[PATCH v6 29/34] arm_mpam: Probe for long/lwd mbwu counters
From: Ben Horgan <ben.horgan@arm.com>
Date: 2025-11-19 12:26:08
Also in:
linux-acpi, lkml
Subsystem:
mpam driver, the rest · Maintainers:
James Morse, Ben Horgan, Linus Torvalds
From: Rohit Mathew <redacted> mpam v0.1 and versions above v1.0 support optional long counter for memory bandwidth monitoring. The MPAMF_MBWUMON_IDR register has fields indicating support for long counters. Probe these feature bits. The mpam_feat_msmon_mbwu feature is used to indicate that bandwidth monitors are supported, instead of muddling this with which size of bandwidth monitors, add an explicit 31 bit counter feature. Signed-off-by: Rohit Mathew <redacted> [ morse: Added 31bit counter feature to simplify later logic ] Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Ben Horgan <ben.horgan@arm.com> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> Reviewed-by: Gavin Shan <redacted> Reviewed-by: Shaopeng Tan <redacted> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Shaopeng Tan <redacted> Tested-by: Peter Newman <redacted> Tested-by: Carl Worth <redacted> Tested-by: Gavin Shan <redacted> Tested-by: Zeng Heng <redacted> Tested-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Ben Horgan <ben.horgan@arm.com> --- Changes since v3: Only set the exact counter length that is supported --- drivers/resctrl/mpam_devices.c | 35 ++++++++++++++++++++++----------- drivers/resctrl/mpam_internal.h | 3 +++ 2 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index ecb5ecad50f8..380386cceb74 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c@@ -783,25 +783,36 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris) dev_err_once(dev, "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; + bool has_long, hw_managed; u32 mbwumon_idr = mpam_read_partsel_reg(msc, MBWUMON_IDR); props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumon_idr); - if (props->num_mbwu_mon) + if (props->num_mbwu_mon) { mpam_set_feature(mpam_feat_msmon_mbwu, props); - if (FIELD_GET(MPAMF_MBWUMON_IDR_HAS_RWBW, mbwumon_idr)) - mpam_set_feature(mpam_feat_msmon_mbwu_rwbw, props); + if (FIELD_GET(MPAMF_MBWUMON_IDR_HAS_RWBW, mbwumon_idr)) + mpam_set_feature(mpam_feat_msmon_mbwu_rwbw, props); - /* Is NRDY hardware managed? */ - hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, MBWU); - if (hw_managed) - mpam_set_feature(mpam_feat_msmon_mbwu_hw_nrdy, props); + has_long = FIELD_GET(MPAMF_MBWUMON_IDR_HAS_LONG, mbwumon_idr); + if (has_long) { + if (FIELD_GET(MPAMF_MBWUMON_IDR_LWD, mbwumon_idr)) + mpam_set_feature(mpam_feat_msmon_mbwu_63counter, props); + else + mpam_set_feature(mpam_feat_msmon_mbwu_44counter, props); + } else { + mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props); + } - /* - * Don't warn about any missing firmware property for - * MBWU NRDY - it doesn't make any sense! - */ + /* Is NRDY hardware managed? */ + hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, MBWU); + 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! + */ + } } }
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 218e2f48c7bf..693a315c4710 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h@@ -164,6 +164,9 @@ enum mpam_device_features { mpam_feat_msmon_csu_xcl, mpam_feat_msmon_csu_hw_nrdy, mpam_feat_msmon_mbwu, + mpam_feat_msmon_mbwu_31counter, + mpam_feat_msmon_mbwu_44counter, + mpam_feat_msmon_mbwu_63counter, mpam_feat_msmon_mbwu_capture, mpam_feat_msmon_mbwu_rwbw, mpam_feat_msmon_mbwu_hw_nrdy,
--
2.43.0