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185 lines
4.7 KiB
185 lines
4.7 KiB
// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) |
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// Copyright(c) 2015-2021 Intel Corporation. |
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/* |
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* SDW Intel ACPI scan helpers |
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*/ |
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#include <linux/acpi.h> |
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#include <linux/bits.h> |
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#include <linux/bitfield.h> |
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#include <linux/device.h> |
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#include <linux/errno.h> |
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#include <linux/export.h> |
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#include <linux/fwnode.h> |
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#include <linux/module.h> |
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#include <linux/soundwire/sdw_intel.h> |
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#include <linux/string.h> |
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#define SDW_LINK_TYPE 4 /* from Intel ACPI documentation */ |
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#define SDW_MAX_LINKS 4 |
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static int ctrl_link_mask; |
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module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444); |
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MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)"); |
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static bool is_link_enabled(struct fwnode_handle *fw_node, int i) |
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{ |
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struct fwnode_handle *link; |
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char name[32]; |
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u32 quirk_mask = 0; |
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/* Find master handle */ |
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snprintf(name, sizeof(name), |
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"mipi-sdw-link-%d-subproperties", i); |
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link = fwnode_get_named_child_node(fw_node, name); |
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if (!link) |
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return false; |
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fwnode_property_read_u32(link, |
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"intel-quirk-mask", |
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&quirk_mask); |
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if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE) |
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return false; |
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return true; |
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} |
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static int |
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sdw_intel_scan_controller(struct sdw_intel_acpi_info *info) |
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{ |
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struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle); |
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int ret, i; |
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u8 count; |
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if (!adev) |
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return -EINVAL; |
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/* Found controller, find links supported */ |
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count = 0; |
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ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev), |
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"mipi-sdw-master-count", &count, 1); |
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/* |
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* In theory we could check the number of links supported in |
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* hardware, but in that step we cannot assume SoundWire IP is |
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* powered. |
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* |
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* In addition, if the BIOS doesn't even provide this |
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* 'master-count' property then all the inits based on link |
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* masks will fail as well. |
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* |
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* We will check the hardware capabilities in the startup() step |
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*/ |
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if (ret) { |
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dev_err(&adev->dev, |
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"Failed to read mipi-sdw-master-count: %d\n", ret); |
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return -EINVAL; |
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} |
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/* Check count is within bounds */ |
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if (count > SDW_MAX_LINKS) { |
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dev_err(&adev->dev, "Link count %d exceeds max %d\n", |
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count, SDW_MAX_LINKS); |
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return -EINVAL; |
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} |
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if (!count) { |
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dev_warn(&adev->dev, "No SoundWire links detected\n"); |
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return -EINVAL; |
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} |
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dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count); |
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info->count = count; |
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info->link_mask = 0; |
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for (i = 0; i < count; i++) { |
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if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) { |
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dev_dbg(&adev->dev, |
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"Link %d masked, will not be enabled\n", i); |
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continue; |
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} |
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if (!is_link_enabled(acpi_fwnode_handle(adev), i)) { |
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dev_dbg(&adev->dev, |
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"Link %d not selected in firmware\n", i); |
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continue; |
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} |
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info->link_mask |= BIT(i); |
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} |
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return 0; |
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} |
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static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level, |
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void *cdata, void **return_value) |
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{ |
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struct sdw_intel_acpi_info *info = cdata; |
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acpi_status status; |
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u64 adr; |
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status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr); |
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if (ACPI_FAILURE(status)) |
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return AE_OK; /* keep going */ |
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if (!acpi_fetch_acpi_dev(handle)) { |
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pr_err("%s: Couldn't find ACPI handle\n", __func__); |
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return AE_NOT_FOUND; |
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} |
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/* |
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* On some Intel platforms, multiple children of the HDAS |
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* device can be found, but only one of them is the SoundWire |
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* controller. The SNDW device is always exposed with |
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* Name(_ADR, 0x40000000), with bits 31..28 representing the |
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* SoundWire link so filter accordingly |
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*/ |
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if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE) |
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return AE_OK; /* keep going */ |
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/* found the correct SoundWire controller */ |
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info->handle = handle; |
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/* device found, stop namespace walk */ |
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return AE_CTRL_TERMINATE; |
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} |
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/** |
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* sdw_intel_acpi_scan() - SoundWire Intel init routine |
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* @parent_handle: ACPI parent handle |
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* @info: description of what firmware/DSDT tables expose |
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* |
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* This scans the namespace and queries firmware to figure out which |
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* links to enable. A follow-up use of sdw_intel_probe() and |
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* sdw_intel_startup() is required for creation of devices and bus |
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* startup |
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*/ |
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int sdw_intel_acpi_scan(acpi_handle *parent_handle, |
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struct sdw_intel_acpi_info *info) |
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{ |
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acpi_status status; |
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info->handle = NULL; |
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/* |
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* In the HDAS ACPI scope, 'SNDW' may be either the child of |
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* 'HDAS' or the grandchild of 'HDAS'. So let's go through |
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* the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW' |
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* device. |
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*/ |
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, |
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parent_handle, 2, |
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sdw_intel_acpi_cb, |
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NULL, info, NULL); |
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if (ACPI_FAILURE(status) || info->handle == NULL) |
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return -ENODEV; |
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return sdw_intel_scan_controller(info); |
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} |
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EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI); |
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MODULE_LICENSE("Dual BSD/GPL"); |
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MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");
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