root/drivers/firmware/imx/imx-scu-irq.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2019,2023 NXP
 *
 * Implementation of the SCU IRQ functions using MU.
 *
 */

#include <dt-bindings/firmware/imx/rsrc.h>
#include <linux/firmware/imx/ipc.h>
#include <linux/firmware/imx/sci.h>
#include <linux/kobject.h>
#include <linux/mailbox_client.h>
#include <linux/of.h>
#include <linux/suspend.h>
#include <linux/sysfs.h>

#define IMX_SC_IRQ_FUNC_ENABLE  1
#define IMX_SC_IRQ_FUNC_STATUS  2
#define IMX_SC_IRQ_NUM_GROUP    9

static u32 mu_resource_id;

struct imx_sc_msg_irq_get_status {
        struct imx_sc_rpc_msg hdr;
        union {
                struct {
                        u16 resource;
                        u8 group;
                        u8 reserved;
                } __packed req;
                struct {
                        u32 status;
                } resp;
        } data;
};

struct imx_sc_msg_irq_enable {
        struct imx_sc_rpc_msg hdr;
        u32 mask;
        u16 resource;
        u8 group;
        u8 enable;
} __packed;

struct scu_wakeup {
        u32 mask;
        u32 wakeup_src;
        bool valid;
};

/* Sysfs functions */
static struct kobject *wakeup_obj;
static ssize_t wakeup_source_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf);
static struct kobj_attribute wakeup_source_attr =
                __ATTR(wakeup_src, 0660, wakeup_source_show, NULL);

static struct scu_wakeup scu_irq_wakeup[IMX_SC_IRQ_NUM_GROUP];

static struct imx_sc_ipc *imx_sc_irq_ipc_handle;
static struct work_struct imx_sc_irq_work;
static BLOCKING_NOTIFIER_HEAD(imx_scu_irq_notifier_chain);

int imx_scu_irq_register_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(
                &imx_scu_irq_notifier_chain, nb);
}
EXPORT_SYMBOL(imx_scu_irq_register_notifier);

int imx_scu_irq_unregister_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(
                &imx_scu_irq_notifier_chain, nb);
}
EXPORT_SYMBOL(imx_scu_irq_unregister_notifier);

static int imx_scu_irq_notifier_call_chain(unsigned long status, u8 *group)
{
        return blocking_notifier_call_chain(&imx_scu_irq_notifier_chain,
                status, (void *)group);
}

static void imx_scu_irq_work_handler(struct work_struct *work)
{
        u32 irq_status;
        int ret;
        u8 i;

        for (i = 0; i < IMX_SC_IRQ_NUM_GROUP; i++) {
                if (scu_irq_wakeup[i].mask) {
                        scu_irq_wakeup[i].valid = false;
                        scu_irq_wakeup[i].wakeup_src = 0;
                }

                ret = imx_scu_irq_get_status(i, &irq_status);
                if (ret) {
                        pr_err("get irq group %d status failed, ret %d\n",
                               i, ret);
                        return;
                }

                if (!irq_status)
                        continue;
                if (scu_irq_wakeup[i].mask & irq_status) {
                        scu_irq_wakeup[i].valid = true;
                        scu_irq_wakeup[i].wakeup_src = irq_status & scu_irq_wakeup[i].mask;
                } else {
                        scu_irq_wakeup[i].wakeup_src = irq_status;
                }

                pm_system_wakeup();
                imx_scu_irq_notifier_call_chain(irq_status, &i);
        }
}

int imx_scu_irq_get_status(u8 group, u32 *irq_status)
{
        struct imx_sc_msg_irq_get_status msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;
        int ret;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_IRQ;
        hdr->func = IMX_SC_IRQ_FUNC_STATUS;
        hdr->size = 2;

        msg.data.req.resource = mu_resource_id;
        msg.data.req.group = group;

        ret = imx_scu_call_rpc(imx_sc_irq_ipc_handle, &msg, true);
        if (ret)
                return ret;

        if (irq_status)
                *irq_status = msg.data.resp.status;

        return 0;
}
EXPORT_SYMBOL(imx_scu_irq_get_status);

int imx_scu_irq_group_enable(u8 group, u32 mask, u8 enable)
{
        struct imx_sc_msg_irq_enable msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;
        int ret;

        if (!imx_sc_irq_ipc_handle)
                return -EPROBE_DEFER;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_IRQ;
        hdr->func = IMX_SC_IRQ_FUNC_ENABLE;
        hdr->size = 3;

        msg.resource = mu_resource_id;
        msg.group = group;
        msg.mask = mask;
        msg.enable = enable;

        ret = imx_scu_call_rpc(imx_sc_irq_ipc_handle, &msg, true);
        if (ret)
                pr_err("enable irq failed, group %d, mask %d, ret %d\n",
                        group, mask, ret);

        if (enable)
                scu_irq_wakeup[group].mask |= mask;
        else
                scu_irq_wakeup[group].mask &= ~mask;

        return ret;
}
EXPORT_SYMBOL(imx_scu_irq_group_enable);

static void imx_scu_irq_callback(struct mbox_client *c, void *msg)
{
        schedule_work(&imx_sc_irq_work);
}

static ssize_t wakeup_source_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
        int i;

        for (i = 0; i < IMX_SC_IRQ_NUM_GROUP; i++) {
                if (!scu_irq_wakeup[i].wakeup_src)
                        continue;

                if (scu_irq_wakeup[i].valid)
                        sprintf(buf, "Wakeup source group = %d, irq = 0x%x\n",
                                i, scu_irq_wakeup[i].wakeup_src);
                else
                        sprintf(buf, "Spurious SCU wakeup, group = %d, irq = 0x%x\n",
                                i, scu_irq_wakeup[i].wakeup_src);
        }

        return strlen(buf);
}

int imx_scu_enable_general_irq_channel(struct device *dev)
{
        struct of_phandle_args spec;
        struct mbox_client *cl;
        struct mbox_chan *ch;
        int ret = 0, i = 0;

        if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
                                       "#mbox-cells", 0, &spec)) {
                i = of_alias_get_id(spec.np, "mu");
                of_node_put(spec.np);
        }

        /* use mu1 as general mu irq channel if failed */
        if (i < 0)
                i = 1;

        mu_resource_id = IMX_SC_R_MU_0A + i;

        ret = imx_scu_get_handle(&imx_sc_irq_ipc_handle);
        if (ret)
                return ret;

        cl = devm_kzalloc(dev, sizeof(*cl), GFP_KERNEL);
        if (!cl)
                return -ENOMEM;

        cl->dev = dev;
        cl->rx_callback = imx_scu_irq_callback;

        INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);

        /* SCU general IRQ uses general interrupt channel 3 */
        ch = mbox_request_channel_byname(cl, "gip3");
        if (IS_ERR(ch)) {
                ret = PTR_ERR(ch);
                dev_err(dev, "failed to request mbox chan gip3, ret %d\n", ret);
                goto free_cl;
        }

        /* Create directory under /sysfs/firmware */
        wakeup_obj = kobject_create_and_add("scu_wakeup_source", firmware_kobj);
        if (!wakeup_obj) {
                ret = -ENOMEM;
                goto free_ch;
        }

        ret = sysfs_create_file(wakeup_obj, &wakeup_source_attr.attr);
        if (ret) {
                dev_err(dev, "Cannot create wakeup source src file......\n");
                kobject_put(wakeup_obj);
                goto free_ch;
        }

        return 0;

free_ch:
        mbox_free_channel(ch);
free_cl:
        devm_kfree(dev, cl);

        return ret;
}