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a7ba70f178
Using a mask to represent bus DMA constraints has a set of limitations. The biggest one being it can only hold a power of two (minus one). The DMA mapping code is already aware of this and treats dev->bus_dma_mask as a limit. This quirk is already used by some architectures although still rare. With the introduction of the Raspberry Pi 4 we've found a new contender for the use of bus DMA limits, as its PCIe bus can only address the lower 3GB of memory (of a total of 4GB). This is impossible to represent with a mask. To make things worse the device-tree code rounds non power of two bus DMA limits to the next power of two, which is unacceptable in this case. In the light of this, rename dev->bus_dma_mask to dev->bus_dma_limit all over the tree and treat it as such. Note that dev->bus_dma_limit should contain the higher accessible DMA address. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
340 lines
8.2 KiB
C
340 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/of_address.h>
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#include <linux/of_iommu.h>
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#include <linux/dma-mapping.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <asm/errno.h>
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#include "of_private.h"
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/**
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* of_match_device - Tell if a struct device matches an of_device_id list
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* @matches: array of of device match structures to search in
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* @dev: the of device structure to match against
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*
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* Used by a driver to check whether an platform_device present in the
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* system is in its list of supported devices.
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*/
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const struct of_device_id *of_match_device(const struct of_device_id *matches,
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const struct device *dev)
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{
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if ((!matches) || (!dev->of_node))
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return NULL;
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return of_match_node(matches, dev->of_node);
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}
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EXPORT_SYMBOL(of_match_device);
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struct platform_device *of_dev_get(struct platform_device *dev)
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{
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struct device *tmp;
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if (!dev)
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return NULL;
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tmp = get_device(&dev->dev);
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if (tmp)
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return to_platform_device(tmp);
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else
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return NULL;
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}
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EXPORT_SYMBOL(of_dev_get);
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void of_dev_put(struct platform_device *dev)
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{
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if (dev)
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put_device(&dev->dev);
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}
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EXPORT_SYMBOL(of_dev_put);
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int of_device_add(struct platform_device *ofdev)
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{
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BUG_ON(ofdev->dev.of_node == NULL);
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/* name and id have to be set so that the platform bus doesn't get
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* confused on matching */
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ofdev->name = dev_name(&ofdev->dev);
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ofdev->id = PLATFORM_DEVID_NONE;
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/*
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* If this device has not binding numa node in devicetree, that is
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* of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
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* device is on the same node as the parent.
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*/
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set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
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return device_add(&ofdev->dev);
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}
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/**
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* of_dma_configure - Setup DMA configuration
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* @dev: Device to apply DMA configuration
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* @np: Pointer to OF node having DMA configuration
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* @force_dma: Whether device is to be set up by of_dma_configure() even if
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* DMA capability is not explicitly described by firmware.
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*
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* Try to get devices's DMA configuration from DT and update it
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* accordingly.
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*
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* If platform code needs to use its own special DMA configuration, it
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* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
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* to fix up DMA configuration.
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*/
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int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
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{
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u64 dma_addr, paddr, size = 0;
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int ret;
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bool coherent;
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unsigned long offset;
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const struct iommu_ops *iommu;
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u64 mask, end;
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ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
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if (ret < 0) {
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/*
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* For legacy reasons, we have to assume some devices need
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* DMA configuration regardless of whether "dma-ranges" is
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* correctly specified or not.
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*/
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if (!force_dma)
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return ret == -ENODEV ? 0 : ret;
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dma_addr = offset = 0;
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} else {
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offset = PFN_DOWN(paddr - dma_addr);
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/*
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* Add a work around to treat the size as mask + 1 in case
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* it is defined in DT as a mask.
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*/
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if (size & 1) {
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dev_warn(dev, "Invalid size 0x%llx for dma-range\n",
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size);
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size = size + 1;
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}
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if (!size) {
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dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
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return -EINVAL;
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}
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dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
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}
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/*
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* If @dev is expected to be DMA-capable then the bus code that created
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* it should have initialised its dma_mask pointer by this point. For
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* now, we'll continue the legacy behaviour of coercing it to the
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* coherent mask if not, but we'll no longer do so quietly.
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*/
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if (!dev->dma_mask) {
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dev_warn(dev, "DMA mask not set\n");
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dev->dma_mask = &dev->coherent_dma_mask;
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}
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if (!size && dev->coherent_dma_mask)
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size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
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else if (!size)
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size = 1ULL << 32;
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dev->dma_pfn_offset = offset;
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/*
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* Limit coherent and dma mask based on size and default mask
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* set by the driver.
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*/
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end = dma_addr + size - 1;
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mask = DMA_BIT_MASK(ilog2(end) + 1);
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dev->coherent_dma_mask &= mask;
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*dev->dma_mask &= mask;
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/* ...but only set bus limit if we found valid dma-ranges earlier */
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if (!ret)
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dev->bus_dma_limit = end;
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coherent = of_dma_is_coherent(np);
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dev_dbg(dev, "device is%sdma coherent\n",
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coherent ? " " : " not ");
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iommu = of_iommu_configure(dev, np);
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if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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dev_dbg(dev, "device is%sbehind an iommu\n",
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iommu ? " " : " not ");
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arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
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return 0;
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}
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EXPORT_SYMBOL_GPL(of_dma_configure);
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int of_device_register(struct platform_device *pdev)
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{
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device_initialize(&pdev->dev);
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return of_device_add(pdev);
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}
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EXPORT_SYMBOL(of_device_register);
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void of_device_unregister(struct platform_device *ofdev)
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{
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device_unregister(&ofdev->dev);
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}
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EXPORT_SYMBOL(of_device_unregister);
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const void *of_device_get_match_data(const struct device *dev)
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{
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const struct of_device_id *match;
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match = of_match_device(dev->driver->of_match_table, dev);
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if (!match)
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return NULL;
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return match->data;
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}
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EXPORT_SYMBOL(of_device_get_match_data);
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static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
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{
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const char *compat;
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char *c;
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struct property *p;
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ssize_t csize;
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ssize_t tsize;
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if ((!dev) || (!dev->of_node))
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return -ENODEV;
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/* Name & Type */
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/* %p eats all alphanum characters, so %c must be used here */
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csize = snprintf(str, len, "of:N%pOFn%c%s", dev->of_node, 'T',
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of_node_get_device_type(dev->of_node));
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tsize = csize;
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len -= csize;
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if (str)
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str += csize;
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of_property_for_each_string(dev->of_node, "compatible", p, compat) {
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csize = strlen(compat) + 1;
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tsize += csize;
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if (csize > len)
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continue;
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csize = snprintf(str, len, "C%s", compat);
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for (c = str; c; ) {
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c = strchr(c, ' ');
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if (c)
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*c++ = '_';
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}
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len -= csize;
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str += csize;
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}
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return tsize;
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}
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int of_device_request_module(struct device *dev)
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{
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char *str;
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ssize_t size;
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int ret;
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size = of_device_get_modalias(dev, NULL, 0);
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if (size < 0)
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return size;
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str = kmalloc(size + 1, GFP_KERNEL);
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if (!str)
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return -ENOMEM;
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of_device_get_modalias(dev, str, size);
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str[size] = '\0';
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ret = request_module(str);
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kfree(str);
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return ret;
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}
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EXPORT_SYMBOL_GPL(of_device_request_module);
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/**
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* of_device_modalias - Fill buffer with newline terminated modalias string
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*/
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ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
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{
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ssize_t sl = of_device_get_modalias(dev, str, len - 2);
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if (sl < 0)
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return sl;
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if (sl > len - 2)
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return -ENOMEM;
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str[sl++] = '\n';
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str[sl] = 0;
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return sl;
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}
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EXPORT_SYMBOL_GPL(of_device_modalias);
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/**
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* of_device_uevent - Display OF related uevent information
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*/
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void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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const char *compat, *type;
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struct alias_prop *app;
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struct property *p;
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int seen = 0;
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if ((!dev) || (!dev->of_node))
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return;
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add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
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add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
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type = of_node_get_device_type(dev->of_node);
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if (type)
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add_uevent_var(env, "OF_TYPE=%s", type);
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/* Since the compatible field can contain pretty much anything
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* it's not really legal to split it out with commas. We split it
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* up using a number of environment variables instead. */
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of_property_for_each_string(dev->of_node, "compatible", p, compat) {
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add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
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seen++;
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}
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add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
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seen = 0;
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mutex_lock(&of_mutex);
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list_for_each_entry(app, &aliases_lookup, link) {
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if (dev->of_node == app->np) {
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add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
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app->alias);
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seen++;
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}
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}
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mutex_unlock(&of_mutex);
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}
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int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
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{
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int sl;
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if ((!dev) || (!dev->of_node))
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return -ENODEV;
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/* Devicetree modalias is tricky, we add it in 2 steps */
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if (add_uevent_var(env, "MODALIAS="))
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return -ENOMEM;
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sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
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sizeof(env->buf) - env->buflen);
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if (sl >= (sizeof(env->buf) - env->buflen))
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return -ENOMEM;
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env->buflen += sl;
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return 0;
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}
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EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
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