[+cc IOMMU and pcie-apple.c folks for comment]
On Tue, May 28, 2024 at 03:39:21PM -0400, Frank Li wrote:
> 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).
This scheme is pretty similar to apple_pcie_bus_notifier(). If we
have to do this, I wish it were *more* similar, i.e., copy the
function names, bitmap tracking, code structure, etc.
I don't really know how stream IDs work, but I assume they are used on
most or all arm64 platforms, so I'm a little surprised that of all the
PCI host drivers used on arm64, only pcie-apple.c and pci-imx6.c need
this notifier.
There's this path, which is pretty generic and does at least the
of_map_id() part of what you're doing in imx_pcie_add_device():
__driver_probe_device
really_probe
pci_dma_configure # pci_bus_type.dma_configure
of_dma_configure
of_dma_configure_id
of_iommu_configure
of_pci_iommu_init
of_iommu_configure_dev_id
of_map_id
of_iommu_xlate
ops = iommu_ops_from_fwnode
iommu_fwspec_init
ops->of_xlate(dev, iommu_spec)
Maybe this needs to be extended somehow with a hook to do the
device-specific work like updating the LUT? Just speculating here,
the IOMMU folks will know how this is expected to work.
Some typos and minor comments below.
> 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 29309ad0e352b..8ecc00049e20b 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -54,6 +54,22 @@
> #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 {
> @@ -79,6 +95,7 @@ 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)
>
> @@ -132,6 +149,8 @@ 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 */
> @@ -215,6 +234,66 @@ 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;
> @@ -1232,6 +1311,85 @@ static int imx_pcie_resume_noirq(struct device *dev)
> return 0;
> }
>
> +static bool imx_pcie_match_device(struct pci_bus *bus);
Can you add the imx_pcie_match_device() earlier in the file so we
don't need this forward declaration?
> +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*/
Capitalize consistently, e.g., the most comments in this file start
with a capital letter.
s/is not existed/does not exist/
Add space before closing */
> + 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)
> @@ -1264,6 +1422,8 @@ 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) {
> @@ -1551,7 +1711,8 @@ 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,
> @@ -1687,6 +1848,8 @@ 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;
>
> @@ -1705,7 +1868,17 @@ 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;
I think this should go in imx6_pcie_probe().
> return platform_driver_register(&imx_pcie_driver);
> }
> +
> +static void __exit imx_pcie_exit(void)
> +{
> + bus_unregister_notifier(&pci_bus_type, &imx_pcie_nb);
It looks like this driver is removable?
What happens when an external abort occurs after the
imx6q_pcie_abort_handler() text is removed?
> +}
> +
> device_initcall(imx_pcie_init);
> +__exitcall(imx_pcie_exit);
>
> --
> 2.34.1
>
