[PATCH v5 09/13] mailbox: Add Gunyah message queue mailbox

Elliot Berman
2022-10-11T00:09:42Z

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>
---
MAINTAINERS | 2 +
drivers/mailbox/Kconfig | 10 ++
drivers/mailbox/Makefile | 2 +
drivers/mailbox/gunyah-msgq.c | 254 ++++++++++++++++++++++++++++++++++
drivers/virt/gunyah/Kconfig | 2 +
include/linux/gunyah.h | 67 +++++++++
6 files changed, 337 insertions(+)
create mode 100644 drivers/mailbox/gunyah-msgq.c
create mode 100644 include/linux/gunyah.h

diff --git a/MAINTAINERS b/MAINTAINERS
index c5458aeec023..599804836d05 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8888,8 +8888,10 @@ F: Documentation/ABI/testing/sysfs-hypervisor-gunyah
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/asm-generic/gunyah.h
+F: include/linux/gunyah.h

HABANALABS PCI DRIVER
M: Oded Gabbay <ogabbay@kernel.org>
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..f0cd96920c64
--- /dev/null
+++ b/drivers/mailbox/gunyah-msgq.c
@@ -0,0 +1,254 @@
+// 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 gunyah_msgq, mbox))
+
+static inline bool gh_msgq_has_tx(struct gunyah_msgq *msgq)
+{
+ return msgq->tx_ghrsc.type == GUNYAH_RESOURCE_TYPE_MSGQ_TX;
+}
+
+static inline bool gh_msgq_has_rx(struct gunyah_msgq *msgq)
+{
+ return msgq->rx_ghrsc.type == GUNYAH_RESOURCE_TYPE_MSGQ_RX;
+}
+
+static ssize_t __gh_msgq_recv(struct gunyah_msgq *msgq, void *buff, size_t size, bool *ready)
+{
+ unsigned long gh_err;
+ size_t recv_size;
+ ssize_t ret;
+
+ gh_err = gh_hypercall_msgq_recv(msgq->rx_ghrsc.capid, (uintptr_t)buff, size,
+ &recv_size, ready);
+ switch (gh_err) {
+ case GH_ERROR_OK:
+ ret = recv_size;
+ break;
+ case GH_ERROR_MSGQUEUE_EMPTY:
+ ret = -EAGAIN;
+ *ready = false;
+ break;
+ default:
+ ret = gh_remap_error(gh_err);
+ break;
+ }
+
+ return ret;
+}
+
+static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
+{
+ struct gunyah_msgq *msgq = data;
+ struct gunyah_msgq_rx_data rx_data;
+ ssize_t ret;
+ bool more;
+
+ do {
+ ret = __gh_msgq_recv(msgq, &rx_data.data, sizeof(rx_data.data), &more);
+
+ if (ret >= 0) {
+ rx_data.length = ret;
+ mbox_chan_received_data(gunyah_msgq_chan(msgq), &rx_data);
+ } else if (ret != -EAGAIN)
+ pr_warn("Failed to receive data from msgq for %s: %ld\n",
+ msgq->mbox.dev ? dev_name(msgq->mbox.dev) : "", ret);
+ } while (ret >= 0);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data)
+{
+ struct gunyah_msgq *msgq = data;
+
+ mbox_chan_txdone(gunyah_msgq_chan(msgq), 0);
+
+ return IRQ_HANDLED;
+}
+
+static void gh_msgq_txdone_tasklet(unsigned long data)
+{
+ struct gunyah_msgq *msgq = (struct gunyah_msgq *)data;
+
+ mbox_chan_txdone(gunyah_msgq_chan(msgq), msgq->last_status);
+}
+
+static int __gh_msgq_send(struct gunyah_msgq *msgq, void *buff, size_t size, u64 tx_flags)
+{
+ unsigned long gh_err;
+ ssize_t ret;
+ bool ready;
+
+ gh_err = gh_hypercall_msgq_send(msgq->tx_ghrsc.capid, size, (uintptr_t)buff, tx_flags,
+ &ready);
+ switch (gh_err) {
+ case GH_ERROR_OK:
+ ret = !ready;
+ break;
+ case GH_ERROR_MSGQUEUE_FULL:
+ ret = -EAGAIN;
+ break;
+ default:
+ /* Not sure how to propagate these out to client. If we get here, nobody is going
+ * to trigger a retry
+ */
+ ret = gh_remap_error(gh_err);
+ break;
+ }
+
+ return ret;
+}
+
+static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
+{
+ struct gunyah_msgq *msgq = mbox_chan_to_msgq(chan);
+ struct gunyah_msgq_tx_data *msgq_data = data;
+ u64 tx_flags = 0;
+ int ret;
+
+ if (msgq_data->push)
+ tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH;
+
+ ret = __gh_msgq_send(msgq, msgq_data->data, msgq_data->length, tx_flags);
+
+ /**
+ * EAGAIN: message didn't send.
+ * ret = 1: message sent, but now the message queue is full and we can't send any more msgs.
+ * Either way, don't report that this message is done.
+ */
+ if (ret == -EAGAIN || ret == 1)
+ return ret;
+
+ /**
+ * Mailbox framework requires that tx done happens asynchronously to sending the message
+ * IOW, a notification that the message was sent happens after sending the message.
+ * To work around this, defer the txdone to a tasklet.
+ */
+ msgq->last_status = ret;
+ tasklet_schedule(&msgq->txdone_tasklet);
+
+ return 0;
+}
+
+struct mbox_chan_ops gunyah_msgq_ops = {
+ .send_data = gh_msgq_send_data,
+};
+
+/**
+ * gunyah_msgq_init() - Initialize a Gunyah message queue with an mbox_client
+ * @parent: optional, device parent used for the mailbox controller
+ * @msgq: Pointer to the gunyah_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(gunyah_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 gunyah_msgq_rx_data will be replaced/destroyed
+ * after the callback.
+ *
+ * Returns - 0 on success, negative otherwise
+ */
+int gunyah_msgq_init(struct device *parent, struct gunyah_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 = &gunyah_msgq_ops;
+ msgq->mbox.chans = kcalloc(1, sizeof(*msgq->mbox.chans), GFP_KERNEL);
+ 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);
+
+ ret = mbox_controller_register(&msgq->mbox);
+ if (ret)
+ goto err_rx_irq;
+
+ ret = mbox_bind_client(gunyah_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(gunyah_msgq_init);
+
+void gunyah_msgq_remove(struct gunyah_msgq *msgq)
+{
+ if (gh_msgq_has_tx(msgq))
+ free_irq(msgq->tx_ghrsc.irq, msgq);
+
+ kfree(msgq->mbox.chans);
+}
+EXPORT_SYMBOL_GPL(gunyah_msgq_remove);
+
+
+static int __init gh_msgq_init(void)
+{
+ if (GH_API_INFO_API_VERSION(gunyah_api.api_info) != GUNYAH_API_V1) {
+ pr_warn("Unrecognized gunyah version: %llu. Currently supported: %d\n",
+ GH_API_INFO_API_VERSION(gunyah_api.api_info), GUNYAH_API_V1);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+module_init(gh_msgq_init);
+
+static void __exit gh_msgq_exit(void)
+{
+}
+module_exit(gh_msgq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Message Queue Driver");
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 7ac917e0aa3f..f4c822a82f1a 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -4,6 +4,8 @@ config GUNYAH
tristate "Gunyah Virtualization drivers"
depends on ARM64
select AUXILIARY_BUS
+ select MAILBOX
+ select GUNYAH_MESSAGE_QUEUES
help
The Gunyah drivers are the helper interfaces that runs in a guest VM
such as basic inter-VM IPC and signaling mechanisms, and higher level
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
new file mode 100644
index 000000000000..0e9709555c79
--- /dev/null
+++ b/include/linux/gunyah.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GUNYAH_H
+#define _GUNYAH_H
+
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
+#include <linux/interrupt.h>
+
+#include <asm-generic/gunyah.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 gunyah_msgq_tx_data {
+ size_t length;
+ bool push;
+ char data[];
+};
+
+struct gunyah_msgq_rx_data {
+ size_t length;
+ char data[GH_MSGQ_MAX_MSG_SIZE];
+};
+
+struct gunyah_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 gunyah_msgq_init(struct device *parent, struct gunyah_msgq *msgq, struct mbox_client *cl,
+ struct gunyah_resource *tx_ghrsc, struct gunyah_resource *rx_ghrsc);
+void gunyah_msgq_remove(struct gunyah_msgq *msgq);
+
+static inline struct mbox_chan *gunyah_msgq_chan(struct gunyah_msgq *msgq)
+{
+ return &msgq->mbox.chans[0];
+}
+
+#endif
--
2.25.1