diff options
Diffstat (limited to 'drivers/mailbox/mailbox.c')
| -rw-r--r-- | drivers/mailbox/mailbox.c | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c new file mode 100644 index 000000000..4229b9b5d --- /dev/null +++ b/drivers/mailbox/mailbox.c @@ -0,0 +1,625 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Mailbox: Common code for Mailbox controllers and users + * + * Copyright (C) 2013-2014 Linaro Ltd. + * Author: Jassi Brar <jassisinghbrar@gmail.com> + */ + +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/bitops.h> +#include <linux/mailbox_client.h> +#include <linux/mailbox_controller.h> + +#include "mailbox.h" + +static LIST_HEAD(mbox_cons); +static DEFINE_MUTEX(con_mutex); + +static int add_to_rbuf(struct mbox_chan *chan, void *mssg) +{ + int idx; + unsigned long flags; + + spin_lock_irqsave(&chan->lock, flags); + + /* See if there is any space left */ + if (chan->msg_count == MBOX_TX_QUEUE_LEN) { + spin_unlock_irqrestore(&chan->lock, flags); + return -ENOBUFS; + } + + idx = chan->msg_free; + chan->msg_data[idx] = mssg; + chan->msg_count++; + + if (idx == MBOX_TX_QUEUE_LEN - 1) + chan->msg_free = 0; + else + chan->msg_free++; + + spin_unlock_irqrestore(&chan->lock, flags); + + return idx; +} + +static void msg_submit(struct mbox_chan *chan) +{ + unsigned count, idx; + unsigned long flags; + void *data; + int err = -EBUSY; + + spin_lock_irqsave(&chan->lock, flags); + + if (!chan->msg_count || chan->active_req) + goto exit; + + count = chan->msg_count; + idx = chan->msg_free; + if (idx >= count) + idx -= count; + else + idx += MBOX_TX_QUEUE_LEN - count; + + data = chan->msg_data[idx]; + + if (chan->cl->tx_prepare) + chan->cl->tx_prepare(chan->cl, data); + /* Try to submit a message to the MBOX controller */ + err = chan->mbox->ops->send_data(chan, data); + if (!err) { + chan->active_req = data; + chan->msg_count--; + } +exit: + spin_unlock_irqrestore(&chan->lock, flags); + + if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { + /* kick start the timer immediately to avoid delays */ + spin_lock_irqsave(&chan->mbox->poll_hrt_lock, flags); + hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + spin_unlock_irqrestore(&chan->mbox->poll_hrt_lock, flags); + } +} + +static void tx_tick(struct mbox_chan *chan, int r) +{ + unsigned long flags; + void *mssg; + + spin_lock_irqsave(&chan->lock, flags); + mssg = chan->active_req; + chan->active_req = NULL; + spin_unlock_irqrestore(&chan->lock, flags); + + /* Submit next message */ + msg_submit(chan); + + if (!mssg) + return; + + /* Notify the client */ + if (chan->cl->tx_done) + chan->cl->tx_done(chan->cl, mssg, r); + + if (r != -ETIME && chan->cl->tx_block) + complete(&chan->tx_complete); +} + +static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer) +{ + struct mbox_controller *mbox = + container_of(hrtimer, struct mbox_controller, poll_hrt); + bool txdone, resched = false; + int i; + unsigned long flags; + + for (i = 0; i < mbox->num_chans; i++) { + struct mbox_chan *chan = &mbox->chans[i]; + + if (chan->active_req && chan->cl) { + txdone = chan->mbox->ops->last_tx_done(chan); + if (txdone) + tx_tick(chan, 0); + else + resched = true; + } + } + + if (resched) { + spin_lock_irqsave(&mbox->poll_hrt_lock, flags); + if (!hrtimer_is_queued(hrtimer)) + hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period)); + spin_unlock_irqrestore(&mbox->poll_hrt_lock, flags); + + return HRTIMER_RESTART; + } + return HRTIMER_NORESTART; +} + +/** + * mbox_chan_received_data - A way for controller driver to push data + * received from remote to the upper layer. + * @chan: Pointer to the mailbox channel on which RX happened. + * @mssg: Client specific message typecasted as void * + * + * After startup and before shutdown any data received on the chan + * is passed on to the API via atomic mbox_chan_received_data(). + * The controller should ACK the RX only after this call returns. + */ +void mbox_chan_received_data(struct mbox_chan *chan, void *mssg) +{ + /* No buffering the received data */ + if (chan->cl->rx_callback) + chan->cl->rx_callback(chan->cl, mssg); +} +EXPORT_SYMBOL_GPL(mbox_chan_received_data); + +/** + * mbox_chan_txdone - A way for controller driver to notify the + * framework that the last TX has completed. + * @chan: Pointer to the mailbox chan on which TX happened. + * @r: Status of last TX - OK or ERROR + * + * The controller that has IRQ for TX ACK calls this atomic API + * to tick the TX state machine. It works only if txdone_irq + * is set by the controller. + */ +void mbox_chan_txdone(struct mbox_chan *chan, int r) +{ + if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) { + dev_err(chan->mbox->dev, + "Controller can't run the TX ticker\n"); + return; + } + + tx_tick(chan, r); +} +EXPORT_SYMBOL_GPL(mbox_chan_txdone); + +/** + * mbox_client_txdone - The way for a client to run the TX state machine. + * @chan: Mailbox channel assigned to this client. + * @r: Success status of last transmission. + * + * The client/protocol had received some 'ACK' packet and it notifies + * the API that the last packet was sent successfully. This only works + * if the controller can't sense TX-Done. + */ +void mbox_client_txdone(struct mbox_chan *chan, int r) +{ + if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) { + dev_err(chan->mbox->dev, "Client can't run the TX ticker\n"); + return; + } + + tx_tick(chan, r); +} +EXPORT_SYMBOL_GPL(mbox_client_txdone); + +/** + * mbox_client_peek_data - A way for client driver to pull data + * received from remote by the controller. + * @chan: Mailbox channel assigned to this client. + * + * A poke to controller driver for any received data. + * The data is actually passed onto client via the + * mbox_chan_received_data() + * The call can be made from atomic context, so the controller's + * implementation of peek_data() must not sleep. + * + * Return: True, if controller has, and is going to push after this, + * some data. + * False, if controller doesn't have any data to be read. + */ +bool mbox_client_peek_data(struct mbox_chan *chan) +{ + if (chan->mbox->ops->peek_data) + return chan->mbox->ops->peek_data(chan); + + return false; +} +EXPORT_SYMBOL_GPL(mbox_client_peek_data); + +/** + * mbox_send_message - For client to submit a message to be + * sent to the remote. + * @chan: Mailbox channel assigned to this client. + * @mssg: Client specific message typecasted. + * + * For client to submit data to the controller destined for a remote + * processor. If the client had set 'tx_block', the call will return + * either when the remote receives the data or when 'tx_tout' millisecs + * run out. + * In non-blocking mode, the requests are buffered by the API and a + * non-negative token is returned for each queued request. If the request + * is not queued, a negative token is returned. Upon failure or successful + * TX, the API calls 'tx_done' from atomic context, from which the client + * could submit yet another request. + * The pointer to message should be preserved until it is sent + * over the chan, i.e, tx_done() is made. + * This function could be called from atomic context as it simply + * queues the data and returns a token against the request. + * + * Return: Non-negative integer for successful submission (non-blocking mode) + * or transmission over chan (blocking mode). + * Negative value denotes failure. + */ +int mbox_send_message(struct mbox_chan *chan, void *mssg) +{ + int t; + + if (!chan || !chan->cl) + return -EINVAL; + + t = add_to_rbuf(chan, mssg); + if (t < 0) { + dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n"); + return t; + } + + msg_submit(chan); + + if (chan->cl->tx_block) { + unsigned long wait; + int ret; + + if (!chan->cl->tx_tout) /* wait forever */ + wait = msecs_to_jiffies(3600000); + else + wait = msecs_to_jiffies(chan->cl->tx_tout); + + ret = wait_for_completion_timeout(&chan->tx_complete, wait); + if (ret == 0) { + t = -ETIME; + tx_tick(chan, t); + } + } + + return t; +} +EXPORT_SYMBOL_GPL(mbox_send_message); + +/** + * mbox_flush - flush a mailbox channel + * @chan: mailbox channel to flush + * @timeout: time, in milliseconds, to allow the flush operation to succeed + * + * Mailbox controllers that need to work in atomic context can implement the + * ->flush() callback to busy loop until a transmission has been completed. + * The implementation must call mbox_chan_txdone() upon success. Clients can + * call the mbox_flush() function at any time after mbox_send_message() to + * flush the transmission. After the function returns success, the mailbox + * transmission is guaranteed to have completed. + * + * Returns: 0 on success or a negative error code on failure. + */ +int mbox_flush(struct mbox_chan *chan, unsigned long timeout) +{ + int ret; + + if (!chan->mbox->ops->flush) + return -ENOTSUPP; + + ret = chan->mbox->ops->flush(chan, timeout); + if (ret < 0) + tx_tick(chan, ret); + + return ret; +} +EXPORT_SYMBOL_GPL(mbox_flush); + +/** + * mbox_request_channel - Request a mailbox channel. + * @cl: Identity of the client requesting the channel. + * @index: Index of mailbox specifier in 'mboxes' property. + * + * The Client specifies its requirements and capabilities while asking for + * a mailbox channel. It can't be called from atomic context. + * The channel is exclusively allocated and can't be used by another + * client before the owner calls mbox_free_channel. + * After assignment, any packet received on this channel will be + * handed over to the client via the 'rx_callback'. + * The framework holds reference to the client, so the mbox_client + * structure shouldn't be modified until the mbox_free_channel returns. + * + * Return: Pointer to the channel assigned to the client if successful. + * ERR_PTR for request failure. + */ +struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) +{ + struct device *dev = cl->dev; + struct mbox_controller *mbox; + struct of_phandle_args spec; + struct mbox_chan *chan; + unsigned long flags; + int ret; + + if (!dev || !dev->of_node) { + pr_debug("%s: No owner device node\n", __func__); + return ERR_PTR(-ENODEV); + } + + mutex_lock(&con_mutex); + + if (of_parse_phandle_with_args(dev->of_node, "mboxes", + "#mbox-cells", index, &spec)) { + dev_dbg(dev, "%s: can't parse \"mboxes\" property\n", __func__); + mutex_unlock(&con_mutex); + return ERR_PTR(-ENODEV); + } + + chan = ERR_PTR(-EPROBE_DEFER); + list_for_each_entry(mbox, &mbox_cons, node) + if (mbox->dev->of_node == spec.np) { + chan = mbox->of_xlate(mbox, &spec); + if (!IS_ERR(chan)) + break; + } + + of_node_put(spec.np); + + if (IS_ERR(chan)) { + mutex_unlock(&con_mutex); + return chan; + } + + if (chan->cl || !try_module_get(mbox->dev->driver->owner)) { + dev_dbg(dev, "%s: mailbox not free\n", __func__); + mutex_unlock(&con_mutex); + return ERR_PTR(-EBUSY); + } + + spin_lock_irqsave(&chan->lock, flags); + chan->msg_free = 0; + chan->msg_count = 0; + chan->active_req = NULL; + chan->cl = cl; + init_completion(&chan->tx_complete); + + if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone) + chan->txdone_method = TXDONE_BY_ACK; + + spin_unlock_irqrestore(&chan->lock, flags); + + if (chan->mbox->ops->startup) { + ret = chan->mbox->ops->startup(chan); + + if (ret) { + dev_err(dev, "Unable to startup the chan (%d)\n", ret); + mbox_free_channel(chan); + chan = ERR_PTR(ret); + } + } + + mutex_unlock(&con_mutex); + return chan; +} +EXPORT_SYMBOL_GPL(mbox_request_channel); + +struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl, + const char *name) +{ + struct device_node *np = cl->dev->of_node; + struct property *prop; + const char *mbox_name; + int index = 0; + + if (!np) { + dev_err(cl->dev, "%s() currently only supports DT\n", __func__); + return ERR_PTR(-EINVAL); + } + + if (!of_get_property(np, "mbox-names", NULL)) { + dev_err(cl->dev, + "%s() requires an \"mbox-names\" property\n", __func__); + return ERR_PTR(-EINVAL); + } + + of_property_for_each_string(np, "mbox-names", prop, mbox_name) { + if (!strncmp(name, mbox_name, strlen(name))) + return mbox_request_channel(cl, index); + index++; + } + + dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n", + __func__, name); + return ERR_PTR(-EINVAL); +} +EXPORT_SYMBOL_GPL(mbox_request_channel_byname); + +/** + * mbox_free_channel - The client relinquishes control of a mailbox + * channel by this call. + * @chan: The mailbox channel to be freed. + */ +void mbox_free_channel(struct mbox_chan *chan) +{ + unsigned long flags; + + if (!chan || !chan->cl) + return; + + if (chan->mbox->ops->shutdown) + chan->mbox->ops->shutdown(chan); + + /* The queued TX requests are simply aborted, no callbacks are made */ + spin_lock_irqsave(&chan->lock, flags); + chan->cl = NULL; + chan->active_req = NULL; + if (chan->txdone_method == TXDONE_BY_ACK) + chan->txdone_method = TXDONE_BY_POLL; + + module_put(chan->mbox->dev->driver->owner); + spin_unlock_irqrestore(&chan->lock, flags); +} +EXPORT_SYMBOL_GPL(mbox_free_channel); + +static struct mbox_chan * +of_mbox_index_xlate(struct mbox_controller *mbox, + const struct of_phandle_args *sp) +{ + int ind = sp->args[0]; + + if (ind >= mbox->num_chans) + return ERR_PTR(-EINVAL); + + return &mbox->chans[ind]; +} + +/** + * mbox_controller_register - Register the mailbox controller + * @mbox: Pointer to the mailbox controller. + * + * The controller driver registers its communication channels + */ +int mbox_controller_register(struct mbox_controller *mbox) +{ + int i, txdone; + + /* Sanity check */ + if (!mbox || !mbox->dev || !mbox->ops || !mbox->num_chans) + return -EINVAL; + + if (mbox->txdone_irq) + txdone = TXDONE_BY_IRQ; + else if (mbox->txdone_poll) + txdone = TXDONE_BY_POLL; + else /* It has to be ACK then */ + txdone = TXDONE_BY_ACK; + + if (txdone == TXDONE_BY_POLL) { + + if (!mbox->ops->last_tx_done) { + dev_err(mbox->dev, "last_tx_done method is absent\n"); + return -EINVAL; + } + + hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + mbox->poll_hrt.function = txdone_hrtimer; + spin_lock_init(&mbox->poll_hrt_lock); + } + + for (i = 0; i < mbox->num_chans; i++) { + struct mbox_chan *chan = &mbox->chans[i]; + + chan->cl = NULL; + chan->mbox = mbox; + chan->txdone_method = txdone; + spin_lock_init(&chan->lock); + } + + if (!mbox->of_xlate) + mbox->of_xlate = of_mbox_index_xlate; + + mutex_lock(&con_mutex); + list_add_tail(&mbox->node, &mbox_cons); + mutex_unlock(&con_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(mbox_controller_register); + +/** + * mbox_controller_unregister - Unregister the mailbox controller + * @mbox: Pointer to the mailbox controller. + */ +void mbox_controller_unregister(struct mbox_controller *mbox) +{ + int i; + + if (!mbox) + return; + + mutex_lock(&con_mutex); + + list_del(&mbox->node); + + for (i = 0; i < mbox->num_chans; i++) + mbox_free_channel(&mbox->chans[i]); + + if (mbox->txdone_poll) + hrtimer_cancel(&mbox->poll_hrt); + + mutex_unlock(&con_mutex); +} +EXPORT_SYMBOL_GPL(mbox_controller_unregister); + +static void __devm_mbox_controller_unregister(struct device *dev, void *res) +{ + struct mbox_controller **mbox = res; + + mbox_controller_unregister(*mbox); +} + +static int devm_mbox_controller_match(struct device *dev, void *res, void *data) +{ + struct mbox_controller **mbox = res; + + if (WARN_ON(!mbox || !*mbox)) + return 0; + + return *mbox == data; +} + +/** + * devm_mbox_controller_register() - managed mbox_controller_register() + * @dev: device owning the mailbox controller being registered + * @mbox: mailbox controller being registered + * + * This function adds a device-managed resource that will make sure that the + * mailbox controller, which is registered using mbox_controller_register() + * as part of this function, will be unregistered along with the rest of + * device-managed resources upon driver probe failure or driver removal. + * + * Returns 0 on success or a negative error code on failure. + */ +int devm_mbox_controller_register(struct device *dev, + struct mbox_controller *mbox) +{ + struct mbox_controller **ptr; + int err; + + ptr = devres_alloc(__devm_mbox_controller_unregister, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + err = mbox_controller_register(mbox); + if (err < 0) { + devres_free(ptr); + return err; + } + + devres_add(dev, ptr); + *ptr = mbox; + + return 0; +} +EXPORT_SYMBOL_GPL(devm_mbox_controller_register); + +/** + * devm_mbox_controller_unregister() - managed mbox_controller_unregister() + * @dev: device owning the mailbox controller being unregistered + * @mbox: mailbox controller being unregistered + * + * This function unregisters the mailbox controller and removes the device- + * managed resource that was set up to automatically unregister the mailbox + * controller on driver probe failure or driver removal. It's typically not + * necessary to call this function. + */ +void devm_mbox_controller_unregister(struct device *dev, struct mbox_controller *mbox) +{ + WARN_ON(devres_release(dev, __devm_mbox_controller_unregister, + devm_mbox_controller_match, mbox)); +} +EXPORT_SYMBOL_GPL(devm_mbox_controller_unregister); |