diff options
| -rw-r--r-- | drivers/cxl/core/region.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 06cac5d28bf1..f492d1291e72 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2923,6 +2923,11 @@ static bool has_hpa_to_spa(struct cxl_root_decoder *cxlrd) return cxlrd->ops && cxlrd->ops->hpa_to_spa; } +static bool has_spa_to_hpa(struct cxl_root_decoder *cxlrd) +{ + return cxlrd->ops && cxlrd->ops->spa_to_hpa; +} + u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd, u64 dpa) { @@ -2993,6 +2998,102 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd, return hpa; } +struct dpa_result { + struct cxl_memdev *cxlmd; + u64 dpa; +}; + +static int __maybe_unused region_offset_to_dpa_result(struct cxl_region *cxlr, + u64 offset, + struct dpa_result *result) +{ + struct cxl_region_params *p = &cxlr->params; + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent); + struct cxl_endpoint_decoder *cxled; + u64 hpa, hpa_offset, dpa_offset; + u64 bits_upper, bits_lower; + u64 shifted, rem, temp; + u16 eig = 0; + u8 eiw = 0; + int pos; + + lockdep_assert_held(&cxl_rwsem.region); + lockdep_assert_held(&cxl_rwsem.dpa); + + /* Input validation ensures valid ways and gran */ + granularity_to_eig(p->interleave_granularity, &eig); + ways_to_eiw(p->interleave_ways, &eiw); + + /* + * If the root decoder has SPA to CXL HPA callback, use it. Otherwise + * CXL HPA is assumed to equal SPA. + */ + if (has_spa_to_hpa(cxlrd)) { + hpa = cxlrd->ops->spa_to_hpa(cxlrd, p->res->start + offset); + hpa_offset = hpa - p->res->start; + } else { + hpa_offset = offset; + } + /* + * Interleave position: CXL Spec 3.2 Section 8.2.4.20.13 + * eiw < 8 + * Position is in the IW bits at HPA_OFFSET[IG+8+IW-1:IG+8]. + * Per spec "remove IW bits starting with bit position IG+8" + * eiw >= 8 + * Position is not explicitly stored in HPA_OFFSET bits. It is + * derived from the modulo operation of the upper bits using + * the total number of interleave ways. + */ + if (eiw < 8) { + pos = (hpa_offset >> (eig + 8)) & GENMASK(eiw - 1, 0); + } else { + shifted = hpa_offset >> (eig + 8); + div64_u64_rem(shifted, p->interleave_ways, &rem); + pos = rem; + } + if (pos < 0 || pos >= p->nr_targets) { + dev_dbg(&cxlr->dev, "Invalid position %d for %d targets\n", + pos, p->nr_targets); + return -ENXIO; + } + + /* + * DPA offset: CXL Spec 3.2 Section 8.2.4.20.13 + * Lower bits [IG+7:0] pass through unchanged + * (eiw < 8) + * Per spec: DPAOffset[51:IG+8] = (HPAOffset[51:IG+IW+8] >> IW) + * Clear the position bits to isolate upper section, then + * reverse the left shift by eiw that occurred during DPA->HPA + * (eiw >= 8) + * Per spec: DPAOffset[51:IG+8] = HPAOffset[51:IG+IW] / 3 + * Extract upper bits from the correct bit range and divide by 3 + * to recover the original DPA upper bits + */ + bits_lower = hpa_offset & GENMASK_ULL(eig + 7, 0); + if (eiw < 8) { + temp = hpa_offset &= ~((u64)GENMASK(eig + eiw + 8 - 1, 0)); + dpa_offset = temp >> eiw; + } else { + bits_upper = div64_u64(hpa_offset >> (eig + eiw), 3); + dpa_offset = bits_upper << (eig + 8); + } + dpa_offset |= bits_lower; + + /* Look-up and return the result: a memdev and a DPA */ + for (int i = 0; i < p->nr_targets; i++) { + cxled = p->targets[i]; + if (cxled->pos != pos) + continue; + result->cxlmd = cxled_to_memdev(cxled); + result->dpa = cxl_dpa_resource_start(cxled) + dpa_offset; + + return 0; + } + dev_err(&cxlr->dev, "No device found for position %d\n", pos); + + return -ENXIO; +} + static struct lock_class_key cxl_pmem_region_key; static int cxl_pmem_region_alloc(struct cxl_region *cxlr) |