From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/... --------------------------- When a CPU comes online, it may bring a newly accessible MSC with it. Only the default partid has its value reset by hardware, and even then the MSC might not have been reset since its config was previously dirtyied. e.g. Kexec. Any in-use partid must have its configuration restored, or reset. In-use partids may be held in caches and evicted later. MSC are also reset when CPUs are taken offline to cover cases where firmware doesn't reset the MSC over reboot using UEFI, or kexec where there is no firmware involvement. If the configuration for a RIS has not been touched since it was brought online, it does not need resetting again. To reset, write the maximum values for all discovered controls. CC: Rohit Mathew <Rohit.Mathew@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/platform/mpam/mpam_devices.c | 126 +++++++++++++++++++++++++- drivers/platform/mpam/mpam_internal.h | 5 +- 2 files changed, 129 insertions(+), 2 deletions(-) diff --git a/drivers/platform/mpam/mpam_devices.c b/drivers/platform/mpam/mpam_devices.c index f1574f393e1d..e281e6e910e0 100644 --- a/drivers/platform/mpam/mpam_devices.c +++ b/drivers/platform/mpam/mpam_devices.c @@ -7,6 +7,7 @@ #include <linux/atomic.h> #include <linux/arm_mpam.h> #include <linux/bitfield.h> +#include <linux/bitmap.h> #include <linux/cacheinfo.h> #include <linux/cpu.h> #include <linux/cpumask.h> @@ -644,8 +645,115 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) return 0; } +static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd) +{ + u32 num_words, msb; + u32 bm = ~0; + int i; + + lockdep_assert_held(&msc->part_sel_lock); + + /* + * Write all ~0 to all but the last 32bit-word, which may + * have fewer bits... + */ + num_words = DIV_ROUND_UP(wd, 32); + for (i = 0; i < num_words - 1; i++, reg += sizeof(bm)) + __mpam_write_reg(msc, reg, bm); + + /* + * ....and then the last (maybe) partial 32bit word. When wd is a + * multiple of 32, msb should be 31 to write a full 32bit word. + */ + msb = (wd - 1) % 32; + bm = GENMASK(msb , 0); + if (bm) + __mpam_write_reg(msc, reg, bm); +} + +static void mpam_reset_ris_partid(struct mpam_msc_ris *ris, u16 partid) +{ + struct mpam_msc *msc = ris->msc; + u16 bwa_fract = MPAMCFG_MBW_MAX_MAX; + struct mpam_props *rprops = &ris->props; + + lockdep_assert_held(&msc->lock); + + spin_lock(&msc->part_sel_lock); + __mpam_part_sel(ris->ris_idx, partid, msc); + + if (mpam_has_feature(mpam_feat_cpor_part, rprops)) + mpam_reset_msc_bitmap(msc, MPAMCFG_CPBM, rprops->cpbm_wd); + + if (mpam_has_feature(mpam_feat_mbw_part, rprops)) + mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM, rprops->mbw_pbm_bits); + + if (mpam_has_feature(mpam_feat_mbw_min, rprops)) + mpam_write_partsel_reg(msc, MBW_MIN, 0); + + if (mpam_has_feature(mpam_feat_mbw_max, rprops)) + mpam_write_partsel_reg(msc, MBW_MAX, bwa_fract); + + if (mpam_has_feature(mpam_feat_mbw_prop, rprops)) + mpam_write_partsel_reg(msc, MBW_PROP, bwa_fract); + spin_unlock(&msc->part_sel_lock); +} + +static void mpam_reset_ris(struct mpam_msc_ris *ris) +{ + u16 partid, partid_max; + struct mpam_msc *msc = ris->msc; + + lockdep_assert_held(&msc->lock); + + if (ris->in_reset_state) + return; + + spin_lock(&partid_max_lock); + partid_max = mpam_partid_max; + spin_unlock(&partid_max_lock); + for (partid = 0; partid < partid_max; partid++) + mpam_reset_ris_partid(ris, partid); +} + +static void mpam_reset_msc(struct mpam_msc *msc, bool online) +{ + int idx; + struct mpam_msc_ris *ris; + + lockdep_assert_held(&msc->lock); + + idx = srcu_read_lock(&mpam_srcu); + list_for_each_entry_rcu(ris, &msc->ris, msc_list) { + mpam_reset_ris(ris); + + /* + * Set in_reset_state when coming online. The reset state + * for non-zero partid may be lost while the CPUs are offline. + */ + ris->in_reset_state = online; + } + srcu_read_unlock(&mpam_srcu, idx); +} + static int mpam_cpu_online(unsigned int cpu) { + int idx; + struct mpam_msc *msc; + + idx = srcu_read_lock(&mpam_srcu); + list_for_each_entry_rcu(msc, &mpam_all_msc, glbl_list) { + if (!cpumask_test_cpu(cpu, &msc->accessibility)) + continue; + + if (atomic_fetch_inc(&msc->online_refs) == 0) { + mutex_lock(&msc->lock); + mpam_reset_msc(msc, true); + mutex_unlock(&msc->lock); + } + } + srcu_read_unlock(&mpam_srcu, idx); + return 0; } @@ -684,6 +792,22 @@ static int mpam_discovery_cpu_online(unsigned int cpu) static int mpam_cpu_offline(unsigned int cpu) { + int idx; + struct mpam_msc *msc; + + idx = srcu_read_lock(&mpam_srcu); + list_for_each_entry_rcu(msc, &mpam_all_msc, glbl_list) { + if (!cpumask_test_cpu(cpu, &msc->accessibility)) + continue; + + if (atomic_dec_and_test(&msc->online_refs)) { + mutex_lock(&msc->lock); + mpam_reset_msc(msc, false); + mutex_unlock(&msc->lock); + } + } + srcu_read_unlock(&mpam_srcu, idx); + return 0; } @@ -1043,7 +1167,7 @@ static void mpam_enable_once(void) mpam_register_cpuhp_callbacks(mpam_cpu_online); pr_info("MPAM enabled with %u partid and %u pmg\n", - mpam_partid_max + 1, mpam_pmg_max + 1); + READ_ONCE(mpam_partid_max) + 1, mpam_pmg_max + 1); } /* diff --git a/drivers/platform/mpam/mpam_internal.h b/drivers/platform/mpam/mpam_internal.h index db50f5e40d98..dd1c017c6e08 100644 --- a/drivers/platform/mpam/mpam_internal.h +++ b/drivers/platform/mpam/mpam_internal.h @@ -5,6 +5,7 @@ #define MPAM_INTERNAL_H #include <linux/arm_mpam.h> +#include <linux/atomic.h> #include <linux/cpumask.h> #include <linux/io.h> #include <linux/mailbox_client.h> @@ -28,7 +29,8 @@ struct mpam_msc struct pcc_mbox_chan *pcc_chan; u32 nrdy_usec; cpumask_t accessibility; - + atomic_t online_refs; + struct mutex lock; bool probed; u16 partid_max; @@ -140,6 +142,7 @@ struct mpam_msc_ris u8 ris_idx; u64 idr; struct mpam_props props; + bool in_reset_state; cpumask_t affinity; -- 2.25.1