// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-2021 Intel Corporation.

/*
 * SDW Intel ACPI scan helpers
 */

#include <linux/acpi.h>
#include <linux/bits.h>
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/soundwire/sdw_intel.h>
#include <linux/string.h>

#define SDW_LINK_TYPE           4 /* from Intel ACPI documentation */

static int ctrl_link_mask;
module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");

static ulong ctrl_addr = 0x40000000;
module_param_named(sdw_ctrl_addr, ctrl_addr, ulong, 0444);
MODULE_PARM_DESC(sdw_ctrl_addr, "Intel SoundWire Controller _ADR");

static bool is_link_enabled(struct fwnode_handle *fw_node, u8 idx)
{
        struct fwnode_handle *link;
        char name[32];
        u32 quirk_mask = 0;

        /* Find master handle */
        snprintf(name, sizeof(name),
                 "mipi-sdw-link-%hhu-subproperties", idx);

        link = fwnode_get_named_child_node(fw_node, name);
        if (!link)
                return false;

        fwnode_property_read_u32(link,
                                 "intel-quirk-mask",
                                 &quirk_mask);

        fwnode_handle_put(link);

        if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
                return false;

        return true;
}

static int
sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
{
        struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);
        struct fwnode_handle *fwnode;
        unsigned long list;
        unsigned int i;
        u32 count;
        u32 tmp;
        int ret;

        if (!adev)
                return -EINVAL;

        fwnode = acpi_fwnode_handle(adev);

        /*
         * Found controller, find links supported
         *
         * In theory we could check the number of links supported in
         * hardware, but in that step we cannot assume SoundWire IP is
         * powered.
         *
         * In addition, if the BIOS doesn't even provide this
         * 'master-count' property then all the inits based on link
         * masks will fail as well.
         *
         * We will check the hardware capabilities in the startup() step
         */
        ret = fwnode_property_read_u32(fwnode, "mipi-sdw-manager-list", &tmp);
        if (ret) {
                ret = fwnode_property_read_u32(fwnode, "mipi-sdw-master-count", &count);
                if (ret) {
                        dev_err(&adev->dev,
                                "Failed to read mipi-sdw-master-count: %d\n",
                                ret);
                        return ret;
                }
                list = GENMASK(count - 1, 0);
        } else {
                list = tmp;
                count = hweight32(list);
        }

        /* Check count is within bounds */
        if (count > SDW_INTEL_MAX_LINKS) {
                dev_err(&adev->dev, "Link count %d exceeds max %d\n",
                        count, SDW_INTEL_MAX_LINKS);
                return -EINVAL;
        }

        if (!count) {
                dev_warn(&adev->dev, "No SoundWire links detected\n");
                return -EINVAL;
        }
        dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);

        info->count = count;
        info->link_mask = 0;

        for_each_set_bit(i, &list, SDW_INTEL_MAX_LINKS) {
                if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
                        dev_dbg(&adev->dev,
                                "Link %d masked, will not be enabled\n", i);
                        continue;
                }

                if (!is_link_enabled(fwnode, i)) {
                        dev_dbg(&adev->dev,
                                "Link %d not selected in firmware\n", i);
                        continue;
                }

                info->link_mask |= BIT(i);
        }

        return 0;
}

static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
                                     void *cdata, void **return_value)
{
        struct sdw_intel_acpi_info *info = cdata;
        u64 adr;
        int ret;

        ret = acpi_get_local_u64_address(handle, &adr);
        if (ret < 0)
                return AE_OK; /* keep going */

        if (!acpi_fetch_acpi_dev(handle)) {
                pr_err("%s: Couldn't find ACPI handle\n", __func__);
                return AE_NOT_FOUND;
        }

        /*
         * On some Intel platforms, multiple children of the HDAS
         * device can be found, but only one of them is the SoundWire
         * controller. The SNDW device is always exposed with
         * Name(_ADR, 0x40000000), with bits 31..28 representing the
         * SoundWire link so filter accordingly
         */
        if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
                return AE_OK; /* keep going */

        if (adr != ctrl_addr)
                return AE_OK; /* keep going */

        /* found the correct SoundWire controller */
        info->handle = handle;

        /* device found, stop namespace walk */
        return AE_CTRL_TERMINATE;
}

/**
 * sdw_intel_acpi_scan() - SoundWire Intel init routine
 * @parent_handle: ACPI parent handle
 * @info: description of what firmware/DSDT tables expose
 *
 * This scans the namespace and queries firmware to figure out which
 * links to enable. A follow-up use of sdw_intel_probe() and
 * sdw_intel_startup() is required for creation of devices and bus
 * startup
 */
int sdw_intel_acpi_scan(acpi_handle parent_handle,
                        struct sdw_intel_acpi_info *info)
{
        acpi_status status;

        info->handle = NULL;
        /*
         * In the HDAS ACPI scope, 'SNDW' may be either the child of
         * 'HDAS' or the grandchild of 'HDAS'. So let's go through
         * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW'
         * device.
         */
        status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
                                     parent_handle, 2,
                                     sdw_intel_acpi_cb,
                                     NULL, info, NULL);
        if (ACPI_FAILURE(status) || info->handle == NULL)
                return -ENODEV;

        return sdw_intel_scan_controller(info);
}
EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, "SND_INTEL_SOUNDWIRE_ACPI");

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");