[PATCH v8 6/7] cdx: add rpmsg communication channel for CDX

From: Nipun Gupta
Date: Fri Feb 17 2023 - 08:30:31 EST

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From: Abhijit Gangurde <abhijit.gangurde@xxxxxxx>

RPMsg is used as a transport communication channel. This
change introduces RPMsg driver and integrates it with the
CDX controller.

Signed-off-by: Abhijit Gangurde <abhijit.gangurde@xxxxxxx>
Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
Tested-by: Nikhil Agarwal <nikhil.agarwal@xxxxxxx>
---
drivers/cdx/controller/Kconfig | 1 +
drivers/cdx/controller/Makefile | 2 +-
drivers/cdx/controller/cdx_controller.c | 31 +++-
drivers/cdx/controller/cdx_controller.h | 30 ++++
drivers/cdx/controller/cdx_rpmsg.c | 202 ++++++++++++++++++++++++
drivers/cdx/controller/mcdi.h | 9 ++
6 files changed, 270 insertions(+), 5 deletions(-)
create mode 100644 drivers/cdx/controller/cdx_controller.h
create mode 100644 drivers/cdx/controller/cdx_rpmsg.c

diff --git a/drivers/cdx/controller/Kconfig b/drivers/cdx/controller/Kconfig
index 17f9c6be2fe1..aea3ac86d3aa 100644
--- a/drivers/cdx/controller/Kconfig
+++ b/drivers/cdx/controller/Kconfig
@@ -9,6 +9,7 @@ if CDX_BUS

config CDX_CONTROLLER
tristate "CDX bus controller"
+ select RPMSG
help
CDX controller drives the CDX bus. It interacts with
firmware to get the hardware devices and registers with
diff --git a/drivers/cdx/controller/Makefile b/drivers/cdx/controller/Makefile
index f7437c882cc9..f071be411d96 100644
--- a/drivers/cdx/controller/Makefile
+++ b/drivers/cdx/controller/Makefile
@@ -6,4 +6,4 @@
#

obj-$(CONFIG_CDX_CONTROLLER) += cdx-controller.o
-cdx-controller-objs := cdx_controller.o mcdi.o mcdi_functions.o
+cdx-controller-objs := cdx_controller.o cdx_rpmsg.o mcdi.o mcdi_functions.o
diff --git a/drivers/cdx/controller/cdx_controller.c b/drivers/cdx/controller/cdx_controller.c
index b27be2097305..c40027cc38aa 100644
--- a/drivers/cdx/controller/cdx_controller.c
+++ b/drivers/cdx/controller/cdx_controller.c
@@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/cdx/cdx_bus.h>

+#include "cdx_controller.h"
#include "../cdx.h"
#include "mcdi_functions.h"
#include "mcdi.h"
@@ -22,10 +23,7 @@ static void cdx_mcdi_request(struct cdx_mcdi *cdx,
const struct cdx_dword *hdr, size_t hdr_len,
const struct cdx_dword *sdu, size_t sdu_len)
{
- /*
- * This will get updated by rpmsg APIs, with RPMSG introduction
- * in CDX controller as a transport layer.
- */
+ cdx_rpmsg_send(cdx, hdr, hdr_len, sdu, sdu_len);
}

static const struct cdx_mcdi_ops mcdi_ops = {
@@ -33,6 +31,19 @@ static const struct cdx_mcdi_ops mcdi_ops = {
.mcdi_request = cdx_mcdi_request,
};

+void cdx_rpmsg_post_probe(struct cdx_controller *cdx)
+{
+ /* Register CDX controller with CDX bus driver */
+ if (cdx_register_controller(cdx))
+ dev_err(cdx->dev, "Failed to register CDX controller\n");
+}
+
+void cdx_rpmsg_pre_remove(struct cdx_controller *cdx)
+{
+ cdx_unregister_controller(cdx);
+ cdx_mcdi_wait_for_quiescence(cdx->priv, MCDI_RPC_TIMEOUT);
+}
+
static int cdx_scan_devices(struct cdx_controller *cdx)
{
struct cdx_mcdi *cdx_mcdi = cdx->priv;
@@ -124,8 +135,18 @@ static int xlnx_cdx_probe(struct platform_device *pdev)
cdx->priv = cdx_mcdi;
cdx->ops = &cdx_ops;

+ ret = cdx_setup_rpmsg(pdev);
+ if (ret) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(&pdev->dev, "Failed to register CDX RPMsg transport\n");
+ goto cdx_rpmsg_fail;
+ }
+
+ dev_info(&pdev->dev, "Successfully registered CDX controller with RPMsg as transport\n");
return 0;

+cdx_rpmsg_fail:
+ kfree(cdx);
cdx_alloc_fail:
cdx_mcdi_finish(cdx_mcdi);
mcdi_init_fail:
@@ -139,6 +160,8 @@ static int xlnx_cdx_remove(struct platform_device *pdev)
struct cdx_controller *cdx = platform_get_drvdata(pdev);
struct cdx_mcdi *cdx_mcdi = cdx->priv;

+ cdx_destroy_rpmsg(pdev);
+
kfree(cdx);

cdx_mcdi_finish(cdx_mcdi);
diff --git a/drivers/cdx/controller/cdx_controller.h b/drivers/cdx/controller/cdx_controller.h
new file mode 100644
index 000000000000..43b7c742df87
--- /dev/null
+++ b/drivers/cdx/controller/cdx_controller.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Header file for the CDX Controller
+ *
+ * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+ */
+
+#ifndef _CDX_CONTROLLER_H_
+#define _CDX_CONTROLLER_H_
+
+#include <linux/cdx/cdx_bus.h>
+#include "mcdi_functions.h"
+
+void cdx_rpmsg_post_probe(struct cdx_controller *cdx);
+
+void cdx_rpmsg_pre_remove(struct cdx_controller *cdx);
+
+int cdx_rpmsg_send(struct cdx_mcdi *cdx_mcdi,
+ const struct cdx_dword *hdr, size_t hdr_len,
+ const struct cdx_dword *sdu, size_t sdu_len);
+
+void cdx_rpmsg_read_resp(struct cdx_mcdi *cdx_mcdi,
+ struct cdx_dword *outbuf, size_t offset,
+ size_t outlen);
+
+int cdx_setup_rpmsg(struct platform_device *pdev);
+
+void cdx_destroy_rpmsg(struct platform_device *pdev);
+
+#endif /* _CDX_CONT_PRIV_H_ */
diff --git a/drivers/cdx/controller/cdx_rpmsg.c b/drivers/cdx/controller/cdx_rpmsg.c
new file mode 100644
index 000000000000..2be9bb279f81
--- /dev/null
+++ b/drivers/cdx/controller/cdx_rpmsg.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Platform driver for CDX bus.
+ *
+ * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/rpmsg.h>
+#include <linux/remoteproc.h>
+#include <linux/of_platform.h>
+#include <linux/cdx/cdx_bus.h>
+#include <linux/module.h>
+
+#include "../cdx.h"
+#include "cdx_controller.h"
+#include "mcdi_functions.h"
+#include "mcdi.h"
+
+static struct rpmsg_device_id cdx_rpmsg_id_table[] = {
+ { .name = "mcdi_ipc" },
+ { },
+};
+MODULE_DEVICE_TABLE(rpmsg, cdx_rpmsg_id_table);
+
+int cdx_rpmsg_send(struct cdx_mcdi *cdx_mcdi,
+ const struct cdx_dword *hdr, size_t hdr_len,
+ const struct cdx_dword *sdu, size_t sdu_len)
+{
+ unsigned char *send_buf;
+ int rc;
+
+ send_buf = kzalloc(hdr_len + sdu_len, GFP_KERNEL);
+ if (!send_buf)
+ return -ENOMEM;
+
+ memcpy(send_buf, hdr, hdr_len);
+ memcpy(send_buf + hdr_len, sdu, sdu_len);
+
+ rc = rpmsg_send(cdx_mcdi->ept, send_buf, hdr_len + sdu_len);
+ kfree(send_buf);
+
+ return rc;
+}
+
+static int cdx_attach_to_rproc(struct platform_device *pdev)
+{
+ struct device_node *r5_core_node;
+ struct cdx_controller *cdx_c;
+ struct cdx_mcdi *cdx_mcdi;
+ struct device *dev;
+ struct rproc *rp;
+ int ret;
+
+ dev = &pdev->dev;
+ cdx_c = platform_get_drvdata(pdev);
+ cdx_mcdi = cdx_c->priv;
+
+ r5_core_node = of_parse_phandle(dev->of_node, "xlnx,rproc", 0);
+ if (!r5_core_node) {
+ dev_err(&pdev->dev, "xlnx,rproc: invalid phandle\n");
+ return -EINVAL;
+ }
+
+ rp = rproc_get_by_phandle(r5_core_node->phandle);
+ if (!rp) {
+ ret = -EPROBE_DEFER;
+ goto pdev_err;
+ }
+
+ /* Attach to remote processor */
+ ret = rproc_boot(rp);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to attach to remote processor\n");
+ rproc_put(rp);
+ goto pdev_err;
+ }
+
+ cdx_mcdi->r5_rproc = rp;
+pdev_err:
+ of_node_put(r5_core_node);
+ return ret;
+}
+
+static void cdx_detach_to_r5(struct platform_device *pdev)
+{
+ struct cdx_controller *cdx_c;
+ struct cdx_mcdi *cdx_mcdi;
+
+ cdx_c = platform_get_drvdata(pdev);
+ cdx_mcdi = cdx_c->priv;
+
+ rproc_detach(cdx_mcdi->r5_rproc);
+ rproc_put(cdx_mcdi->r5_rproc);
+}
+
+static int cdx_rpmsg_cb(struct rpmsg_device *rpdev, void *data,
+ int len, void *priv, u32 src)
+{
+ struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
+ struct cdx_mcdi *cdx_mcdi = cdx_c->priv;
+
+ if (len > MCDI_BUF_LEN)
+ return -EINVAL;
+
+ cdx_mcdi_process_cmd(cdx_mcdi, (struct cdx_dword *)data, len);
+
+ return 0;
+}
+
+static void cdx_rpmsg_post_probe_work(struct work_struct *work)
+{
+ struct cdx_controller *cdx_c;
+ struct cdx_mcdi *cdx_mcdi;
+
+ cdx_mcdi = container_of(work, struct cdx_mcdi, work);
+ cdx_c = dev_get_drvdata(&cdx_mcdi->rpdev->dev);
+ cdx_rpmsg_post_probe(cdx_c);
+}
+
+static int cdx_rpmsg_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_channel_info chinfo = {0};
+ struct cdx_controller *cdx_c;
+ struct cdx_mcdi *cdx_mcdi;
+
+ cdx_c = (struct cdx_controller *)cdx_rpmsg_id_table[0].driver_data;
+ cdx_mcdi = cdx_c->priv;
+
+ chinfo.src = RPMSG_ADDR_ANY;
+ chinfo.dst = rpdev->dst;
+ strscpy(chinfo.name, cdx_rpmsg_id_table[0].name,
+ strlen(cdx_rpmsg_id_table[0].name));
+
+ cdx_mcdi->ept = rpmsg_create_ept(rpdev, cdx_rpmsg_cb, NULL, chinfo);
+ if (!cdx_mcdi->ept) {
+ dev_err_probe(&rpdev->dev, -ENXIO,
+ "Failed to create ept for channel %s\n",
+ chinfo.name);
+ return -EINVAL;
+ }
+
+ cdx_mcdi->rpdev = rpdev;
+ dev_set_drvdata(&rpdev->dev, cdx_c);
+
+ schedule_work(&cdx_mcdi->work);
+ return 0;
+}
+
+static void cdx_rpmsg_remove(struct rpmsg_device *rpdev)
+{
+ struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
+ struct cdx_mcdi *cdx_mcdi = cdx_c->priv;
+
+ flush_work(&cdx_mcdi->work);
+ cdx_rpmsg_pre_remove(cdx_c);
+
+ rpmsg_destroy_ept(cdx_mcdi->ept);
+ dev_set_drvdata(&rpdev->dev, NULL);
+}
+
+static struct rpmsg_driver cdx_rpmsg_driver = {
+ .drv.name = KBUILD_MODNAME,
+ .id_table = cdx_rpmsg_id_table,
+ .probe = cdx_rpmsg_probe,
+ .remove = cdx_rpmsg_remove,
+ .callback = cdx_rpmsg_cb,
+};
+
+int cdx_setup_rpmsg(struct platform_device *pdev)
+{
+ struct cdx_controller *cdx_c;
+ struct cdx_mcdi *cdx_mcdi;
+ int ret;
+
+ /* Attach to remote processor */
+ ret = cdx_attach_to_rproc(pdev);
+ if (ret)
+ return ret;
+
+ cdx_c = platform_get_drvdata(pdev);
+ cdx_mcdi = cdx_c->priv;
+
+ /* Register RPMsg driver */
+ cdx_rpmsg_id_table[0].driver_data = (kernel_ulong_t)cdx_c;
+
+ INIT_WORK(&cdx_mcdi->work, cdx_rpmsg_post_probe_work);
+ ret = register_rpmsg_driver(&cdx_rpmsg_driver);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Failed to register cdx RPMsg driver: %d\n", ret);
+ cdx_detach_to_r5(pdev);
+ }
+
+ return ret;
+}
+
+void cdx_destroy_rpmsg(struct platform_device *pdev)
+{
+ unregister_rpmsg_driver(&cdx_rpmsg_driver);
+
+ cdx_detach_to_r5(pdev);
+}
diff --git a/drivers/cdx/controller/mcdi.h b/drivers/cdx/controller/mcdi.h
index 63933ede33ed..a4d750816bd2 100644
--- a/drivers/cdx/controller/mcdi.h
+++ b/drivers/cdx/controller/mcdi.h
@@ -62,11 +62,20 @@ enum cdx_mcdi_cmd_state {
* with CDX controller.
* @mcdi: MCDI interface
* @mcdi_ops: MCDI operations
+ * @r5_rproc : R5 Remoteproc device handle
+ * @rpdev: RPMsg device
+ * @ept: RPMsg endpoint
+ * @work: Post probe work
*/
struct cdx_mcdi {
/* MCDI interface */
struct cdx_mcdi_data *mcdi;
const struct cdx_mcdi_ops *mcdi_ops;
+
+ struct rproc *r5_rproc;
+ struct rpmsg_device *rpdev;
+ struct rpmsg_endpoint *ept;
+ struct work_struct work;
};

struct cdx_mcdi_ops {
--
2.25.1

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