diff options
Diffstat (limited to 'sound/hda/intel-sdw-acpi.c')
| -rw-r--r-- | sound/hda/intel-sdw-acpi.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/sound/hda/intel-sdw-acpi.c b/sound/hda/intel-sdw-acpi.c new file mode 100644 index 000000000..b57d72ea4 --- /dev/null +++ b/sound/hda/intel-sdw-acpi.c @@ -0,0 +1,185 @@ +// 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, 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); + + 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); + u8 count, i; + int ret; + + if (!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; + 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_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 */ + + /* 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"); |