diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_cec.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_cec.c | 442 |
1 files changed, 0 insertions, 442 deletions
diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c deleted file mode 100644 index b15cee85b702..000000000000 --- a/drivers/gpu/drm/drm_dp_cec.c +++ /dev/null @@ -1,442 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * DisplayPort CEC-Tunneling-over-AUX support - * - * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved. - */ - -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <drm/drm_dp_helper.h> -#include <media/cec.h> - -/* - * Unfortunately it turns out that we have a chicken-and-egg situation - * here. Quite a few active (mini-)DP-to-HDMI or USB-C-to-HDMI adapters - * have a converter chip that supports CEC-Tunneling-over-AUX (usually the - * Parade PS176), but they do not wire up the CEC pin, thus making CEC - * useless. Note that MegaChips 2900-based adapters appear to have good - * support for CEC tunneling. Those adapters that I have tested using - * this chipset all have the CEC line connected. - * - * Sadly there is no way for this driver to know this. What happens is - * that a /dev/cecX device is created that is isolated and unable to see - * any of the other CEC devices. Quite literally the CEC wire is cut - * (or in this case, never connected in the first place). - * - * The reason so few adapters support this is that this tunneling protocol - * was never supported by any OS. So there was no easy way of testing it, - * and no incentive to correctly wire up the CEC pin. - * - * Hopefully by creating this driver it will be easier for vendors to - * finally fix their adapters and test the CEC functionality. - * - * I keep a list of known working adapters here: - * - * https://hverkuil.home.xs4all.nl/cec-status.txt - * - * Please mail me (hverkuil@xs4all.nl) if you find an adapter that works - * and is not yet listed there. - * - * Note that the current implementation does not support CEC over an MST hub. - * As far as I can see there is no mechanism defined in the DisplayPort - * standard to transport CEC interrupts over an MST device. It might be - * possible to do this through polling, but I have not been able to get that - * to work. - */ - -/** - * DOC: dp cec helpers - * - * These functions take care of supporting the CEC-Tunneling-over-AUX - * feature of DisplayPort-to-HDMI adapters. - */ - -/* - * When the EDID is unset because the HPD went low, then the CEC DPCD registers - * typically can no longer be read (true for a DP-to-HDMI adapter since it is - * powered by the HPD). However, some displays toggle the HPD off and on for a - * short period for one reason or another, and that would cause the CEC adapter - * to be removed and added again, even though nothing else changed. - * - * This module parameter sets a delay in seconds before the CEC adapter is - * actually unregistered. Only if the HPD does not return within that time will - * the CEC adapter be unregistered. - * - * If it is set to a value >= NEVER_UNREG_DELAY, then the CEC adapter will never - * be unregistered for as long as the connector remains registered. - * - * If it is set to 0, then the CEC adapter will be unregistered immediately as - * soon as the HPD disappears. - * - * The default is one second to prevent short HPD glitches from unregistering - * the CEC adapter. - * - * Note that for integrated HDMI branch devices that support CEC the DPCD - * registers remain available even if the HPD goes low since it is not powered - * by the HPD. In that case the CEC adapter will never be unregistered during - * the life time of the connector. At least, this is the theory since I do not - * have hardware with an integrated HDMI branch device that supports CEC. - */ -#define NEVER_UNREG_DELAY 1000 -static unsigned int drm_dp_cec_unregister_delay = 1; -module_param(drm_dp_cec_unregister_delay, uint, 0600); -MODULE_PARM_DESC(drm_dp_cec_unregister_delay, - "CEC unregister delay in seconds, 0: no delay, >= 1000: never unregister"); - -static int drm_dp_cec_adap_enable(struct cec_adapter *adap, bool enable) -{ - struct drm_dp_aux *aux = cec_get_drvdata(adap); - u32 val = enable ? DP_CEC_TUNNELING_ENABLE : 0; - ssize_t err = 0; - - err = drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_CONTROL, val); - return (enable && err < 0) ? err : 0; -} - -static int drm_dp_cec_adap_log_addr(struct cec_adapter *adap, u8 addr) -{ - struct drm_dp_aux *aux = cec_get_drvdata(adap); - /* Bit 15 (logical address 15) should always be set */ - u16 la_mask = 1 << CEC_LOG_ADDR_BROADCAST; - u8 mask[2]; - ssize_t err; - - if (addr != CEC_LOG_ADDR_INVALID) - la_mask |= adap->log_addrs.log_addr_mask | (1 << addr); - mask[0] = la_mask & 0xff; - mask[1] = la_mask >> 8; - err = drm_dp_dpcd_write(aux, DP_CEC_LOGICAL_ADDRESS_MASK, mask, 2); - return (addr != CEC_LOG_ADDR_INVALID && err < 0) ? err : 0; -} - -static int drm_dp_cec_adap_transmit(struct cec_adapter *adap, u8 attempts, - u32 signal_free_time, struct cec_msg *msg) -{ - struct drm_dp_aux *aux = cec_get_drvdata(adap); - unsigned int retries = min(5, attempts - 1); - ssize_t err; - - err = drm_dp_dpcd_write(aux, DP_CEC_TX_MESSAGE_BUFFER, - msg->msg, msg->len); - if (err < 0) - return err; - - err = drm_dp_dpcd_writeb(aux, DP_CEC_TX_MESSAGE_INFO, - (msg->len - 1) | (retries << 4) | - DP_CEC_TX_MESSAGE_SEND); - return err < 0 ? err : 0; -} - -static int drm_dp_cec_adap_monitor_all_enable(struct cec_adapter *adap, - bool enable) -{ - struct drm_dp_aux *aux = cec_get_drvdata(adap); - ssize_t err; - u8 val; - - if (!(adap->capabilities & CEC_CAP_MONITOR_ALL)) - return 0; - - err = drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_CONTROL, &val); - if (err >= 0) { - if (enable) - val |= DP_CEC_SNOOPING_ENABLE; - else - val &= ~DP_CEC_SNOOPING_ENABLE; - err = drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_CONTROL, val); - } - return (enable && err < 0) ? err : 0; -} - -static void drm_dp_cec_adap_status(struct cec_adapter *adap, - struct seq_file *file) -{ - struct drm_dp_aux *aux = cec_get_drvdata(adap); - struct drm_dp_desc desc; - struct drm_dp_dpcd_ident *id = &desc.ident; - - if (drm_dp_read_desc(aux, &desc, true)) - return; - seq_printf(file, "OUI: %*phD\n", - (int)sizeof(id->oui), id->oui); - seq_printf(file, "ID: %*pE\n", - (int)strnlen(id->device_id, sizeof(id->device_id)), - id->device_id); - seq_printf(file, "HW Rev: %d.%d\n", id->hw_rev >> 4, id->hw_rev & 0xf); - /* - * Show this both in decimal and hex: at least one vendor - * always reports this in hex. - */ - seq_printf(file, "FW/SW Rev: %d.%d (0x%02x.0x%02x)\n", - id->sw_major_rev, id->sw_minor_rev, - id->sw_major_rev, id->sw_minor_rev); -} - -static const struct cec_adap_ops drm_dp_cec_adap_ops = { - .adap_enable = drm_dp_cec_adap_enable, - .adap_log_addr = drm_dp_cec_adap_log_addr, - .adap_transmit = drm_dp_cec_adap_transmit, - .adap_monitor_all_enable = drm_dp_cec_adap_monitor_all_enable, - .adap_status = drm_dp_cec_adap_status, -}; - -static int drm_dp_cec_received(struct drm_dp_aux *aux) -{ - struct cec_adapter *adap = aux->cec.adap; - struct cec_msg msg; - u8 rx_msg_info; - ssize_t err; - - err = drm_dp_dpcd_readb(aux, DP_CEC_RX_MESSAGE_INFO, &rx_msg_info); - if (err < 0) - return err; - - if (!(rx_msg_info & DP_CEC_RX_MESSAGE_ENDED)) - return 0; - - msg.len = (rx_msg_info & DP_CEC_RX_MESSAGE_LEN_MASK) + 1; - err = drm_dp_dpcd_read(aux, DP_CEC_RX_MESSAGE_BUFFER, msg.msg, msg.len); - if (err < 0) - return err; - - cec_received_msg(adap, &msg); - return 0; -} - -static void drm_dp_cec_handle_irq(struct drm_dp_aux *aux) -{ - struct cec_adapter *adap = aux->cec.adap; - u8 flags; - - if (drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_IRQ_FLAGS, &flags) < 0) - return; - - if (flags & DP_CEC_RX_MESSAGE_INFO_VALID) - drm_dp_cec_received(aux); - - if (flags & DP_CEC_TX_MESSAGE_SENT) - cec_transmit_attempt_done(adap, CEC_TX_STATUS_OK); - else if (flags & DP_CEC_TX_LINE_ERROR) - cec_transmit_attempt_done(adap, CEC_TX_STATUS_ERROR | - CEC_TX_STATUS_MAX_RETRIES); - else if (flags & - (DP_CEC_TX_ADDRESS_NACK_ERROR | DP_CEC_TX_DATA_NACK_ERROR)) - cec_transmit_attempt_done(adap, CEC_TX_STATUS_NACK | - CEC_TX_STATUS_MAX_RETRIES); - drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_IRQ_FLAGS, flags); -} - -/** - * drm_dp_cec_irq() - handle CEC interrupt, if any - * @aux: DisplayPort AUX channel - * - * Should be called when handling an IRQ_HPD request. If CEC-tunneling-over-AUX - * is present, then it will check for a CEC_IRQ and handle it accordingly. - */ -void drm_dp_cec_irq(struct drm_dp_aux *aux) -{ - u8 cec_irq; - int ret; - - /* No transfer function was set, so not a DP connector */ - if (!aux->transfer) - return; - - mutex_lock(&aux->cec.lock); - if (!aux->cec.adap) - goto unlock; - - ret = drm_dp_dpcd_readb(aux, DP_DEVICE_SERVICE_IRQ_VECTOR_ESI1, - &cec_irq); - if (ret < 0 || !(cec_irq & DP_CEC_IRQ)) - goto unlock; - - drm_dp_cec_handle_irq(aux); - drm_dp_dpcd_writeb(aux, DP_DEVICE_SERVICE_IRQ_VECTOR_ESI1, DP_CEC_IRQ); -unlock: - mutex_unlock(&aux->cec.lock); -} -EXPORT_SYMBOL(drm_dp_cec_irq); - -static bool drm_dp_cec_cap(struct drm_dp_aux *aux, u8 *cec_cap) -{ - u8 cap = 0; - - if (drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_CAPABILITY, &cap) != 1 || - !(cap & DP_CEC_TUNNELING_CAPABLE)) - return false; - if (cec_cap) - *cec_cap = cap; - return true; -} - -/* - * Called if the HPD was low for more than drm_dp_cec_unregister_delay - * seconds. This unregisters the CEC adapter. - */ -static void drm_dp_cec_unregister_work(struct work_struct *work) -{ - struct drm_dp_aux *aux = container_of(work, struct drm_dp_aux, - cec.unregister_work.work); - - mutex_lock(&aux->cec.lock); - cec_unregister_adapter(aux->cec.adap); - aux->cec.adap = NULL; - mutex_unlock(&aux->cec.lock); -} - -/* - * A new EDID is set. If there is no CEC adapter, then create one. If - * there was a CEC adapter, then check if the CEC adapter properties - * were unchanged and just update the CEC physical address. Otherwise - * unregister the old CEC adapter and create a new one. - */ -void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid) -{ - u32 cec_caps = CEC_CAP_DEFAULTS | CEC_CAP_NEEDS_HPD; - unsigned int num_las = 1; - u8 cap; - - /* No transfer function was set, so not a DP connector */ - if (!aux->transfer) - return; - -#ifndef CONFIG_MEDIA_CEC_RC - /* - * CEC_CAP_RC is part of CEC_CAP_DEFAULTS, but it is stripped by - * cec_allocate_adapter() if CONFIG_MEDIA_CEC_RC is undefined. - * - * Do this here as well to ensure the tests against cec_caps are - * correct. - */ - cec_caps &= ~CEC_CAP_RC; -#endif - cancel_delayed_work_sync(&aux->cec.unregister_work); - - mutex_lock(&aux->cec.lock); - if (!drm_dp_cec_cap(aux, &cap)) { - /* CEC is not supported, unregister any existing adapter */ - cec_unregister_adapter(aux->cec.adap); - aux->cec.adap = NULL; - goto unlock; - } - - if (cap & DP_CEC_SNOOPING_CAPABLE) - cec_caps |= CEC_CAP_MONITOR_ALL; - if (cap & DP_CEC_MULTIPLE_LA_CAPABLE) - num_las = CEC_MAX_LOG_ADDRS; - - if (aux->cec.adap) { - if (aux->cec.adap->capabilities == cec_caps && - aux->cec.adap->available_log_addrs == num_las) { - /* Unchanged, so just set the phys addr */ - cec_s_phys_addr_from_edid(aux->cec.adap, edid); - goto unlock; - } - /* - * The capabilities changed, so unregister the old - * adapter first. - */ - cec_unregister_adapter(aux->cec.adap); - } - - /* Create a new adapter */ - aux->cec.adap = cec_allocate_adapter(&drm_dp_cec_adap_ops, - aux, aux->cec.name, cec_caps, - num_las); - if (IS_ERR(aux->cec.adap)) { - aux->cec.adap = NULL; - goto unlock; - } - if (cec_register_adapter(aux->cec.adap, aux->cec.parent)) { - cec_delete_adapter(aux->cec.adap); - aux->cec.adap = NULL; - } else { - /* - * Update the phys addr for the new CEC adapter. When called - * from drm_dp_cec_register_connector() edid == NULL, so in - * that case the phys addr is just invalidated. - */ - cec_s_phys_addr_from_edid(aux->cec.adap, edid); - } -unlock: - mutex_unlock(&aux->cec.lock); -} -EXPORT_SYMBOL(drm_dp_cec_set_edid); - -/* - * The EDID disappeared (likely because of the HPD going down). - */ -void drm_dp_cec_unset_edid(struct drm_dp_aux *aux) -{ - /* No transfer function was set, so not a DP connector */ - if (!aux->transfer) - return; - - cancel_delayed_work_sync(&aux->cec.unregister_work); - - mutex_lock(&aux->cec.lock); - if (!aux->cec.adap) - goto unlock; - - cec_phys_addr_invalidate(aux->cec.adap); - /* - * We're done if we want to keep the CEC device - * (drm_dp_cec_unregister_delay is >= NEVER_UNREG_DELAY) or if the - * DPCD still indicates the CEC capability (expected for an integrated - * HDMI branch device). - */ - if (drm_dp_cec_unregister_delay < NEVER_UNREG_DELAY && - !drm_dp_cec_cap(aux, NULL)) { - /* - * Unregister the CEC adapter after drm_dp_cec_unregister_delay - * seconds. This to debounce short HPD off-and-on cycles from - * displays. - */ - schedule_delayed_work(&aux->cec.unregister_work, - drm_dp_cec_unregister_delay * HZ); - } -unlock: - mutex_unlock(&aux->cec.lock); -} -EXPORT_SYMBOL(drm_dp_cec_unset_edid); - -/** - * drm_dp_cec_register_connector() - register a new connector - * @aux: DisplayPort AUX channel - * @name: name of the CEC device - * @parent: parent device - * - * A new connector was registered with associated CEC adapter name and - * CEC adapter parent device. After registering the name and parent - * drm_dp_cec_set_edid() is called to check if the connector supports - * CEC and to register a CEC adapter if that is the case. - */ -void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name, - struct device *parent) -{ - WARN_ON(aux->cec.adap); - if (WARN_ON(!aux->transfer)) - return; - aux->cec.name = name; - aux->cec.parent = parent; - INIT_DELAYED_WORK(&aux->cec.unregister_work, - drm_dp_cec_unregister_work); -} -EXPORT_SYMBOL(drm_dp_cec_register_connector); - -/** - * drm_dp_cec_unregister_connector() - unregister the CEC adapter, if any - * @aux: DisplayPort AUX channel - */ -void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux) -{ - if (!aux->cec.adap) - return; - cancel_delayed_work_sync(&aux->cec.unregister_work); - cec_unregister_adapter(aux->cec.adap); - aux->cec.adap = NULL; -} -EXPORT_SYMBOL(drm_dp_cec_unregister_connector); |