linux-kernel - [PATCH RFT v2 03/18] firmware: arm_ffa: Implement the notification bind and unbind interface

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Message-Id: <20230919-ffa_v1-1_notif-v2-3-6f3a3ca3923c@arm.com>
Date:   Tue, 19 Sep 2023 18:40:51 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Sudeep Holla <sudeep.holla@....com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Marc Bonnici <marc.bonnici@....com>,
        Coboy Chen <coboy.chen@...iatek.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Olivier Deprez <olivier.deprez@....com>
Subject: [PATCH RFT v2 03/18] firmware: arm_ffa: Implement the notification
 bind and unbind interface

A receiver endpoint must bind a notification to any sender endpoint
before the latter can signal the notification to the former. The receiver
assigns one or more doorbells to a specific sender. Only the sender can
ring these doorbells.

A receiver uses the FFA_NOTIFICATION_BIND interface to bind one or more
notifications to the sender. A receiver un-binds a notification from a
sender endpoint to stop the notification from being signaled. It uses
the FFA_NOTIFICATION_UNBIND interface to do this.

Allow the FF-A driver to be able to bind and unbind a given notification
ID to a specific partition ID. This will be used to register and
unregister notification callbacks from the FF-A client drivers.

Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_ffa/driver.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 5522523afefe..ab67cb22a206 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -575,6 +575,35 @@ static int ffa_notification_bitmap_destroy(void)
 	return 0;
 }
 
+#define NOTIFICATION_LOW_MASK		GENMASK(31, 0)
+#define NOTIFICATION_HIGH_MASK		GENMASK(63, 32)
+#define NOTIFICATION_BITMAP_HIGH(x)	\
+		((u32)(FIELD_GET(NOTIFICATION_HIGH_MASK, (x))))
+#define NOTIFICATION_BITMAP_LOW(x)	\
+		((u32)(FIELD_GET(NOTIFICATION_LOW_MASK, (x))))
+
+static int ffa_notification_bind_common(u16 dst_id, u64 bitmap,
+					u32 flags, bool is_bind)
+{
+	ffa_value_t ret;
+	u32 func, src_dst_ids = PACK_TARGET_INFO(drv_info->vm_id, dst_id);
+
+	func = is_bind ? FFA_NOTIFICATION_BIND : FFA_NOTIFICATION_UNBIND;
+
+	invoke_ffa_fn((ffa_value_t){
+		  .a0 = func, .a1 = src_dst_ids, .a2 = flags,
+		  .a3 = NOTIFICATION_BITMAP_LOW(bitmap),
+		  .a4 = NOTIFICATION_BITMAP_HIGH(bitmap),
+		  }, &ret);
+
+	if (ret.a0 == FFA_ERROR)
+		return ffa_to_linux_errno((int)ret.a2);
+	else if (ret.a0 != FFA_SUCCESS)
+		return -EINVAL;
+
+	return 0;
+}
+
 static void ffa_set_up_mem_ops_native_flag(void)
 {
 	if (!ffa_features(FFA_FN_NATIVE(MEM_LEND), 0, NULL, NULL) ||

-- 
2.42.0