diff options
Diffstat (limited to 'drivers/cxl/core/pci.c')
| -rw-r--r-- | drivers/cxl/core/pci.c | 48 |
1 files changed, 31 insertions, 17 deletions
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 3b80e9a76ba8..b50551601c2e 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -415,17 +415,20 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm, */ if (global_ctrl & CXL_HDM_DECODER_ENABLE || (!hdm && info->mem_enabled)) return devm_cxl_enable_mem(&port->dev, cxlds); - else if (!hdm) - return -ENODEV; - root = to_cxl_port(port->dev.parent); - while (!is_cxl_root(root) && is_cxl_port(root->dev.parent)) - root = to_cxl_port(root->dev.parent); - if (!is_cxl_root(root)) { - dev_err(dev, "Failed to acquire root port for HDM enable\n"); + /* + * If the HDM Decoder Capability does not exist and DVSEC was + * not setup, the DVSEC based emulation cannot be used. + */ + if (!hdm) return -ENODEV; - } + /* The HDM Decoder Capability exists but is globally disabled. */ + + /* + * If the DVSEC CXL Range registers are not enabled, just + * enable and use the HDM Decoder Capability registers. + */ if (!info->mem_enabled) { rc = devm_cxl_enable_hdm(&port->dev, cxlhdm); if (rc) @@ -434,6 +437,26 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm, return devm_cxl_enable_mem(&port->dev, cxlds); } + /* + * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base + * [High,Low] when HDM operation is enabled the range register values + * are ignored by the device, but the spec also recommends matching the + * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges + * are expected even though Linux does not require or maintain that + * match. Check if at least one DVSEC range is enabled and allowed by + * the platform. That is, the DVSEC range must be covered by a locked + * platform window (CFMWS). Fail otherwise as the endpoint's decoders + * cannot be used. + */ + + root = to_cxl_port(port->dev.parent); + while (!is_cxl_root(root) && is_cxl_port(root->dev.parent)) + root = to_cxl_port(root->dev.parent); + if (!is_cxl_root(root)) { + dev_err(dev, "Failed to acquire root port for HDM enable\n"); + return -ENODEV; + } + for (i = 0, allowed = 0; i < info->ranges; i++) { struct device *cxld_dev; @@ -453,15 +476,6 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm, return -ENXIO; } - /* - * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base - * [High,Low] when HDM operation is enabled the range register values - * are ignored by the device, but the spec also recommends matching the - * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges - * are expected even though Linux does not require or maintain that - * match. If at least one DVSEC range is enabled and allowed, skip HDM - * Decoder Capability Enable. - */ return 0; } EXPORT_SYMBOL_NS_GPL(cxl_hdm_decode_init, "CXL"); |