| Message ID | 20221219225850.2397345-8-quic_eberman@quicinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Drivers for gunyah hypervisor | expand |
On 1/9/2023 1:34 PM, Alex Elder wrote: > 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? Both of the current drivers that use mbox_bind_client use TXDONE_BY_IRQ, so this doesn't cause issue for checking whether the client has txdone_method. > > 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. The function for this is "mbox_free_channel". Thanks, Elliot
On 1/10/23 11:57 AM, Elliot Berman wrote: > > > On 1/9/2023 1:34 PM, Alex Elder wrote: >> 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? Sorry, reading that now, I see I placed an "if" in the wrong spot. > Both of the current drivers that use mbox_bind_client use TXDONE_BY_IRQ, > so this doesn't cause issue for checking whether the client has > txdone_method. I'm not so sure, but it's on you to make sure you don't break anything... I see only two spots where TXDONE_BY_IRQ is set, and TXDONE_BY_IRQ seems to be set when channels are freed. I spent (too much) time trying to track this back but I'm giving up. If you're sure it's correct, I accept that... >> >> 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. > n > The function for this is "mbox_free_channel". My point is about the way you are abstracting the "bind" operation as a (now encapsulated) part of requesting the channel. Yes, when mbox_free_channel() is called, it effectively "unbinds" the channel. But you're creating a "bind" abstraction, where it's not explicit that you're requesting the channel. I'm suggesting you also create an "unbind" operation to reverse that. This is more important for the mbox_bind_client() call than mbox_request_channel(). (And by the way, it looks like pcc_mbox_free_channel() doesn't call pcc_mbox_free_channel() as it should, but this unfamiliar code...) And... it's weird to me that gh_rm_drv_probe() calls gh_msgq_init() (to initialize the Gunhah message queue code), but then has to call mbox_free_channel() *separate* from gh_msgq_remove(); the free channel (or better, unbind client) should happen in the message queue code. It's not a critically important point, but now at least I hope you understand what I'm trying to say. -Alex > > Thanks, > Elliot
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) +{ + 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);
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. 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(-)