Re: [PATCH v2 3/7] iommu: mtk_iommu: Lookup phandle to retrieve syscon to pericfg

Yong Wu via iommu
2022-05-26T08:22:39Z

On Wed, 2022-05-18 at 12:04 +0200, AngeloGioacchino Del Regno wrote:
> On some SoCs (of which only MT8195 is supported at the time of
> writing),
> the "R" and "W" (I/O) enable bits for the IOMMUs are in the
> pericfg_ao
> register space and not in the IOMMU space: as it happened already
> with
> infracfg, it is expected that this list will grow.
>
> Instead of specifying pericfg compatibles on a per-SoC basis,
> following
> what was done with infracfg, let's lookup the syscon by phandle
> instead.
> Also following the previous infracfg change, add a warning for
> outdated
> devicetrees, in hope that the user will take action.
>
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> ---
> drivers/iommu/mtk_iommu.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index d16b95e71ded..090cf6e15f85 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -138,6 +138,8 @@
> /* PM and clock always on. e.g. infra iommu */
> #define PM_CLK_AO BIT(15)
> #define IFA_IOMMU_PCIE_SUPPORT BIT(16)
> +/* IOMMU I/O (r/w) is enabled using PERICFG_IOMMU_1 register */
> +#define HAS_PERI_IOMMU1_REG BIT(17)
>
> #define MTK_IOMMU_HAS_FLAG_MASK(pdata, _x, mask) \
> ((((pdata)->flags) & (mask)) == (_x))
> @@ -187,7 +189,6 @@ struct mtk_iommu_plat_data {
> u32 flags;
> u32 inv_sel_reg;
>
> - char *pericfg_comp_str;
> struct list_head *hw_list;
> unsigned int iova_region_nr;
> const struct mtk_iommu_iova_region *iova_region;
> @@ -1214,14 +1215,19 @@ static int mtk_iommu_probe(struct
> platform_device *pdev)
> goto out_runtime_disable;
> }
> } else if (MTK_IOMMU_IS_TYPE(data->plat_data,
> MTK_IOMMU_TYPE_INFRA) &&
> - data->plat_data->pericfg_comp_str) {
> - infracfg = syscon_regmap_lookup_by_compatible(data-
> >plat_data->pericfg_comp_str);
> - if (IS_ERR(infracfg)) {
> - ret = PTR_ERR(infracfg);
> - goto out_runtime_disable;
> - }
> + MTK_IOMMU_HAS_FLAG(data->plat_data,
> HAS_PERI_IOMMU1_REG)) {
> + data->pericfg = syscon_regmap_lookup_by_phandle(dev-
> >of_node, "mediatek,pericfg");

I'm not keen to add this property. Currently only mt8195 use this
setting. In the lastest SoC, we move this setting to ATF. thus I think
we could keep the current way, no need add a new DT property only for
mt8195.

> + if (IS_ERR(data->pericfg)) {
> + dev_info(dev, "Cannot find phandle to
> mediatek,pericfg:"
> + " Please update your
> devicetree.\n");
>
> - data->pericfg = infracfg;
> + p = "mediatek,mt8195-pericfg_ao";
> + data->pericfg =
> syscon_regmap_lookup_by_compatible(p);
> + if (IS_ERR(data->pericfg)) {
> + ret = PTR_ERR(data->pericfg);
> + goto out_runtime_disable;
> + }
> + }
> }
>
> platform_set_drvdata(pdev, data);
> @@ -1480,8 +1486,8 @@ static const struct mtk_iommu_plat_data
> mt8192_data = {
> static const struct mtk_iommu_plat_data mt8195_data_infra = {
> .m4u_plat = M4U_MT8195,
> .flags = WR_THROT_EN | DCM_DISABLE | STD_AXI_MODE |
> PM_CLK_AO |
> - MTK_IOMMU_TYPE_INFRA |
> IFA_IOMMU_PCIE_SUPPORT,
> - .pericfg_comp_str = "mediatek,mt8195-pericfg_ao",
> + HAS_PERI_IOMMU1_REG | MTK_IOMMU_TYPE_INFRA
> |
> + IFA_IOMMU_PCIE_SUPPORT,
> .inv_sel_reg = REG_MMU_INV_SEL_GEN2,
> .banks_num = 5,
> .banks_enable = {true, false, false, false, true},