[PATCH v3 4/4] arm_mpam: Update architecture version check for MPAM MSC

[James Morse]

From: Zeng Heng <zengheng4 at huawei.com>

In addition to updating the CPU MPAM version check, the MPAM MSC version
check also need to be updated. mpam_msc_check_aidr() is added to check
the MSC AIDR register, ensuring that both the major and minor version
numbers fall within the supported range of the MPAM architecture version.

Signed-off-by: Zeng Heng <zengheng4 at huawei.com>
[ morse: changed mpam_msc_check_aidr() to accept versions like v1.2 ]
Signed-off-by: James Morse <james.morse at arm.com>
---
 drivers/resctrl/mpam_devices.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 916d8fd45ed5..1771e9712ca2 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -224,6 +224,24 @@ static inline void _mpam_write_monsel_reg(struct mpam_msc *msc, u16 reg, u32 val
 
 #define mpam_write_monsel_reg(msc, reg, val)   _mpam_write_monsel_reg(msc, MSMON_##reg, val)
 
+static bool mpam_msc_check_aidr(struct mpam_msc *msc)
+{
+	u32 aidr = __mpam_read_reg(msc, MPAMF_AIDR);
+	u32 major = FIELD_GET(MPAMF_AIDR_ARCH_MAJOR_REV, aidr);
+	u32 minor = FIELD_GET(MPAMF_AIDR_ARCH_MINOR_REV, aidr);
+
+	/*
+	 * v0.0 and >v2.x aren't supported, but anything else should be backward
+	 * compatible to v0.1 or v1.0.
+	 */
+	if (!major && !minor)
+		return false;
+	if (major > 1)
+		return false;
+
+	return true;
+}
+
 static u64 mpam_msc_read_idr(struct mpam_msc *msc)
 {
 	u64 idr_high = 0, idr_low;
@@ -951,9 +969,8 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
 
 	lockdep_assert_held(&msc->probe_lock);
 
-	idr = __mpam_read_reg(msc, MPAMF_AIDR);
-	if ((idr & MPAMF_AIDR_ARCH_MAJOR_REV) != MPAM_ARCHITECTURE_V1) {
-		dev_err_once(dev, "MSC does not match MPAM architecture v1.x\n");
+	if (!mpam_msc_check_aidr(msc)) {
+		dev_err_once(dev, "MSC does not match architecture v1.x\n");
 		return -EIO;
 	}
 
-- 
2.53.0