PCI: dwc: endpoint: Add multiple PFs support for dbi2

The commit 24ede43 ("PCI: designware-ep: Add multiple PFs support
for DWC") added .func_conf_select() to get the configuration space of
different PFs and assumed that the offsets between dbi and dbi2 would
be the same.

However, Renesas R-Car Gen4 PCIe controllers have different offsets of
function 1: dbi (+0x1000) and dbi2 (+0x800). To get the offset for dbi2,
add .get_dbi2_offset() and dw_pcie_ep_get_dbi2_offset().

Note:
 - .func_conf_select() should be renamed later.
 - dw_pcie_ep_get_dbi2_offset() will call .func_conf_select()
   if .get_dbi2_offset() doesn't exist for backward compatibility.
 - dw_pcie_writeX_{dbi/dbi2} APIs accepted the func_no argument,
   so that these offset calculations are contained in the API
   definitions itself as it should.

Link: https://lore.kernel.org/linux-pci/20231018085631.1121289-6-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Author: shimoday

drivers/pci/controller/dwc/pcie-designware-ep.c

@@ -52,21 +52,35 @@ static unsigned int dw_pcie_ep_func_select(struct dw_pcie_ep *ep, u8 func_no)
 	return func_offset;
 }
 
+static unsigned int dw_pcie_ep_get_dbi2_offset(struct dw_pcie_ep *ep, u8 func_no)
+{
+	unsigned int dbi2_offset = 0;
+
+	if (ep->ops->get_dbi2_offset)
+		dbi2_offset = ep->ops->get_dbi2_offset(ep, func_no);
+	else if (ep->ops->func_conf_select)     /* for backward compatibility */
+		dbi2_offset = ep->ops->func_conf_select(ep, func_no);
+
+	return dbi2_offset;
+}
+
 static void __dw_pcie_ep_reset_bar(struct dw_pcie *pci, u8 func_no,
 				   enum pci_barno bar, int flags)
 {
-	u32 reg;
-	unsigned int func_offset = 0;
+	unsigned int func_offset, dbi2_offset;
 	struct dw_pcie_ep *ep = &pci->ep;
+	u32 reg, reg_dbi2;
 
 	func_offset = dw_pcie_ep_func_select(ep, func_no);
+	dbi2_offset = dw_pcie_ep_get_dbi2_offset(ep, func_no);
 
 	reg = func_offset + PCI_BASE_ADDRESS_0 + (4 * bar);
+	reg_dbi2 = dbi2_offset + PCI_BASE_ADDRESS_0 + (4 * bar);
 	dw_pcie_dbi_ro_wr_en(pci);
-	dw_pcie_writel_dbi2(pci, reg, 0x0);
+	dw_pcie_writel_dbi2(pci, reg_dbi2, 0x0);
 	dw_pcie_writel_dbi(pci, reg, 0x0);
 	if (flags & PCI_BASE_ADDRESS_MEM_TYPE_64) {
-		dw_pcie_writel_dbi2(pci, reg + 4, 0x0);
+		dw_pcie_writel_dbi2(pci, reg_dbi2 + 4, 0x0);
 		dw_pcie_writel_dbi(pci, reg + 4, 0x0);
 	}
 	dw_pcie_dbi_ro_wr_dis(pci);
@@ -228,16 +242,18 @@ static int dw_pcie_ep_set_bar(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);
+	unsigned int func_offset, dbi2_offset;
 	enum pci_barno bar = epf_bar->barno;
 	size_t size = epf_bar->size;
 	int flags = epf_bar->flags;
-	unsigned int func_offset = 0;
+	u32 reg, reg_dbi2;
 	int ret, type;
-	u32 reg;
 
 	func_offset = dw_pcie_ep_func_select(ep, func_no);
+	dbi2_offset = dw_pcie_ep_get_dbi2_offset(ep, func_no);
 
 	reg = PCI_BASE_ADDRESS_0 + (4 * bar) + func_offset;
+	reg_dbi2 = PCI_BASE_ADDRESS_0 + (4 * bar) + dbi2_offset;
 
 	if (!(flags & PCI_BASE_ADDRESS_SPACE))
 		type = PCIE_ATU_TYPE_MEM;
@@ -253,11 +269,11 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 
 	dw_pcie_dbi_ro_wr_en(pci);
 
-	dw_pcie_writel_dbi2(pci, reg, lower_32_bits(size - 1));
+	dw_pcie_writel_dbi2(pci, reg_dbi2, lower_32_bits(size - 1));
 	dw_pcie_writel_dbi(pci, reg, flags);
 
 	if (flags & PCI_BASE_ADDRESS_MEM_TYPE_64) {
-		dw_pcie_writel_dbi2(pci, reg + 4, upper_32_bits(size - 1));
+		dw_pcie_writel_dbi2(pci, reg_dbi2 + 4, upper_32_bits(size - 1));
 		dw_pcie_writel_dbi(pci, reg + 4, 0);
 	}
 

drivers/pci/controller/dwc/pcie-designware.h

@@ -341,6 +341,7 @@ struct dw_pcie_ep_ops {
 	 * driver.
 	 */
 	unsigned int (*func_conf_select)(struct dw_pcie_ep *ep, u8 func_no);
+	unsigned int (*get_dbi2_offset)(struct dw_pcie_ep *ep, u8 func_no);
 };
 
 struct dw_pcie_ep_func {