Messages in this thread | | | Date | Mon, 9 Jan 2023 15:34:33 -0600 | Subject | Re: [PATCH v8 07/28] mailbox: Allow direct registration to a channel | From | Alex Elder <> |
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On 12/19/22 4:58 PM, Elliot Berman wrote: > Support virtual mailbox controllers and clients which are not platform > devices or come from the devicetree by allowing them to match client to > channel via some other mechanism.
The new function behaves very much like mbox_request_channel() did before.
The new function differs from omap_mbox_request_channel() in that it can change the if chan->txdone_method is TXDONE_BY_POLL, it is changed to TXDONE_BY_ACK if the client's knows_txdone field is set. Is this OK? Why?
It also assumes chan->mbox->ops->startup us non-null (though that isn't really a problem).
> > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> > --- > drivers/mailbox/mailbox.c | 96 ++++++++++++++++++++++++---------- > drivers/mailbox/omap-mailbox.c | 18 ++----- > drivers/mailbox/pcc.c | 18 ++----- > include/linux/mailbox_client.h | 1 + > 4 files changed, 76 insertions(+), 57 deletions(-) > > diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c > index 4229b9b5da98..adf36c05fa43 100644 > --- a/drivers/mailbox/mailbox.c > +++ b/drivers/mailbox/mailbox.c > @@ -317,6 +317,71 @@ int mbox_flush(struct mbox_chan *chan, unsigned long timeout) > } > EXPORT_SYMBOL_GPL(mbox_flush); > > +static int __mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
There should be an unbind_client() call. At a minimum, you are calling try_module_get(), and the matching module_put() call would belong there. And even though one might just call module_put() elsewhere for this, it would be cleaner to have a function that similarly encapsulates the shutdown call as well.
-Alex
> +{ > + struct device *dev = cl->dev; > + unsigned long flags; > + int ret; > + > + if (chan->cl || !try_module_get(chan->mbox->dev->driver->owner)) { > + dev_dbg(dev, "%s: mailbox not free\n", __func__); > + return -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); > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * mbox_bind_client - Request a mailbox channel. > + * @chan: The mailbox channel to bind the client to. > + * @cl: Identity of the client requesting the channel. > + * > + * 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: 0 if the channel was assigned to the client successfully. > + * <0 for request failure. > + */ > +int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl) > +{ > + int ret; > + > + mutex_lock(&con_mutex); > + ret = __mbox_bind_client(chan, cl); > + mutex_unlock(&con_mutex); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(mbox_bind_client); > + > /** > * mbox_request_channel - Request a mailbox channel. > * @cl: Identity of the client requesting the channel. > @@ -340,7 +405,6 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) > struct mbox_controller *mbox; > struct of_phandle_args spec; > struct mbox_chan *chan; > - unsigned long flags; > int ret; > > if (!dev || !dev->of_node) { > @@ -372,33 +436,9 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index) > 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); > - } > - } > + ret = __mbox_bind_client(chan, cl); > + if (ret) > + chan = ERR_PTR(ret); > > mutex_unlock(&con_mutex); > return chan; > diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c > index 098c82d87137..711a56ec8592 100644 > --- a/drivers/mailbox/omap-mailbox.c > +++ b/drivers/mailbox/omap-mailbox.c > @@ -441,21 +441,9 @@ struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl, > if (!mbox || !mbox->chan) > return ERR_PTR(-ENOENT); > > - chan = mbox->chan; > - 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); > - spin_unlock_irqrestore(&chan->lock, flags); > - > - ret = chan->mbox->ops->startup(chan); > - if (ret) { > - pr_err("Unable to startup the chan (%d)\n", ret); > - mbox_free_channel(chan); > - chan = ERR_PTR(ret); > - } > + ret = mbox_bind_client(mbox->chan, cl); > + if (ret) > + return ERR_PTR(ret); > > return chan; > } > diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c > index 3c2bc0ca454c..f655be083369 100644 > --- a/drivers/mailbox/pcc.c > +++ b/drivers/mailbox/pcc.c > @@ -283,7 +283,7 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) > struct pcc_chan_info *pchan; > struct mbox_chan *chan; > struct device *dev; > - unsigned long flags; > + int rc; > > if (subspace_id < 0 || subspace_id >= pcc_chan_count) > return ERR_PTR(-ENOENT); > @@ -296,21 +296,11 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) > } > dev = chan->mbox->dev; > > - 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); > + rc = mbox_bind_client(chan, cl); > + if (rc) > + return ERR_PTR(rc); > > if (pchan->plat_irq > 0) { > - int rc; > - > rc = devm_request_irq(dev, pchan->plat_irq, pcc_mbox_irq, 0, > MBOX_IRQ_NAME, chan); > if (unlikely(rc)) { > diff --git a/include/linux/mailbox_client.h b/include/linux/mailbox_client.h > index 65229a45590f..734694912ef7 100644 > --- a/include/linux/mailbox_client.h > +++ b/include/linux/mailbox_client.h > @@ -37,6 +37,7 @@ struct mbox_client { > void (*tx_done)(struct mbox_client *cl, void *mssg, int r); > }; > > +int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl); > struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl, > const char *name); > struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index);
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