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    Subject[PATCH v7 09/20] mailbox: Add Gunyah message queue mailbox
    Date
    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>
    ---
    Documentation/virt/gunyah/message-queue.rst | 8 +
    MAINTAINERS | 1 +
    drivers/mailbox/Kconfig | 10 +
    drivers/mailbox/Makefile | 2 +
    drivers/mailbox/gunyah-msgq.c | 229 ++++++++++++++++++++
    include/linux/gunyah.h | 61 +++++-
    6 files changed, 309 insertions(+), 2 deletions(-)
    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 be4ab289236a..9245dbe6dd8a 100644
    --- a/Documentation/virt/gunyah/message-queue.rst
    +++ b/Documentation/virt/gunyah/message-queue.rst
    @@ -54,3 +54,11 @@ 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/MAINTAINERS b/MAINTAINERS
    index 69c1835b3bb4..502798197b80 100644
    --- a/MAINTAINERS
    +++ b/MAINTAINERS
    @@ -8946,6 +8946,7 @@ S: Supported
    F: Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
    F: Documentation/virt/gunyah/
    F: arch/arm64/gunyah/
    +F: drivers/mailbox/gunyah-msgq.c
    F: drivers/virt/gunyah/
    F: include/linux/gunyah.h

    diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
    index 05d6fae800e3..baf9451c5f04 100644
    --- a/drivers/mailbox/Kconfig
    +++ b/drivers/mailbox/Kconfig
    @@ -41,6 +41,16 @@ config IMX_MBOX
    help
    Mailbox implementation for i.MX Messaging Unit (MU).

    +config GUNYAH_MESSAGE_QUEUES
    + tristate "Gunyah Message Queue Mailbox"
    + depends on GUNYAH
    + help
    + Mailbox implementation for Gunyah Message Queues. Gunyah message queues
    + are an IPC mechanism to pass short messages between virtual machines
    + running under the Gunyah hypervisor.
    +
    + Say Y here if you run Linux as a Gunyah virtual machine.
    +
    config PLATFORM_MHU
    tristate "Platform MHU Mailbox"
    depends on OF
    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..d5a324e85428
    --- /dev/null
    +++ b/drivers/mailbox/gunyah-msgq.c
    @@ -0,0 +1,229 @@
    +// SPDX-License-Identifier: GPL-2.0-only
    +/*
    + * Copyright (c) 2022 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 inline bool gh_msgq_has_tx(struct gh_msgq *msgq)
    +{
    + return msgq->tx_ghrsc->type == GUNYAH_RESOURCE_TYPE_MSGQ_TX;
    +}
    +
    +static inline bool gh_msgq_has_rx(struct gh_msgq *msgq)
    +{
    + return msgq->rx_ghrsc->type == GUNYAH_RESOURCE_TYPE_MSGQ_RX;
    +}
    +
    +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
    +{
    + struct gh_msgq *msgq = data;
    + struct gh_msgq_rx_data rx_data;
    + unsigned long gh_err;
    + ssize_t ret;
    + bool ready = false;
    +
    + do {
    + gh_err = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
    + (uintptr_t)&rx_data.data, sizeof(rx_data.data),
    + &rx_data.length, &ready);
    + if (gh_err == GH_ERROR_OK) {
    + mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
    + } else if (GH_ERROR_MSGQUEUE_EMPTY) {
    + break;
    + } else {
    + pr_warn("Failed to receive data from msgq for %s: %ld\n",
    + msgq->mbox.dev ? dev_name(msgq->mbox.dev) : "", ret);
    + break;
    + }
    + } while (ready);
    +
    + return IRQ_HANDLED;
    +}
    +
    +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(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_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);
    +
    + 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.num_chans = 1;
    + msgq->mbox.chans = kcalloc(msgq->mbox.num_chans, sizeof(*msgq->mbox.chans), GFP_KERNEL);
    + if (!msgq->mbox.chans)
    + return -ENOMEM;
    + 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_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 (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)
    +{
    + mbox_controller_unregister(&msgq->mbox);
    +
    + 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);
    +
    +
    +static int __init gh_msgq_init_module(void)
    +{
    + if (gh_api_version() != GUNYAH_API_V1) {
    + pr_warn("Unrecognized gunyah version: %u. Currently supported: %d\n",
    + gh_api_version(), GUNYAH_API_V1);
    + return -ENODEV;
    + }
    +
    + return 0;
    +}
    +module_init(gh_msgq_init_module);
    +
    +MODULE_LICENSE("GPL");
    +MODULE_DESCRIPTION("Gunyah Message Queue Driver");
    diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
    index c863cac4a3cf..e317d7ac938f 100644
    --- a/include/linux/gunyah.h
    +++ b/include/linux/gunyah.h
    @@ -7,10 +7,67 @@
    #define _GUNYAH_H

    #include <linux/bitfield.h>
    -#include <linux/types.h>
    #include <linux/errno.h>
    +#include <linux/interrupt.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 */
    +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_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 macros and definitions for Gunyah hypercalls */

    -/* Common Gunyah macros */
    #define GH_CAPID_INVAL U64_MAX
    #define GH_VMID_ROOT_VM 0xff

    --
    2.25.1
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      Last update: 2022-11-21 15:03    [W:2.554 / U:0.592 seconds]
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