Hi,
Am Dienstag, 21. Januar 2025, 16:05:32 CET schrieb Peng Fan (OSS):
> From: Peng Fan <peng.fan@xxxxxxx>
>
> i.MX9 OCOTP supports a specific peripheral or function being fused
> which means disabled, so
> - Introduce ocotp_access_gates to be container of efuse gate info
> - Iterate all nodes to check accessing permission. If not
> allowed to be accessed, detach the node
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/nvmem/Kconfig | 3 +
> drivers/nvmem/imx-ocotp-ele.c | 172 +++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 174 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 8671b7c974b933e147154bb40b5d41b5730518d2..77cc496fd5e0e1afd753534b56fe1f5ef3e3ec55 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -93,6 +93,9 @@ config NVMEM_IMX_OCOTP_ELE
> This is a driver for the On-Chip OTP Controller (OCOTP)
> available on i.MX SoCs which has ELE.
>
> + If built as modules, any other driver relying on this working
> + as access controller also needs to be a module as well.
> +
> config NVMEM_IMX_OCOTP_SCU
> tristate "i.MX8 SCU On-Chip OTP Controller support"
> depends on IMX_SCU
> diff --git a/drivers/nvmem/imx-ocotp-ele.c b/drivers/nvmem/imx-ocotp-ele.c
> index ca6dd71d8a2e29888c6e556aaea116c1a967cb5f..5ea6d959ce38760eeed44a989992fb35c462c0b4 100644
> --- a/drivers/nvmem/imx-ocotp-ele.c
> +++ b/drivers/nvmem/imx-ocotp-ele.c
> @@ -5,6 +5,8 @@
> * Copyright 2023 NXP
> */
>
> +#include <dt-bindings/nvmem/fsl,imx93-ocotp.h>
> +#include <dt-bindings/nvmem/fsl,imx95-ocotp.h>
> #include <linux/device.h>
> #include <linux/io.h>
> #include <linux/module.h>
> @@ -27,6 +29,7 @@ struct ocotp_map_entry {
> };
>
> struct ocotp_devtype_data {
> + const struct ocotp_access_gates *access_gates;
> u32 reg_off;
> char *name;
> u32 size;
> @@ -36,6 +39,20 @@ struct ocotp_devtype_data {
> struct ocotp_map_entry entry[];
> };
>
> +#define OCOTP_MAX_NUM_GATE_WORDS 4
> +
> +struct access_gate {
> + u32 word;
> + u32 mask;
> +};
> +
> +struct ocotp_access_gates {
> + u32 num_words;
> + u32 words[OCOTP_MAX_NUM_GATE_WORDS];
> + u32 num_gates;
> + struct access_gate *gates;
> +};
> +
> struct imx_ocotp_priv {
> struct device *dev;
> void __iomem *base;
> @@ -131,6 +148,82 @@ static void imx_ocotp_fixup_dt_cell_info(struct nvmem_device *nvmem,
> cell->read_post_process = imx_ocotp_cell_pp;
> }
>
> +static int imx_ele_ocotp_check_access(struct imx_ocotp_priv *priv, u32 id)
> +{
> + const struct ocotp_access_gates *access_gates = priv->data->access_gates;
> + void __iomem *reg = priv->base + priv->data->reg_off;
> + u32 word, mask, val;
> +
> + if (id >= access_gates->num_gates) {
> + dev_err(priv->config.dev, "Index %d too large\n", id);
> + return -EACCES;
> + }
> +
> + word = access_gates->gates[id].word;
> + mask = access_gates->gates[id].mask;
> +
> + reg = priv->base + priv->data->reg_off + (word << 2);
> + val = readl(reg);
> +
> + dev_dbg(priv->config.dev, "id:%d word:%d mask:0x%08x\n", id, word, mask);
> + /* true means not allow access */
> + if (val & mask)
> + return -EACCES;
> +
> + return 0;
> +}
> +
> +static int imx_ele_ocotp_grant_access(struct imx_ocotp_priv *priv, struct device_node *parent)
> +{
> + struct device *dev = priv->config.dev;
> +
> + for_each_available_child_of_node_scoped(parent, child) {
> + struct of_phandle_args args;
> + u32 id, idx = 0;
> +
> + while (!of_parse_phandle_with_args(child, "access-controllers",
> + "#access-controller-cells",
> + idx++, &args)) {
> + of_node_put(args.np);
> + if (args.np != dev->of_node)
> + continue;
> +
> + /* Only support one cell */
> + if (args.args_count != 1) {
> + dev_err(dev, "wrong args count\n");
> + continue;
> + }
> +
> + id = args.args[0];
> +
> + dev_dbg(dev, "Checking node: %pOF gate: %d\n", child, id);
> +
> + if (imx_ele_ocotp_check_access(priv, id)) {
> + of_detach_node(child);
> + dev_info(dev, "%pOF: Not granted, device driver will not be probed\n",
> + child);
> + }
> + }
> +
> + imx_ele_ocotp_grant_access(priv, child);
> + }
> +
> + return 0;
> +}
> +
> +static int imx_ele_ocotp_access_control(struct imx_ocotp_priv *priv)
> +{
> + struct device_node *root __free(device_node) = of_find_node_by_path("/");
> +
> + if (!priv->data->access_gates)
> + return 0;
> +
> + /* This should never happen */
> + WARN_ON(!root);
Even if you warning something is wrong, aka root == NULL, you are still
using it on imx_ele_ocotp_grant_access(). Just return early.
if (WARN_ON(!))
return -EINVAL;
Best regards
Alexander
> +
> + return imx_ele_ocotp_grant_access(priv, root);
> +}
> +
> static int imx_ele_ocotp_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -161,14 +254,45 @@ static int imx_ele_ocotp_probe(struct platform_device *pdev)
> priv->config.fixup_dt_cell_info = imx_ocotp_fixup_dt_cell_info;
> mutex_init(&priv->lock);
>
> + platform_set_drvdata(pdev, priv);
> +
> nvmem = devm_nvmem_register(dev, &priv->config);
> if (IS_ERR(nvmem))
> return PTR_ERR(nvmem);
>
> - return 0;
> +
> + return imx_ele_ocotp_access_control(priv);
> }
--
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