[PATCH v7 2/2] PCI: imx6: Add IOMMU and ITS MSI support for i.MX95

Frank Li
2024-12-03T23:30:55Z

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.

Register a PCI bus callback function to handle enable_device() and
disable_device() operations, setting up the LUT whenever a new PCI device
is enabled.

Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v5 to v6
- change comment rid to RID
- some mini change according to mani's feedback

Change from v4 to v5
- rework commt message
- add comment for mutex
- s/reqid/rid/
- keep only one loop when enable lut
- add warning when try to add duplicate rid
- Replace hardcode 0xffff with IMX95_PE0_LUT_MASK
- Fix some error message

Change from v3 to v4
- Check target value at of_map_id().
- of_node_put() for target.
- add case for msi-map exist, but rid entry is not exist.

Change from v2 to v3
- Use the "target" argument of of_map_id()
- Check if rid already in lut table when enable device

change from v1 to v2
- set callback to pci_host_bridge instead pci->ops.
---
drivers/pci/controller/dwc/pci-imx6.c | 183 +++++++++++++++++++++++++++++++++-
1 file changed, 182 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index c8d5c90aa4d45..ac5caa7b05075 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 {
@@ -87,6 +103,7 @@ enum imx_pcie_variants {
* workaround suspend resume on some devices which are affected by this errata.
*/
#define IMX_PCIE_FLAG_BROKEN_SUSPEND BIT(9)
+#define IMX_PCIE_FLAG_HAS_LUT BIT(10)

#define imx_check_flag(pci, val) (pci->drvdata->flags & val)

@@ -139,6 +156,9 @@ struct imx_pcie {
struct device *pd_pcie_phy;
struct phy *phy;
const struct imx_pcie_drvdata *drvdata;
+
+ /* Ensure that only one device's LUT is configured at any given time */
+ struct mutex lock;
};

/* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@@ -930,6 +950,159 @@ static void imx_pcie_stop_link(struct dw_pcie *pci)
imx_pcie_ltssm_disable(dev);
}

+static int imx_pcie_add_lut(struct imx_pcie *imx_pcie, u16 rid, u8 sid)
+{
+ struct dw_pcie *pci = imx_pcie->pci;
+ struct device *dev = pci->dev;
+ u32 data1, data2;
+ int free = -1;
+ int i;
+
+ if (sid >= 64) {
+ dev_err(dev, "Invalid SID for index %d\n", sid);
+ return -EINVAL;
+ }
+
+ guard(mutex)(&imx_pcie->lock);
+
+ /*
+ * Iterate through all LUT entries to check for duplicate RID and
+ * identify the first available entry. Configure this available entry
+ * immediately after verification to avoid rescanning it.
+ */
+ 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)) {
+ if (free < 0)
+ free = i;
+ continue;
+ }
+
+ regmap_read(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, &data2);
+
+ /* Do not add duplicate RID */
+ if (rid == FIELD_GET(IMX95_PE0_LUT_REQID, data2)) {
+ dev_warn(dev, "Existing LUT entry available for RID (%d)", rid);
+ return 0;
+ }
+ }
+
+ if (free < 0) {
+ dev_err(dev, "LUT entry is not available\n");
+ return -ENOSPC;
+ }
+
+ 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 = IMX95_PE0_LUT_MASK; /* Match all bits of RID */
+ data2 |= FIELD_PREP(IMX95_PE0_LUT_REQID, rid);
+ regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, data2);
+
+ regmap_write(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_ACSCTRL, free);
+
+ return 0;
+}
+
+static void imx_pcie_remove_lut(struct imx_pcie *imx_pcie, u16 rid)
+{
+ u32 data2;
+ 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) == rid) {
+ 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);
+
+ break;
+ }
+ }
+}
+
+static int imx_pcie_enable_device(struct pci_host_bridge *bridge, struct pci_dev *pdev)
+{
+ struct imx_pcie *imx_pcie = to_imx_pcie(to_dw_pcie_from_pp(bridge->sysdata));
+ u32 sid_i, sid_m, rid = pci_dev_id(pdev);
+ struct device_node *target;
+ struct device *dev;
+ int err_i, err_m;
+
+ dev = imx_pcie->pci->dev;
+
+ target = NULL;
+ err_i = of_map_id(dev->of_node, rid, "iommu-map", "iommu-map-mask", &target, &sid_i);
+ if (target)
+ of_node_put(target);
+ else
+ err_i = -EINVAL;
+
+ target = NULL;
+ err_m = of_map_id(dev->of_node, rid, "msi-map", "msi-map-mask", &target, &sid_m);
+
+ /*
+ * Return failure if msi-map exist and no entry for RID because dwc common
+ * driver will skip setting up built-in MSI controller if msi-map existed.
+ *
+ * err_m target
+ * 0 NULL Return failure, function not work.
+ * !0 NULL msi-map not exist, use built-in MSI.
+ * 0 !NULL Find one entry.
+ * !0 !NULL Invalidate case.
+ */
+ if (!err_m && !target)
+ return -EINVAL;
+ else if (target)
+ of_node_put(target); /* Find entry for RID in msi-map */
+
+ /*
+ * msi-map iommu-map
+ * Y Y ITS + SMMU, require the same sid
+ * Y N ITS
+ * N Y DWC MSI Ctrl + SMMU
+ * N N DWC MSI Ctrl
+ */
+ if (!err_i && !err_m)
+ if ((sid_i & IMX95_SID_MASK) != (sid_m & IMX95_SID_MASK)) {
+ dev_err(dev, "iommu-map and msi-map entries mismatch!\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Both iommu-map and msi-map not exist, use dwc built-in MSI
+ * controller, do nothing here.
+ */
+ if (err_i && err_m)
+ return 0;
+
+ if (!err_i)
+ return imx_pcie_add_lut(imx_pcie, rid, sid_i);
+ else if (!err_m)
+ /*
+ * Hardware auto add 2 bits controller id ahead of stream ID,
+ * so mask this 2bits to get stream ID.
+ */
+ return imx_pcie_add_lut(imx_pcie, rid, sid_m & IMX95_SID_MASK);
+
+ return 0;
+}
+
+static void imx_pcie_disable_device(struct pci_host_bridge *bridge, struct pci_dev *pdev)
+{
+ struct imx_pcie *imx_pcie;
+
+ imx_pcie = to_imx_pcie(to_dw_pcie_from_pp(bridge->sysdata));
+ imx_pcie_remove_lut(imx_pcie, pci_dev_id(pdev));
+}
+
static int imx_pcie_host_init(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -946,6 +1119,11 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
}
}

+ if (pp->bridge && imx_check_flag(imx_pcie, IMX_PCIE_FLAG_HAS_LUT)) {
+ pp->bridge->enable_device = imx_pcie_enable_device;
+ pp->bridge->disable_device = imx_pcie_disable_device;
+ }
+
imx_pcie_assert_core_reset(imx_pcie);

if (imx_pcie->drvdata->init_phy)
@@ -1330,6 +1508,8 @@ 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) {
@@ -1627,7 +1807,8 @@ 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_HAS_LUT,
.clk_names = imx8mq_clks,
.clks_cnt = ARRAY_SIZE(imx8mq_clks),
.ltssm_off = IMX95_PE0_GEN_CTRL_3,

--
2.34.1