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Message-Id: <20250711183648.30766-21-james.morse@arm.com>
Date: Fri, 11 Jul 2025 18:36:32 +0000
From: James Morse <james.morse@....com>
To: linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Cc: Rob Herring <robh@...nel.org>,
Ben Horgan <ben.horgan@....com>,
Rohit Mathew <rohit.mathew@....com>,
Shanker Donthineni <sdonthineni@...dia.com>,
Zeng Heng <zengheng4@...wei.com>,
Lecopzer Chen <lecopzerc@...dia.com>,
Carl Worth <carl@...amperecomputing.com>,
shameerali.kolothum.thodi@...wei.com,
D Scott Phillips OS <scott@...amperecomputing.com>,
lcherian@...vell.com,
bobo.shaobowang@...wei.com,
tan.shaopeng@...itsu.com,
baolin.wang@...ux.alibaba.com,
Jamie Iles <quic_jiles@...cinc.com>,
Xin Hao <xhao@...ux.alibaba.com>,
peternewman@...gle.com,
dfustini@...libre.com,
amitsinght@...vell.com,
David Hildenbrand <david@...hat.com>,
Rex Nie <rex.nie@...uarmicro.com>,
Dave Martin <dave.martin@....com>,
Koba Ko <kobak@...dia.com>,
James Morse <james.morse@....com>,
Dave Martin <Dave.Martin@....com>
Subject: [RFC PATCH 20/36] arm_mpam: Probe the hardware features resctrl supports
Expand the probing support with the control and monitor types
we can use with resctrl.
CC: Dave Martin <Dave.Martin@....com>
Signed-off-by: James Morse <james.morse@....com>
---
drivers/platform/arm64/mpam/mpam_devices.c | 154 +++++++++++++++++++-
drivers/platform/arm64/mpam/mpam_internal.h | 53 +++++++
2 files changed, 206 insertions(+), 1 deletion(-)
diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index 8646fb85ad09..61911831ab39 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -102,7 +102,7 @@ static LLIST_HEAD(mpam_garbage);
static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg)
{
- WARN_ON_ONCE(reg > msc->mapped_hwpage_sz);
+ WARN_ON_ONCE(reg + sizeof(u32) > msc->mapped_hwpage_sz);
WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility));
return readl_relaxed(msc->mapped_hwpage + reg);
@@ -131,6 +131,20 @@ static inline void _mpam_write_partsel_reg(struct mpam_msc *msc, u16 reg, u32 va
}
#define mpam_write_partsel_reg(msc, reg, val) _mpam_write_partsel_reg(msc, MPAMCFG_##reg, val)
+static inline u32 _mpam_read_monsel_reg(struct mpam_msc *msc, u16 reg)
+{
+ mpam_mon_sel_lock_held(msc);
+ return __mpam_read_reg(msc, reg);
+}
+#define mpam_read_monsel_reg(msc, reg) _mpam_read_monsel_reg(msc, MSMON_##reg)
+
+static inline void _mpam_write_monsel_reg(struct mpam_msc *msc, u16 reg, u32 val)
+{
+ mpam_mon_sel_lock_held(msc);
+ __mpam_write_reg(msc, reg, val);
+}
+#define mpam_write_monsel_reg(msc, reg, val) _mpam_write_monsel_reg(msc, MSMON_##reg, val)
+
static u64 mpam_msc_read_idr(struct mpam_msc *msc)
{
u64 idr_high = 0, idr_low;
@@ -645,6 +659,137 @@ static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc,
return found;
}
+/*
+ * IHI009A.a has this nugget: "If a monitor does not support automatic behaviour
+ * of NRDY, software can use this bit for any purpose" - so hardware might not
+ * implement this - but it isn't RES0.
+ *
+ * Try and see what values stick in this bit. If we can write either value,
+ * its probably not implemented by hardware.
+ */
+#define mpam_ris_hw_probe_hw_nrdy(_ris, _mon_reg, _result) \
+do { \
+ u32 now; \
+ u64 mon_sel; \
+ bool can_set, can_clear; \
+ struct mpam_msc *_msc = _ris->vmsc->msc; \
+ \
+ if (WARN_ON_ONCE(!mpam_mon_sel_inner_lock(_msc))) { \
+ _result = false; \
+ break; \
+ } \
+ mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, 0) | \
+ FIELD_PREP(MSMON_CFG_MON_SEL_RIS, _ris->ris_idx); \
+ mpam_write_monsel_reg(_msc, CFG_MON_SEL, mon_sel); \
+ \
+ mpam_write_monsel_reg(_msc, _mon_reg, MSMON___NRDY); \
+ now = mpam_read_monsel_reg(_msc, _mon_reg); \
+ can_set = now & MSMON___NRDY; \
+ \
+ mpam_write_monsel_reg(_msc, _mon_reg, 0); \
+ now = mpam_read_monsel_reg(_msc, _mon_reg); \
+ can_clear = !(now & MSMON___NRDY); \
+ mpam_mon_sel_inner_unlock(_msc); \
+ \
+ _result = (!can_set || !can_clear); \
+} while (0)
+
+static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
+{
+ int err;
+ struct mpam_msc *msc = ris->vmsc->msc;
+ struct mpam_props *props = &ris->props;
+
+ lockdep_assert_held(&msc->probe_lock);
+ lockdep_assert_held(&msc->part_sel_lock);
+
+ /* Cache Portion partitioning */
+ if (FIELD_GET(MPAMF_IDR_HAS_CPOR_PART, ris->idr)) {
+ u32 cpor_features = mpam_read_partsel_reg(msc, CPOR_IDR);
+
+ props->cpbm_wd = FIELD_GET(MPAMF_CPOR_IDR_CPBM_WD, cpor_features);
+ if (props->cpbm_wd)
+ mpam_set_feature(mpam_feat_cpor_part, props);
+ }
+
+ /* Memory bandwidth partitioning */
+ if (FIELD_GET(MPAMF_IDR_HAS_MBW_PART, ris->idr)) {
+ u32 mbw_features = mpam_read_partsel_reg(msc, MBW_IDR);
+
+ /* portion bitmap resolution */
+ props->mbw_pbm_bits = FIELD_GET(MPAMF_MBW_IDR_BWPBM_WD, mbw_features);
+ if (props->mbw_pbm_bits &&
+ FIELD_GET(MPAMF_MBW_IDR_HAS_PBM, mbw_features))
+ mpam_set_feature(mpam_feat_mbw_part, props);
+
+ props->bwa_wd = FIELD_GET(MPAMF_MBW_IDR_BWA_WD, mbw_features);
+ if (props->bwa_wd && FIELD_GET(MPAMF_MBW_IDR_HAS_MAX, mbw_features))
+ mpam_set_feature(mpam_feat_mbw_max, props);
+ }
+
+ /* Performance Monitoring */
+ if (FIELD_GET(MPAMF_IDR_HAS_MSMON, ris->idr)) {
+ u32 msmon_features = mpam_read_partsel_reg(msc, MSMON_IDR);
+
+ /*
+ * If the firmware max-nrdy-us property is missing, the
+ * CSU counters can't be used. Should we wait forever?
+ */
+ err = device_property_read_u32(&msc->pdev->dev,
+ "arm,not-ready-us",
+ &msc->nrdy_usec);
+
+ if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_CSU, msmon_features)) {
+ u32 csumonidr;
+
+ csumonidr = mpam_read_partsel_reg(msc, CSUMON_IDR);
+ props->num_csu_mon = FIELD_GET(MPAMF_CSUMON_IDR_NUM_MON, csumonidr);
+ if (props->num_csu_mon) {
+ bool hw_managed;
+
+ mpam_set_feature(mpam_feat_msmon_csu, props);
+
+ /* Is NRDY hardware managed? */
+ mpam_mon_sel_outer_lock(msc);
+ mpam_ris_hw_probe_hw_nrdy(ris, CSU, hw_managed);
+ mpam_mon_sel_outer_unlock(msc);
+ if (hw_managed)
+ mpam_set_feature(mpam_feat_msmon_csu_hw_nrdy, props);
+ }
+
+ /*
+ * Accept the missing firmware property if NRDY appears
+ * un-implemented.
+ */
+ if (err && mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, props))
+ pr_err_once("Counters are not usable because not-ready timeout was not provided by firmware.");
+ }
+ if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_MBWU, msmon_features)) {
+ bool hw_managed;
+ u32 mbwumonidr = mpam_read_partsel_reg(msc, MBWUMON_IDR);
+
+ props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumonidr);
+ if (props->num_mbwu_mon)
+ mpam_set_feature(mpam_feat_msmon_mbwu, props);
+
+ if (FIELD_GET(MPAMF_MBWUMON_IDR_HAS_RWBW, mbwumonidr))
+ mpam_set_feature(mpam_feat_msmon_mbwu_rwbw, props);
+
+ /* Is NRDY hardware managed? */
+ mpam_mon_sel_outer_lock(msc);
+ mpam_ris_hw_probe_hw_nrdy(ris, MBWU, hw_managed);
+ mpam_mon_sel_outer_unlock(msc);
+ if (hw_managed)
+ mpam_set_feature(mpam_feat_msmon_mbwu_hw_nrdy, props);
+
+ /*
+ * Don't warn about any missing firmware property for
+ * MBWU NRDY - it doesn't make any sense!
+ */
+ }
+ }
+}
+
static int mpam_msc_hw_probe(struct mpam_msc *msc)
{
u64 idr;
@@ -665,6 +810,7 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
idr = mpam_msc_read_idr(msc);
mutex_unlock(&msc->part_sel_lock);
+
msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr);
/* Use these values so partid/pmg always starts with a valid value */
@@ -685,6 +831,12 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
ris = mpam_get_or_create_ris(msc, ris_idx);
if (IS_ERR(ris))
return PTR_ERR(ris);
+ ris->idr = idr;
+
+ mutex_lock(&msc->part_sel_lock);
+ __mpam_part_sel(ris_idx, 0, msc);
+ mpam_ris_hw_probe(ris);
+ mutex_unlock(&msc->part_sel_lock);
}
spin_lock(&partid_max_lock);
diff --git a/drivers/platform/arm64/mpam/mpam_internal.h b/drivers/platform/arm64/mpam/mpam_internal.h
index 42a454d5f914..ae6fd1f62cc4 100644
--- a/drivers/platform/arm64/mpam/mpam_internal.h
+++ b/drivers/platform/arm64/mpam/mpam_internal.h
@@ -136,6 +136,55 @@ static inline void mpam_mon_sel_lock_held(struct mpam_msc *msc)
lockdep_assert_preemption_enabled();
}
+/*
+ * When we compact the supported features, we don't care what they are.
+ * Storing them as a bitmap makes life easy.
+ */
+typedef u16 mpam_features_t;
+
+/* Bits for mpam_features_t */
+enum mpam_device_features {
+ mpam_feat_ccap_part = 0,
+ mpam_feat_cpor_part,
+ mpam_feat_mbw_part,
+ mpam_feat_mbw_min,
+ mpam_feat_mbw_max,
+ mpam_feat_mbw_prop,
+ mpam_feat_msmon,
+ mpam_feat_msmon_csu,
+ mpam_feat_msmon_csu_capture,
+ mpam_feat_msmon_csu_hw_nrdy,
+ mpam_feat_msmon_mbwu,
+ mpam_feat_msmon_mbwu_capture,
+ mpam_feat_msmon_mbwu_rwbw,
+ mpam_feat_msmon_mbwu_hw_nrdy,
+ mpam_feat_msmon_capt,
+ MPAM_FEATURE_LAST,
+};
+#define MPAM_ALL_FEATURES ((1 << MPAM_FEATURE_LAST) - 1)
+
+struct mpam_props {
+ mpam_features_t features;
+
+ u16 cpbm_wd;
+ u16 mbw_pbm_bits;
+ u16 bwa_wd;
+ u16 num_csu_mon;
+ u16 num_mbwu_mon;
+};
+
+static inline bool mpam_has_feature(enum mpam_device_features feat,
+ struct mpam_props *props)
+{
+ return (1 << feat) & props->features;
+}
+
+static inline void mpam_set_feature(enum mpam_device_features feat,
+ struct mpam_props *props)
+{
+ props->features |= (1 << feat);
+}
+
struct mpam_class {
/* mpam_components in this class */
struct list_head components;
@@ -175,6 +224,8 @@ struct mpam_vmsc {
/* mpam_msc_ris in this vmsc */
struct list_head ris;
+ struct mpam_props props;
+
/* All RIS in this vMSC are members of this MSC */
struct mpam_msc *msc;
@@ -186,6 +237,8 @@ struct mpam_vmsc {
struct mpam_msc_ris {
u8 ris_idx;
+ u64 idr;
+ struct mpam_props props;
cpumask_t affinity;
--
2.39.5
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