From: Koichiro Den Date: Tue, 14 Apr 2026 14:15:10 +0000 (+0900) Subject: PCI: dwc: ep: Expose integrated eDMA resources via EPC aux-resource API X-Git-Tag: v7.2-rc1~40^2~21^2~22 X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=ec2075cfc629eed09d8865621be76ff2197781d6;p=thirdparty%2Fkernel%2Flinux.git PCI: dwc: ep: Expose integrated eDMA resources via EPC aux-resource API Implement the EPC aux-resource API for DesignWare endpoint controllers with integrated eDMA. Currently, only report an interrupt-emulation doorbell register (PCI_EPC_AUX_DOORBELL_MMIO), including its Linux IRQ and the write data needed to trigger the interrupt. 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 Signed-off-by: Manivannan Sadhasivam Reviewed-by: Frank Li Link: https://patch.msgid.link/20260414141514.1341429-4-den@valinux.co.jp --- diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index d4dc3b24da607..e4c6f71934950 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include "pcie-designware.h" @@ -817,6 +818,122 @@ 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_count(struct pci_epc *epc, u8 func_no, + u8 vfunc_no) +{ + struct dw_pcie_ep *ep = epc_get_drvdata(epc); + struct dw_pcie *pci = to_dw_pcie_from_ep(ep); + struct dw_edma_chip *edma = &pci->edma; + + if (!pci->edma_reg_size) + return 0; + + if (edma->db_offset == ~0) + return 0; + + return 1; +} + +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; + resource_size_t db_offset = edma->db_offset; + resource_size_t dma_ctrl_bar_offset = 0; + resource_size_t dma_reg_size; + int count; + + count = dw_pcie_ep_get_aux_resources_count(epc, func_no, vfunc_no); + if (count < 0) + return count; + + if (num_resources < count) + return -ENOSPC; + + if (!count) + return 0; + + dma_reg_size = pci->edma_reg_size; + + 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; + + /* + * For interrupt-emulation doorbells, report a standalone resource + * instead of bundling it into the DMA controller MMIO resource. + */ + if (range_end_overflows_t(resource_size_t, db_offset, + sizeof(u32), dma_reg_size)) + return -EINVAL; + + resources[0] = (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, + .data = 0, /* write 0 to assert */ + }, + }; + + return 0; +} + static const struct pci_epc_ops epc_ops = { .write_header = dw_pcie_ep_write_header, .set_bar = dw_pcie_ep_set_bar, @@ -832,6 +949,8 @@ 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_count = dw_pcie_ep_get_aux_resources_count, + .get_aux_resources = dw_pcie_ep_get_aux_resources, }; /**