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![Andy Shevchenko](/assets/img/avatar_default.png)
Kernel documentation script is not happy about absence of function parameter descriptions: drivers/dma/acpi-dma.c:163: warning: Function parameter or member 'data' not described in 'acpi_dma_controller_register' drivers/dma/acpi-dma.c:247: warning: Function parameter or member 'data' not described in 'devm_acpi_dma_controller_register' drivers/dma/acpi-dma.c:274: warning: Function parameter or member 'dev' not described in 'devm_acpi_dma_controller_free' Append the descriptions of above mentioned function parameters. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20190820131546.75744-3-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
472 lines
13 KiB
C
472 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ACPI helpers for DMA request / controller
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*
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* Based on of-dma.c
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*
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* Copyright (C) 2013, Intel Corporation
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* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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* Mika Westerberg <mika.westerberg@linux.intel.com>
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*/
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/ioport.h>
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#include <linux/acpi.h>
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#include <linux/acpi_dma.h>
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#include <linux/property.h>
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static LIST_HEAD(acpi_dma_list);
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static DEFINE_MUTEX(acpi_dma_lock);
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/**
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* acpi_dma_parse_resource_group - match device and parse resource group
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* @grp: CSRT resource group
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* @adev: ACPI device to match with
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* @adma: struct acpi_dma of the given DMA controller
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*
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* In order to match a device from DSDT table to the corresponding CSRT device
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* we use MMIO address and IRQ.
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*
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* Return:
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* 1 on success, 0 when no information is available, or appropriate errno value
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* on error.
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*/
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static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
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struct acpi_device *adev, struct acpi_dma *adma)
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{
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const struct acpi_csrt_shared_info *si;
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struct list_head resource_list;
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struct resource_entry *rentry;
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resource_size_t mem = 0, irq = 0;
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int ret;
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if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
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return -ENODEV;
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INIT_LIST_HEAD(&resource_list);
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ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
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if (ret <= 0)
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return 0;
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list_for_each_entry(rentry, &resource_list, node) {
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if (resource_type(rentry->res) == IORESOURCE_MEM)
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mem = rentry->res->start;
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else if (resource_type(rentry->res) == IORESOURCE_IRQ)
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irq = rentry->res->start;
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}
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acpi_dev_free_resource_list(&resource_list);
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/* Consider initial zero values as resource not found */
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if (mem == 0 && irq == 0)
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return 0;
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si = (const struct acpi_csrt_shared_info *)&grp[1];
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/* Match device by MMIO and IRQ */
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if (si->mmio_base_low != lower_32_bits(mem) ||
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si->mmio_base_high != upper_32_bits(mem) ||
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si->gsi_interrupt != irq)
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return 0;
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dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
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(char *)&grp->vendor_id, grp->device_id, grp->revision);
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/* Check if the request line range is available */
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if (si->base_request_line == 0 && si->num_handshake_signals == 0)
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return 0;
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/* Set up DMA mask based on value from CSRT */
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ret = dma_coerce_mask_and_coherent(&adev->dev,
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DMA_BIT_MASK(si->dma_address_width));
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if (ret)
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return 0;
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adma->base_request_line = si->base_request_line;
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adma->end_request_line = si->base_request_line +
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si->num_handshake_signals - 1;
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dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
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adma->base_request_line, adma->end_request_line);
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return 1;
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}
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/**
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* acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
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* @adev: ACPI device to match with
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* @adma: struct acpi_dma of the given DMA controller
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*
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* CSRT or Core System Resources Table is a proprietary ACPI table
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* introduced by Microsoft. This table can contain devices that are not in
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* the system DSDT table. In particular DMA controllers might be described
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* here.
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*
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* We are using this table to get the request line range of the specific DMA
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* controller to be used later.
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*/
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static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
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{
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struct acpi_csrt_group *grp, *end;
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struct acpi_table_csrt *csrt;
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acpi_status status;
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int ret;
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status = acpi_get_table(ACPI_SIG_CSRT, 0,
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(struct acpi_table_header **)&csrt);
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if (ACPI_FAILURE(status)) {
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if (status != AE_NOT_FOUND)
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dev_warn(&adev->dev, "failed to get the CSRT table\n");
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return;
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}
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grp = (struct acpi_csrt_group *)(csrt + 1);
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end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
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while (grp < end) {
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ret = acpi_dma_parse_resource_group(grp, adev, adma);
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if (ret < 0) {
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dev_warn(&adev->dev,
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"error in parsing resource group\n");
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return;
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}
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grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
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}
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}
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/**
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* acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
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* @dev: struct device of DMA controller
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* @acpi_dma_xlate: translation function which converts a dma specifier
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* into a dma_chan structure
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* @data: pointer to controller specific data to be used by
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* translation function
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*
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* Allocated memory should be freed with appropriate acpi_dma_controller_free()
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* call.
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*
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* Return:
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* 0 on success or appropriate errno value on error.
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*/
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int acpi_dma_controller_register(struct device *dev,
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struct dma_chan *(*acpi_dma_xlate)
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(struct acpi_dma_spec *, struct acpi_dma *),
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void *data)
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{
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struct acpi_device *adev;
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struct acpi_dma *adma;
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if (!dev || !acpi_dma_xlate)
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return -EINVAL;
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/* Check if the device was enumerated by ACPI */
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adev = ACPI_COMPANION(dev);
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if (!adev)
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return -EINVAL;
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adma = kzalloc(sizeof(*adma), GFP_KERNEL);
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if (!adma)
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return -ENOMEM;
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adma->dev = dev;
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adma->acpi_dma_xlate = acpi_dma_xlate;
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adma->data = data;
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acpi_dma_parse_csrt(adev, adma);
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/* Now queue acpi_dma controller structure in list */
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mutex_lock(&acpi_dma_lock);
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list_add_tail(&adma->dma_controllers, &acpi_dma_list);
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mutex_unlock(&acpi_dma_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(acpi_dma_controller_register);
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/**
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* acpi_dma_controller_free - Remove a DMA controller from ACPI DMA helpers list
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* @dev: struct device of DMA controller
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*
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* Memory allocated by acpi_dma_controller_register() is freed here.
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*
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* Return:
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* 0 on success or appropriate errno value on error.
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*/
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int acpi_dma_controller_free(struct device *dev)
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{
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struct acpi_dma *adma;
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if (!dev)
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return -EINVAL;
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mutex_lock(&acpi_dma_lock);
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list_for_each_entry(adma, &acpi_dma_list, dma_controllers)
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if (adma->dev == dev) {
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list_del(&adma->dma_controllers);
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mutex_unlock(&acpi_dma_lock);
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kfree(adma);
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return 0;
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}
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mutex_unlock(&acpi_dma_lock);
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return -ENODEV;
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}
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EXPORT_SYMBOL_GPL(acpi_dma_controller_free);
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static void devm_acpi_dma_release(struct device *dev, void *res)
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{
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acpi_dma_controller_free(dev);
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}
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/**
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* devm_acpi_dma_controller_register - resource managed acpi_dma_controller_register()
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* @dev: device that is registering this DMA controller
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* @acpi_dma_xlate: translation function
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* @data: pointer to controller specific data
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*
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* Managed acpi_dma_controller_register(). DMA controller registered by this
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* function are automatically freed on driver detach. See
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* acpi_dma_controller_register() for more information.
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*
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* Return:
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* 0 on success or appropriate errno value on error.
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*/
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int devm_acpi_dma_controller_register(struct device *dev,
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struct dma_chan *(*acpi_dma_xlate)
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(struct acpi_dma_spec *, struct acpi_dma *),
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void *data)
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{
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void *res;
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int ret;
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res = devres_alloc(devm_acpi_dma_release, 0, GFP_KERNEL);
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if (!res)
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return -ENOMEM;
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ret = acpi_dma_controller_register(dev, acpi_dma_xlate, data);
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if (ret) {
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devres_free(res);
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return ret;
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}
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devres_add(dev, res);
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return 0;
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}
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EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
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/**
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* devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
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* @dev: device that is unregistering as DMA controller
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*
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* Unregister a DMA controller registered with
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* devm_acpi_dma_controller_register(). Normally this function will not need to
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* be called and the resource management code will ensure that the resource is
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* freed.
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*/
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void devm_acpi_dma_controller_free(struct device *dev)
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{
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WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
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}
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EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
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/**
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* acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
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* @adma: struct acpi_dma of DMA controller
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* @dma_spec: dma specifier to update
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*
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* Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
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* Descriptor":
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* DMA Request Line bits is a platform-relative number uniquely
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* identifying the request line assigned. Request line-to-Controller
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* mapping is done in a controller-specific OS driver.
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* That's why we can safely adjust slave_id when the appropriate controller is
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* found.
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*
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* Return:
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* 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
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*/
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static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
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struct acpi_dma_spec *dma_spec)
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{
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/* Set link to the DMA controller device */
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dma_spec->dev = adma->dev;
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/* Check if the request line range is available */
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if (adma->base_request_line == 0 && adma->end_request_line == 0)
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return 0;
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/* Check if slave_id falls to the range */
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if (dma_spec->slave_id < adma->base_request_line ||
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dma_spec->slave_id > adma->end_request_line)
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return -1;
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/*
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* Here we adjust slave_id. It should be a relative number to the base
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* request line.
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*/
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dma_spec->slave_id -= adma->base_request_line;
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return 1;
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}
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struct acpi_dma_parser_data {
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struct acpi_dma_spec dma_spec;
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size_t index;
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size_t n;
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};
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/**
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* acpi_dma_parse_fixed_dma - Parse FixedDMA ACPI resources to a DMA specifier
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* @res: struct acpi_resource to get FixedDMA resources from
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* @data: pointer to a helper struct acpi_dma_parser_data
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*/
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static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
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{
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struct acpi_dma_parser_data *pdata = data;
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if (res->type == ACPI_RESOURCE_TYPE_FIXED_DMA) {
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struct acpi_resource_fixed_dma *dma = &res->data.fixed_dma;
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if (pdata->n++ == pdata->index) {
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pdata->dma_spec.chan_id = dma->channels;
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pdata->dma_spec.slave_id = dma->request_lines;
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}
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}
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/* Tell the ACPI core to skip this resource */
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return 1;
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}
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/**
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* acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
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* @dev: struct device to get DMA request from
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* @index: index of FixedDMA descriptor for @dev
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*
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* Return:
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* Pointer to appropriate dma channel on success or an error pointer.
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*/
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struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
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size_t index)
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{
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struct acpi_dma_parser_data pdata;
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struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
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struct list_head resource_list;
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struct acpi_device *adev;
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struct acpi_dma *adma;
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struct dma_chan *chan = NULL;
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int found;
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/* Check if the device was enumerated by ACPI */
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if (!dev)
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return ERR_PTR(-ENODEV);
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adev = ACPI_COMPANION(dev);
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if (!adev)
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return ERR_PTR(-ENODEV);
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memset(&pdata, 0, sizeof(pdata));
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pdata.index = index;
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/* Initial values for the request line and channel */
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dma_spec->chan_id = -1;
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dma_spec->slave_id = -1;
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INIT_LIST_HEAD(&resource_list);
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acpi_dev_get_resources(adev, &resource_list,
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acpi_dma_parse_fixed_dma, &pdata);
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acpi_dev_free_resource_list(&resource_list);
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if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
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return ERR_PTR(-ENODEV);
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mutex_lock(&acpi_dma_lock);
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list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
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/*
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* We are not going to call translation function if slave_id
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* doesn't fall to the request range.
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*/
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found = acpi_dma_update_dma_spec(adma, dma_spec);
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if (found < 0)
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continue;
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chan = adma->acpi_dma_xlate(dma_spec, adma);
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/*
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* Try to get a channel only from the DMA controller that
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* matches the slave_id. See acpi_dma_update_dma_spec()
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* description for the details.
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*/
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if (found > 0 || chan)
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break;
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}
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mutex_unlock(&acpi_dma_lock);
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return chan ? chan : ERR_PTR(-EPROBE_DEFER);
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}
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EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
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/**
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* acpi_dma_request_slave_chan_by_name - Get the DMA slave channel
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* @dev: struct device to get DMA request from
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* @name: represents corresponding FixedDMA descriptor for @dev
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*
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* In order to support both Device Tree and ACPI in a single driver we
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* translate the names "tx" and "rx" here based on the most common case where
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* the first FixedDMA descriptor is TX and second is RX.
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*
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* If the device has "dma-names" property the FixedDMA descriptor indices
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* are retrieved based on those. Otherwise the function falls back using
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* hardcoded indices.
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*
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* Return:
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* Pointer to appropriate dma channel on success or an error pointer.
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*/
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struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
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const char *name)
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{
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int index;
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index = device_property_match_string(dev, "dma-names", name);
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if (index < 0) {
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if (!strcmp(name, "tx"))
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index = 0;
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else if (!strcmp(name, "rx"))
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index = 1;
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else
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return ERR_PTR(-ENODEV);
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}
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dev_dbg(dev, "Looking for DMA channel \"%s\" at index %d...\n", name, index);
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return acpi_dma_request_slave_chan_by_index(dev, index);
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}
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EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name);
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/**
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* acpi_dma_simple_xlate - Simple ACPI DMA engine translation helper
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* @dma_spec: pointer to ACPI DMA specifier
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* @adma: pointer to ACPI DMA controller data
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*
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* A simple translation function for ACPI based devices. Passes &struct
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* dma_spec to the DMA controller driver provided filter function.
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*
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* Return:
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* Pointer to the channel if found or %NULL otherwise.
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*/
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struct dma_chan *acpi_dma_simple_xlate(struct acpi_dma_spec *dma_spec,
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struct acpi_dma *adma)
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{
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struct acpi_dma_filter_info *info = adma->data;
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if (!info || !info->filter_fn)
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return NULL;
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return dma_request_channel(info->dma_cap, info->filter_fn, dma_spec);
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}
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EXPORT_SYMBOL_GPL(acpi_dma_simple_xlate);
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