PCI: dwc: Add outbound MSG TLPs support

Add "code" and "routing" into struct dw_pcie_ob_atu_cfg for triggering
INTx IRQs by iATU in the PCIe endpoint mode in near the future.
PCIE_ATU_INHIBIT_PAYLOAD is set to issue TLP type of Msg instead of
MsgD. This implementation supports the data-less messages only for now.

Link: https://lore.kernel.org/linux-pci/20240418-pme_msg-v8-3-a54265c39742@nxp.com
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>

Author: shimoday

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

@@ -499,15 +499,20 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
 	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_UPPER_TARGET,
 			      upper_32_bits(atu->pci_addr));
 
-	val = atu->type | PCIE_ATU_FUNC_NUM(atu->func_no);
+	val = atu->type | atu->routing | PCIE_ATU_FUNC_NUM(atu->func_no);
 	if (upper_32_bits(limit_addr) > upper_32_bits(cpu_addr) &&
 	    dw_pcie_ver_is_ge(pci, 460A))
 		val |= PCIE_ATU_INCREASE_REGION_SIZE;
 	if (dw_pcie_ver_is(pci, 490A))
 		val = dw_pcie_enable_ecrc(val);
 	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL1, val);
 
-	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL2, PCIE_ATU_ENABLE);
+	val = PCIE_ATU_ENABLE;
+	if (atu->type == PCIE_ATU_TYPE_MSG) {
+		/* The data-less messages only for now */
+		val |= PCIE_ATU_INHIBIT_PAYLOAD | atu->code;
+	}
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL2, val);
 
 	/*
 	 * Make sure ATU enable takes effect before any subsequent config

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

@@ -147,11 +147,13 @@
 #define PCIE_ATU_TYPE_IO		0x2
 #define PCIE_ATU_TYPE_CFG0		0x4
 #define PCIE_ATU_TYPE_CFG1		0x5
+#define PCIE_ATU_TYPE_MSG		0x10
 #define PCIE_ATU_TD			BIT(8)
 #define PCIE_ATU_FUNC_NUM(pf)           ((pf) << 20)
 #define PCIE_ATU_REGION_CTRL2		0x004
 #define PCIE_ATU_ENABLE			BIT(31)
 #define PCIE_ATU_BAR_MODE_ENABLE	BIT(30)
+#define PCIE_ATU_INHIBIT_PAYLOAD	BIT(22)
 #define PCIE_ATU_FUNC_NUM_MATCH_EN      BIT(19)
 #define PCIE_ATU_LOWER_BASE		0x008
 #define PCIE_ATU_UPPER_BASE		0x00C
@@ -302,6 +304,8 @@ struct dw_pcie_ob_atu_cfg {
 	int index;
 	int type;
 	u8 func_no;
+	u8 code;
+	u8 routing;
 	u64 cpu_addr;
 	u64 pci_addr;
 	u64 size;