[PATCH 2/3] PCI: dw-rockchip: Support fixed MSI-X table and PBA on RK3588

[Koichiro Den]

The RK3588 PCIe endpoint controller exposes its MSI-X table at
BAR4+0x4000 and its PBA at BAR4+0x5000. Describe both as reserved regions
so EPF drivers can select the hardware-owned layout.

The regular DesignWare MSI-X interrupt path reads an EPF-owned table
through epf_bar[]. A reserved, hardware-owned table has no such backing.
Record whether the layout selected for each function matches the
hardware-owned layout, and use the controller MSI-X doorbell on RK3588
only in that case. Continue to use the regular path for EPF-owned
layouts.

Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
---
 .../pci/controller/dwc/pcie-designware-ep.c   | 21 ++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h  |  1 +
 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 28 +++++++++++++++++--
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 147b043589f0..bc2b63814dea 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -736,6 +736,26 @@ static int dw_pcie_ep_get_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
 	return val + 1;
 }
 
+static bool
+dw_pcie_ep_msix_layout_is_hw_owned(struct dw_pcie_ep *ep,
+				   const struct pci_epc_msix_layout *layout)
+{
+	const struct pci_epc_features *features;
+	struct pci_epc_msix_layout hw_layout;
+
+	if (!ep->ops->get_features)
+		return false;
+
+	features = ep->ops->get_features(ep);
+	if (pci_epc_get_hw_msix_layout(features, &hw_layout))
+		return false;
+
+	return layout->table_bar == hw_layout.table_bar &&
+	       layout->table_offset == hw_layout.table_offset &&
+	       layout->pba_bar == hw_layout.pba_bar &&
+	       layout->pba_offset == hw_layout.pba_offset;
+}
+
 static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 			       u16 nr_irqs,
 			       const struct pci_epc_msix_layout *layout)
@@ -764,6 +784,7 @@ static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	reg = ep_func->msix_cap + PCI_MSIX_PBA;
 	val = layout->pba_offset | layout->pba_bar;
 	dw_pcie_ep_writel_dbi(ep, func_no, reg, val);
+	ep_func->msix_hw_owned = dw_pcie_ep_msix_layout_is_hw_owned(ep, layout);
 
 	dw_pcie_dbi_ro_wr_dis(pci);
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index de4b245b1758..043c39b5881d 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -495,6 +495,7 @@ struct dw_pcie_ep_func {
 	u8			func_no;
 	u8			msi_cap;	/* MSI capability offset */
 	u8			msix_cap;	/* MSI-X capability offset */
+	bool			msix_hw_owned;
 	u8			bar_to_atu[PCI_STD_NUM_BARS];
 	struct pci_epf_bar	*epf_bar[PCI_STD_NUM_BARS];
 
diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 731d93663cca..d622723dfcf8 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -120,6 +120,7 @@ struct rockchip_pcie {
 struct rockchip_pcie_of_data {
 	enum dw_pcie_device_mode mode;
 	const struct pci_epc_features *epc_features;
+	bool msix_doorbell;
 };
 
 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip, u32 reg)
@@ -481,6 +482,8 @@ static int rockchip_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
 				   unsigned int type, u16 interrupt_num)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+	struct dw_pcie_ep_func *ep_func;
 
 	switch (type) {
 	case PCI_IRQ_INTX:
@@ -488,6 +491,12 @@ static int rockchip_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
 	case PCI_IRQ_MSI:
 		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
 	case PCI_IRQ_MSIX:
+		ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
+		if (rockchip->data->msix_doorbell && ep_func &&
+		    ep_func->msix_hw_owned)
+			return dw_pcie_ep_raise_msix_irq_doorbell(ep, func_no,
+							      interrupt_num);
+
 		return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num);
 	default:
 		dev_err(pci->dev, "UNKNOWN IRQ type\n");
@@ -517,12 +526,24 @@ static const struct pci_epc_bar_rsvd_region rk3588_bar4_rsvd[] = {
 		.offset = 0x0,
 		.size = 0x2000,
 	},
+	{
+		/* MSI-X Table (BAR4: MSI-X Table) */
+		.type = PCI_EPC_BAR_RSVD_MSIX_TBL_RAM,
+		.offset = 0x4000,
+		.size = SZ_4K,
+	},
+	{
+		/* MSI-X PBA (BAR4: MSI-X PBA) */
+		.type = PCI_EPC_BAR_RSVD_MSIX_PBA_RAM,
+		.offset = 0x5000,
+		.size = SZ_4K,
+	},
 };
 
 /*
- * BAR4 on rk3588 exposes the ATU Port Logic Structure to the host regardless of
- * iATU settings for BAR4. This means that BAR4 cannot be used by an EPF driver,
- * so mark it as RESERVED.
+ * BAR4 on RK3588 exposes the DMA and ATU Port Logic Structures and the MSI-X
+ * table and PBA to the host regardless of iATU settings for BAR4. This means
+ * that BAR4 cannot be used by an EPF driver, so mark it as RESERVED.
  */
 static const struct pci_epc_features rockchip_pcie_epc_features_rk3588 = {
 	DWC_EPC_COMMON_FEATURES,
@@ -841,6 +862,7 @@ static const struct rockchip_pcie_of_data rockchip_pcie_ep_of_data_rk3568 = {
 static const struct rockchip_pcie_of_data rockchip_pcie_ep_of_data_rk3588 = {
 	.mode = DW_PCIE_EP_TYPE,
 	.epc_features = &rockchip_pcie_epc_features_rk3588,
+	.msix_doorbell = true,
 };
 
 static const struct of_device_id rockchip_pcie_of_match[] = {
-- 
2.51.0