From 57a4591df70900252265ecfd6eeba95ce2021504 Mon Sep 17 00:00:00 2001 From: Krishna Chaitanya Chundru Date: Fri, 28 Mar 2025 15:58:30 +0530 Subject: [PATCH 1/6] PCI: of: Add of_pci_get_equalization_presets() API PCIe equalization presets are predefined settings used to optimize signal integrity by compensating for signal loss and distortion in high-speed data transmission. As per PCIe spec 6.0.1 revision section 8.3.3.3 & 4.2.4 for data rates of 8.0 GT/s, 16.0 GT/s, 32.0 GT/s, and 64.0 GT/s, there is a way to configure lane equalization presets for each lane to enhance the PCIe link reliability. Each preset value represents a different combination of pre-shoot and de-emphasis values. For each data rate, different registers are defined: for 8.0 GT/s, registers are defined in section 7.7.3.4; for 16.0 GT/s, in section 7.7.5.9, etc. The 8.0 GT/s rate has an extra receiver preset hint, requiring 16 bits per lane, while the remaining data rates use 8 bits per lane. Based on the number of lanes and the supported data rate, of_pci_get_equalization_presets() reads the device tree property and stores in the presets structure. Signed-off-by: Krishna Chaitanya Chundru Signed-off-by: Manivannan Sadhasivam Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250328-preset_v6-v9-2-22cfa0490518@oss.qualcomm.com --- drivers/pci/of.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 32 +++++++++++++++++++++++++++++++- 2 files changed, 75 insertions(+), 1 deletion(-) diff --git a/drivers/pci/of.c b/drivers/pci/of.c index ab7a8252bf41..3579265f1198 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -966,3 +966,47 @@ u32 of_pci_get_slot_power_limit(struct device_node *node, return slot_power_limit_mw; } EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit); + +/** + * of_pci_get_equalization_presets - Parses the "eq-presets-Ngts" property. + * + * @dev: Device containing the properties. + * @presets: Pointer to store the parsed data. + * @num_lanes: Maximum number of lanes supported. + * + * If the property is present, read and store the data in the @presets structure. + * Else, assign a default value of PCI_EQ_RESV. + * + * Return: 0 if the property is not available or successfully parsed else + * errno otherwise. + */ +int of_pci_get_equalization_presets(struct device *dev, + struct pci_eq_presets *presets, + int num_lanes) +{ + char name[20]; + int ret; + + presets->eq_presets_8gts[0] = PCI_EQ_RESV; + ret = of_property_read_u16_array(dev->of_node, "eq-presets-8gts", + presets->eq_presets_8gts, num_lanes); + if (ret && ret != -EINVAL) { + dev_err(dev, "Error reading eq-presets-8gts: %d\n", ret); + return ret; + } + + for (int i = 0; i < EQ_PRESET_TYPE_MAX - 1; i++) { + presets->eq_presets_Ngts[i][0] = PCI_EQ_RESV; + snprintf(name, sizeof(name), "eq-presets-%dgts", 8 << (i + 1)); + ret = of_property_read_u8_array(dev->of_node, name, + presets->eq_presets_Ngts[i], + num_lanes); + if (ret && ret != -EINVAL) { + dev_err(dev, "Error reading %s: %d\n", name, ret); + return ret; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(of_pci_get_equalization_presets); diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index b81e99cd4b62..f9e345ee634c 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -9,6 +9,8 @@ struct pcie_tlp_log; /* Number of possible devfns: 0.0 to 1f.7 inclusive */ #define MAX_NR_DEVFNS 256 +#define MAX_NR_LANES 16 + #define PCI_FIND_CAP_TTL 48 #define PCI_VSEC_ID_INTEL_TBT 0x1234 /* Thunderbolt */ @@ -876,6 +878,21 @@ static inline u64 pci_rebar_size_to_bytes(int size) struct device_node; +#define PCI_EQ_RESV 0xff + +enum equalization_preset_type { + EQ_PRESET_TYPE_8GTS, + EQ_PRESET_TYPE_16GTS, + EQ_PRESET_TYPE_32GTS, + EQ_PRESET_TYPE_64GTS, + EQ_PRESET_TYPE_MAX +}; + +struct pci_eq_presets { + u16 eq_presets_8gts[MAX_NR_LANES]; + u8 eq_presets_Ngts[EQ_PRESET_TYPE_MAX - 1][MAX_NR_LANES]; +}; + #ifdef CONFIG_OF int of_get_pci_domain_nr(struct device_node *node); int of_pci_get_max_link_speed(struct device_node *node); @@ -890,7 +907,9 @@ void pci_release_bus_of_node(struct pci_bus *bus); int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge); bool of_pci_supply_present(struct device_node *np); - +int of_pci_get_equalization_presets(struct device *dev, + struct pci_eq_presets *presets, + int num_lanes); #else static inline int of_get_pci_domain_nr(struct device_node *node) @@ -935,6 +954,17 @@ static inline bool of_pci_supply_present(struct device_node *np) { return false; } + +static inline int of_pci_get_equalization_presets(struct device *dev, + struct pci_eq_presets *presets, + int num_lanes) +{ + presets->eq_presets_8gts[0] = PCI_EQ_RESV; + for (int i = 0; i < EQ_PRESET_TYPE_MAX - 1; i++) + presets->eq_presets_Ngts[i][0] = PCI_EQ_RESV; + + return 0; +} #endif /* CONFIG_OF */ struct of_changeset; From f9eb654fb194e7c404d4984481a18edb9b1c1d7c Mon Sep 17 00:00:00 2001 From: Krishna Chaitanya Chundru Date: Fri, 28 Mar 2025 15:58:31 +0530 Subject: [PATCH 2/6] PCI: dwc: Update pci->num_lanes to maximum supported link width If the num-lanes property is not present in the devicetree, update pci->num_lanes with the hardware supported maximum link width using the newly introduced dw_pcie_link_get_max_link_width() API. The API is used to get the Maximum Link Width (MLW) of the controller. Signed-off-by: Krishna Chaitanya Chundru [mani: reworded commit message a bit] Signed-off-by: Manivannan Sadhasivam Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250328-preset_v6-v9-3-22cfa0490518@oss.qualcomm.com --- drivers/pci/controller/dwc/pcie-designware-host.c | 3 +++ drivers/pci/controller/dwc/pcie-designware.c | 8 ++++++++ drivers/pci/controller/dwc/pcie-designware.h | 1 + 3 files changed, 12 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index ecc33f6789e3..e8eccf6a1b2f 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -523,6 +523,9 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) dw_pcie_iatu_detect(pci); + if (pci->num_lanes < 1) + pci->num_lanes = dw_pcie_link_get_max_link_width(pci); + /* * Allocate the resource for MSG TLP before programming the iATU * outbound window in dw_pcie_setup_rc(). Since the allocation depends diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 97d76d3dc066..cafe91bd9c34 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -781,6 +781,14 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci) } +int dw_pcie_link_get_max_link_width(struct dw_pcie *pci) +{ + u8 cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + u32 lnkcap = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP); + + return FIELD_GET(PCI_EXP_LNKCAP_MLW, lnkcap); +} + static void dw_pcie_link_set_max_link_width(struct dw_pcie *pci, u32 num_lanes) { u32 lnkcap, lwsc, plc; diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 56aafdbcdaca..dda788e3bd24 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -540,6 +540,7 @@ void dw_pcie_write_dbi2(struct dw_pcie *pci, u32 reg, size_t size, u32 val); int dw_pcie_link_up(struct dw_pcie *pci); void dw_pcie_upconfig_setup(struct dw_pcie *pci); int dw_pcie_wait_for_link(struct dw_pcie *pci); +int dw_pcie_link_get_max_link_width(struct dw_pcie *pci); int dw_pcie_prog_outbound_atu(struct dw_pcie *pci, const struct dw_pcie_ob_atu_cfg *atu); int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type, From 178af54a678d08735233e070a9329651e1589587 Mon Sep 17 00:00:00 2001 From: Krishna Chaitanya Chundru Date: Fri, 28 Mar 2025 15:58:32 +0530 Subject: [PATCH 3/6] PCI: Add lane equalization register offsets As per PCIe spec 6.0.1, add PCIe lane equalization register offset for data rates 8.0 GT/s, 32.0 GT/s and 64.0 GT/s. Also add a macro for defining data rate 64.0 GT/s physical layer capability ID. Signed-off-by: Krishna Chaitanya Chundru Signed-off-by: Manivannan Sadhasivam Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250328-preset_v6-v9-4-22cfa0490518@oss.qualcomm.com --- include/uapi/linux/pci_regs.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index ba326710f9c8..a3a3e942dedf 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -750,7 +750,8 @@ #define PCI_EXT_CAP_ID_NPEM 0x29 /* Native PCIe Enclosure Management */ #define PCI_EXT_CAP_ID_PL_32GT 0x2A /* Physical Layer 32.0 GT/s */ #define PCI_EXT_CAP_ID_DOE 0x2E /* Data Object Exchange */ -#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_DOE +#define PCI_EXT_CAP_ID_PL_64GT 0x31 /* Physical Layer 64.0 GT/s */ +#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PL_64GT #define PCI_EXT_CAP_DSN_SIZEOF 12 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40 @@ -1144,12 +1145,21 @@ #define PCI_DLF_CAP 0x04 /* Capabilities Register */ #define PCI_DLF_EXCHANGE_ENABLE 0x80000000 /* Data Link Feature Exchange Enable */ +/* Secondary PCIe Capability 8.0 GT/s */ +#define PCI_SECPCI_LE_CTRL 0x0c /* Lane Equalization Control Register */ + /* Physical Layer 16.0 GT/s */ #define PCI_PL_16GT_LE_CTRL 0x20 /* Lane Equalization Control Register */ #define PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK 0x0000000F #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK 0x000000F0 #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT 4 +/* Physical Layer 32.0 GT/s */ +#define PCI_PL_32GT_LE_CTRL 0x20 /* Lane Equalization Control Register */ + +/* Physical Layer 64.0 GT/s */ +#define PCI_PL_64GT_LE_CTRL 0x20 /* Lane Equalization Control Register */ + /* Native PCIe Enclosure Management */ #define PCI_NPEM_CAP 0x04 /* NPEM capability register */ #define PCI_NPEM_CAP_CAPABLE 0x00000001 /* NPEM Capable */ From 09483959e34d2577142ad7c56491c82f50da540d Mon Sep 17 00:00:00 2001 From: Krishna Chaitanya Chundru Date: Fri, 28 Mar 2025 15:58:33 +0530 Subject: [PATCH 4/6] PCI: dwc: Add support for configuring lane equalization presets PCIe equalization presets are predefined settings used to optimize signal integrity by compensating for signal loss and distortion in high-speed data transmission. Based upon the number of lanes and the data rate supported, write the preset data read from the device tree in to the lane equalization control registers. These preset values will be used by the controller during the LTSSM lane equalization procedure. Signed-off-by: Krishna Chaitanya Chundru [mani: reworded the commit message and comments in the driver] Signed-off-by: Manivannan Sadhasivam Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250328-preset_v6-v9-5-22cfa0490518@oss.qualcomm.com --- .../pci/controller/dwc/pcie-designware-host.c | 76 +++++++++++++++++++ drivers/pci/controller/dwc/pcie-designware.h | 3 + 2 files changed, 79 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index e8eccf6a1b2f..b7faef26ed44 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -526,6 +526,10 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) if (pci->num_lanes < 1) pci->num_lanes = dw_pcie_link_get_max_link_width(pci); + ret = of_pci_get_equalization_presets(dev, &pp->presets, pci->num_lanes); + if (ret) + goto err_free_msi; + /* * Allocate the resource for MSG TLP before programming the iATU * outbound window in dw_pcie_setup_rc(). Since the allocation depends @@ -831,6 +835,77 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp) return 0; } +static void dw_pcie_program_presets(struct dw_pcie_rp *pp, enum pci_bus_speed speed) +{ + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + u8 lane_eq_offset, lane_reg_size, cap_id; + u8 *presets; + u32 cap; + int i; + + if (speed == PCIE_SPEED_8_0GT) { + presets = (u8 *)pp->presets.eq_presets_8gts; + lane_eq_offset = PCI_SECPCI_LE_CTRL; + cap_id = PCI_EXT_CAP_ID_SECPCI; + /* For data rate of 8 GT/S each lane equalization control is 16bits wide*/ + lane_reg_size = 0x2; + } else if (speed == PCIE_SPEED_16_0GT) { + presets = pp->presets.eq_presets_Ngts[EQ_PRESET_TYPE_16GTS - 1]; + lane_eq_offset = PCI_PL_16GT_LE_CTRL; + cap_id = PCI_EXT_CAP_ID_PL_16GT; + lane_reg_size = 0x1; + } else if (speed == PCIE_SPEED_32_0GT) { + presets = pp->presets.eq_presets_Ngts[EQ_PRESET_TYPE_32GTS - 1]; + lane_eq_offset = PCI_PL_32GT_LE_CTRL; + cap_id = PCI_EXT_CAP_ID_PL_32GT; + lane_reg_size = 0x1; + } else if (speed == PCIE_SPEED_64_0GT) { + presets = pp->presets.eq_presets_Ngts[EQ_PRESET_TYPE_64GTS - 1]; + lane_eq_offset = PCI_PL_64GT_LE_CTRL; + cap_id = PCI_EXT_CAP_ID_PL_64GT; + lane_reg_size = 0x1; + } else { + return; + } + + if (presets[0] == PCI_EQ_RESV) + return; + + cap = dw_pcie_find_ext_capability(pci, cap_id); + if (!cap) + return; + + /* + * Write preset values to the registers byte-by-byte for the given + * number of lanes and register size. + */ + for (i = 0; i < pci->num_lanes * lane_reg_size; i++) + dw_pcie_writeb_dbi(pci, cap + lane_eq_offset + i, presets[i]); +} + +static void dw_pcie_config_presets(struct dw_pcie_rp *pp) +{ + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + enum pci_bus_speed speed = pcie_link_speed[pci->max_link_speed]; + + /* + * Lane equalization settings need to be applied for all data rates the + * controller supports and for all supported lanes. + */ + + if (speed >= PCIE_SPEED_8_0GT) + dw_pcie_program_presets(pp, PCIE_SPEED_8_0GT); + + if (speed >= PCIE_SPEED_16_0GT) + dw_pcie_program_presets(pp, PCIE_SPEED_16_0GT); + + if (speed >= PCIE_SPEED_32_0GT) + dw_pcie_program_presets(pp, PCIE_SPEED_32_0GT); + + if (speed >= PCIE_SPEED_64_0GT) + dw_pcie_program_presets(pp, PCIE_SPEED_64_0GT); +} + int dw_pcie_setup_rc(struct dw_pcie_rp *pp) { struct dw_pcie *pci = to_dw_pcie_from_pp(pp); @@ -884,6 +959,7 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp) PCI_COMMAND_MASTER | PCI_COMMAND_SERR; dw_pcie_writel_dbi(pci, PCI_COMMAND, val); + dw_pcie_config_presets(pp); /* * If the platform provides its own child bus config accesses, it means * the platform uses its own address translation component rather than diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index dda788e3bd24..7add69f13759 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -25,6 +25,8 @@ #include #include +#include "../../pci.h" + /* DWC PCIe IP-core versions (native support since v4.70a) */ #define DW_PCIE_VER_365A 0x3336352a #define DW_PCIE_VER_460A 0x3436302a @@ -412,6 +414,7 @@ struct dw_pcie_rp { int msg_atu_index; struct resource *msg_res; bool use_linkup_irq; + struct pci_eq_presets presets; }; struct dw_pcie_ep_ops { From b649d91322e65f9ea455da58c54b353826dc2dd5 Mon Sep 17 00:00:00 2001 From: Nitheesh Sekar Date: Wed, 26 Mar 2025 12:10:57 +0400 Subject: [PATCH 5/6] dt-bindings: PCI: qcom: Add IPQ5018 SoC Add support for the PCIe controller on the Qualcomm IPQ5108 SoC to the bindings. Signed-off-by: Nitheesh Sekar Signed-off-by: Sricharan Ramabadhran Signed-off-by: George Moussalem Signed-off-by: Manivannan Sadhasivam Reviewed-by: Krzysztof Kozlowski Acked-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250326-ipq5018-pcie-v7-3-e1828fef06c9@outlook.com --- .../devicetree/bindings/pci/qcom,pcie.yaml | 50 +++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml index 8f628939209e..b1643c079429 100644 --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml @@ -21,6 +21,7 @@ properties: - qcom,pcie-apq8064 - qcom,pcie-apq8084 - qcom,pcie-ipq4019 + - qcom,pcie-ipq5018 - qcom,pcie-ipq6018 - qcom,pcie-ipq8064 - qcom,pcie-ipq8064-v2 @@ -168,6 +169,7 @@ allOf: compatible: contains: enum: + - qcom,pcie-ipq5018 - qcom,pcie-ipq6018 - qcom,pcie-ipq8074-gen3 - qcom,pcie-ipq9574 @@ -322,6 +324,53 @@ allOf: - const: ahb # AHB reset - const: phy_ahb # PHY AHB reset + - if: + properties: + compatible: + contains: + enum: + - qcom,pcie-ipq5018 + then: + properties: + clocks: + minItems: 6 + maxItems: 6 + clock-names: + items: + - const: iface # PCIe to SysNOC BIU clock + - const: axi_m # AXI Master clock + - const: axi_s # AXI Slave clock + - const: ahb # AHB clock + - const: aux # Auxiliary clock + - const: axi_bridge # AXI bridge clock + resets: + minItems: 8 + maxItems: 8 + reset-names: + items: + - const: pipe # PIPE reset + - const: sleep # Sleep reset + - const: sticky # Core sticky reset + - const: axi_m # AXI master reset + - const: axi_s # AXI slave reset + - const: ahb # AHB reset + - const: axi_m_sticky # AXI master sticky reset + - const: axi_s_sticky # AXI slave sticky reset + interrupts: + minItems: 9 + maxItems: 9 + interrupt-names: + items: + - const: msi0 + - const: msi1 + - const: msi2 + - const: msi3 + - const: msi4 + - const: msi5 + - const: msi6 + - const: msi7 + - const: global + - if: properties: compatible: @@ -562,6 +611,7 @@ allOf: enum: - qcom,pcie-apq8064 - qcom,pcie-ipq4019 + - qcom,pcie-ipq5018 - qcom,pcie-ipq8064 - qcom,pcie-ipq8064v2 - qcom,pcie-ipq8074 From 3e5127469a8d41153fb30031a271788f52dd17ec Mon Sep 17 00:00:00 2001 From: Nitheesh Sekar Date: Wed, 26 Mar 2025 12:10:58 +0400 Subject: [PATCH 6/6] PCI: qcom: Add support for IPQ5018 Add IPQ5018 platform with is based on Qcom IP rev. 2.9.0 and Synopsys IP rev. 5.00a. The platform itself has two PCIe Gen2 controllers: one single-lane and one dual-lane. So add the IPQ5018 compatible and re-use 2_9_0 ops. Signed-off-by: Nitheesh Sekar Signed-off-by: Sricharan R Signed-off-by: George Moussalem Signed-off-by: Manivannan Sadhasivam Reviewed-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20250326-ipq5018-pcie-v7-4-e1828fef06c9@outlook.com --- drivers/pci/controller/dwc/pcie-qcom.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index dc98ae63362d..e91bbe218569 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1840,6 +1840,7 @@ static const struct of_device_id qcom_pcie_match[] = { { .compatible = "qcom,pcie-apq8064", .data = &cfg_2_1_0 }, { .compatible = "qcom,pcie-apq8084", .data = &cfg_1_0_0 }, { .compatible = "qcom,pcie-ipq4019", .data = &cfg_2_4_0 }, + { .compatible = "qcom,pcie-ipq5018", .data = &cfg_2_9_0 }, { .compatible = "qcom,pcie-ipq6018", .data = &cfg_2_9_0 }, { .compatible = "qcom,pcie-ipq8064", .data = &cfg_2_1_0 }, { .compatible = "qcom,pcie-ipq8064-v2", .data = &cfg_2_1_0 },