[PATCH 2/4] firmware: arm_ffa: Register core as a platform driver

[Sudeep Holla]

Move the FF-A core bring-up and teardown paths into platform driver
probe and remove callbacks, and register a synthetic arm-ffa platform
device to bind the driver.

This makes the FF-A core lifetime follow the driver model while keeping
the device creation internal to the FF-A core. Use normal platform driver
registration so the probe path has standard driver-core semantics.

The synthetic platform device is a temporary bridge until ACPI and
devicetree describe the FF-A core device or object. Once those firmware
description paths are defined, the internal platform device creation can
be dropped and the driver can bind to the firmware-described device
directly.

Since the transport selection now happens from the platform probe path,
drop the __init annotation from ffa_transport_init().

Signed-off-by: Sudeep Holla <sudeep.holla at kernel.org>
---
 drivers/firmware/arm_ffa/common.h |  4 +--
 drivers/firmware/arm_ffa/driver.c | 53 ++++++++++++++++++++++++++++++++++-----
 drivers/firmware/arm_ffa/smccc.c  |  2 +-
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/drivers/firmware/arm_ffa/common.h b/drivers/firmware/arm_ffa/common.h
index 9c6425a81d0d..5cdf4bd222c6 100644
--- a/drivers/firmware/arm_ffa/common.h
+++ b/drivers/firmware/arm_ffa/common.h
@@ -18,9 +18,9 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev);
 void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid);
 
 #ifdef CONFIG_ARM_FFA_SMCCC
-int __init ffa_transport_init(ffa_fn **invoke_ffa_fn);
+int ffa_transport_init(ffa_fn **invoke_ffa_fn);
 #else
-static inline int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
+static inline int ffa_transport_init(ffa_fn **invoke_ffa_fn)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 6efb85787e6e..97ecdb5dac09 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -36,6 +36,7 @@
 #include <linux/mm.h>
 #include <linux/mutex.h>
 #include <linux/of_irq.h>
+#include <linux/platform_device.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
@@ -46,6 +47,7 @@
 
 #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
 #define FFA_MIN_VERSION		FFA_VERSION_1_0
+#define FFA_PLATFORM_NAME	"arm-ffa"
 
 #define SENDER_ID_MASK		GENMASK(31, 16)
 #define RECEIVER_ID_MASK	GENMASK(15, 0)
@@ -114,6 +116,7 @@ struct ffa_drv_info {
 };
 
 static struct ffa_drv_info *drv_info;
+static struct platform_device *ffa_pdev;
 
 /*
  * The driver must be able to support all the versions from the earliest
@@ -2029,7 +2032,7 @@ static void ffa_notifications_setup(void)
 	ffa_notifications_cleanup();
 }
 
-static int __init ffa_init(void)
+static int ffa_probe(struct platform_device *pdev)
 {
 	int ret;
 	u32 buf_sz;
@@ -2042,6 +2045,7 @@ static int __init ffa_init(void)
 	drv_info = kzalloc_obj(*drv_info);
 	if (!drv_info)
 		return -ENOMEM;
+	platform_set_drvdata(pdev, drv_info);
 
 	ret = ffa_version_check(&drv_info->version);
 	if (ret)
@@ -2103,19 +2107,56 @@ static int __init ffa_init(void)
 		free_pages_exact(drv_info->tx_buffer, rxtx_bufsz);
 	free_pages_exact(drv_info->rx_buffer, rxtx_bufsz);
 free_drv_info:
+	platform_set_drvdata(pdev, NULL);
 	kfree(drv_info);
+	drv_info = NULL;
 	return ret;
 }
-module_init(ffa_init);
 
-static void __exit ffa_exit(void)
+static void ffa_remove(struct platform_device *pdev)
 {
+	struct ffa_drv_info *info = platform_get_drvdata(pdev);
+
 	ffa_notifications_cleanup();
 	ffa_partitions_cleanup();
 	ffa_rxtx_unmap();
-	free_pages_exact(drv_info->tx_buffer, drv_info->rxtx_bufsz);
-	free_pages_exact(drv_info->rx_buffer, drv_info->rxtx_bufsz);
-	kfree(drv_info);
+	free_pages_exact(info->tx_buffer, info->rxtx_bufsz);
+	free_pages_exact(info->rx_buffer, info->rxtx_bufsz);
+	kfree(info);
+	platform_set_drvdata(pdev, NULL);
+	drv_info = NULL;
+}
+
+static struct platform_driver ffa_driver = {
+	.probe = ffa_probe,
+	.remove = ffa_remove,
+	.driver = {
+		.name = FFA_PLATFORM_NAME,
+	},
+};
+
+static int __init ffa_init(void)
+{
+	int ret;
+
+	ffa_pdev = platform_device_register_simple(FFA_PLATFORM_NAME,
+						   PLATFORM_DEVID_NONE,
+						   NULL, 0);
+	if (IS_ERR(ffa_pdev))
+		return PTR_ERR(ffa_pdev);
+
+	ret = platform_driver_register(&ffa_driver);
+	if (ret)
+		platform_device_unregister(ffa_pdev);
+
+	return ret;
+}
+module_init(ffa_init);
+
+static void __exit ffa_exit(void)
+{
+	platform_device_unregister(ffa_pdev);
+	platform_driver_unregister(&ffa_driver);
 }
 module_exit(ffa_exit);
 
diff --git a/drivers/firmware/arm_ffa/smccc.c b/drivers/firmware/arm_ffa/smccc.c
index 4d85bfff0a4e..e6125dd9f58f 100644
--- a/drivers/firmware/arm_ffa/smccc.c
+++ b/drivers/firmware/arm_ffa/smccc.c
@@ -17,7 +17,7 @@ static void __arm_ffa_fn_hvc(ffa_value_t args, ffa_value_t *res)
 	arm_smccc_1_2_hvc(&args, res);
 }
 
-int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
+int ffa_transport_init(ffa_fn **invoke_ffa_fn)
 {
 	enum arm_smccc_conduit conduit;
 

-- 
2.43.0