[PATCH mpam/v6.10-rc1 RFC 3/4] arm_mpam: Correct the judgment condition of the CMAX feature

[Zeng Heng <zengheng4@huawei.com>]

According to Arm Architecture MPAM Reference Manual (version DDI 0598D.b),
to check whether hardware supports the CMAX feature or not, not only needs
to check the CMAX_WD field of the MPAMF_CCAP_IDR register, but also needs
to check the NO_CMAX field.

Fixes: a275036b6767 ("arm_mpam: Probe and reset the rest of the features")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
 drivers/platform/arm64/mpam/mpam_devices.c  | 6 ++++--
 drivers/platform/arm64/mpam/mpam_internal.h | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index acb91352c524..9acac8a22573 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -779,8 +779,10 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
 		u32 ccap_features = mpam_read_partsel_reg(msc, CCAP_IDR);
 
 		props->cmax_wd = FIELD_GET(MPAMF_CCAP_IDR_CMAX_WD, ccap_features);
-		if (props->cmax_wd)
-			mpam_set_feature(mpam_feat_ccap_part, props);
+		if (props->cmax_wd) {
+			if (!FIELD_GET(MPAMF_CCAP_IDR_NO_CMAX, ccap_features))
+				mpam_set_feature(mpam_feat_ccap_part, props);
+		}
 	}
 
 	/* Cache Portion partitioning */
diff --git a/drivers/platform/arm64/mpam/mpam_internal.h b/drivers/platform/arm64/mpam/mpam_internal.h
index 61aea729aa73..0e714ce7fa96 100644
--- a/drivers/platform/arm64/mpam/mpam_internal.h
+++ b/drivers/platform/arm64/mpam/mpam_internal.h
@@ -450,6 +450,7 @@ void mpam_resctrl_exit(void);
 
 /* MPAMF_CCAP_IDR - MPAM features cache capacity partitioning ID register */
 #define MPAMF_CCAP_IDR_CMAX_WD                  GENMASK(5, 0)
+#define MPAMF_CCAP_IDR_NO_CMAX                  BIT(30)
 
 /* MPAMF_MBW_IDR - MPAM features memory bandwidth partitioning ID register */
 #define MPAMF_MBW_IDR_BWA_WD            GENMASK(5, 0)
-- 
2.25.1