linux-kernel - [PATCH] PCI: imx: make msi work without pcieportbus

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Date:   Thu, 13 Dec 2018 06:22:13 +0000
From:   Richard Zhu <hongxing.zhu@....com>
To:     "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        "andrew.smirnov@...il.com" <andrew.smirnov@...il.com>
CC:     "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Richard Zhu <hongxing.zhu@....com>
Subject: [PATCH] PCI: imx: make msi work without pcieportbus

MSI_EN of iMX PCIe RC would be asserted when
PCIEPORTBUS driver is selected.
Thus, the MSI works fine on iMX PCIe before.
Make a double check on this bit, and assert it
when it is not set and MSI is supported.
Otherwise, the MSI wouldn't be triggered although
the EP is present and the MSIs are assigned.

Signed-off-by: Richard Zhu <hongxing.zhu@....com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 26087b3..6c3e56b 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -74,6 +74,7 @@ struct imx6_pcie {
 #define PHY_PLL_LOCK_WAIT_USLEEP_MAX	200
 
 /* PCIe Root Complex registers (memory-mapped) */
+#define PCI_MSI_CAP				0x50
 #define PCIE_RC_LCR				0x7c
 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1	0x1
 #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2	0x2
@@ -926,6 +927,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	struct resource *dbi_base;
 	struct device_node *node = dev->of_node;
 	int ret;
+	u16 val;
 
 	imx6_pcie = devm_kzalloc(dev, sizeof(*imx6_pcie), GFP_KERNEL);
 	if (!imx6_pcie)
@@ -1070,6 +1072,14 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	ret = imx6_add_pcie_port(imx6_pcie, pdev);
 	if (ret < 0)
 		return ret;
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		val = dw_pcie_readw_dbi(pci, PCI_MSI_CAP + PCI_MSI_FLAGS);
+		if ((val & PCI_MSI_FLAGS_ENABLE) == 0) {
+			val |= PCI_MSI_FLAGS_ENABLE;
+			dw_pcie_writew_dbi(pci, PCI_MSI_CAP +
+					PCI_MSI_FLAGS, val);
+		}
+	}
 
 	return 0;
 }
-- 
2.7.4