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Message-ID: <20241113174841.olnyu5l6rbmr3tqh@thinkpad>
Date: Wed, 13 Nov 2024 23:18:41 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Frank Li <Frank.Li@....com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, Richard Zhu <hongxing.zhu@....com>,
Lucas Stach <l.stach@...gutronix.de>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Krzysztof Wilczyński <kw@...ux.com>,
Rob Herring <robh@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
imx@...ts.linux.dev, alyssa@...enzweig.io, bpf@...r.kernel.org,
broonie@...nel.org, jgg@...pe.ca, joro@...tes.org,
lgirdwood@...il.com, maz@...nel.org, p.zabel@...gutronix.de,
robin.murphy@....com, will@...nel.org
Subject: Re: [PATCH v5 2/2] PCI: imx6: Add IOMMU and ITS MSI support for
i.MX95
On Mon, Nov 04, 2024 at 02:23:00PM -0500, 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.
>
> 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@....com>
> Signed-off-by: Frank Li <Frank.Li@....com>
Some minor comments below. It'd be good to get Robin's Ack for this patch.
> ---
> 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 | 176 +++++++++++++++++++++++++++++++++-
> 1 file changed, 175 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 94f3411352bf0..e75dc361e284e 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 {
> @@ -82,6 +98,7 @@ 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_HAS_LUT BIT(8)
>
> #define imx_check_flag(pci, val) (pci->drvdata->flags & val)
>
> @@ -134,6 +151,9 @@ 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 */
> @@ -925,6 +945,152 @@ 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);
> +
> + 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;
So you don't increment 'free' once it becomes >=0? Why can't you use the loop
iterator 'i' itself instead of 'free'?
> + continue;
> + }
> +
> + regmap_read(imx_pcie->iomuxc_gpr, IMX95_PE0_LUT_DATA2, &data2);
> +
> + /* Needn't add duplicated Request ID */
"Do not add duplicate RID"
> + if (rid == FIELD_GET(IMX95_PE0_LUT_REQID, data2)) {
> + dev_warn(dev, "Try to enable rid(%d) twice without disable it\n", rid);
"Existing LUT entry available for RID (%d)\n"
> + return 0;
> + }
> + }
> +
> + if (free < 0) {
> + dev_err(dev, "LUT entry is not available\n");
> + return -EINVAL;
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 */
Please use 'RID' in comments everywhere.
> + 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);
> +
Remove newline.
> + 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 = 0, sid_m = 0, rid = pci_dev_id(pdev);
No need to initialize sid_{i/m}.
> + 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 bit controller id ahead of stream ID */
What is this comment for? I don't find it relevant here.
- Mani
--
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