| Message ID | 20210826034411.281998-1-deborahbrouwer3563@gmail.com |
|---|---|
| State | Accepted |
| Commit | c6c709ee55ec73a0d794cac4c711b8078f71b884 |
| Headers | show |
| Series | [v3] media: vivid: add signal-free time for cec message xfer | expand |
Hi Deb, This patch looks good, and I'll add it to a pull request for v5.16 next week. I've been testing it overnight with the CEC regression tests and I had no more errors, so this is now much more accurate than the old implementation. Thank you very much for working on this as part of the Outreachy project, it's been great working on this with you, and I hope you'll continue working (for fun) on some of the other open vivid volunteer tasks. Thank you! Hans On 26/08/2021 05:44, Deborah Brouwer wrote: > Currently, the vivid emulation of cec message transmission does not force > adapters to wait until the cec bus has been signal-free for a certain > number of bit periods before transmitting or re-transmitting a message. > Without enforcing the signal-free time requirements, adapters do not share > the bus very well and some messages are sent too quickly while other > messages are lost. By emulating a signal-free time and forcing adapters > to wait their turn to transmit, the vivid emulation of cec transmission > is much more reliable. > > Signed-off-by: Deborah Brouwer <deborahbrouwer3563@gmail.com> > --- > Changes since v2: > - initialize first_idx and first_status and move inside bus loop > - properly return error code > > Changes since v1: > - use actual message length instead of max when copying > - check for kthread_stop() within bus > - store the last_initiator in the vivid state > - update the last_initiator as soon as it is known and adjust sfts > - use last_initiator to assign sft when transmit is called > - use function for division > > drivers/media/test-drivers/vivid/vivid-cec.c | 341 ++++++++++-------- > drivers/media/test-drivers/vivid/vivid-cec.h | 9 +- > drivers/media/test-drivers/vivid/vivid-core.c | 38 +- > drivers/media/test-drivers/vivid/vivid-core.h | 23 +- > 4 files changed, 219 insertions(+), 192 deletions(-) > > diff --git a/drivers/media/test-drivers/vivid/vivid-cec.c b/drivers/media/test-drivers/vivid/vivid-cec.c > index 4d2413e87730..d6d7dbcb8437 100644 > --- a/drivers/media/test-drivers/vivid/vivid-cec.c > +++ b/drivers/media/test-drivers/vivid/vivid-cec.c > @@ -5,40 +5,23 @@ > * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved. > */ > > +#include <linux/delay.h> > #include <media/cec.h> > > #include "vivid-core.h" > #include "vivid-cec.h" > > -#define CEC_TIM_START_BIT_TOTAL 4500 > -#define CEC_TIM_START_BIT_LOW 3700 > -#define CEC_TIM_START_BIT_HIGH 800 > -#define CEC_TIM_DATA_BIT_TOTAL 2400 > -#define CEC_TIM_DATA_BIT_0_LOW 1500 > -#define CEC_TIM_DATA_BIT_0_HIGH 900 > -#define CEC_TIM_DATA_BIT_1_LOW 600 > -#define CEC_TIM_DATA_BIT_1_HIGH 1800 > +#define CEC_START_BIT_US 4500 > +#define CEC_DATA_BIT_US 2400 > +#define CEC_MARGIN_US 350 > > -void vivid_cec_bus_free_work(struct vivid_dev *dev) > -{ > - spin_lock(&dev->cec_slock); > - while (!list_empty(&dev->cec_work_list)) { > - struct vivid_cec_work *cw = > - list_first_entry(&dev->cec_work_list, > - struct vivid_cec_work, list); > - > - spin_unlock(&dev->cec_slock); > - cancel_delayed_work_sync(&cw->work); > - spin_lock(&dev->cec_slock); > - list_del(&cw->list); > - cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_LOW_DRIVE); > - kfree(cw); > - } > - spin_unlock(&dev->cec_slock); > -} > +struct xfer_on_bus { > + struct cec_adapter *adap; > + u8 status; > +}; > > -static bool vivid_cec_find_dest_adap(struct vivid_dev *dev, > - struct cec_adapter *adap, u8 dest) > +static bool find_dest_adap(struct vivid_dev *dev, > + struct cec_adapter *adap, u8 dest) > { > unsigned int i; > > @@ -61,116 +44,187 @@ static bool vivid_cec_find_dest_adap(struct vivid_dev *dev, > return false; > } > > -static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts, > - const struct cec_msg *msg, bool nacked) > +static bool xfer_ready(struct vivid_dev *dev) > { > - unsigned int len = nacked ? 1 : msg->len; > unsigned int i; > - bool bit; > - > - if (adap == NULL) > - return; > + bool ready = false; > > - /* > - * Suffix ULL on constant 10 makes the expression > - * CEC_TIM_START_BIT_TOTAL + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL > - * to be evaluated using 64-bit unsigned arithmetic (u64), which > - * is what ktime_sub_us expects as second argument. > - */ > - ts = ktime_sub_us(ts, CEC_TIM_START_BIT_TOTAL + > - 10ULL * len * CEC_TIM_DATA_BIT_TOTAL); > - cec_queue_pin_cec_event(adap, false, false, ts); > - ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW); > - cec_queue_pin_cec_event(adap, true, false, ts); > - ts = ktime_add_us(ts, CEC_TIM_START_BIT_HIGH); > - > - for (i = 0; i < 10 * len; i++) { > - switch (i % 10) { > - case 0 ... 7: > - bit = msg->msg[i / 10] & (0x80 >> (i % 10)); > - break; > - case 8: /* EOM */ > - bit = i / 10 == msg->len - 1; > - break; > - case 9: /* ACK */ > - bit = cec_msg_is_broadcast(msg) ^ nacked; > + spin_lock(&dev->cec_xfers_slock); > + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { > + if (dev->xfers[i].sft && > + dev->xfers[i].sft <= dev->cec_sft) { > + ready = true; > break; > } > - cec_queue_pin_cec_event(adap, false, false, ts); > - if (bit) > - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_LOW); > - else > - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_LOW); > - cec_queue_pin_cec_event(adap, true, false, ts); > - if (bit) > - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_HIGH); > - else > - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_HIGH); > } > -} > + spin_unlock(&dev->cec_xfers_slock); > > -static void vivid_cec_pin_events(struct vivid_dev *dev, > - const struct cec_msg *msg, bool nacked) > -{ > - ktime_t ts = ktime_get(); > - unsigned int i; > - > - vivid_cec_pin_adap_events(dev->cec_rx_adap, ts, msg, nacked); > - for (i = 0; i < MAX_OUTPUTS; i++) > - vivid_cec_pin_adap_events(dev->cec_tx_adap[i], ts, msg, nacked); > + return ready; > } > > -static void vivid_cec_xfer_done_worker(struct work_struct *work) > +/* > + * If an adapter tries to send successive messages, it must wait for the > + * longest signal-free time between its transmissions. But, if another > + * adapter sends a message in the interim, then the wait can be reduced > + * because the messages are no longer successive. Make these adjustments > + * if necessary. Should be called holding cec_xfers_slock. > + */ > +static void adjust_sfts(struct vivid_dev *dev) > { > - struct vivid_cec_work *cw = > - container_of(work, struct vivid_cec_work, work.work); > - struct vivid_dev *dev = cw->dev; > - struct cec_adapter *adap = cw->adap; > - u8 dest = cec_msg_destination(&cw->msg); > - bool valid_dest; > unsigned int i; > + u8 initiator; > > - valid_dest = cec_msg_is_broadcast(&cw->msg); > - if (!valid_dest) > - valid_dest = vivid_cec_find_dest_adap(dev, adap, dest); > - > - cw->tx_status = valid_dest ? CEC_TX_STATUS_OK : CEC_TX_STATUS_NACK; > - spin_lock(&dev->cec_slock); > - dev->cec_xfer_time_jiffies = 0; > - dev->cec_xfer_start_jiffies = 0; > - list_del(&cw->list); > - spin_unlock(&dev->cec_slock); > - vivid_cec_pin_events(dev, &cw->msg, !valid_dest); > - cec_transmit_attempt_done(cw->adap, cw->tx_status); > - > - /* Broadcast message */ > - if (adap != dev->cec_rx_adap) > - cec_received_msg(dev->cec_rx_adap, &cw->msg); > - for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++) > - if (adap != dev->cec_tx_adap[i]) > - cec_received_msg(dev->cec_tx_adap[i], &cw->msg); > - kfree(cw); > + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { > + if (dev->xfers[i].sft <= CEC_SIGNAL_FREE_TIME_RETRY) > + continue; > + initiator = dev->xfers[i].msg[0] >> 4; > + if (initiator == dev->last_initiator) > + dev->xfers[i].sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; > + else > + dev->xfers[i].sft = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR; > + } > } > > -static void vivid_cec_xfer_try_worker(struct work_struct *work) > +/* > + * The main emulation of the bus on which CEC adapters attempt to send > + * messages to each other. The bus keeps track of how long it has been > + * signal-free and accepts a pending transmission only if the state of > + * the bus matches the transmission's signal-free requirements. It calls > + * cec_transmit_attempt_done() for all transmits that enter the bus and > + * cec_received_msg() for successful transmits. > + */ > +int vivid_cec_bus_thread(void *_dev) > { > - struct vivid_cec_work *cw = > - container_of(work, struct vivid_cec_work, work.work); > - struct vivid_dev *dev = cw->dev; > - > - spin_lock(&dev->cec_slock); > - if (dev->cec_xfer_time_jiffies) { > - list_del(&cw->list); > - spin_unlock(&dev->cec_slock); > - cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_ARB_LOST); > - kfree(cw); > - } else { > - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker); > - dev->cec_xfer_start_jiffies = jiffies; > - dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs); > - spin_unlock(&dev->cec_slock); > - schedule_delayed_work(&cw->work, dev->cec_xfer_time_jiffies); > + u32 last_sft; > + unsigned int i; > + unsigned int dest; > + ktime_t start, end; > + s64 delta_us, retry_us; > + struct vivid_dev *dev = _dev; > + > + dev->cec_sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; > + for (;;) { > + bool first = true; > + int wait_xfer_us = 0; > + bool valid_dest = false; > + int wait_arb_lost_us = 0; > + unsigned int first_idx = 0; > + unsigned int first_status = 0; > + struct cec_msg first_msg = {}; > + struct xfer_on_bus xfers_on_bus[MAX_OUTPUTS] = {}; > + > + wait_event_interruptible(dev->kthread_waitq_cec, xfer_ready(dev) || > + kthread_should_stop()); > + if (kthread_should_stop()) > + break; > + last_sft = dev->cec_sft; > + dev->cec_sft = 0; > + /* > + * Move the messages that are ready onto the bus. The adapter with > + * the most leading zeros will win control of the bus and any other > + * adapters will lose arbitration. > + */ > + spin_lock(&dev->cec_xfers_slock); > + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { > + if (!dev->xfers[i].sft || dev->xfers[i].sft > last_sft) > + continue; > + if (first) { > + first = false; > + first_idx = i; > + xfers_on_bus[first_idx].adap = dev->xfers[i].adap; > + memcpy(first_msg.msg, dev->xfers[i].msg, dev->xfers[i].len); > + first_msg.len = dev->xfers[i].len; > + } else { > + xfers_on_bus[i].adap = dev->xfers[i].adap; > + xfers_on_bus[i].status = CEC_TX_STATUS_ARB_LOST; > + /* > + * For simplicity wait for all 4 bits of the initiator's > + * address even though HDMI specification uses bit-level > + * precision. > + */ > + wait_arb_lost_us = 4 * CEC_DATA_BIT_US + CEC_START_BIT_US; > + } > + dev->xfers[i].sft = 0; > + } > + dev->last_initiator = cec_msg_initiator(&first_msg); > + adjust_sfts(dev); > + spin_unlock(&dev->cec_xfers_slock); > + > + dest = cec_msg_destination(&first_msg); > + valid_dest = cec_msg_is_broadcast(&first_msg); > + if (!valid_dest) > + valid_dest = find_dest_adap(dev, xfers_on_bus[first_idx].adap, dest); > + if (valid_dest) { > + first_status = CEC_TX_STATUS_OK; > + /* > + * Message length is in bytes, but each byte is transmitted in > + * a block of 10 bits. > + */ > + wait_xfer_us = first_msg.len * 10 * CEC_DATA_BIT_US; > + } else { > + first_status = CEC_TX_STATUS_NACK; > + /* > + * A message that is not acknowledged stops transmitting after > + * the header block of 10 bits. > + */ > + wait_xfer_us = 10 * CEC_DATA_BIT_US; > + } > + wait_xfer_us += CEC_START_BIT_US; > + xfers_on_bus[first_idx].status = first_status; > + > + /* Sleep as if sending messages on a real hardware bus. */ > + start = ktime_get(); > + if (wait_arb_lost_us) { > + usleep_range(wait_arb_lost_us - CEC_MARGIN_US, wait_arb_lost_us); > + for (i = 0; i < ARRAY_SIZE(xfers_on_bus); i++) { > + if (xfers_on_bus[i].status != CEC_TX_STATUS_ARB_LOST) > + continue; > + cec_transmit_attempt_done(xfers_on_bus[i].adap, > + CEC_TX_STATUS_ARB_LOST); > + } > + if (kthread_should_stop()) > + break; > + } > + wait_xfer_us -= wait_arb_lost_us; > + usleep_range(wait_xfer_us - CEC_MARGIN_US, wait_xfer_us); > + cec_transmit_attempt_done(xfers_on_bus[first_idx].adap, first_status); > + if (kthread_should_stop()) > + break; > + if (first_status == CEC_TX_STATUS_OK) { > + if (xfers_on_bus[first_idx].adap != dev->cec_rx_adap) > + cec_received_msg(dev->cec_rx_adap, &first_msg); > + for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++) > + if (xfers_on_bus[first_idx].adap != dev->cec_tx_adap[i]) > + cec_received_msg(dev->cec_tx_adap[i], &first_msg); > + } > + end = ktime_get(); > + /* > + * If the emulated transfer took more or less time than it should > + * have, then compensate by adjusting the wait time needed for the > + * bus to be signal-free for 3 bit periods (the retry time). > + */ > + delta_us = div_s64(end - start, 1000); > + delta_us -= wait_xfer_us + wait_arb_lost_us; > + retry_us = CEC_SIGNAL_FREE_TIME_RETRY * CEC_DATA_BIT_US - delta_us; > + if (retry_us > CEC_MARGIN_US) > + usleep_range(retry_us - CEC_MARGIN_US, retry_us); > + dev->cec_sft = CEC_SIGNAL_FREE_TIME_RETRY; > + /* > + * If there are no messages that need to be retried, check if any > + * adapters that did not just transmit a message are ready to > + * transmit. If none of these adapters are ready, then increase > + * the signal-free time so that the bus is available to all > + * adapters and go back to waiting for a transmission. > + */ > + while (dev->cec_sft >= CEC_SIGNAL_FREE_TIME_RETRY && > + dev->cec_sft < CEC_SIGNAL_FREE_TIME_NEXT_XFER && > + !xfer_ready(dev) && !kthread_should_stop()) { > + usleep_range(2 * CEC_DATA_BIT_US - CEC_MARGIN_US, > + 2 * CEC_DATA_BIT_US); > + dev->cec_sft += 2; > + } > } > + return 0; > } > > static int vivid_cec_adap_enable(struct cec_adapter *adap, bool enable) > @@ -184,41 +238,26 @@ static int vivid_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr) > return 0; > } > > -/* > - * One data bit takes 2400 us, each byte needs 10 bits so that's 24000 us > - * per byte. > - */ > -#define USECS_PER_BYTE 24000 > - > static int vivid_cec_adap_transmit(struct cec_adapter *adap, u8 attempts, > u32 signal_free_time, struct cec_msg *msg) > { > struct vivid_dev *dev = cec_get_drvdata(adap); > - struct vivid_cec_work *cw = kzalloc(sizeof(*cw), GFP_KERNEL); > - long delta_jiffies = 0; > - > - if (cw == NULL) > - return -ENOMEM; > - cw->dev = dev; > - cw->adap = adap; > - cw->usecs = CEC_FREE_TIME_TO_USEC(signal_free_time) + > - msg->len * USECS_PER_BYTE; > - cw->msg = *msg; > - > - spin_lock(&dev->cec_slock); > - list_add(&cw->list, &dev->cec_work_list); > - if (dev->cec_xfer_time_jiffies == 0) { > - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker); > - dev->cec_xfer_start_jiffies = jiffies; > - dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs); > - delta_jiffies = dev->cec_xfer_time_jiffies; > - } else { > - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_try_worker); > - delta_jiffies = dev->cec_xfer_start_jiffies + > - dev->cec_xfer_time_jiffies - jiffies; > + u8 idx = cec_msg_initiator(msg); > + > + spin_lock(&dev->cec_xfers_slock); > + dev->xfers[idx].adap = adap; > + memcpy(dev->xfers[idx].msg, msg->msg, CEC_MAX_MSG_SIZE); > + dev->xfers[idx].len = msg->len; > + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_RETRY; > + if (signal_free_time > CEC_SIGNAL_FREE_TIME_RETRY) { > + if (idx == dev->last_initiator) > + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; > + else > + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR; > } > - spin_unlock(&dev->cec_slock); > - schedule_delayed_work(&cw->work, delta_jiffies < 0 ? 0 : delta_jiffies); > + spin_unlock(&dev->cec_xfers_slock); > + wake_up_interruptible(&dev->kthread_waitq_cec); > + > return 0; > } > > diff --git a/drivers/media/test-drivers/vivid/vivid-cec.h b/drivers/media/test-drivers/vivid/vivid-cec.h > index 7524ed48a914..b2bcddb50b83 100644 > --- a/drivers/media/test-drivers/vivid/vivid-cec.h > +++ b/drivers/media/test-drivers/vivid/vivid-cec.h > @@ -9,12 +9,5 @@ > struct cec_adapter *vivid_cec_alloc_adap(struct vivid_dev *dev, > unsigned int idx, > bool is_source); > -void vivid_cec_bus_free_work(struct vivid_dev *dev); > - > -#else > - > -static inline void vivid_cec_bus_free_work(struct vivid_dev *dev) > -{ > -} > - > +int vivid_cec_bus_thread(void *_dev); > #endif > diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c > index d2bd2653cf54..53feecba962d 100644 > --- a/drivers/media/test-drivers/vivid/vivid-core.c > +++ b/drivers/media/test-drivers/vivid/vivid-core.c > @@ -1878,18 +1878,7 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) > INIT_LIST_HEAD(&dev->meta_out_active); > INIT_LIST_HEAD(&dev->touch_cap_active); > > - INIT_LIST_HEAD(&dev->cec_work_list); > - spin_lock_init(&dev->cec_slock); > - /* > - * Same as create_singlethread_workqueue, but now I can use the > - * string formatting of alloc_ordered_workqueue. > - */ > - dev->cec_workqueue = alloc_ordered_workqueue("vivid-%03d-cec", > - WQ_MEM_RECLAIM, inst); > - if (!dev->cec_workqueue) { > - ret = -ENOMEM; > - goto unreg_dev; > - } > + spin_lock_init(&dev->cec_xfers_slock); > > if (allocators[inst] == 1) > dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); > @@ -1929,6 +1918,19 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) > cec_tx_bus_cnt++; > } > } > + > + if (dev->cec_rx_adap || cec_tx_bus_cnt) { > + init_waitqueue_head(&dev->kthread_waitq_cec); > + dev->kthread_cec = kthread_run(vivid_cec_bus_thread, dev, > + "vivid_cec-%s", dev->v4l2_dev.name); > + if (IS_ERR(dev->kthread_cec)) { > + dev->kthread_cec = NULL; > + v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n"); > + ret = PTR_ERR(dev->kthread_cec); > + goto unreg_dev; > + } > + } > + > #endif > > v4l2_ctrl_handler_setup(&dev->ctrl_hdl_vid_cap); > @@ -1968,10 +1970,8 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) > cec_unregister_adapter(dev->cec_rx_adap); > for (i = 0; i < MAX_OUTPUTS; i++) > cec_unregister_adapter(dev->cec_tx_adap[i]); > - if (dev->cec_workqueue) { > - vivid_cec_bus_free_work(dev); > - destroy_workqueue(dev->cec_workqueue); > - } > + if (dev->kthread_cec) > + kthread_stop(dev->kthread_cec); > free_dev: > v4l2_device_put(&dev->v4l2_dev); > return ret; > @@ -2093,10 +2093,8 @@ static int vivid_remove(struct platform_device *pdev) > cec_unregister_adapter(dev->cec_rx_adap); > for (j = 0; j < MAX_OUTPUTS; j++) > cec_unregister_adapter(dev->cec_tx_adap[j]); > - if (dev->cec_workqueue) { > - vivid_cec_bus_free_work(dev); > - destroy_workqueue(dev->cec_workqueue); > - } > + if (dev->kthread_cec) > + kthread_stop(dev->kthread_cec); > v4l2_device_put(&dev->v4l2_dev); > vivid_devs[i] = NULL; > } > diff --git a/drivers/media/test-drivers/vivid/vivid-core.h b/drivers/media/test-drivers/vivid/vivid-core.h > index 1e3c4f5a9413..45f96706edde 100644 > --- a/drivers/media/test-drivers/vivid/vivid-core.h > +++ b/drivers/media/test-drivers/vivid/vivid-core.h > @@ -110,15 +110,11 @@ enum vivid_colorspace { > #define VIVID_INVALID_SIGNAL(mode) \ > ((mode) == NO_SIGNAL || (mode) == NO_LOCK || (mode) == OUT_OF_RANGE) > > -struct vivid_cec_work { > - struct list_head list; > - struct delayed_work work; > +struct vivid_cec_xfer { > struct cec_adapter *adap; > - struct vivid_dev *dev; > - unsigned int usecs; > - unsigned int timeout_ms; > - u8 tx_status; > - struct cec_msg msg; > + u8 msg[CEC_MAX_MSG_SIZE]; > + u32 len; > + u32 sft; > }; > > struct vivid_dev { > @@ -560,12 +556,13 @@ struct vivid_dev { > /* CEC */ > struct cec_adapter *cec_rx_adap; > struct cec_adapter *cec_tx_adap[MAX_OUTPUTS]; > - struct workqueue_struct *cec_workqueue; > - spinlock_t cec_slock; > - struct list_head cec_work_list; > - unsigned int cec_xfer_time_jiffies; > - unsigned long cec_xfer_start_jiffies; > u8 cec_output2bus_map[MAX_OUTPUTS]; > + struct task_struct *kthread_cec; > + wait_queue_head_t kthread_waitq_cec; > + struct vivid_cec_xfer xfers[MAX_OUTPUTS]; > + spinlock_t cec_xfers_slock; /* read and write cec messages */ > + u32 cec_sft; /* bus signal free time, in bit periods */ > + u8 last_initiator; > > /* CEC OSD String */ > char osd[14]; >
diff --git a/drivers/media/test-drivers/vivid/vivid-cec.c b/drivers/media/test-drivers/vivid/vivid-cec.c index 4d2413e87730..d6d7dbcb8437 100644 --- a/drivers/media/test-drivers/vivid/vivid-cec.c +++ b/drivers/media/test-drivers/vivid/vivid-cec.c @@ -5,40 +5,23 @@ * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved. */ +#include <linux/delay.h> #include <media/cec.h> #include "vivid-core.h" #include "vivid-cec.h" -#define CEC_TIM_START_BIT_TOTAL 4500 -#define CEC_TIM_START_BIT_LOW 3700 -#define CEC_TIM_START_BIT_HIGH 800 -#define CEC_TIM_DATA_BIT_TOTAL 2400 -#define CEC_TIM_DATA_BIT_0_LOW 1500 -#define CEC_TIM_DATA_BIT_0_HIGH 900 -#define CEC_TIM_DATA_BIT_1_LOW 600 -#define CEC_TIM_DATA_BIT_1_HIGH 1800 +#define CEC_START_BIT_US 4500 +#define CEC_DATA_BIT_US 2400 +#define CEC_MARGIN_US 350 -void vivid_cec_bus_free_work(struct vivid_dev *dev) -{ - spin_lock(&dev->cec_slock); - while (!list_empty(&dev->cec_work_list)) { - struct vivid_cec_work *cw = - list_first_entry(&dev->cec_work_list, - struct vivid_cec_work, list); - - spin_unlock(&dev->cec_slock); - cancel_delayed_work_sync(&cw->work); - spin_lock(&dev->cec_slock); - list_del(&cw->list); - cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_LOW_DRIVE); - kfree(cw); - } - spin_unlock(&dev->cec_slock); -} +struct xfer_on_bus { + struct cec_adapter *adap; + u8 status; +}; -static bool vivid_cec_find_dest_adap(struct vivid_dev *dev, - struct cec_adapter *adap, u8 dest) +static bool find_dest_adap(struct vivid_dev *dev, + struct cec_adapter *adap, u8 dest) { unsigned int i; @@ -61,116 +44,187 @@ static bool vivid_cec_find_dest_adap(struct vivid_dev *dev, return false; } -static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts, - const struct cec_msg *msg, bool nacked) +static bool xfer_ready(struct vivid_dev *dev) { - unsigned int len = nacked ? 1 : msg->len; unsigned int i; - bool bit; - - if (adap == NULL) - return; + bool ready = false; - /* - * Suffix ULL on constant 10 makes the expression - * CEC_TIM_START_BIT_TOTAL + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL - * to be evaluated using 64-bit unsigned arithmetic (u64), which - * is what ktime_sub_us expects as second argument. - */ - ts = ktime_sub_us(ts, CEC_TIM_START_BIT_TOTAL + - 10ULL * len * CEC_TIM_DATA_BIT_TOTAL); - cec_queue_pin_cec_event(adap, false, false, ts); - ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW); - cec_queue_pin_cec_event(adap, true, false, ts); - ts = ktime_add_us(ts, CEC_TIM_START_BIT_HIGH); - - for (i = 0; i < 10 * len; i++) { - switch (i % 10) { - case 0 ... 7: - bit = msg->msg[i / 10] & (0x80 >> (i % 10)); - break; - case 8: /* EOM */ - bit = i / 10 == msg->len - 1; - break; - case 9: /* ACK */ - bit = cec_msg_is_broadcast(msg) ^ nacked; + spin_lock(&dev->cec_xfers_slock); + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { + if (dev->xfers[i].sft && + dev->xfers[i].sft <= dev->cec_sft) { + ready = true; break; } - cec_queue_pin_cec_event(adap, false, false, ts); - if (bit) - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_LOW); - else - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_LOW); - cec_queue_pin_cec_event(adap, true, false, ts); - if (bit) - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_HIGH); - else - ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_HIGH); } -} + spin_unlock(&dev->cec_xfers_slock); -static void vivid_cec_pin_events(struct vivid_dev *dev, - const struct cec_msg *msg, bool nacked) -{ - ktime_t ts = ktime_get(); - unsigned int i; - - vivid_cec_pin_adap_events(dev->cec_rx_adap, ts, msg, nacked); - for (i = 0; i < MAX_OUTPUTS; i++) - vivid_cec_pin_adap_events(dev->cec_tx_adap[i], ts, msg, nacked); + return ready; } -static void vivid_cec_xfer_done_worker(struct work_struct *work) +/* + * If an adapter tries to send successive messages, it must wait for the + * longest signal-free time between its transmissions. But, if another + * adapter sends a message in the interim, then the wait can be reduced + * because the messages are no longer successive. Make these adjustments + * if necessary. Should be called holding cec_xfers_slock. + */ +static void adjust_sfts(struct vivid_dev *dev) { - struct vivid_cec_work *cw = - container_of(work, struct vivid_cec_work, work.work); - struct vivid_dev *dev = cw->dev; - struct cec_adapter *adap = cw->adap; - u8 dest = cec_msg_destination(&cw->msg); - bool valid_dest; unsigned int i; + u8 initiator; - valid_dest = cec_msg_is_broadcast(&cw->msg); - if (!valid_dest) - valid_dest = vivid_cec_find_dest_adap(dev, adap, dest); - - cw->tx_status = valid_dest ? CEC_TX_STATUS_OK : CEC_TX_STATUS_NACK; - spin_lock(&dev->cec_slock); - dev->cec_xfer_time_jiffies = 0; - dev->cec_xfer_start_jiffies = 0; - list_del(&cw->list); - spin_unlock(&dev->cec_slock); - vivid_cec_pin_events(dev, &cw->msg, !valid_dest); - cec_transmit_attempt_done(cw->adap, cw->tx_status); - - /* Broadcast message */ - if (adap != dev->cec_rx_adap) - cec_received_msg(dev->cec_rx_adap, &cw->msg); - for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++) - if (adap != dev->cec_tx_adap[i]) - cec_received_msg(dev->cec_tx_adap[i], &cw->msg); - kfree(cw); + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { + if (dev->xfers[i].sft <= CEC_SIGNAL_FREE_TIME_RETRY) + continue; + initiator = dev->xfers[i].msg[0] >> 4; + if (initiator == dev->last_initiator) + dev->xfers[i].sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; + else + dev->xfers[i].sft = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR; + } } -static void vivid_cec_xfer_try_worker(struct work_struct *work) +/* + * The main emulation of the bus on which CEC adapters attempt to send + * messages to each other. The bus keeps track of how long it has been + * signal-free and accepts a pending transmission only if the state of + * the bus matches the transmission's signal-free requirements. It calls + * cec_transmit_attempt_done() for all transmits that enter the bus and + * cec_received_msg() for successful transmits. + */ +int vivid_cec_bus_thread(void *_dev) { - struct vivid_cec_work *cw = - container_of(work, struct vivid_cec_work, work.work); - struct vivid_dev *dev = cw->dev; - - spin_lock(&dev->cec_slock); - if (dev->cec_xfer_time_jiffies) { - list_del(&cw->list); - spin_unlock(&dev->cec_slock); - cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_ARB_LOST); - kfree(cw); - } else { - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker); - dev->cec_xfer_start_jiffies = jiffies; - dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs); - spin_unlock(&dev->cec_slock); - schedule_delayed_work(&cw->work, dev->cec_xfer_time_jiffies); + u32 last_sft; + unsigned int i; + unsigned int dest; + ktime_t start, end; + s64 delta_us, retry_us; + struct vivid_dev *dev = _dev; + + dev->cec_sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; + for (;;) { + bool first = true; + int wait_xfer_us = 0; + bool valid_dest = false; + int wait_arb_lost_us = 0; + unsigned int first_idx = 0; + unsigned int first_status = 0; + struct cec_msg first_msg = {}; + struct xfer_on_bus xfers_on_bus[MAX_OUTPUTS] = {}; + + wait_event_interruptible(dev->kthread_waitq_cec, xfer_ready(dev) || + kthread_should_stop()); + if (kthread_should_stop()) + break; + last_sft = dev->cec_sft; + dev->cec_sft = 0; + /* + * Move the messages that are ready onto the bus. The adapter with + * the most leading zeros will win control of the bus and any other + * adapters will lose arbitration. + */ + spin_lock(&dev->cec_xfers_slock); + for (i = 0; i < ARRAY_SIZE(dev->xfers); i++) { + if (!dev->xfers[i].sft || dev->xfers[i].sft > last_sft) + continue; + if (first) { + first = false; + first_idx = i; + xfers_on_bus[first_idx].adap = dev->xfers[i].adap; + memcpy(first_msg.msg, dev->xfers[i].msg, dev->xfers[i].len); + first_msg.len = dev->xfers[i].len; + } else { + xfers_on_bus[i].adap = dev->xfers[i].adap; + xfers_on_bus[i].status = CEC_TX_STATUS_ARB_LOST; + /* + * For simplicity wait for all 4 bits of the initiator's + * address even though HDMI specification uses bit-level + * precision. + */ + wait_arb_lost_us = 4 * CEC_DATA_BIT_US + CEC_START_BIT_US; + } + dev->xfers[i].sft = 0; + } + dev->last_initiator = cec_msg_initiator(&first_msg); + adjust_sfts(dev); + spin_unlock(&dev->cec_xfers_slock); + + dest = cec_msg_destination(&first_msg); + valid_dest = cec_msg_is_broadcast(&first_msg); + if (!valid_dest) + valid_dest = find_dest_adap(dev, xfers_on_bus[first_idx].adap, dest); + if (valid_dest) { + first_status = CEC_TX_STATUS_OK; + /* + * Message length is in bytes, but each byte is transmitted in + * a block of 10 bits. + */ + wait_xfer_us = first_msg.len * 10 * CEC_DATA_BIT_US; + } else { + first_status = CEC_TX_STATUS_NACK; + /* + * A message that is not acknowledged stops transmitting after + * the header block of 10 bits. + */ + wait_xfer_us = 10 * CEC_DATA_BIT_US; + } + wait_xfer_us += CEC_START_BIT_US; + xfers_on_bus[first_idx].status = first_status; + + /* Sleep as if sending messages on a real hardware bus. */ + start = ktime_get(); + if (wait_arb_lost_us) { + usleep_range(wait_arb_lost_us - CEC_MARGIN_US, wait_arb_lost_us); + for (i = 0; i < ARRAY_SIZE(xfers_on_bus); i++) { + if (xfers_on_bus[i].status != CEC_TX_STATUS_ARB_LOST) + continue; + cec_transmit_attempt_done(xfers_on_bus[i].adap, + CEC_TX_STATUS_ARB_LOST); + } + if (kthread_should_stop()) + break; + } + wait_xfer_us -= wait_arb_lost_us; + usleep_range(wait_xfer_us - CEC_MARGIN_US, wait_xfer_us); + cec_transmit_attempt_done(xfers_on_bus[first_idx].adap, first_status); + if (kthread_should_stop()) + break; + if (first_status == CEC_TX_STATUS_OK) { + if (xfers_on_bus[first_idx].adap != dev->cec_rx_adap) + cec_received_msg(dev->cec_rx_adap, &first_msg); + for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++) + if (xfers_on_bus[first_idx].adap != dev->cec_tx_adap[i]) + cec_received_msg(dev->cec_tx_adap[i], &first_msg); + } + end = ktime_get(); + /* + * If the emulated transfer took more or less time than it should + * have, then compensate by adjusting the wait time needed for the + * bus to be signal-free for 3 bit periods (the retry time). + */ + delta_us = div_s64(end - start, 1000); + delta_us -= wait_xfer_us + wait_arb_lost_us; + retry_us = CEC_SIGNAL_FREE_TIME_RETRY * CEC_DATA_BIT_US - delta_us; + if (retry_us > CEC_MARGIN_US) + usleep_range(retry_us - CEC_MARGIN_US, retry_us); + dev->cec_sft = CEC_SIGNAL_FREE_TIME_RETRY; + /* + * If there are no messages that need to be retried, check if any + * adapters that did not just transmit a message are ready to + * transmit. If none of these adapters are ready, then increase + * the signal-free time so that the bus is available to all + * adapters and go back to waiting for a transmission. + */ + while (dev->cec_sft >= CEC_SIGNAL_FREE_TIME_RETRY && + dev->cec_sft < CEC_SIGNAL_FREE_TIME_NEXT_XFER && + !xfer_ready(dev) && !kthread_should_stop()) { + usleep_range(2 * CEC_DATA_BIT_US - CEC_MARGIN_US, + 2 * CEC_DATA_BIT_US); + dev->cec_sft += 2; + } } + return 0; } static int vivid_cec_adap_enable(struct cec_adapter *adap, bool enable) @@ -184,41 +238,26 @@ static int vivid_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr) return 0; } -/* - * One data bit takes 2400 us, each byte needs 10 bits so that's 24000 us - * per byte. - */ -#define USECS_PER_BYTE 24000 - static int vivid_cec_adap_transmit(struct cec_adapter *adap, u8 attempts, u32 signal_free_time, struct cec_msg *msg) { struct vivid_dev *dev = cec_get_drvdata(adap); - struct vivid_cec_work *cw = kzalloc(sizeof(*cw), GFP_KERNEL); - long delta_jiffies = 0; - - if (cw == NULL) - return -ENOMEM; - cw->dev = dev; - cw->adap = adap; - cw->usecs = CEC_FREE_TIME_TO_USEC(signal_free_time) + - msg->len * USECS_PER_BYTE; - cw->msg = *msg; - - spin_lock(&dev->cec_slock); - list_add(&cw->list, &dev->cec_work_list); - if (dev->cec_xfer_time_jiffies == 0) { - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker); - dev->cec_xfer_start_jiffies = jiffies; - dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs); - delta_jiffies = dev->cec_xfer_time_jiffies; - } else { - INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_try_worker); - delta_jiffies = dev->cec_xfer_start_jiffies + - dev->cec_xfer_time_jiffies - jiffies; + u8 idx = cec_msg_initiator(msg); + + spin_lock(&dev->cec_xfers_slock); + dev->xfers[idx].adap = adap; + memcpy(dev->xfers[idx].msg, msg->msg, CEC_MAX_MSG_SIZE); + dev->xfers[idx].len = msg->len; + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_RETRY; + if (signal_free_time > CEC_SIGNAL_FREE_TIME_RETRY) { + if (idx == dev->last_initiator) + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_NEXT_XFER; + else + dev->xfers[idx].sft = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR; } - spin_unlock(&dev->cec_slock); - schedule_delayed_work(&cw->work, delta_jiffies < 0 ? 0 : delta_jiffies); + spin_unlock(&dev->cec_xfers_slock); + wake_up_interruptible(&dev->kthread_waitq_cec); + return 0; } diff --git a/drivers/media/test-drivers/vivid/vivid-cec.h b/drivers/media/test-drivers/vivid/vivid-cec.h index 7524ed48a914..b2bcddb50b83 100644 --- a/drivers/media/test-drivers/vivid/vivid-cec.h +++ b/drivers/media/test-drivers/vivid/vivid-cec.h @@ -9,12 +9,5 @@ struct cec_adapter *vivid_cec_alloc_adap(struct vivid_dev *dev, unsigned int idx, bool is_source); -void vivid_cec_bus_free_work(struct vivid_dev *dev); - -#else - -static inline void vivid_cec_bus_free_work(struct vivid_dev *dev) -{ -} - +int vivid_cec_bus_thread(void *_dev); #endif diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c index d2bd2653cf54..53feecba962d 100644 --- a/drivers/media/test-drivers/vivid/vivid-core.c +++ b/drivers/media/test-drivers/vivid/vivid-core.c @@ -1878,18 +1878,7 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) INIT_LIST_HEAD(&dev->meta_out_active); INIT_LIST_HEAD(&dev->touch_cap_active); - INIT_LIST_HEAD(&dev->cec_work_list); - spin_lock_init(&dev->cec_slock); - /* - * Same as create_singlethread_workqueue, but now I can use the - * string formatting of alloc_ordered_workqueue. - */ - dev->cec_workqueue = alloc_ordered_workqueue("vivid-%03d-cec", - WQ_MEM_RECLAIM, inst); - if (!dev->cec_workqueue) { - ret = -ENOMEM; - goto unreg_dev; - } + spin_lock_init(&dev->cec_xfers_slock); if (allocators[inst] == 1) dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); @@ -1929,6 +1918,19 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) cec_tx_bus_cnt++; } } + + if (dev->cec_rx_adap || cec_tx_bus_cnt) { + init_waitqueue_head(&dev->kthread_waitq_cec); + dev->kthread_cec = kthread_run(vivid_cec_bus_thread, dev, + "vivid_cec-%s", dev->v4l2_dev.name); + if (IS_ERR(dev->kthread_cec)) { + dev->kthread_cec = NULL; + v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n"); + ret = PTR_ERR(dev->kthread_cec); + goto unreg_dev; + } + } + #endif v4l2_ctrl_handler_setup(&dev->ctrl_hdl_vid_cap); @@ -1968,10 +1970,8 @@ static int vivid_create_instance(struct platform_device *pdev, int inst) cec_unregister_adapter(dev->cec_rx_adap); for (i = 0; i < MAX_OUTPUTS; i++) cec_unregister_adapter(dev->cec_tx_adap[i]); - if (dev->cec_workqueue) { - vivid_cec_bus_free_work(dev); - destroy_workqueue(dev->cec_workqueue); - } + if (dev->kthread_cec) + kthread_stop(dev->kthread_cec); free_dev: v4l2_device_put(&dev->v4l2_dev); return ret; @@ -2093,10 +2093,8 @@ static int vivid_remove(struct platform_device *pdev) cec_unregister_adapter(dev->cec_rx_adap); for (j = 0; j < MAX_OUTPUTS; j++) cec_unregister_adapter(dev->cec_tx_adap[j]); - if (dev->cec_workqueue) { - vivid_cec_bus_free_work(dev); - destroy_workqueue(dev->cec_workqueue); - } + if (dev->kthread_cec) + kthread_stop(dev->kthread_cec); v4l2_device_put(&dev->v4l2_dev); vivid_devs[i] = NULL; } diff --git a/drivers/media/test-drivers/vivid/vivid-core.h b/drivers/media/test-drivers/vivid/vivid-core.h index 1e3c4f5a9413..45f96706edde 100644 --- a/drivers/media/test-drivers/vivid/vivid-core.h +++ b/drivers/media/test-drivers/vivid/vivid-core.h @@ -110,15 +110,11 @@ enum vivid_colorspace { #define VIVID_INVALID_SIGNAL(mode) \ ((mode) == NO_SIGNAL || (mode) == NO_LOCK || (mode) == OUT_OF_RANGE) -struct vivid_cec_work { - struct list_head list; - struct delayed_work work; +struct vivid_cec_xfer { struct cec_adapter *adap; - struct vivid_dev *dev; - unsigned int usecs; - unsigned int timeout_ms; - u8 tx_status; - struct cec_msg msg; + u8 msg[CEC_MAX_MSG_SIZE]; + u32 len; + u32 sft; }; struct vivid_dev { @@ -560,12 +556,13 @@ struct vivid_dev { /* CEC */ struct cec_adapter *cec_rx_adap; struct cec_adapter *cec_tx_adap[MAX_OUTPUTS]; - struct workqueue_struct *cec_workqueue; - spinlock_t cec_slock; - struct list_head cec_work_list; - unsigned int cec_xfer_time_jiffies; - unsigned long cec_xfer_start_jiffies; u8 cec_output2bus_map[MAX_OUTPUTS]; + struct task_struct *kthread_cec; + wait_queue_head_t kthread_waitq_cec; + struct vivid_cec_xfer xfers[MAX_OUTPUTS]; + spinlock_t cec_xfers_slock; /* read and write cec messages */ + u32 cec_sft; /* bus signal free time, in bit periods */ + u8 last_initiator; /* CEC OSD String */ char osd[14];
Currently, the vivid emulation of cec message transmission does not force adapters to wait until the cec bus has been signal-free for a certain number of bit periods before transmitting or re-transmitting a message. Without enforcing the signal-free time requirements, adapters do not share the bus very well and some messages are sent too quickly while other messages are lost. By emulating a signal-free time and forcing adapters to wait their turn to transmit, the vivid emulation of cec transmission is much more reliable. Signed-off-by: Deborah Brouwer <deborahbrouwer3563@gmail.com> --- Changes since v2: - initialize first_idx and first_status and move inside bus loop - properly return error code Changes since v1: - use actual message length instead of max when copying - check for kthread_stop() within bus - store the last_initiator in the vivid state - update the last_initiator as soon as it is known and adjust sfts - use last_initiator to assign sft when transmit is called - use function for division drivers/media/test-drivers/vivid/vivid-cec.c | 341 ++++++++++-------- drivers/media/test-drivers/vivid/vivid-cec.h | 9 +- drivers/media/test-drivers/vivid/vivid-core.c | 38 +- drivers/media/test-drivers/vivid/vivid-core.h | 23 +- 4 files changed, 219 insertions(+), 192 deletions(-)