Messages in this thread | | | Date | Tue, 1 Nov 2022 10:44:59 -0700 | Subject | Re: [PATCH v6 09/21] mailbox: Add Gunyah message queue mailbox | From | Elliot Berman <> |
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On 10/27/2022 6:55 AM, Pavan Kondeti wrote: > Hi Elliot, > > On Wed, Oct 26, 2022 at 11:58:34AM -0700, Elliot Berman wrote: >> Gunyah message queues are a unidirectional inter-VM pipe for messages up >> to 1024 bytes. This driver supports pairing a receiver message queue and >> a transmitter message queue to expose a single mailbox channel. >> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> > > <snip> > >> +static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data) >> +{ >> + struct gh_msgq *msgq = data; >> + >> + mbox_chan_txdone(gh_msgq_chan(msgq), 0); >> + >> + return IRQ_HANDLED; >> +} >> + >> +static void gh_msgq_txdone_tasklet(unsigned long data) >> +{ >> + struct gh_msgq *msgq = (struct gh_msgq *)data; >> + >> + mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_status); >> +} >> + >> +static int gh_msgq_send_data(struct mbox_chan *chan, void *data) >> +{ >> + struct gh_msgq *msgq = mbox_chan_to_msgq(chan); >> + struct gh_msgq_tx_data *msgq_data = data; >> + u64 tx_flags = 0; >> + unsigned long ret; >> + bool ready; >> + >> + if (msgq_data->push) >> + tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH; >> + >> + ret = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, msgq_data->length, >> + (uintptr_t)msgq_data->data, tx_flags, &ready); >> + >> + /** >> + * unlikely because Linux tracks state of msgq and should not try to >> + * send message when msgq is full. >> + */ >> + if (unlikely(ret == GH_ERROR_MSGQUEUE_FULL)) >> + return -EAGAIN; >> + >> + /** >> + * Propagate all other errors to client. If we return error to mailbox >> + * framework, then no other messages can be sent and nobody will know >> + * to retry this message. >> + */ >> + msgq->last_status = gh_remap_error(ret); >> + >> + /** >> + * This message was successfully sent, but message queue isn't ready to >> + * receive more messages because it's now full. Mailbox framework >> + * requires that we only report that message was transmitted only when >> + * we're ready to transmit another message. We'll get that in the form >> + * of tx IRQ once the other side starts to drain the msgq. >> + */ >> + if (ret == GH_ERROR_OK && !ready) >> + return 0; >> + >> + /** >> + * We can send more messages. Mailbox framework requires that tx done >> + * happens asynchronously to sending the message. Gunyah message queues >> + * tell us right away on the hypercall return whether we can send more >> + * messages. To work around this, defer the txdone to a tasklet. >> + */ >> + tasklet_schedule(&msgq->txdone_tasklet); >> + > > Nice comments. > > irq_work would be a better choice. > >> + return 0; >> +} >> + >> +struct mbox_chan_ops gh_msgq_ops = { >> + .send_data = gh_msgq_send_data, >> +}; >> + >> +/** >> + * gh_msgq_init() - Initialize a Gunyah message queue with an mbox_client >> + * @parent: optional, device parent used for the mailbox controller >> + * @msgq: Pointer to the gh_msgq to initialize >> + * @cl: A mailbox client to bind to the mailbox channel that the message queue creates >> + * @tx_ghrsc: optional, the transmission side of the message queue >> + * @rx_ghrsc: optional, the receiving side of the message queue >> + * >> + * At least one of tx_ghrsc and rx_ghrsc should be not NULL. Most message queue use cases come with >> + * a pair of message queues to facilitiate bidirectional communication. When tx_ghrsc is set, >> + * the client can send messages with mbox_send_message(gh_msgq_chan(msgq), msg). When rx_ghrsc >> + * is set, the mbox_client should register an .rx_callback() and the message queue driver will >> + * push all available messages upon receiving the RX ready interrupt. The messages should be >> + * consumed or copied by the client right away as the gh_msgq_rx_data will be replaced/destroyed >> + * after the callback. >> + * >> + * Returns - 0 on success, negative otherwise >> + */ >> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl, >> + struct gunyah_resource *tx_ghrsc, struct gunyah_resource *rx_ghrsc) >> +{ >> + int ret; >> + >> + /* Must have at least a tx_ghrsc or rx_ghrsc and that they are the right device types */ >> + if ((!tx_ghrsc && !rx_ghrsc) || >> + (tx_ghrsc && tx_ghrsc->type != GUNYAH_RESOURCE_TYPE_MSGQ_TX) || >> + (rx_ghrsc && rx_ghrsc->type != GUNYAH_RESOURCE_TYPE_MSGQ_RX)) >> + return -EINVAL; >> + >> + msgq->tx_ghrsc = tx_ghrsc; >> + msgq->rx_ghrsc = rx_ghrsc; >> + >> + msgq->mbox.dev = parent; >> + msgq->mbox.ops = &gh_msgq_ops; >> + msgq->mbox.chans = kcalloc(1, sizeof(*msgq->mbox.chans), GFP_KERNEL); > > Error handling missing. > > minor nit pick: > > If you initialize num_chans to 1 before, then you can use that as the first > argument to kcalloc() which makes it more readable since you opted for kcalloc() > instead of kzalloc() there. > >> + msgq->mbox.num_chans = 1; >> + msgq->mbox.txdone_irq = true; >> + >> + if (gh_msgq_has_tx(msgq)) { >> + ret = request_irq(msgq->tx_ghrsc->irq, gh_msgq_tx_irq_handler, 0, "gh_msgq_tx", >> + msgq); >> + if (ret) >> + goto err_chans; >> + } >> + >> + if (gh_msgq_has_rx(msgq)) { >> + ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL, gh_msgq_rx_irq_handler, >> + IRQF_ONESHOT, "gh_msgq_rx", msgq); >> + if (ret) >> + goto err_tx_irq; >> + } >> + >> + tasklet_init(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet, (unsigned long)msgq); > > If you wish to use tasklets, use tasklet_setup(). > >> + >> + ret = mbox_controller_register(&msgq->mbox); >> + if (ret) >> + goto err_rx_irq; >> + >> + ret = mbox_bind_client(gh_msgq_chan(msgq), cl); >> + if (ret) >> + goto err_mbox; >> + >> + return 0; >> +err_mbox: >> + mbox_controller_unregister(&msgq->mbox); >> +err_rx_irq: >> + if (gh_msgq_has_rx(msgq)) >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> +err_tx_irq: >> + if (gh_msgq_has_tx(msgq)) >> + free_irq(msgq->tx_ghrsc->irq, msgq); >> +err_chans: >> + kfree(msgq->mbox.chans); >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(gh_msgq_init); >> + >> +void gh_msgq_remove(struct gh_msgq *msgq) >> +{ >> + if (gh_msgq_has_rx(msgq)) >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> + >> + if (gh_msgq_has_tx(msgq)) >> + free_irq(msgq->tx_ghrsc->irq, msgq); >> + >> + kfree(msgq->mbox.chans); >> +} >> +EXPORT_SYMBOL_GPL(gh_msgq_remove); >> + > > Is gh_msgq_remove() supposed to undo every thing done in gh_msgq_init()? > ex: mbox controller and channel are not unregistered. >
Ah thanks for catching, updated this as well as rest of your comments.
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