Re: [PATCH v13 05/24] mailbox: Add Gunyah message queue mailbox
From: Alex Elder
Date: Mon Jun 05 2023 - 15:48:03 EST
On 5/9/23 3:47 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 <quic_eberman@xxxxxxxxxxx>
This patch does not apply properly, because it updates
"message-queue.rst", which does not currently exist.
I'm going to ignore that for now, though.
I'm generally OK with giving you my "Reviewed-by" on this
but I'll wait until you send v14 with the full content
of "message-queue.rst".
Also, I suggest below that you update all your SPDX tags
to no longer use the deprecated "GPL-2.0" identifier.
-Alex
---
Documentation/virt/gunyah/message-queue.rst | 8 +
drivers/mailbox/Makefile | 2 +
drivers/mailbox/gunyah-msgq.c | 212 ++++++++++++++++++++
include/linux/gunyah.h | 57 ++++++
4 files changed, 279 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..b7a54f233680
--- /dev/null
+++ b/drivers/mailbox/gunyah-msgq.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0-only
After seeing this tag I looked into it, and see that SPDX
has deprecated "GPL-2.0" in favor of "GPL-2.0-only".
Please update all SPDX licenses that use "GPL-2.0" to use
this new tag instead.
+/*
+ * 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))
Parentheses are not needed around a container_of() call.
+
+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;
+ }
+ if (likely(gh_msgq_chan(msgq)->cl))
+ 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->tx_ghrsc)
+ return -EOPNOTSUPP;
+
+ 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.
+ */
+ msgq->last_ret = gh_error_remap(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.
+ */
+ if (gh_error == GH_ERROR_OK) {
+ if (!ready)
+ return 0;
+ } else
Standard style would add curly braces to the else block.
} 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.
+ */
+ tasklet_schedule(&msgq->txdone_tasklet);
+
+ return 0;
+}
. . .