This driver register as a subsystem restart notifier and will send out
notifications to remote processors that has opened the "glink_ssr" GLINK
channel.
This mechanism is used to signal any GLINK participants that a 3rd party
is gone and that the communication state has to be reset; i.e. that read
and write pointers of the GLINK FIFOs are stale.
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
drivers/soc/qcom/Kconfig | 9 +++
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/glink_ssr.c | 164 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 174 insertions(+)
create mode 100644 drivers/soc/qcom/glink_ssr.c
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 9fca977ef18d..d0fc331972d2 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -1,6 +1,15 @@
#
# QCOM Soc drivers
#
+config QCOM_GLINK_SSR
+ tristate "Qualcomm Glink SSR driver"
+ depends on RPMSG
+ depends on QCOM_RPROC_COMMON
+ help
+ Say y here to enable GLINK SSR support. The GLINK SSR driver
+ implements the SSR protocol for notifying the remote processor about
+ neighboring subsystems going up or down.
+
config QCOM_GSBI
tristate "QCOM General Serial Bus Interface"
depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 414f0de274fa..f151de41eb93 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_QCOM_GLINK_SSR) += glink_ssr.o
obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o
obj-$(CONFIG_QCOM_MDT_LOADER) += mdt_loader.o
obj-$(CONFIG_QCOM_PM) += spm.o
diff --git a/drivers/soc/qcom/glink_ssr.c b/drivers/soc/qcom/glink_ssr.c
new file mode 100644
index 000000000000..19c7399eddb5
--- /dev/null
+++ b/drivers/soc/qcom/glink_ssr.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017, Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/rpmsg.h>
+#include <linux/remoteproc/qcom_rproc.h>
+
+/**
+ * struct do_cleanup_msg - The data structure for an SSR do_cleanup message
+ * version: The G-Link SSR protocol version
+ * command: The G-Link SSR command - do_cleanup
+ * seq_num: Sequence number
+ * name_len: Length of the name of the subsystem being restarted
+ * name: G-Link edge name of the subsystem being restarted
+ */
+struct do_cleanup_msg {
+ __le32 version;
+ __le32 command;
+ __le32 seq_num;
+ __le32 name_len;
+ char name[32];
+};
+
+/**
+ * struct cleanup_done_msg - The data structure for an SSR cleanup_done message
+ * version: The G-Link SSR protocol version
+ * response: The G-Link SSR response to a do_cleanup command, cleanup_done
+ * seq_num: Sequence number
+ */
+struct cleanup_done_msg {
+ __le32 version;
+ __le32 response;
+ __le32 seq_num;
+};
+
+/**
+ * G-Link SSR protocol commands
+ */
+#define GLINK_SSR_DO_CLEANUP 0
+#define GLINK_SSR_CLEANUP_DONE 1
+
+struct glink_ssr {
+ struct device *dev;
+ struct rpmsg_endpoint *ept;
+
+ struct notifier_block nb;
+
+ u32 seq_num;
+ struct completion completion;
+};
+
+static int qcom_glink_ssr_callback(struct rpmsg_device *rpdev,
+ void *data, int len, void *priv, u32 addr)
+{
+ struct cleanup_done_msg *msg = data;
+ struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
+
+ if (len < sizeof(*msg)) {
+ dev_err(ssr->dev, "message too short\n");
+ return -EINVAL;
+ }
+
+ if (le32_to_cpu(msg->version) != 0)
+ return -EINVAL;
+
+ if (le32_to_cpu(msg->response) != GLINK_SSR_CLEANUP_DONE)
+ return 0;
+
+ if (le32_to_cpu(msg->seq_num) != ssr->seq_num) {
+ dev_err(ssr->dev, "invalid sequence number of response\n");
+ return -EINVAL;
+ }
+
+ complete(&ssr->completion);
+
+ return 0;
+}
+
+static int qcom_glink_ssr_notify(struct notifier_block *nb, unsigned long event,
+ void *data)
+{
+ struct glink_ssr *ssr = container_of(nb, struct glink_ssr, nb);
+ struct do_cleanup_msg msg;
+ char *ssr_name = data;
+ int ret;
+
+ ssr->seq_num++;
+ reinit_completion(&ssr->completion);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.command = cpu_to_le32(GLINK_SSR_DO_CLEANUP);
+ msg.seq_num = cpu_to_le32(ssr->seq_num);
+ msg.name_len = cpu_to_le32(strlen(ssr_name));
+ strlcpy(msg.name, ssr_name, sizeof(msg.name));
+
+ ret = rpmsg_send(ssr->ept, &msg, sizeof(msg));
+ if (ret < 0)
+ dev_err(ssr->dev, "failed to send cleanup message\n");
+
+ ret = wait_for_completion_timeout(&ssr->completion, HZ);
+ if (!ret)
+ dev_err(ssr->dev, "timeout waiting for cleanup done message\n");
+
+ return NOTIFY_DONE;
+}
+
+static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev)
+{
+ struct glink_ssr *ssr;
+
+ ssr = devm_kzalloc(&rpdev->dev, sizeof(*ssr), GFP_KERNEL);
+ if (!ssr)
+ return -ENOMEM;
+
+ init_completion(&ssr->completion);
+
+ ssr->dev = &rpdev->dev;
+ ssr->ept = rpdev->ept;
+ ssr->nb.notifier_call = qcom_glink_ssr_notify;
+
+ dev_set_drvdata(&rpdev->dev, ssr);
+
+ return qcom_register_ssr_notifier(&ssr->nb);
+}
+
+static void qcom_glink_ssr_remove(struct rpmsg_device *rpdev)
+{
+ struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
+
+ qcom_unregister_ssr_notifier(&ssr->nb);
+}
+
+static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
+ { "glink_ssr" },
+ {}
+};
+
+static struct rpmsg_driver qcom_glink_ssr_driver = {
+ .probe = qcom_glink_ssr_probe,
+ .remove = qcom_glink_ssr_remove,
+ .callback = qcom_glink_ssr_callback,
+ .id_table = qcom_glink_ssr_match,
+ .drv = {
+ .name = "qcom_glink_ssr",
+ },
+};
+module_rpmsg_driver(qcom_glink_ssr_driver);
+
+MODULE_ALIAS("rpmsg:glink_ssr");
+MODULE_DESCRIPTION("Qualcomm GLINK SSR notifier");
+MODULE_LICENSE("GPL v2");
--
2.12.0
--
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