soc: qcom: GLINK SSR notifier

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.

Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 9fca977..d0fc331 100644 (file)
--- 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 414f0de..f151de4 100644 (file)
--- 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 (file)
index 0000000..19c7399
--- /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");