hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAKAKN -------------------------------- According to the bit width of the fixed-point fraction implemented by hardware, the maximum supported precision is calculated to reduce the conversion granularity as much as possible, so that improving conversion accuracy between percent and fixed-point fraction. Fixes: 58db5c68e84a ("untested: arm_mpam: resctrl: Add support for MB resource") Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/platform/mpam/mpam_resctrl.c | 40 ++++++++++++++++++---------- 1 file changed, 26 insertions(+), 14 deletions(-) diff --git a/drivers/platform/mpam/mpam_resctrl.c b/drivers/platform/mpam/mpam_resctrl.c index 347b7a66c598..d67d29c913f0 100644 --- a/drivers/platform/mpam/mpam_resctrl.c +++ b/drivers/platform/mpam/mpam_resctrl.c @@ -536,21 +536,31 @@ static u32 mbw_pbm_to_percent(unsigned long mbw_pbm, struct mpam_props *cprops) return result; } -static u32 mbw_max_to_percent(u16 mbw_max, struct mpam_props *cprops) +static int get_wd_precision(u8 wd) +{ + int ret = (1 << wd) / MAX_MBA_BW; + + if (!ret) + return 1; + + return ret; +} + +static u32 mbw_max_to_percent(u16 mbw_max, u8 wd) { u8 bit; - u32 divisor = 2, value = 0; + u32 divisor = 2, value = 0, precision = get_wd_precision(wd); for (bit = 15; bit; bit--) { if (mbw_max & BIT(bit)) - value += MAX_MBA_BW / divisor; + value += MAX_MBA_BW * precision / divisor; divisor <<= 1; } - return value; + return DIV_ROUND_UP(value, precision); } -static u32 percent_to_mbw_pbm(u8 pc, struct mpam_props *cprops) +static u32 percent_to_mbw_pbm(u32 pc, struct mpam_props *cprops) { u32 granularity = get_mba_granularity(cprops); u8 num_bits = pc / granularity; @@ -562,26 +572,28 @@ static u32 percent_to_mbw_pbm(u8 pc, struct mpam_props *cprops) return (1 << num_bits) - 1; } -static u16 percent_to_mbw_max(u8 pc, struct mpam_props *cprops) +static u16 percent_to_mbw_max(u32 pc, u8 wd) { u8 bit; - u32 divisor = 2, value = 0; + u32 divisor = 2, value = 0, precision = get_wd_precision(wd); - if (WARN_ON_ONCE(cprops->bwa_wd > 15)) + if (WARN_ON_ONCE(wd > 15)) return MAX_MBA_BW; + pc *= precision; + for (bit = 15; bit; bit--) { - if (pc >= MAX_MBA_BW / divisor) { - pc -= MAX_MBA_BW / divisor; + if (pc >= MAX_MBA_BW * precision / divisor) { + pc -= MAX_MBA_BW * precision / divisor; value |= BIT(bit); } divisor <<= 1; - if (!pc || !(MAX_MBA_BW / divisor)) + if (!pc || !(MAX_MBA_BW * precision / divisor)) break; } - value &= GENMASK(15, 15 - cprops->bwa_wd + 1); + value &= GENMASK(15, 15 - wd + 1); return value; } @@ -947,7 +959,7 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d, /* TODO: Scaling is not yet supported */ return mbw_pbm_to_percent(cfg->mbw_pbm, cprops); case mpam_feat_mbw_max: - return mbw_max_to_percent(cfg->mbw_max, cprops); + return mbw_max_to_percent(cfg->mbw_max, cprops->bwa_wd); default: return -EINVAL; } @@ -989,7 +1001,7 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_domain *d, mpam_set_feature(mpam_feat_mbw_part, &cfg); break; } else if (mpam_has_feature(mpam_feat_mbw_max, cprops)) { - cfg.mbw_max = percent_to_mbw_max(cfg_val, cprops); + cfg.mbw_max = percent_to_mbw_max(cfg_val, cprops->bwa_wd); mpam_set_feature(mpam_feat_mbw_max, &cfg); break; } -- 2.25.1