[PATCH 1/3] PCI: rcar-gen4: Configure AXIINTC if iMSI-RX not used

[Marek Vasut]

In case MSI are enabled, but DWC built-in iMSI-RX is not in use, the
MSI are handled via GIC ITS. Configure all controller MSI registers
fully.

Set or clear MSI capability register MSICAP0 MSI enable MSIE bit and
PCIe Interrupt Status 0 Enable register PCIEINTSTS0EN MSI interrupt
enable MSI_CTRL_INT bit according to MSI enable state, set both bits
if MSI are enabled, clear both bits if MSI are disabled.

If MSI are disabled, or MSI are enabled and iMSI-RX is used, then
deconfigure AXIINTCADDR and AXIINTCCONT to 0, which disables any
pass through of MSI TLPs onto the AXI bus and then further into
GIC ITS translation registers.

If MSI are enabled and iMSI-RX is not used, the configure AXIINTCADDR
with target address of GIC ITS translation registers, and configure
AXIINTCCONT to enable MSI TLP pass through onto AXI bus and into the
GIC ITS. This specific configuration allows handling of MSI via the
GIC ITS instead of integrated iMSI-RX.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
---
NOTE: This would not be possible without prior work from Shimoda-san
---
Cc: "Krzysztof Wilczyński" <kwilczynski at kernel.org>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Conor Dooley <conor+dt at kernel.org>
Cc: Geert Uytterhoeven <geert+renesas at glider.be>
Cc: Krzysztof Kozlowski <krzk+dt at kernel.org>
Cc: Lorenzo Pieralisi <lpieralisi at kernel.org>
Cc: Manivannan Sadhasivam <mani at kernel.org>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Rob Herring <robh at kernel.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Cc: devicetree at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-doc at vger.kernel.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-pci at vger.kernel.org
Cc: linux-renesas-soc at vger.kernel.org
---
 drivers/pci/controller/dwc/pcie-rcar-gen4.c | 53 +++++++++++++++++++--
 1 file changed, 48 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index 485cfa8bd9692..ba6e3bedd6d0a 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -31,6 +31,10 @@
 #define DEVICE_TYPE_RC		BIT(4)
 #define BIFUR_MOD_SET_ON	BIT(0)
 
+/* MSI Capability */
+#define MSICAP0			0x0050
+#define MSICAP0_MSIE		BIT(16)
+
 /* PCIe Interrupt Status 0 */
 #define PCIEINTSTS0		0x0084
 
@@ -55,6 +59,16 @@
 #define APP_HOLD_PHY_RST	BIT(16)
 #define APP_LTSSM_ENABLE	BIT(0)
 
+/* INTC address */
+#define AXIINTCADDR		0x0a00
+/* GITS GIC ITS translation register */
+#define AXIINTCADDR_VAL		0xf1050000
+
+/* INTC control & mask */
+#define AXIINTCCONT		0x0a04
+#define INTC_EN			BIT(31)
+#define INTC_MASK		GENMASK(11, 2)
+
 /* PCIe Power Management Control */
 #define PCIEPWRMNGCTRL		0x0070
 #define APP_CLK_REQ_N		BIT(11)
@@ -305,6 +319,39 @@ static struct rcar_gen4_pcie *rcar_gen4_pcie_alloc(struct platform_device *pdev)
 	return rcar;
 }
 
+static void rcar_gen4_pcie_host_msi_init(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *dw = to_dw_pcie_from_pp(pp);
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+	u32 val;
+
+	/* Make sure MSICAP0 MSIE is configured. */
+	val = dw_pcie_readl_dbi(dw, MSICAP0);
+	if (pci_msi_enabled())
+		val |= MSICAP0_MSIE;
+	else
+		val &= ~MSICAP0_MSIE;
+	dw_pcie_writel_dbi(dw, MSICAP0, val);
+
+	if (!pci_msi_enabled() || pp->use_imsi_rx) {
+		/* Clear AXIINTC mapping. */
+		writel(0, rcar->base + AXIINTCADDR);
+		writel(0, rcar->base + AXIINTCCONT);
+	} else {
+		/* Point AXIINTC to GIC ITS and enable. */
+		writel(AXIINTCADDR_VAL, rcar->base + AXIINTCADDR);
+		writel(INTC_EN | INTC_MASK, rcar->base + AXIINTCCONT);
+	}
+
+	/* Configure MSI interrupt signal */
+	val = readl(rcar->base + PCIEINTSTS0EN);
+	if (pci_msi_enabled())
+		val |= MSI_CTRL_INT;
+	else
+		val &= ~MSI_CTRL_INT;
+	writel(val, rcar->base + PCIEINTSTS0EN);
+}
+
 static int rcar_gen4_pcie_enable_device(struct pci_host_bridge *bridge,
 					struct pci_dev *dev)
 {
@@ -359,7 +406,6 @@ static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
 	struct dw_pcie *dw = to_dw_pcie_from_pp(pp);
 	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
 	int ret;
-	u32 val;
 
 	if (pp->bridge)
 		pp->bridge->enable_device = rcar_gen4_pcie_enable_device;
@@ -379,10 +425,7 @@ static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
 	dw_pcie_writel_dbi2(dw, PCI_BASE_ADDRESS_0, 0x0);
 	dw_pcie_writel_dbi2(dw, PCI_BASE_ADDRESS_1, 0x0);
 
-	/* Enable MSI interrupt signal */
-	val = readl(rcar->base + PCIEINTSTS0EN);
-	val |= MSI_CTRL_INT;
-	writel(val, rcar->base + PCIEINTSTS0EN);
+	rcar_gen4_pcie_host_msi_init(pp);
 
 	msleep(PCIE_T_PVPERL_MS);	/* pe_rst requires 100msec delay */
 
-- 
2.53.0