Implement pci_epc_ops.get_remote_resources() for DesignWare PCIe
endpoint controllers with integrated eDMA.
Report:
- the eDMA controller MMIO window (physical base + size),
- each non-empty per-channel linked-list region, along with
per-channel metadata such as the Linux IRQ number and the
interrupt-emulation doorbell register offset.
This allows endpoint function drivers (e.g. pci-epf-test) to discover
the eDMA resources and map a suitable doorbell target into BAR space.
Signed-off-by: Koichiro Den <[email protected]>
---
.../pci/controller/dwc/pcie-designware-ep.c | 85 +++++++++++++++++++
1 file changed, 85 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c
b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 7e7844ff0f7e..29dedac86190 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -8,6 +8,7 @@
#include <linux/align.h>
#include <linux/bitfield.h>
+#include <linux/dma/edma.h>
#include <linux/of.h>
#include <linux/platform_device.h>
@@ -808,6 +809,89 @@ dw_pcie_ep_get_features(struct pci_epc *epc, u8 func_no,
u8 vfunc_no)
return ep->ops->get_features(ep);
}
+static int
+dw_pcie_ep_get_remote_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+ struct pci_epc_remote_resource *resources,
+ int num_resources)
+{
+ 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;
+ struct dw_edma_chan_info info;
+ int ll_cnt = 0, needed, idx = 0;
+ resource_size_t dma_size;
+ phys_addr_t dma_phys;
+ unsigned int i;
+ int ret;
+
+ if (!pci->edma_reg_size)
+ return 0;
+
+ dma_phys = pci->edma_reg_phys;
+ dma_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;
+
+ /* Count query mode */
+ if (!resources || !num_resources)
+ return needed;
+
+ if (num_resources < needed)
+ return -ENOSPC;
+
+ resources[idx++] = (struct pci_epc_remote_resource) {
+ .type = PCI_EPC_RR_DMA_CTRL_MMIO,
+ .phys_addr = dma_phys,
+ .size = dma_size,
+ };
+
+ /* One LL region per write channel */
+ for (i = 0; i < edma->ll_wr_cnt; i++) {
+ if (!edma->ll_region_wr[i].sz)
+ continue;
+
+ ret = dw_edma_chan_info(edma, i, &info);
+ if (ret)
+ return ret;
+
+ resources[idx++] = (struct pci_epc_remote_resource) {
+ .type = PCI_EPC_RR_DMA_CHAN_DESC,
+ .phys_addr = edma->ll_region_wr[i].paddr,
+ .size = edma->ll_region_wr[i].sz,
+ .u.dma_chan_desc.irq = info.irq,
+ .u.dma_chan_desc.db_offset = info.db_offset,
+ };
+ }
+
+ /* One LL region per read channel */
+ for (i = 0; i < edma->ll_rd_cnt; i++) {
+ if (!edma->ll_region_rd[i].sz)
+ continue;
+
+ ret = dw_edma_chan_info(edma, i + edma->ll_wr_cnt, &info);
+ if (ret)
+ return ret;
+
+ resources[idx++] = (struct pci_epc_remote_resource) {
+ .type = PCI_EPC_RR_DMA_CHAN_DESC,
+ .phys_addr = edma->ll_region_rd[i].paddr,
+ .size = edma->ll_region_rd[i].sz,
+ .u.dma_chan_desc.irq = info.irq,
+ .u.dma_chan_desc.db_offset = info.db_offset,
+ };
+ }
+
+ 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 +907,7 @@ 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_remote_resources = dw_pcie_ep_get_remote_resources,
};
/**
--
2.51.0
