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 <den@valinux.co.jp>
---
 .../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

On Mon, Feb 16, 2026 at 01:38:43AM +0900, Koichiro Den wrote:
> 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 <den@valinux.co.jp>
> ---
Reviewed-by: Frank Li <Frank.Li@nxp.com>
>  .../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
>

On Mon, Feb 16, 2026 at 01:38:43AM +0900, Koichiro Den wrote:
> 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 <den@valinux.co.jp>
> ---
>  .../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))

In your other patch, you used:

	if (size_add(offset, sizeof(u32)) > epf->bar[bar].size)

For consistency, do you perhaps want to use the same here?

size_add(db_offset, sizeof(u32)) > dma_reg_size ?




Kind regards,
Niklas

On Mon, Feb 16, 2026 at 03:12:53PM +0100, Niklas Cassel wrote:
> On Mon, Feb 16, 2026 at 01:38:43AM +0900, Koichiro Den wrote:
> > 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 <den@valinux.co.jp>
> > ---
> >  .../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))
> 
> In your other patch, you used:
> 
> 	if (size_add(offset, sizeof(u32)) > epf->bar[bar].size)
> 
> For consistency, do you perhaps want to use the same here?
> 
> size_add(db_offset, sizeof(u32)) > dma_reg_size ?

db_offset and dma_reg_size are resource_size_t, not size_t. resource_size_t can
be wider than size_t on some 32-bit builds with CONFIG_PHYS_ADDR_T_64BIT, so
using size_add() would potentially introduce a narrowing conversion. For that
reason, I avoided it.

If that would be preferable, I'm happy to switch this part to something like:

        if (db_offset != ~0) {
                if (range_end_overflows_t(resource_size_t, db_offset,
                                          sizeof(u32), dma_reg_size))
                        return -EINVAL;

or alternatively use check_add_overflow().

Best regards,
Koichiro

> 
> 
> 
> 
> Kind regards,
> Niklas