[PATCH v7 5/9] PCI: dwc: ep: Expose integrated eDMA resources via EPC aux-resource API
From: Koichiro Den <hidden>
Date: 2026-02-15 16:39:11
Also in:
linux-pci, linux-rockchip, lkml
Subsystem:
pci driver for synopsys designware, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Jingoo Han, Manivannan Sadhasivam, Lorenzo Pieralisi, Krzysztof Wilczyński, Bjorn Helgaas, Linus Torvalds
Implement the EPC aux-resource API for DesignWare endpoint controllers
with integrated eDMA.
Report:
- DMA controller MMIO window (PCI_EPC_AUX_DMA_CTRL_MMIO)
- interrupt-emulation doorbell register (PCI_EPC_AUX_DOORBELL_MMIO),
including its Linux IRQ
- per-channel LL descriptor regions (PCI_EPC_AUX_DMA_CHAN_DESC)
If the DMA controller MMIO window is already exposed via a
platform-owned fixed BAR subregion, also provide the BAR number and
offset so EPF drivers can reuse it without reprogramming the BAR.
Signed-off-by: Koichiro Den <redacted>
---
.../pci/controller/dwc/pcie-designware-ep.c | 149 ++++++++++++++++++
1 file changed, 149 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 7e7844ff0f7e..ffd2797b7b81 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c@@ -808,6 +808,154 @@ dw_pcie_ep_get_features(struct pci_epc *epc, u8 func_no, u8 vfunc_no) return ep->ops->get_features(ep); } +static const struct pci_epc_bar_rsvd_region * +dw_pcie_ep_find_bar_rsvd_region(struct dw_pcie_ep *ep, + enum pci_epc_bar_rsvd_region_type type, + enum pci_barno *bar, + resource_size_t *bar_offset) +{ + const struct pci_epc_features *features; + const struct pci_epc_bar_desc *bar_desc; + const struct pci_epc_bar_rsvd_region *r; + int i, j; + + if (!ep->ops->get_features) + return NULL; + + features = ep->ops->get_features(ep); + if (!features) + return NULL; + + for (i = BAR_0; i <= BAR_5; i++) { + bar_desc = &features->bar[i]; + + if (!bar_desc->nr_rsvd_regions || !bar_desc->rsvd_regions) + continue; + + for (j = 0; j < bar_desc->nr_rsvd_regions; j++) { + r = &bar_desc->rsvd_regions[j]; + + if (r->type != type) + continue; + + if (bar) + *bar = i; + if (bar_offset) + *bar_offset = r->offset; + return r; + } + } + + return NULL; +} + +static int +dw_pcie_ep_get_aux_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no, + struct pci_epc_aux_resource *resources, + int num_resources) +{ + struct dw_pcie_ep *ep = epc_get_drvdata(epc); + struct dw_pcie *pci = to_dw_pcie_from_ep(ep); + const struct pci_epc_bar_rsvd_region *rsvd; + struct dw_edma_chip *edma = &pci->edma; + enum pci_barno dma_ctrl_bar = NO_BAR; + int ll_cnt = 0, needed, idx = 0; + resource_size_t db_offset = edma->db_offset; + resource_size_t dma_ctrl_bar_offset = 0; + resource_size_t dma_reg_size; + unsigned int i; + + if (!pci->edma_reg_size) + return 0; + + dma_reg_size = pci->edma_reg_size; + + for (i = 0; i < edma->ll_wr_cnt; i++) + if (edma->ll_region_wr[i].sz) + ll_cnt++; + + for (i = 0; i < edma->ll_rd_cnt; i++) + if (edma->ll_region_rd[i].sz) + ll_cnt++; + + needed = 1 + ll_cnt + (db_offset != ~0 ? 1 : 0); + + /* Count query mode */ + if (!resources || !num_resources) + return needed; + + if (num_resources < needed) + return -ENOSPC; + + rsvd = dw_pcie_ep_find_bar_rsvd_region(ep, + PCI_EPC_BAR_RSVD_DMA_CTRL_MMIO, + &dma_ctrl_bar, + &dma_ctrl_bar_offset); + if (rsvd && rsvd->size < dma_reg_size) + dma_reg_size = rsvd->size; + + /* DMA register block */ + resources[idx++] = (struct pci_epc_aux_resource) { + .type = PCI_EPC_AUX_DMA_CTRL_MMIO, + .phys_addr = pci->edma_reg_phys, + .size = dma_reg_size, + .bar = dma_ctrl_bar, + .bar_offset = dma_ctrl_bar_offset, + }; + + /* + * For interrupt-emulation doorbells, report a standalone resource + * instead of bundling it into the DMA controller MMIO resource. + */ + if (db_offset != ~0) { + if (dma_reg_size < sizeof(u32) || + db_offset > dma_reg_size - sizeof(u32)) + return -EINVAL; + + resources[idx++] = (struct pci_epc_aux_resource) { + .type = PCI_EPC_AUX_DOORBELL_MMIO, + .phys_addr = pci->edma_reg_phys + db_offset, + .size = sizeof(u32), + .bar = dma_ctrl_bar, + .bar_offset = dma_ctrl_bar != NO_BAR ? + dma_ctrl_bar_offset + db_offset : 0, + .u.db_mmio = { + .irq = edma->db_irq, + }, + }; + } + + /* One LL region per write channel */ + for (i = 0; i < edma->ll_wr_cnt; i++) { + if (!edma->ll_region_wr[i].sz) + continue; + + resources[idx++] = (struct pci_epc_aux_resource) { + .type = PCI_EPC_AUX_DMA_CHAN_DESC, + .phys_addr = edma->ll_region_wr[i].paddr, + .size = edma->ll_region_wr[i].sz, + .bar = NO_BAR, + .bar_offset = 0, + }; + } + + /* One LL region per read channel */ + for (i = 0; i < edma->ll_rd_cnt; i++) { + if (!edma->ll_region_rd[i].sz) + continue; + + resources[idx++] = (struct pci_epc_aux_resource) { + .type = PCI_EPC_AUX_DMA_CHAN_DESC, + .phys_addr = edma->ll_region_rd[i].paddr, + .size = edma->ll_region_rd[i].sz, + .bar = NO_BAR, + .bar_offset = 0, + }; + } + + return idx; +} + static const struct pci_epc_ops epc_ops = { .write_header = dw_pcie_ep_write_header, .set_bar = dw_pcie_ep_set_bar,
@@ -823,6 +971,7 @@ static const struct pci_epc_ops epc_ops = { .start = dw_pcie_ep_start, .stop = dw_pcie_ep_stop, .get_features = dw_pcie_ep_get_features, + .get_aux_resources = dw_pcie_ep_get_aux_resources, }; /**
--
2.51.0