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 <[email protected]>
---
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)
+{
+ 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);
--
2.25.1
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 <[email protected]>
> ---
> 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);
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 <[email protected]>
>> ---
>> 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 <[email protected]>
>>> ---
>>> 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