diff options
| -rw-r--r-- | drivers/cxl/core/pci.c | 167 |
1 files changed, 152 insertions, 15 deletions
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 3305e9b750af..c4c99ff7b55e 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -175,16 +175,149 @@ static int wait_for_valid(struct cxl_dev_state *cxlds) return -ETIMEDOUT; } +static int cxl_set_mem_enable(struct cxl_dev_state *cxlds, u16 val) +{ + struct pci_dev *pdev = to_pci_dev(cxlds->dev); + int d = cxlds->cxl_dvsec; + u16 ctrl; + int rc; + + rc = pci_read_config_word(pdev, d + CXL_DVSEC_CTRL_OFFSET, &ctrl); + if (rc < 0) + return rc; + + if ((ctrl & CXL_DVSEC_MEM_ENABLE) == val) + return 1; + ctrl &= ~CXL_DVSEC_MEM_ENABLE; + ctrl |= val; + + rc = pci_write_config_word(pdev, d + CXL_DVSEC_CTRL_OFFSET, ctrl); + if (rc < 0) + return rc; + + return 0; +} + +static void clear_mem_enable(void *cxlds) +{ + cxl_set_mem_enable(cxlds, 0); +} + +static int devm_cxl_enable_mem(struct device *host, struct cxl_dev_state *cxlds) +{ + int rc; + + rc = cxl_set_mem_enable(cxlds, CXL_DVSEC_MEM_ENABLE); + if (rc < 0) + return rc; + if (rc > 0) + return 0; + return devm_add_action_or_reset(host, clear_mem_enable, cxlds); +} + +static bool range_contains(struct range *r1, struct range *r2) +{ + return r1->start <= r2->start && r1->end >= r2->end; +} + +/* require dvsec ranges to be covered by a locked platform window */ +static int dvsec_range_allowed(struct device *dev, void *arg) +{ + struct range *dev_range = arg; + struct cxl_decoder *cxld; + struct range root_range; + + if (!is_root_decoder(dev)) + return 0; + + cxld = to_cxl_decoder(dev); + + if (!(cxld->flags & CXL_DECODER_F_LOCK)) + return 0; + if (!(cxld->flags & CXL_DECODER_F_RAM)) + return 0; + + root_range = (struct range) { + .start = cxld->platform_res.start, + .end = cxld->platform_res.end, + }; + + return range_contains(&root_range, dev_range); +} + +static void disable_hdm(void *_cxlhdm) +{ + u32 global_ctrl; + struct cxl_hdm *cxlhdm = _cxlhdm; + void __iomem *hdm = cxlhdm->regs.hdm_decoder; + + global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET); + writel(global_ctrl & ~CXL_HDM_DECODER_ENABLE, + hdm + CXL_HDM_DECODER_CTRL_OFFSET); +} + +static int devm_cxl_enable_hdm(struct device *host, struct cxl_hdm *cxlhdm) +{ + void __iomem *hdm = cxlhdm->regs.hdm_decoder; + u32 global_ctrl; + + global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET); + writel(global_ctrl | CXL_HDM_DECODER_ENABLE, + hdm + CXL_HDM_DECODER_CTRL_OFFSET); + + return devm_add_action_or_reset(host, disable_hdm, cxlhdm); +} + static bool __cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm, struct cxl_endpoint_dvsec_info *info) { void __iomem *hdm = cxlhdm->regs.hdm_decoder; - bool global_enable; + struct cxl_port *port = cxlhdm->port; + struct device *dev = cxlds->dev; + struct cxl_port *root; + int i, rc, allowed; u32 global_ctrl; global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET); - global_enable = global_ctrl & CXL_HDM_DECODER_ENABLE; + + /* + * If the HDM Decoder Capability is already enabled then assume + * that some other agent like platform firmware set it up. + */ + if (global_ctrl & CXL_HDM_DECODER_ENABLE) { + rc = devm_cxl_enable_mem(&port->dev, cxlds); + if (rc) + return false; + return true; + } + + 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 false; + } + + for (i = 0, allowed = 0; info->mem_enabled && i < info->ranges; i++) { + struct device *cxld_dev; + + cxld_dev = device_find_child(&root->dev, &info->dvsec_range[i], + dvsec_range_allowed); + if (!cxld_dev) { + dev_dbg(dev, "DVSEC Range%d denied by platform\n", i); + continue; + } + dev_dbg(dev, "DVSEC Range%d allowed by platform\n", i); + put_device(cxld_dev); + allowed++; + } + + if (!allowed) { + cxl_set_mem_enable(cxlds, 0); + info->mem_enabled = 0; + } /* * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base @@ -192,21 +325,19 @@ static bool __cxl_hdm_decode_init(struct cxl_dev_state *cxlds, * 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. + * match. If at least one DVSEC range is enabled and allowed, skip HDM + * Decoder Capability Enable. */ - if (!global_enable && info->mem_enabled && info->ranges) + if (info->mem_enabled) return false; - /* - * Permanently (for this boot at least) opt the device into HDM - * operation. Individual HDM decoders still need to be enabled after - * this point. - */ - if (!global_enable) { - dev_dbg(cxlds->dev, "Enabling HDM decode\n"); - writel(global_ctrl | CXL_HDM_DECODER_ENABLE, - hdm + CXL_HDM_DECODER_CTRL_OFFSET); - } + rc = devm_cxl_enable_hdm(&port->dev, cxlhdm); + if (rc) + return false; + + rc = devm_cxl_enable_mem(&port->dev, cxlds); + if (rc) + return false; return true; } @@ -261,9 +392,14 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm) return rc; } + /* + * The current DVSEC values are moot if the memory capability is + * disabled, and they will remain moot after the HDM Decoder + * capability is enabled. + */ info.mem_enabled = FIELD_GET(CXL_DVSEC_MEM_ENABLE, ctrl); if (!info.mem_enabled) - return 0; + goto hdm_init; for (i = 0; i < hdm_count; i++) { u64 base, size; @@ -312,6 +448,7 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm) * If DVSEC ranges are being used instead of HDM decoder registers there * is no use in trying to manage those. */ +hdm_init: if (!__cxl_hdm_decode_init(cxlds, cxlhdm, &info)) { dev_err(dev, "Legacy range registers configuration prevents HDM operation.\n"); |