[PATCH v2 12/18] firmware: arm_ffa: Reject higher major version as incompatible

[Sudeep Holla <sudeep.holla@arm.com>]

When the firmware compatibility was handled previously in the commit
8e3f9da608f1 ("firmware: arm_ffa: Handle compatibility with different firmware versions"),
we only addressed firmware versions that have higher minor versions
compared to the driver version which is should be considered compatible
unless the firmware returns NOT_SUPPORTED.

However, if the firmware reports higher major version than the driver
supported, we need to reject it. If the firmware can work in a compatible
mode with the driver requested version, it must return the same major
version as requested.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/firmware/arm_ffa/driver.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 8188c8dd3ed6ceb9e9966148b42ef2f88baa6dd3..1a0f2d1d7a2220e341d4e78240e799a2919fca30 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -150,6 +150,14 @@ static int ffa_version_check(u32 *version)
 		return -EOPNOTSUPP;
 	}
 
+	if (FFA_MAJOR_VERSION(ver.a0) > FFA_MAJOR_VERSION(FFA_DRIVER_VERSION)) {
+		pr_err("Incompatible v%d.%d! Latest supported v%d.%d\n",
+		       FFA_MAJOR_VERSION(ver.a0), FFA_MINOR_VERSION(ver.a0),
+		       FFA_MAJOR_VERSION(FFA_DRIVER_VERSION),
+		       FFA_MINOR_VERSION(FFA_DRIVER_VERSION));
+		return -EINVAL;
+	}
+
 	if (ver.a0 < FFA_MIN_VERSION) {
 		pr_err("Incompatible v%d.%d! Earliest supported v%d.%d\n",
 		       FFA_MAJOR_VERSION(ver.a0), FFA_MINOR_VERSION(ver.a0),

-- 
2.34.1