Messages in this thread | | | Date | Thu, 31 Jul 2014 18:32:45 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCHv9 2/4] mailbox: Introduce framework for mailbox |
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On 22/07/14 19:56, Jassi Brar wrote: > 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 <jaswinder.singh@linaro.org> > --- > MAINTAINERS | 8 + > drivers/mailbox/Makefile | 4 + > drivers/mailbox/mailbox.c | 467 +++++++++++++++++++++++++++++++++++++ > include/linux/mailbox_client.h | 45 ++++ > include/linux/mailbox_controller.h | 131 +++++++++++ > 5 files changed, 655 insertions(+) > create mode 100644 drivers/mailbox/mailbox.c > create mode 100644 include/linux/mailbox_client.h > create mode 100644 include/linux/mailbox_controller.h >
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> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c > new file mode 100644 > index 0000000..99c0d23 > --- /dev/null > +++ b/drivers/mailbox/mailbox.c > @@ -0,0 +1,467 @@ > +/* > + * Mailbox: Common code for Mailbox controllers and users > + * > + * Copyright (C) 2013-2014 Linaro Ltd. > + * Author: Jassi Brar <jassisinghbrar@gmail.com> > + * > + * 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 <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/mailbox_client.h> > +#include <linux/mailbox_controller.h> > + > +#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 */ > + > +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 -ENOMEM; > + } > + > + 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; > + > + spin_lock_irqsave(&chan->lock, flags); > + > + if (!chan->msg_count || chan->active_req) { > + 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 MBOX controller */ > + err = chan->mbox->ops->send_data(chan, data);
Probably this is discussed already, but again I missed to find it in archives, so asking here. If the protocol has some payload associated with the message and controller expects it to be in place before calling send_data, we essentially end up not using this queue at all by waiting in the protocol layer(may be in it's own queue)
Instead can we have some kind of chan->cl->prepare_data callback so that client can prepare payload ? This in turn avoids to implement it's *own Tx queue* and *reusing the mailbox queue*.
Or am I missing something ?
> + if (!err) { > + chan->active_req = data; > + chan->msg_count--; > + } > + > + spin_unlock_irqrestore(&chan->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); > + > + /* Notify the client */ > + if (mssg && chan->cl->tx_done) > + chan->cl->tx_done(chan->cl, mssg, r); > + > + if (chan->cl->tx_block) > + complete(&chan->tx_complete); > +} > + > +static void poll_txdone(unsigned long data) > +{ > + struct mbox_controller *mbox = (struct mbox_controller *)data; > + bool txdone, resched = false; > + int i; > + > + for (i = 0; i < mbox->num_chans; i++) { > + struct mbox_chan *chan = &mbox->chans[i]; > + > + if (chan->active_req && chan->cl) { > + resched = true; > + txdone = chan->mbox->ops->last_tx_done(chan); > + if (txdone) > + tx_tick(chan, 0);
What if all the active channels finished Tx(i.e. txdone = 1), we still have resched = true and add a timer, not really harmful though. But IMO you can move it to else part instead ?
Regards, Sudeep
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