On 1/9/2023 1:34 PM, Alex Elder wrote:
On 12/19/22 4:58 PM, Elliot Berman wrote:
Gunyah message queues are a unidirectional inter-VM pipe for messages up
s/Gunyah message queues are/A Gunyah message queue is/
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@xxxxxxxxxxx>
---
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 36698df6b0e5..667480bfd387 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8942,6 +8942,7 @@ 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
Is Gunyah useful without message queues? Are Gunyah message
queues useful without the rest of Gunyah? Are there other
possible message queue implementations? My point is that
maybe this isn't a necessary kernel config option.
I can drop this.
+ 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-$(CONFIG_GUNYAH) += gunyah-msgq.o
Assuming you keep the Kconfig option, should this be
referring to CONFIG_GUNYAH_MESSAGE_QUEUES?
+
obj-$(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;
I think this was pointed out elsewhere; I think msgq->tx_ghrsc
can be null. Same for msgq->rx_ghrsc below.
+}
+
+static inline bool gh_msgq_has_rx(struct gh_msgq *msgq)
+{
+ return msgq->rx_ghrsc->type == GUNYAH_RESOURCE_TYPE_MSGQ_RX;
Is there any chance that a message queue would be created whose
type was anything other than MSGQ_RX? It's possible that there
is some generic resource code that needs this type field, but
in this case I don't see why it's important.
And... If that's the case, I think it's perhaps clearer to
just replace calls to gs_msgq_has_rx(msgq) with:
if (msgq->rx_ghrsc)
/* there is an RX message queue */
Yep, that's what I've done for v9.
+}
+
+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 {
Maybe: bool ready = true;
while (ready) {
+ 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);
Maybe continue;
}
if (gh_err != GH_ERROR_MSGQUEUE_EMPTY)
pr_warn(...);
break;
+ } else if (GH_ERROR_MSGQUEUE_EMPTY) {
+ break;
+ } else {
+ pr_warn("Failed to receive data from msgq for %s: %ld\n",
s/%ld/%zd/
+ 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;
+
I probably missed something, but where is gh_hypercall_msgq_send()
defined? I'm interested in what the ready flag is used for.
(Can the return value encode that?)
It's in arch/arm64/gunyah/gunyah_hypercall.c. The return values of
encode whether more data can be received (ready flag).
+ 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.
+ */
Is it just unlikely, or is it impossible?
This would require multiple mailbox controllers interacting with the
same message queue.
The only way I can think this is possible is if the Gunyah drivers are
unloaded when the message queue is full; drivers are then re-loaded
before the receiver processes the messages. The initial internal state
of the message queue controller assumes that there is space in the
message queue. We would get a Tx vIRQ once space becomes available and
the message would then be attempted to sent again. Since there's a safe
flow to recover from a inconsistent internal state and it's very
unlikely to start in that state, I don't think we need to add calls to
check if the message queue is full during initialization.
+ 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
s/only // (for one of them)
+ * 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 frameworkrequires 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,
s/facilitiate/facilitate/
+ * 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))
The internal parenthesis pairs above aren't really required.
I think it's cleaner/easier to read this way.
+ 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)) {
Maybe if (tx_ghrsc) {
+ ret = request_irq(msgq->tx_ghrsc->irq,
gh_msgq_tx_irq_handler, 0, "gh_msgq_tx",
+ msgq);
+ if (ret)
+ gotoerr_chans;
+ }
+
+ if (gh_msgq_has_rx(msgq)) {
Maybe if (rx_ghrsc) {
+ ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL,
gh_msgq_rx_irq_handler,
+ IRQF_ONESHOT, "gh_msgq_rx", msgq);
+ if (ret)
+ gotoerr_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))
if (rx_ghrsc)
+ free_irq(msgq->rx_ghrsc->irq, msgq);
+err_tx_irq:
+ if (gh_msgq_has_tx(msgq))
if (tx_ghrsc)
Applied for the suggestions above.
+ 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 gunyahversion: %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;
Maybe note that last_status is an errno (and not GH_ERROR_*)
Done, renamed to "last_ret".
-Alex
+ 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
