool intel_link_bw_compute_pipe_bpp(struct intel_crtc_state *crtc_state) +{ + int pipe_bpp = min(crtc_state->pipe_bpp, + fxp_q4_to_int(crtc_state->max_link_bpp_x16)); + + pipe_bpp = rounddown(pipe_bpp, 2 * 3); + + if (pipe_bpp < 6 * 3) + return false; + + crtc_state->pipe_bpp = pipe_bpp; + + return true; +} + +/** + * intel_link_bw_set_bpp_limit_for_pipe - set link bpp limit for a pipe to its minimum + * @state: atomic state + * @old_limits: link BW limits + * @new_limits: link BW limits + * @pipe: pipe + * + * Set the link bpp limit for @pipe in @new_limits to its value in + * @old_limits and mark this limit as the minimum. This function must be + * called after a pipe's compute config function failed, @old_limits + * containing the bpp limit with which compute config previously passed. + * + * The function will fail if setting a minimum is not possible, either + * because the old and new limits match (and so would lead to a pipe compute + * config failure) or the limit is already at the minimum. + * + * Returns %true in case of success. + */ +bool +intel_link_bw_set_bpp_limit_for_pipe(struct intel_atomic_state *state, + const struct intel_link_bw_limits *old_limits, + struct intel_link_bw_limits *new_limits, + enum pipe pipe) +{ + struct intel_display *display = to_intel_display(state); + + if (pipe == INVALID_PIPE) + return false; + + if (new_limits->max_bpp_x16[pipe] == + old_limits->max_bpp_x16[pipe]) + return false; + + if (drm_WARN_ON(display->drm, + new_limits->bpp_limit_reached_pipes & BIT(pipe))) + return false; + + new_limits->max_bpp_x16[pipe] = + old_limits->max_bpp_x16[pipe]; + new_limits->bpp_limit_reached_pipes |= BIT(pipe); + + return true; +} + +static int check_all_link_config(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits) +{ + /* TODO: Check additional shared display link configurations like MST */ + int ret; + + ret = intel_dp_mst_atomic_check_link(state, limits); + if (ret) + return ret; + + ret = intel_dp_tunnel_atomic_check_link(state, limits); + if (ret) + return ret; + + ret = intel_fdi_atomic_check_link(state, limits); + if (ret) + return ret; + + return 0; +} + +static bool +assert_link_limit_change_valid(struct intel_display *display, + const struct intel_link_bw_limits *old_limits, + const struct intel_link_bw_limits *new_limits) +{ + bool bpps_changed = false; + enum pipe pipe; + + /* DSC can't be disabled after it was enabled. */ + if (drm_WARN_ON(display->drm, + (old_limits->link_dsc_pipes & new_limits->link_dsc_pipes) != + old_limits->link_dsc_pipes)) + return false; + + for_each_pipe(display, pipe) { + /* The bpp limit can only decrease. */ + if (drm_WARN_ON(display->drm, + new_limits->max_bpp_x16[pipe] > + old_limits->max_bpp_x16[pipe])) + return false; + + if (new_limits->max_bpp_x16[pipe] < + old_limits->max_bpp_x16[pipe]) + bpps_changed = true; + } + + /* At least one limit must change. */ + if (drm_WARN_ON(display->drm, + !bpps_changed && + new_limits->link_dsc_pipes == + old_limits->link_dsc_pipes)) + return false; + + return true; +} + +/** + * intel_link_bw_atomic_check - check display link states and set a fallback config if needed + * @state: atomic state + * @new_limits: link BW limits + * + * Check the configuration of all shared display links in @state and set new BW + * limits in @new_limits if there is a BW limitation. + * + * Returns: + * - 0 if the configuration is valid + * - %-EAGAIN, if the configuration is invalid and @new_limits got updated + * with fallback values with which the configuration of all CRTCs + * in @state must be recomputed + * - Other negative error, if the configuration is invalid without a + * fallback possibility, or the check failed for another reason + */ +int intel_link_bw_atomic_check(struct intel_atomic_state *state, + struct intel_link_bw_limits *new_limits) +{ + struct intel_display *display = to_intel_display(state); + struct intel_link_bw_limits old_limits = *new_limits; + int ret; + + ret = check_all_link_config(state, new_limits); + if (ret != -EAGAIN) + return ret; + + if (!assert_link_limit_change_valid(display, &old_limits, new_limits)) + return -EINVAL; + + return -EAGAIN; +} + +static int force_link_bpp_show(struct seq_file *m, void *data) +{ + struct intel_connector *connector = m->private; + + seq_printf(m, FXP_Q4_FMT "\n", FXP_Q4_ARGS(connector->link.force_bpp_x16)); + + return 0; +} + +static int str_to_fxp_q4_nonneg_int(const char *str, int *val_x16) +{ + unsigned int val; + int err; + + err = kstrtouint(str, 10, &val); + if (err) + return err; + + if (val > INT_MAX >> 4) + return -ERANGE; + + *val_x16 = fxp_q4_from_int(val); + + return 0; +} + +/* modifies str */ +static int str_to_fxp_q4_nonneg(char *str, int *val_x16) +{ + const char *int_str; + char *frac_str; + int frac_digits; + int frac_val; + int err; + + int_str = strim(str); + frac_str = strchr(int_str, '.'); + + if (frac_str) + *frac_str++ = '\0'; + + err = str_to_fxp_q4_nonneg_int(int_str, val_x16); + if (err) + return err; + + if (!frac_str) + return 0; + + /* prevent negative number/leading +- sign mark */ + if (!isdigit(*frac_str)) + return -EINVAL; + + err = str_to_fxp_q4_nonneg_int(frac_str, &frac_val); + if (err) + return err; + + frac_digits = strlen(frac_str); + if (frac_digits > intlog10(INT_MAX) >> 24 || + frac_val > INT_MAX - int_pow(10, frac_digits) / 2) + return -ERANGE; + + frac_val = DIV_ROUND_CLOSEST(frac_val, (int)int_pow(10, frac_digits)); + + if (*val_x16 > INT_MAX - frac_val) + return -ERANGE; + + *val_x16 += frac_val; + + return 0; +} + +static int user_str_to_fxp_q4_nonneg(const char __user *ubuf, size_t len, int *val_x16) +{ + char *kbuf; + int err; + + kbuf = memdup_user_nul(ubuf, len); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + err = str_to_fxp_q4_nonneg(kbuf, val_x16); + + kfree(kbuf); + + return err; +} + +static bool connector_supports_dsc(struct intel_connector *connector) +{ + struct intel_display *display = to_intel_display(connector); + + switch (connector->base.connector_type) { + case DRM_MODE_CONNECTOR_eDP: + return intel_dp_has_dsc(connector); + case DRM_MODE_CONNECTOR_DisplayPort: + if (connector->mst.dp) + return HAS_DSC_MST(display); + + return HAS_DSC(display); + default: + return false; + } +} + +static ssize_t +force_link_bpp_write(struct file *file, const char __user *ubuf, size_t len, loff_t *offp) +{ + struct seq_file *m = file->private_data; + struct intel_connector *connector = m->private; + struct intel_display *display = to_intel_display(connector); + int min_bpp; + int bpp_x16; + int err; + + err = user_str_to_fxp_q4_nonneg(ubuf, len, &bpp_x16); + if (err) + return err; + + /* TODO: Make the non-DSC min_bpp value connector specific. */ + if (connector_supports_dsc(connector)) + min_bpp = intel_dp_dsc_min_src_compressed_bpp(); + else + min_bpp = intel_display_min_pipe_bpp(); + + if (bpp_x16 && + (bpp_x16 < fxp_q4_from_int(min_bpp) || + bpp_x16 > fxp_q4_from_int(intel_display_max_pipe_bpp(display)))) + return -EINVAL; + + err = drm_modeset_lock_single_interruptible(&display->drm->mode_config.connection_mutex); + if (err) + return err; + + connector->link.force_bpp_x16 = bpp_x16; + + drm_modeset_unlock(&display->drm->mode_config.connection_mutex); + + *offp += len; + + return len; +} +DEFINE_SHOW_STORE_ATTRIBUTE(force_link_bpp); + +void intel_link_bw_connector_debugfs_add(struct intel_connector *connector) +{ + struct intel_display *display = to_intel_display(connector); + struct dentry *root = connector->base.debugfs_entry; + + switch (connector->base.connector_type) { + case DRM_MODE_CONNECTOR_DisplayPort: + case DRM_MODE_CONNECTOR_eDP: + case DRM_MODE_CONNECTOR_HDMIA: + break; + case DRM_MODE_CONNECTOR_VGA: + case DRM_MODE_CONNECTOR_SVIDEO: + case DRM_MODE_CONNECTOR_LVDS: + case DRM_MODE_CONNECTOR_DVID: + if (HAS_FDI(display)) + break; + + return; + default: + return; + } + + debugfs_create_file("intel_force_link_bpp", 0644, root, + connector, &force_link_bpp_fops); +} |