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// 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/fwnode.h>
#include <linux/module.h>
#include <linux/soundwire/sdw_intel.h>
#include <linux/string.h>
#define SDW_LINK_TYPE 4 /* from Intel ACPI documentation */
#define SDW_MAX_LINKS 4
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 bool is_link_enabled(struct fwnode_handle *fw_node, int i)
{
struct fwnode_handle *link;
char name[32];
u32 quirk_mask = 0;
/* Find master handle */
snprintf(name, sizeof(name),
"mipi-sdw-link-%d-subproperties", i);
link = fwnode_get_named_child_node(fw_node, name);
if (!link)
return false;
fwnode_property_read_u32(link,
"intel-quirk-mask",
&quirk_mask);
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;
int ret, i;
u8 count;
if (acpi_bus_get_device(info->handle, &adev))
return -EINVAL;
/* Found controller, find links supported */
count = 0;
ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
"mipi-sdw-master-count", &count, 1);
/*
* 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
*/
if (ret) {
dev_err(&adev->dev,
"Failed to read mipi-sdw-master-count: %d\n", ret);
return -EINVAL;
}
/* Check count is within bounds */
if (count > SDW_MAX_LINKS) {
dev_err(&adev->dev, "Link count %d exceeds max %d\n",
count, SDW_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 (i = 0; i < count; i++) {
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(acpi_fwnode_handle(adev), 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;
struct acpi_device *adev;
acpi_status status;
u64 adr;
status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
if (ACPI_FAILURE(status))
return AE_OK; /* keep going */
if (acpi_bus_get_device(handle, &adev)) {
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 */
/* 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");
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