From patchwork Mon May 6 07:24:06 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jassi Brar X-Patchwork-Id: 2523201 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork2.kernel.org (Postfix) with ESMTP id BACADDF230 for ; Mon, 6 May 2013 07:26:14 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZFng-00031i-P2; Mon, 06 May 2013 07:25:34 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZFnR-0007yt-6u; Mon, 06 May 2013 07:25:17 +0000 Received: from mail-da0-x22a.google.com ([2607:f8b0:400e:c00::22a]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZFnM-0007wd-Se for linux-arm-kernel@lists.infradead.org; Mon, 06 May 2013 07:25:15 +0000 Received: by mail-da0-f42.google.com with SMTP id r6so1699890dad.29 for ; Mon, 06 May 2013 00:24:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; bh=MvziWAl847JG60Ogfsy4SuQ/C/7XmwcEFhNFP4NoLJY=; b=LBDcVVTzBjBxBSif6YlVqC4iWMj5nXcCqUUAyhchk7ke9pPr8W0PcOTxMHNG4kiCwZ oL3G2aRAWjY3Xd8NHPcS29kPRVrx443xxYE23d+snRkzNcUPrdS3pD4QwytqpQJ+hC9u b+o6t8ykjuayJ8w3pPA1epeqH6xMX3AQdHnuWooVh8x37XbG7/uqqokcPwFaxKrW1m/J vS+rwJxy7Cb/G6B/RSvoN1b0wCnn0EJrSRNYyy9pQh0TYaBnX3lLIS3hUX1tvp0pwtpd L3PSmxn4Rx3Bn7J01IACVjBUuVPKQxPJRmoPBp174P/r2EDEcW+2jqN6s1qMGFDQHHYg 6r6w== X-Received: by 10.68.228.161 with SMTP id sj1mr25049413pbc.151.1367825091043; Mon, 06 May 2013 00:24:51 -0700 (PDT) Received: from localhost.localdomain ([117.212.48.250]) by mx.google.com with ESMTPSA id c5sm22780815pbl.37.2013.05.06.00.24.46 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 06 May 2013 00:24:50 -0700 (PDT) From: Jassi Brar To: s-anna@ti.com, loic.pallardy@st.com Subject: [PATCHv2 2/4] mailbox: Introduce a new common API Date: Mon, 6 May 2013 12:54:06 +0530 Message-Id: <1367825046-6229-1-git-send-email-jaswinder.singh@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1367824946-6160-1-git-send-email-jaswinder.singh@linaro.org> References: <1367824946-6160-1-git-send-email-jaswinder.singh@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130506_032513_208377_3836C466 X-CRM114-Status: GOOD ( 27.42 ) X-Spam-Score: -2.0 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jassisinghbrar[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature Cc: linux-arm-kernel@lists.infradead.org, Jassi Brar , linux-kernel@vger.kernel.org, arnd@arndb.de X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Introduce common framework for client/protocol drivers and controller drivers of Inter-Processor-Communication (IPC). Client driver developers should have a look at include/linux/mailbox_client.h to understand the part of the API exposed to client drivers. Similarly controller driver developers should have a look at include/linux/mailbox_controller.h Signed-off-by: Jassi Brar --- drivers/mailbox/Makefile | 4 + drivers/mailbox/mailbox.c | 494 ++++++++++++++++++++++++++++++++++++ include/linux/mailbox.h | 17 ++ include/linux/mailbox_client.h | 85 +++++++ include/linux/mailbox_controller.h | 102 ++++++++ 5 files changed, 702 insertions(+) create mode 100644 drivers/mailbox/mailbox.c create mode 100644 include/linux/mailbox.h create mode 100644 include/linux/mailbox_client.h create mode 100644 include/linux/mailbox_controller.h diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index 543ad6a..fefef7e 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -1 +1,5 @@ +# Generic MAILBOX API + +obj-$(CONFIG_MAILBOX) += mailbox.o + obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c new file mode 100644 index 0000000..a93c22f --- /dev/null +++ b/drivers/mailbox/mailbox.c @@ -0,0 +1,494 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * The length of circular buffer for queuing messages from a client. + * 'msg_count' tracks the number of buffered messages while 'msg_free' + * is the index where the next message would be buffered. + * We shouldn't need it too big because every transferr is interrupt + * triggered and if we have lots of data to transfer, the interrupt + * latencies are going to be the bottleneck, not the buffer length. + * Besides, ipc_send_message could be called from atomic context and + * the client could also queue another message from the notifier 'txcb' + * of the last transfer done. + */ +#define MBOX_TX_QUEUE_LEN 10 + +#define TXDONE_BY_IRQ (1 << 0) /* controller has remote RTR irq */ +#define TXDONE_BY_POLL (1 << 1) /* controller can read status of last TX */ +#define TXDONE_BY_ACK (1 << 2) /* S/W ACK recevied by Client ticks the TX */ + +struct ipc_chan { + char chan_name[32]; /* controller_name:link_name */ + unsigned txdone_method; + + /* Cached values from controller */ + struct ipc_link *link; + struct ipc_link_ops *link_ops; + + /* Cached values from client */ + void (*rxcb)(void *data); + void (*txcb)(request_token_t t, enum xfer_result r); + bool tx_block; + unsigned long tx_tout; + struct completion tx_complete; + + request_token_t active_token; + unsigned msg_count, msg_free; + void *msg_data[MBOX_TX_QUEUE_LEN]; + /* Timer shared by all links of a controller */ + struct tx_poll_timer *timer; + bool assigned; + /* Serialize access to the channel */ + spinlock_t lock; + /* Hook to add to the global list of channels */ + struct list_head node; + /* Notifier to all clients waiting on aquiring this channel */ + struct blocking_notifier_head avail; +}; + +/* + * If the controller supports only TXDONE_BY_POLL, this + * timer polls all the links for txdone. + */ +struct tx_poll_timer { + struct timer_list poll; + unsigned period; +}; + +static LIST_HEAD(ipc_channels); +static DEFINE_MUTEX(chpool_mutex); + +static request_token_t _add_to_rbuf(struct ipc_chan *chan, void *data) +{ + request_token_t 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 0; + } + + idx = chan->msg_free; + chan->msg_data[idx] = data; + 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 + 1; +} + +static void _msg_submit(struct ipc_chan *chan) +{ + struct ipc_link *link = chan->link; + unsigned count, idx; + unsigned long flags; + void *data; + int err; + + spin_lock_irqsave(&chan->lock, flags); + + if (!chan->msg_count || chan->active_token) { + spin_unlock_irqrestore(&chan->lock, flags); + return; + } + + 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]; + + /* Try to submit a message to the IPC controller */ + err = chan->link_ops->send_data(link, data); + if (!err) { + chan->active_token = idx + 1; + chan->msg_count--; + } + + spin_unlock_irqrestore(&chan->lock, flags); +} + +static void tx_tick(struct ipc_chan *chan, enum xfer_result r) +{ + unsigned long flags; + request_token_t t; + + spin_lock_irqsave(&chan->lock, flags); + t = chan->active_token; + chan->active_token = 0; + spin_unlock_irqrestore(&chan->lock, flags); + + /* Submit next message */ + _msg_submit(chan); + + /* Notify the client */ + if (chan->tx_block) + complete(&chan->tx_complete); + else if (t && chan->txcb) + chan->txcb(t, r); +} + +static void poll_txdone(unsigned long data) +{ + struct tx_poll_timer *timer = (struct tx_poll_timer *)data; + bool txdone, resched = false; + struct ipc_chan *chan; + + list_for_each_entry(chan, &ipc_channels, node) { + if (chan->timer == timer + && chan->active_token && chan->assigned) { + resched = true; + txdone = chan->link_ops->last_tx_done(chan->link); + if (txdone) + tx_tick(chan, XFER_OK); + } + } + + if (resched) + mod_timer(&timer->poll, + jiffies + msecs_to_jiffies(timer->period)); +} + +/* + * After 'startup' and before 'shutdown', the IPC controller driver + * notifies the API of data received over the link. + * The controller driver should make sure the 'RTR' is de-asserted since + * reception of the packet and until after this call returns. + * This call could be made from atomic context. + */ +void ipc_link_received_data(struct ipc_link *link, void *data) +{ + struct ipc_chan *chan = (struct ipc_chan *)link->api_priv; + + /* No buffering the received data */ + if (chan->rxcb) + chan->rxcb(data); +} +EXPORT_SYMBOL(ipc_link_received_data); + +/* + * The IPC controller driver notifies the API that the remote has + * asserted RTR and it could now send another message on the link. + */ +void ipc_link_txdone(struct ipc_link *link, enum xfer_result r) +{ + struct ipc_chan *chan = (struct ipc_chan *)link->api_priv; + + if (unlikely(!(chan->txdone_method & TXDONE_BY_IRQ))) { + pr_err("Controller can't run the TX ticker\n"); + return; + } + + tx_tick(chan, r); +} +EXPORT_SYMBOL(ipc_link_txdone); + +/* + * 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 doesn't get IRQ for TX done. + */ +void ipc_client_txdone(void *channel, enum xfer_result r) +{ + struct ipc_chan *chan = (struct ipc_chan *)channel; + bool txdone = true; + + if (unlikely(!(chan->txdone_method & TXDONE_BY_ACK))) { + pr_err("Client can't run the TX ticker\n"); + return; + } + + if (chan->txdone_method & TXDONE_BY_POLL) + txdone = chan->link_ops->last_tx_done(chan->link); + + if (txdone) + tx_tick(chan, r); +} +EXPORT_SYMBOL(ipc_client_txdone); + +/* + * Called by a client to "put data on the h/w channel" so that if + * everything else is fine we don't need to do anything more locally + * for the remote to receive the data intact. + * In reality, the remote may receive it intact, corrupted or not at all. + * This could be called from atomic context as it simply + * queues the data and returns a token (request_token_t) + * against the request. + * The client is later notified of successful transmission of + * data over the channel via the 'txcb'. The client could in + * turn queue more messages from txcb. + */ +request_token_t ipc_send_message(void *channel, void *data) +{ + struct ipc_chan *chan = (struct ipc_chan *)channel; + request_token_t t; + + if (!chan || !chan->assigned) + return 0; + + t = _add_to_rbuf(chan, data); + if (!t) + pr_err("Try increasing MBOX_TX_QUEUE_LEN\n"); + + _msg_submit(chan); + + if (chan->txdone_method == TXDONE_BY_POLL) + poll_txdone((unsigned long)chan->timer); + + if (chan->tx_block && chan->active_token) { + int ret; + init_completion(&chan->tx_complete); + ret = wait_for_completion_timeout(&chan->tx_complete, + chan->tx_tout); + if (ret == 0) { + t = 0; + tx_tick(chan, XFER_ERR); + } + } + + return t; +} +EXPORT_SYMBOL(ipc_send_message); + +/* + * A client driver asks for exclusive use of a channel/mailbox. + * If assigned, the channel has to be 'freed' before it could + * be assigned to some other client. + * After assignment, any packet received on this channel will be + * handed over to the client via the 'rxcb' callback. + * The 'txcb' callback is used to notify client upon sending the + * packet over the channel, which may or may not have been yet + * read by the remote processor. + */ +void *ipc_request_channel(struct ipc_client *cl) +{ + struct ipc_chan *chan; + unsigned long flags; + int ret = 0; + + mutex_lock(&chpool_mutex); + + list_for_each_entry(chan, &ipc_channels, node) + if (!chan->assigned + && !strcmp(cl->chan_name, chan->chan_name)) { + spin_lock_irqsave(&chan->lock, flags); + chan->msg_free = 0; + chan->msg_count = 0; + chan->active_token = 0; + chan->rxcb = cl->rxcb; + chan->txcb = cl->txcb; + chan->assigned = true; + chan->tx_block = cl->tx_block; + if (!cl->tx_tout) + chan->tx_tout = ~0; + else + chan->tx_tout = msecs_to_jiffies(cl->tx_tout); + if (chan->txdone_method == TXDONE_BY_POLL + && cl->knows_txdone) + chan->txdone_method |= TXDONE_BY_ACK; + spin_unlock_irqrestore(&chan->lock, flags); + ret = 1; + break; + } + + mutex_unlock(&chpool_mutex); + + if (!ret) { + pr_err("Unable to assign mailbox(%s)\n", cl->chan_name); + return NULL; + } + + ret = chan->link_ops->startup(chan->link, cl->cntlr_data); + if (ret) { + pr_err("Unable to startup the link\n"); + ipc_free_channel((void *)chan); + return NULL; + } + + return (void *)chan; +} +EXPORT_SYMBOL(ipc_request_channel); + +/* Drop any messages queued and release the channel */ +void ipc_free_channel(void *ch) +{ + struct ipc_chan *chan = (struct ipc_chan *)ch; + unsigned long flags; + + if (!chan || !chan->assigned) + return; + + chan->link_ops->shutdown(chan->link); + + /* The queued TX requests are simply aborted, no callbacks are made */ + spin_lock_irqsave(&chan->lock, flags); + chan->assigned = false; + chan->active_token = 0; + if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK)) + chan->txdone_method = TXDONE_BY_POLL; + spin_unlock_irqrestore(&chan->lock, flags); + + del_timer_sync(chan->timer); + + blocking_notifier_call_chain(&chan->avail, 0, NULL); +} +EXPORT_SYMBOL(ipc_free_channel); + +static struct ipc_chan *name_to_chan(const char *name) +{ + struct ipc_chan *chan; + int ret = 0; + + mutex_lock(&chpool_mutex); + list_for_each_entry(chan, &ipc_channels, node) + if (!strcmp(name, chan->chan_name)) { + ret = 1; + break; + } + mutex_unlock(&chpool_mutex); + + if (!ret) + return NULL; + + return chan; +} + +int ipc_notify_chan_register(const char *name, struct notifier_block *nb) +{ + struct ipc_chan *chan = name_to_chan(name); + + if (chan && nb) + return blocking_notifier_chain_register(&chan->avail, nb); + + return -EINVAL; +} +EXPORT_SYMBOL(ipc_notify_chan_register); + +void ipc_notify_chan_unregister(const char *name, struct notifier_block *nb) +{ + struct ipc_chan *chan = name_to_chan(name); + + if (chan && nb) + blocking_notifier_chain_unregister(&chan->avail, nb); +} +EXPORT_SYMBOL(ipc_notify_chan_unregister); + +/* + * Call for IPC controller drivers to register a controller, adding + * its channels/mailboxes to the global pool. + */ +int ipc_links_register(struct ipc_controller *ipc_con) +{ + struct tx_poll_timer *timer = NULL; + struct ipc_chan *channel; + int i, num_links, txdone; + + /* Are you f***ing with us, sir? */ + if (!ipc_con || !ipc_con->ops) + return -EINVAL; + + for (i = 0; ipc_con->links[i]; i++) + ; + if (!i) + return -EINVAL; + num_links = i; + + if (ipc_con->txdone_irq) + txdone = TXDONE_BY_IRQ; + else if (ipc_con->txdone_poll) + txdone = TXDONE_BY_POLL; + else /* It has to be at least ACK */ + txdone = TXDONE_BY_ACK; + + if (txdone == TXDONE_BY_POLL) { + timer = kzalloc(sizeof(struct tx_poll_timer), GFP_KERNEL); + if (!timer) + return -ENOMEM; + timer->period = ipc_con->txpoll_period; + timer->poll.function = &poll_txdone; + timer->poll.data = (unsigned long)timer; + init_timer(&timer->poll); + } + + channel = kzalloc(sizeof(struct ipc_chan) * num_links, GFP_KERNEL); + if (!channel) { + kfree(timer); + return -ENOMEM; + } + + for (i = 0; i < num_links; i++) { + channel[i].timer = timer; + channel[i].assigned = false; + channel[i].txdone_method = txdone; + channel[i].link_ops = ipc_con->ops; + channel[i].link = ipc_con->links[i]; + channel[i].link->api_priv = &channel[i]; + snprintf(channel[i].chan_name, 32, "%s:%s", + ipc_con->controller_name, + ipc_con->links[i]->link_name); + spin_lock_init(&channel[i].lock); + BLOCKING_INIT_NOTIFIER_HEAD(&channel[i].avail); + mutex_lock(&chpool_mutex); + list_add_tail(&channel[i].node, &ipc_channels); + mutex_unlock(&chpool_mutex); + } + + return 0; +} +EXPORT_SYMBOL(ipc_links_register); + +void ipc_links_unregister(struct ipc_controller *ipc_con) +{ + struct ipc_chan *chan, *t, *first = NULL; + struct tx_poll_timer *timer = NULL; + char *name; + int i; + + mutex_lock(&chpool_mutex); + for (i = 0; ipc_con->links[i]; i++) { + snprintf(name, 32, "%s:%s", + ipc_con->controller_name, + ipc_con->links[i]->link_name); + list_for_each_entry_safe(chan, t, &ipc_channels, node) { + if (!strcmp(name, chan->chan_name)) { + if (!first) + first = chan; + if (!timer) + timer = chan->timer; + list_del(&chan->node); + ipc_free_channel((void *)chan); + break; + } + } + } + mutex_unlock(&chpool_mutex); + + kfree(first); + kfree(timer); +} +EXPORT_SYMBOL(ipc_links_unregister); diff --git a/include/linux/mailbox.h b/include/linux/mailbox.h new file mode 100644 index 0000000..232e2c4 --- /dev/null +++ b/include/linux/mailbox.h @@ -0,0 +1,17 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __MAILBOX_H +#define __MAILBOX_H + +enum xfer_result { + XFER_OK = 0, + XFER_ERR, +}; + +typedef unsigned request_token_t; + +#endif /* __MAILBOX_H */ diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h new file mode 100644 index 0000000..232fdc7 --- /dev/null +++ b/include/linux/mailbox_client.h @@ -0,0 +1,85 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __MAILBOX_CLIENT_H +#define __MAILBOX_CLIENT_H + +#include + +/** + * struct ipc_client - User of a mailbox + * @chan_name: the "controller:channel" this client wants + * @rxcb: atomic callback to provide client the data received + * @txcb: atomic callback to tell client of data transmission + * @tx_block: if the ipc_send_message should block until data is transmitted + * @tx_tout: Max block period in ms before TX is assumed failure + * @knows_txdone: if the client could run the TX state machine. Usually if + * the client receives some ACK packet for transmission. Unused if the + * controller already has TX_Done/RTR IRQ. + * @cntlr_data: Optional controller specific parameters during channel request + */ +struct ipc_client { + char *chan_name; + void (*rxcb)(void *data); + void (*txcb)(request_token_t t, enum xfer_result r); + bool tx_block; + unsigned long tx_tout; + bool knows_txdone; + void *cntlr_data; +}; + +/** + * The Client specifies it requirements and capabilities while asking for + * a channel/mailbox by name. 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 ipc_free_channel. + */ +void *ipc_request_channel(struct ipc_client *cl); + +/** + * 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-zero token is returned for each queued request. If the queue + * was full the returned token will be 0. Upon failure or successful + * TX, the API calls 'txcb' from atomic context, from which the client + * could submit yet another request. + * In blocking mode, 'txcb' is not called, effectively making the + * queue length 1. The returned value is 0 if TX timed out, some + * non-zero value upon success. + */ +request_token_t ipc_send_message(void *channel, void *data); + +/** + * The way for a client to run the TX state machine. This works + * only if the client sets 'knows_txdone' and the IPC controller + * don't get an IRQ for TX_Done. + */ +void ipc_client_txdone(void *channel, enum xfer_result r); + +/** + * The client relinquishes control of a mailbox by this call, + * make it available to other clients. + * The ipc_request/free_channel are light weight calls, so the + * client should avoid holding it when it doesn't need to + * transfer data. + */ +void ipc_free_channel(void *ch); + +/** + * The client make ask the API to be notified when a particular channel + * becomes available to be acquired again. + */ +int ipc_notify_chan_register(const char *name, struct notifier_block *nb); + +/** + * The client is no more interested in acquiring the channel. + */ +void ipc_notify_chan_unregister(const char *name, struct notifier_block *nb); + +#endif /* __MAILBOX_CLIENT_H */ diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h new file mode 100644 index 0000000..23b80e3 --- /dev/null +++ b/include/linux/mailbox_controller.h @@ -0,0 +1,102 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __MAILBOX_CONTROLLER_H +#define __MAILBOX_CONTROLLER_H + +#include + +/** + * struct ipc_link - s/w representation of a communication link + * @link_name: Literal name assigned to the link. Physically + * identical channels may have the same name. + * @api_priv: hook for the API to map its private data on the link + * Controller driver must not touch it. + */ +struct ipc_link { + char link_name[16]; + void *api_priv; +}; + +/** + * struct ipc_link - s/w representation of a communication link + * @send_data: The API asks the IPC controller driver, in atomic + * context try to transmit a message on the bus. Returns 0 if + * data is accepted for transmission, -EBUSY while rejecting + * if the remote hasn't yet read the last data sent. Actual + * transmission of data is reported by the controller via + * ipc_link_txdone (if it has some TX ACK irq). It must not + * block. + * @startup: Called when a client requests the link. The controller + * could ask clients for additional parameters of communication + * to be provided via client's cntlr_data. This call may block. + * After this call the Controller must forward any data received + * on the link by calling ipc_link_received_data (which won't block) + * @shutdown: Called when a client relinquishes control of a link. + * This call may block too. The controller must not forwared + * any received data anymore. + * @last_tx_done: If the controller sets 'txdone_poll', the API calls + * this to poll status of last TX. The controller must give priority + * to IRQ method over polling and never set both txdone_poll and + * txdone_irq. Only in polling mode 'send_data' is expected to + * return -EBUSY. Used only if txdone_poll:=true && txdone_irq:=false + */ +struct ipc_link_ops { + int (*send_data)(struct ipc_link *link, void *data); + int (*startup)(struct ipc_link *link, void *params); + void (*shutdown)(struct ipc_link *link); + bool (*last_tx_done)(struct ipc_link *link); +}; + +/** + * struct ipc_controller - Controller of a class of communication links + * @controller_name: Literal name of the controller. + * @ops: Operators that work on each communication link + * @links: Null terminated array of links. + * @txdone_irq: Indicates if the controller can report to API when the + * last transmitted data was read by the remote. Eg, if it has some + * TX ACK irq. + * @txdone_poll: If the controller can read but not report the TX done. + * Eg, is some register shows the TX status but no interrupt rises. + * Ignored if 'txdone_irq' is set. + * @txpoll_period: If 'txdone_poll' is in effect, the API polls for + * last TX's status after these many millisecs + */ +struct ipc_controller { + char controller_name[16]; + struct ipc_link_ops *ops; + struct ipc_link **links; + bool txdone_irq; + bool txdone_poll; + unsigned txpoll_period; +}; + +/** + * The controller driver registers its communication links to the + * global pool managed by the API. + */ +int ipc_links_register(struct ipc_controller *ipc_con); + +/** + * After startup and before shutdown any data received on the link + * is pused to the API via atomic ipc_link_received_data() API. + * The controller should ACK the RX only after this call returns. + */ +void ipc_link_received_data(struct ipc_link *link, void *data); + +/** + * The controller the 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 ipc_link_txdone(struct ipc_link *link, enum xfer_result r); + +/** + * Purge the links from the global pool maintained by the API. + */ +void ipc_links_unregister(struct ipc_controller *ipc_con); + +#endif /* __MAILBOX_CONTROLLER_H */