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[73.221.130.71]) by smtp.gmail.com with ESMTPSA id y11-20020a170902700b00b0019ac9c4f32esm5992380plk.309.2023.02.23.10.24.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Feb 2023 10:25:01 -0800 (PST) Message-ID: <18e90758-472e-31b2-65d4-c2504b185d4e@linaro.org> Date: Thu, 23 Feb 2023 12:24:57 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v10 07/26] mailbox: Add Gunyah message queue mailbox Content-Language: en-US To: Elliot Berman , Alex Elder , Srinivas Kandagatla , Prakruthi Deepak Heragu , Jonathan Corbet , Jassi Brar Cc: Murali Nalajala , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Dmitry Baryshkov , Bjorn Andersson , Konrad Dybcio , Arnd Bergmann , Greg Kroah-Hartman , Rob Herring , Krzysztof Kozlowski , Bagas Sanjaya , Catalin Marinas , linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20230214211229.3239350-1-quic_eberman@quicinc.com> <20230214212316.3309053-1-quic_eberman@quicinc.com> From: Alex Elder In-Reply-To: <20230214212316.3309053-1-quic_eberman@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 2/14/23 3:23 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. > > Signed-off-by: Elliot Berman I have a general comment for "include/linux/gunyah.h". You sometimes use "gunyah" in exported names (for example, enum gunyah_resource_type, or struct gunyah_resource). In many cases, though, you use "gh_ or "GH_" (such as in struct gh_msgq, or GH_DBL_NONBLOCK). Is there a reason that you don't pick one and use it everywhere? I think it would be best--certainly for exported symbols like these--to use a single symbol prefix for all cases. Sometimes there might be a reason to distinguish two names (maybe "gunyah_" symbols are truly public, while "gh_" symbols are helpers meant generally to be private). But I don't think that's the case here. It seems that "gh" is your most frequent prefix, so that might be easier to implement. But "gunyah" is more expressive and is only 4 characters wider. -Alex > --- > Documentation/virt/gunyah/message-queue.rst | 8 + > drivers/mailbox/Makefile | 2 + > drivers/mailbox/gunyah-msgq.c | 214 ++++++++++++++++++++ > include/linux/gunyah.h | 56 +++++ > 4 files changed, 280 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 0667b3eb1ff9..082085e981e0 100644 > --- a/Documentation/virt/gunyah/message-queue.rst > +++ b/Documentation/virt/gunyah/message-queue.rst > @@ -59,3 +59,11 @@ 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..03ffaa30ce9b > --- /dev/null > +++ b/drivers/mailbox/gunyah-msgq.c > @@ -0,0 +1,214 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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 err; > + bool ready = true; > + > + while (ready) { > + err = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid, > + (uintptr_t)&rx_data.data, sizeof(rx_data.data), > + &rx_data.length, &ready); > + if (err != GH_ERROR_OK) { > + if (err != GH_ERROR_MSGQUEUE_EMPTY) > + pr_warn("Failed to receive data from msgq for %s: %d\n", > + msgq->mbox.dev ? dev_name(msgq->mbox.dev) : "", err); > + 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, > + (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(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. > + */ > + msgq->last_ret = gh_remap_error(gh_error); > + > + /** > + * 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 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 (gh_error == 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); > + > + 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 should 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 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; > + > + if (gh_api_version() != GUNYAH_API_V1) { > + pr_err("Unrecognized gunyah version: %u. Currently supported: %d\n", > + gh_api_version(), GUNYAH_API_V1); > + return -EOPNOTSUPP; > + } > + > + if (!gh_api_has_feature(GH_API_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 = kcalloc(msgq->mbox.num_chans, sizeof(*msgq->mbox.chans), GFP_KERNEL); > + if (!msgq->mbox.chans) > + return -ENOMEM; > + > + 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) > +{ > + 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 cb6df4eec5c2..2e13669c6363 100644 > --- a/include/linux/gunyah.h > +++ b/include/linux/gunyah.h > @@ -8,11 +8,67 @@ > > #include > #include > +#include > #include > +#include > +#include > #include > > +/* Follows resource manager's resource types for VM_GET_HYP_RESOURCES */ > +enum gunyah_resource_type { > + GUNYAH_RESOURCE_TYPE_BELL_TX = 0, > + GUNYAH_RESOURCE_TYPE_BELL_RX = 1, > + GUNYAH_RESOURCE_TYPE_MSGQ_TX = 2, > + GUNYAH_RESOURCE_TYPE_MSGQ_RX = 3, > + GUNYAH_RESOURCE_TYPE_VCPU = 4, > +}; > + > +struct gunyah_resource { > + enum gunyah_resource_type type; > + u64 capid; > + int irq; > +}; > + > +/** > + * Gunyah Message Queues > + */ > + > +#define GH_MSGQ_MAX_MSG_SIZE 240 > + > +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 gunyah_resource *tx_ghrsc; > + struct gunyah_resource *rx_ghrsc; > + > + /* msgq private */ > + int last_ret; /* Linux error, not GH_STATUS_* */ > + 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 gunyah_resource *tx_ghrsc, struct gunyah_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 >