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481 lines
13 KiB
481 lines
13 KiB
// 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 <[email protected]> |
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* Mika Westerberg <[email protected]> |
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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 */ |
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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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return 0; |
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/* |
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* acpi_gsi_to_irq() can't be used because some platforms do not save |
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* registered IRQs in the MP table. Instead we just try to register |
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* the GSI, which is the core part of the above mentioned function. |
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*/ |
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ret = acpi_register_gsi(NULL, si->gsi_interrupt, si->interrupt_mode, si->interrupt_polarity); |
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if (ret < 0) |
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return 0; |
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/* Match device by Linux vIRQ */ |
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if (ret != 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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break; |
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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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acpi_put_table((struct acpi_table_header *)csrt); |
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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 acpi_device *adev = ACPI_COMPANION(dev); |
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struct list_head resource_list; |
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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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int ret; |
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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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ret = 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 (ret < 0) |
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return ERR_PTR(ret); |
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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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