[PATCH v4 08/12] PCI: imx6: Config look up table(LUT) to support MSI ITS and IOMMU for i.MX95

[Frank Li]

For the i.MX95, configuration of a LUT is necessary to convert Bus Device
Function (BDF) to stream IDs, which are utilized by both IOMMU and ITS.
This involves examining the msi-map and smmu-map to ensure consistent
mapping of PCI BDF to the same stream IDs. Subsequently, LUT-related
registers are configured. In the absence of an msi-map, the built-in MSI
controller is utilized as a fallback.

Additionally, register a PCI bus notifier to trigger imx_pcie_add_device()
upon the appearance of a new PCI device and when the bus is an iMX6 PCI
controller. This function configures the correct LUT based on Device Tree
Settings (DTS).

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
 drivers/pci/controller/dwc/pci-imx6.c | 175 +++++++++++++++++++++++++++++++++-
 1 file changed, 174 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index b33d8790a93af..66573ef7a002b 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -55,6 +55,22 @@
 #define IMX95_PE0_GEN_CTRL_3			0x1058
 #define IMX95_PCIE_LTSSM_EN			BIT(0)
 
+#define IMX95_PE0_LUT_ACSCTRL			0x1008
+#define IMX95_PEO_LUT_RWA			BIT(16)
+#define IMX95_PE0_LUT_ENLOC			GENMASK(4, 0)
+
+#define IMX95_PE0_LUT_DATA1			0x100c
+#define IMX95_PE0_LUT_VLD			BIT(31)
+#define IMX95_PE0_LUT_DAC_ID			GENMASK(10, 8)
+#define IMX95_PE0_LUT_STREAM_ID			GENMASK(5, 0)
+
+#define IMX95_PE0_LUT_DATA2			0x1010
+#define IMX95_PE0_LUT_REQID			GENMASK(31, 16)
+#define IMX95_PE0_LUT_MASK			GENMASK(15, 0)
+
+#define IMX95_SID_MASK				GENMASK(5, 0)
+#define IMX95_MAX_LUT				32
+
 #define to_imx_pcie(x)	dev_get_drvdata((x)->dev)
 
 enum imx_pcie_variants {
@@ -80,6 +96,7 @@ enum imx_pcie_variants {
 #define IMX_PCIE_FLAG_HAS_PHY_RESET		BIT(5)
 #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
 #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
+#define IMX_PCIE_FLAG_MONITOR_DEV		BIT(8)
 
 #define imx_check_flag(pci, val)     (pci->drvdata->flags & val)
 
@@ -134,6 +151,8 @@ struct imx_pcie {
 	struct device		*pd_pcie_phy;
 	struct phy		*phy;
 	const struct imx_pcie_drvdata *drvdata;
+
+	struct mutex		lock;
 };
 
 /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@@ -217,6 +236,66 @@ static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie)
 	return 0;
 }
 
+static int imx_pcie_config_lut(struct imx_pcie *imx_pcie, u16 reqid, u8 sid)
+{
+	struct dw_pcie *pci = imx_pcie->pci;
+	struct device *dev = pci->dev;
+	u32 data1, data2;
+	int i;
+
+	if (sid >= 64) {
+		dev_err(dev, "Invalid SID for index %d\n", sid);
+		return -EINVAL;
+	}
+
+	guard(mutex)(&imx_pcie->lock);
+
+	for (i = 0; i < IMX95_MAX_LUT; i++) {
+		regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_ACSCTRL, IMX95_PEO_LUT_RWA | i);
+
+		regmap_read(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA1, &data1);
+		if (data1 & IMX95_PE0_LUT_VLD)
+			continue;
+
+		data1 = FIELD_PREP(IMX95_PE0_LUT_DAC_ID, 0);
+		data1 |= FIELD_PREP(IMX95_PE0_LUT_STREAM_ID, sid);
+		data1 |= IMX95_PE0_LUT_VLD;
+
+		regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA1, data1);
+
+		data2 = 0xffff;
+		data2 |= FIELD_PREP(IMX95_PE0_LUT_REQID, reqid);
+
+		regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, data2);
+
+		regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_ACSCTRL, i);
+
+		return 0;
+	}
+
+	dev_err(dev, "All lut already used\n");
+	return -EINVAL;
+}
+
+static void imx_pcie_remove_lut(struct imx_pcie *imx_pcie, u16 reqid)
+{
+	u32 data2 = 0;
+	int i;
+
+	guard(mutex)(&imx_pcie->lock);
+
+	for (i = 0; i < IMX95_MAX_LUT; i++) {
+		regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_ACSCTRL, IMX95_PEO_LUT_RWA | i);
+
+		regmap_read(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, &data2);
+		if (FIELD_GET(IMX95_PE0_LUT_REQID, data2) == reqid) {
+			regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA1, 0);
+			regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, 0);
+			regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_ACSCTRL, i);
+		}
+	}
+}
+
 static void imx_pcie_configure_type(struct imx_pcie *imx_pcie)
 {
 	const struct imx_pcie_drvdata *drvdata = imx_pcie->drvdata;
@@ -1227,6 +1306,85 @@ static int imx_pcie_resume_noirq(struct device *dev)
 	return 0;
 }
 
+static bool imx_pcie_match_device(struct pci_bus *bus);
+
+static int imx_pcie_add_device(struct imx_pcie *imx_pcie, struct pci_dev *pdev)
+{
+	u32 sid_i = 0, sid_m = 0, rid = pci_dev_id(pdev);
+	struct device *dev = imx_pcie->pci->dev;
+	int err;
+
+	err = of_map_id(dev->of_node, rid, "iommu-map", "iommu-map-mask", NULL, &sid_i);
+	if (err)
+		return err;
+
+	err = of_map_id(dev->of_node, rid, "msi-map", "msi-map-mask", NULL, &sid_m);
+	if (err)
+		return err;
+
+	if (sid_i != rid && sid_m != rid)
+		if ((sid_i & IMX95_SID_MASK) != (sid_m & IMX95_SID_MASK)) {
+			dev_err(dev, "its and iommu stream id miss match, please check dts file\n");
+			return -EINVAL;
+		}
+
+	/* if iommu-map is not existed then use msi-map's stream id*/
+	if (sid_i == rid)
+		sid_i = sid_m;
+
+	sid_i &= IMX95_SID_MASK;
+
+	if (sid_i != rid)
+		return imx_pcie_config_lut(imx_pcie, rid, sid_i);
+
+	/* Use dwc built-in MSI controller */
+	return 0;
+}
+
+static void imx_pcie_del_device(struct imx_pcie *imx_pcie, struct pci_dev *pdev)
+{
+	imx_pcie_remove_lut(imx_pcie, pci_dev_id(pdev));
+}
+
+
+static int imx_pcie_bus_notifier(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct pci_host_bridge *host;
+	struct imx_pcie *imx_pcie;
+	struct pci_dev *pdev;
+	int err;
+
+	pdev = to_pci_dev(data);
+	host = pci_find_host_bridge(pdev->bus);
+
+	if (!imx_pcie_match_device(host->bus))
+		return NOTIFY_OK;
+
+	imx_pcie = to_imx_pcie(to_dw_pcie_from_pp(host->sysdata));
+
+	if (!imx_check_flag(imx_pcie, IMX_PCIE_FLAG_MONITOR_DEV))
+		return NOTIFY_OK;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		err = imx_pcie_add_device(imx_pcie, pdev);
+		if (err)
+			return notifier_from_errno(err);
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+		imx_pcie_del_device(imx_pcie, pdev);
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block imx_pcie_nb = {
+	.notifier_call = imx_pcie_bus_notifier,
+};
+
 static const struct dev_pm_ops imx_pcie_pm_ops = {
 	NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_pcie_suspend_noirq,
 				  imx_pcie_resume_noirq)
@@ -1259,6 +1417,8 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	imx_pcie->pci = pci;
 	imx_pcie->drvdata = of_device_get_match_data(dev);
 
+	mutex_init(&imx_pcie->lock);
+
 	/* Find the PHY if one is defined, only imx7d uses it */
 	np = of_parse_phandle(node, "fsl,imx7d-pcie-phy", 0);
 	if (np) {
@@ -1557,7 +1717,8 @@ static const struct imx_pcie_drvdata drvdata[] = {
 	},
 	[IMX95] = {
 		.variant = IMX95,
-		.flags = IMX_PCIE_FLAG_HAS_SERDES,
+		.flags = IMX_PCIE_FLAG_HAS_SERDES |
+			 IMX_PCIE_FLAG_MONITOR_DEV,
 		.clk_names = imx8mq_clks,
 		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
 		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
@@ -1693,6 +1854,8 @@ DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_SYNOPSYS, 0xabcd,
 
 static int __init imx_pcie_init(void)
 {
+	int ret;
+
 #ifdef CONFIG_ARM
 	struct device_node *np;
 
@@ -1711,7 +1874,17 @@ static int __init imx_pcie_init(void)
 	hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
 			"external abort on non-linefetch");
 #endif
+	ret = bus_register_notifier(&pci_bus_type, &imx_pcie_nb);
+	if (ret)
+		return ret;
 
 	return platform_driver_register(&imx_pcie_driver);
 }
+
+static void __exit imx_pcie_exit(void)
+{
+	bus_unregister_notifier(&pci_bus_type, &imx_pcie_nb);
+}
+
 device_initcall(imx_pcie_init);
+__exitcall(imx_pcie_exit);

-- 
2.34.1