Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 3 Apr 2023 13:15:42 -0700 | Subject | Re: [PATCH v11 07/26] mailbox: Add Gunyah message queue mailbox | From | Elliot Berman <> |
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On 3/31/2023 7:25 AM, Alex Elder wrote: > On 3/3/23 7:06 PM, 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. > > I think it's good to reuse existing frameworks, for example, using > the mailbox abstraction to implement your messaging code. But I > find there are some minor mismatches between what you need and > the way the mailbox code works. > > I'm not really suggesting you change anything, but I'll just say > it seemed like there were a few spots you needed to do things > that were slightly awkward in order to satisfy mailbox requirements. > > I'll point out in a few comments what I mean below. > > I'll take one more look at it again next time, but I assume this > works and I have no other new comments today. > > -Alex > >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> >> --- >> Documentation/virt/gunyah/message-queue.rst | 8 + >> drivers/mailbox/Makefile | 2 + >> drivers/mailbox/gunyah-msgq.c | 209 ++++++++++++++++++++ >> include/linux/gunyah.h | 57 ++++++ >> 4 files changed, 276 insertions(+) >> create mode 100644 drivers/mailbox/gunyah-msgq.c >> >> diff --git a/Documentation/virt/gunyah/message-queue.rst >> b/Documentation/virt/gunyah/message-queue.rst >> index b352918ae54b..70d82a4ef32d 100644 >> --- a/Documentation/virt/gunyah/message-queue.rst >> +++ b/Documentation/virt/gunyah/message-queue.rst >> @@ -61,3 +61,11 @@ vIRQ: two TX message queues will have two vIRQs >> (and two capability IDs). >> | | | | >> | | >> | | | | >> | | >> +---------------+ +-----------------+ >> +---------------+ >> + >> +Gunyah message queues are exposed as mailboxes. To create the >> mailbox, create >> +a mbox_client and call `gh_msgq_init()`. On receipt of the RX_READY >> interrupt, >> +all messages in the RX message queue are read and pushed via the >> `rx_callback` >> +of the registered mbox_client. >> + >> +.. kernel-doc:: drivers/mailbox/gunyah-msgq.c >> + :identifiers: gh_msgq_init >> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile >> index fc9376117111..5f929bb55e9a 100644 >> --- a/drivers/mailbox/Makefile >> +++ b/drivers/mailbox/Makefile >> @@ -55,6 +55,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o >> obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o >> +obj-$(CONFIG_GUNYAH) += gunyah-msgq.o >> + >> obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o >> obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox.o >> diff --git a/drivers/mailbox/gunyah-msgq.c >> b/drivers/mailbox/gunyah-msgq.c >> new file mode 100644 >> index 000000000000..1989298653f9 >> --- /dev/null >> +++ b/drivers/mailbox/gunyah-msgq.c >> @@ -0,0 +1,209 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All >> rights reserved. >> + */ >> + >> +#include <linux/mailbox_controller.h> >> +#include <linux/module.h> >> +#include <linux/interrupt.h> >> +#include <linux/gunyah.h> >> +#include <linux/printk.h> >> +#include <linux/init.h> >> +#include <linux/slab.h> >> +#include <linux/wait.h> >> + >> +#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct >> gh_msgq, mbox)) >> + >> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data) >> +{ >> + struct gh_msgq *msgq = data; >> + struct gh_msgq_rx_data rx_data; >> + enum gh_error gh_error; >> + bool ready = true; >> + >> + while (ready) { >> + gh_error = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid, >> + &rx_data.data, sizeof(rx_data.data), >> + &rx_data.length, &ready); >> + if (gh_error != GH_ERROR_OK) { >> + if (gh_error != GH_ERROR_MSGQUEUE_EMPTY) >> + dev_warn(msgq->mbox.dev, "Failed to receive data: >> %d\n", gh_error); >> + break; >> + } >> + mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data); >> + } >> + >> + return IRQ_HANDLED; >> +} >> + >> +/* Fired when message queue transitions from "full" to "space >> available" to send messages */ >> +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; >> +} >> + >> +/* Fired after sending message and hypercall told us there was more >> space available. */ >> +static void gh_msgq_txdone_tasklet(struct tasklet_struct *tasklet) >> +{ >> + struct gh_msgq *msgq = container_of(tasklet, struct gh_msgq, >> txdone_tasklet); >> + >> + mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_ret); >> +} >> + >> +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; >> + enum gh_error gh_error; >> + bool ready; >> + >> + if (msgq_data->push) >> + tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH; >> + >> + gh_error = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, >> msgq_data->length, 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(gh_error == 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. > > If you weren't using the mailbox framework, would you be > sending the error to the client in this case? (I'm just > curious; it's good to document the behavior if you were > to return it to the mailbox framework.) > >> + */ >> + msgq->last_ret = gh_remap_error(gh_error); >> + >> + /** >> + * This message was successfully sent, but message queue isn't >> ready to >> + * accept more messages because it's now full. Mailbox framework >> + * requires that we only report that message was transmitted 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. > > So you are forced to delay reporting the completion > here because you're using the mailbox framework. > >> + */ >> + if (gh_error == GH_ERROR_OK) { >> + if (!ready) >> + return 0; >> + } else >> + dev_err(msgq->mbox.dev, "Failed to send data: %d (%d)\n", >> gh_error, msgq->last_ret); >> + >> + /** >> + * 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. >> + */ > > If you weren't using the mailbox framework, you'd send the next > message directly rather than scheduling this tasklet to do it. >
That's correct for this and the other 2 comments above.
>> + tasklet_schedule(&msgq->txdone_tasklet); >> + >> + return 0; >> +} >> + >> +static 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 must be not NULL. Most >> message queue use cases come with >> + * a pair of message queues to facilitate 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 must register an .rx_callback() and the >> message queue driver will >> + * deliver 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 gh_resource *tx_ghrsc, struct gh_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 != GH_RESOURCE_TYPE_MSGQ_TX) || >> + (rx_ghrsc && rx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_RX)) >> + return -EINVAL; >> + >> + if (!gh_api_has_feature(GH_FEATURE_MSGQUEUE)) >> + return -EOPNOTSUPP; >> + >> + msgq->tx_ghrsc = tx_ghrsc; >> + msgq->rx_ghrsc = rx_ghrsc; >> + >> + msgq->mbox.dev = parent; >> + msgq->mbox.ops = &gh_msgq_ops; >> + msgq->mbox.num_chans = 1; >> + msgq->mbox.txdone_irq = true; >> + msgq->mbox.chans = &msgq->mbox_chan; >> + >> + if (msgq->tx_ghrsc) { >> + ret = request_irq(msgq->tx_ghrsc->irq, >> gh_msgq_tx_irq_handler, 0, "gh_msgq_tx", >> + msgq); >> + if (ret) >> + goto err_chans; >> + } >> + >> + if (msgq->rx_ghrsc) { >> + 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_setup(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet); >> + >> + 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 (msgq->rx_ghrsc) >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> +err_tx_irq: >> + if (msgq->tx_ghrsc) >> + 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) >> +{ >> + tasklet_kill(&msgq->txdone_tasklet); >> + mbox_controller_unregister(&msgq->mbox); >> + >> + if (msgq->rx_ghrsc) >> + free_irq(msgq->rx_ghrsc->irq, msgq); >> + >> + if (msgq->tx_ghrsc) >> + free_irq(msgq->tx_ghrsc->irq, msgq); >> + >> + kfree(msgq->mbox.chans); >> +} >> +EXPORT_SYMBOL_GPL(gh_msgq_remove); >> + >> +MODULE_LICENSE("GPL"); >> +MODULE_DESCRIPTION("Gunyah Message Queue Driver"); >> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h >> index 18cfbf5ee48b..378bec0f2ce1 100644 >> --- a/include/linux/gunyah.h >> +++ b/include/linux/gunyah.h >> @@ -8,11 +8,68 @@ >> #include <linux/bitfield.h> >> #include <linux/errno.h> >> +#include <linux/interrupt.h> >> #include <linux/limits.h> >> +#include <linux/mailbox_controller.h> >> +#include <linux/mailbox_client.h> >> #include <linux/types.h> >> +/* Follows resource manager's resource types for VM_GET_HYP_RESOURCES */ > > I'm not sure what you mean by "Follows" here. You mean that these are > the gh_rm_hyp_resource type values that GET_HYP_RESOURCES can return? >
Correct. I will say "Matches ... for VM_GET_HYP_RESOURCES RPC" if it helps make it clearer.
> Note that gh_resource_type values must fit in an 8 bit field. > >> +enum gh_resource_type { >> + GH_RESOURCE_TYPE_BELL_TX = 0, >> + GH_RESOURCE_TYPE_BELL_RX = 1, >> + GH_RESOURCE_TYPE_MSGQ_TX = 2, >> + GH_RESOURCE_TYPE_MSGQ_RX = 3, > > Fix alignment below. > >> + GH_RESOURCE_TYPE_VCPU = 4, >> +}; >> + >> +struct gh_resource { >> + enum gh_resource_type type; >> + u64 capid; >> + unsigned int irq; >> +}; >> + >> +/** >> + * Gunyah Message Queues >> + */ >> + >> +#define GH_MSGQ_MAX_MSG_SIZE 240 > > Maybe insert another tab the before 240. You later define > GH_BELL_NONBLOCK that far out, and aligning them will look > better. > >> + >> +struct gh_msgq_tx_data { >> + size_t length; >> + bool push; >> + char data[]; >> +}; >> + >> +struct gh_msgq_rx_data { >> + size_t length; >> + char data[GH_MSGQ_MAX_MSG_SIZE]; >> +}; >> + >> +struct gh_msgq { >> + struct gh_resource *tx_ghrsc; >> + struct gh_resource *rx_ghrsc; >> + >> + /* msgq private */ >> + int last_ret; /* Linux error, not GH_STATUS_* */ >> + struct mbox_chan mbox_chan; >> + struct mbox_controller mbox; >> + struct tasklet_struct txdone_tasklet; >> +}; >> + >> + >> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct >> mbox_client *cl, >> + struct gh_resource *tx_ghrsc, struct gh_resource >> *rx_ghrsc); >> +void gh_msgq_remove(struct gh_msgq *msgq); >> + >> +static inline struct mbox_chan *gh_msgq_chan(struct gh_msgq *msgq) >> +{ >> + return &msgq->mbox.chans[0]; >> +} >> + >> >> /******************************************************************************/ >> /* Common arch-independent definitions for Gunyah >> hypercalls */ >> + >> #define GH_CAPID_INVAL U64_MAX >> #define GH_VMID_ROOT_VM 0xff >
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