linux/drivers/of/device.c
Robin Murphy 4d8bde883b OF: Don't set default coherent DMA mask
Now that we can track upstream DMA constraints properly with
bus_dma_mask instead of trying (and failing) to maintain it in
coherent_dma_mask, it doesn't make much sense for the firmware code to
be touching the latter at all. It's merely papering over bugs wherein a
driver has failed to call dma_set_coherent_mask() *and* the bus code has
not initialised any default value.

We don't really want to encourage more drivers coercing dma_mask so
we'll continue to fix that up if necessary, but add a warning to help
flush out any such buggy bus code that remains.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-07-27 19:01:07 +02:00

347 lines
8.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <asm/errno.h>
#include "of_private.h"
/**
* of_match_device - Tell if a struct device matches an of_device_id list
* @ids: array of of device match structures to search in
* @dev: the of device structure to match against
*
* Used by a driver to check whether an platform_device present in the
* system is in its list of supported devices.
*/
const struct of_device_id *of_match_device(const struct of_device_id *matches,
const struct device *dev)
{
if ((!matches) || (!dev->of_node))
return NULL;
return of_match_node(matches, dev->of_node);
}
EXPORT_SYMBOL(of_match_device);
struct platform_device *of_dev_get(struct platform_device *dev)
{
struct device *tmp;
if (!dev)
return NULL;
tmp = get_device(&dev->dev);
if (tmp)
return to_platform_device(tmp);
else
return NULL;
}
EXPORT_SYMBOL(of_dev_get);
void of_dev_put(struct platform_device *dev)
{
if (dev)
put_device(&dev->dev);
}
EXPORT_SYMBOL(of_dev_put);
int of_device_add(struct platform_device *ofdev)
{
BUG_ON(ofdev->dev.of_node == NULL);
/* name and id have to be set so that the platform bus doesn't get
* confused on matching */
ofdev->name = dev_name(&ofdev->dev);
ofdev->id = PLATFORM_DEVID_NONE;
/*
* If this device has not binding numa node in devicetree, that is
* of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
* device is on the same node as the parent.
*/
set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
return device_add(&ofdev->dev);
}
/**
* of_dma_configure - Setup DMA configuration
* @dev: Device to apply DMA configuration
* @np: Pointer to OF node having DMA configuration
* @force_dma: Whether device is to be set up by of_dma_configure() even if
* DMA capability is not explicitly described by firmware.
*
* Try to get devices's DMA configuration from DT and update it
* accordingly.
*
* If platform code needs to use its own special DMA configuration, it
* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
* to fix up DMA configuration.
*/
int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
{
u64 dma_addr, paddr, size = 0;
int ret;
bool coherent;
unsigned long offset;
const struct iommu_ops *iommu;
u64 mask;
ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
if (ret < 0) {
/*
* For legacy reasons, we have to assume some devices need
* DMA configuration regardless of whether "dma-ranges" is
* correctly specified or not.
*/
if (!force_dma)
return ret == -ENODEV ? 0 : ret;
dma_addr = offset = 0;
} else {
offset = PFN_DOWN(paddr - dma_addr);
/*
* Add a work around to treat the size as mask + 1 in case
* it is defined in DT as a mask.
*/
if (size & 1) {
dev_warn(dev, "Invalid size 0x%llx for dma-range\n",
size);
size = size + 1;
}
if (!size) {
dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
return -EINVAL;
}
dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
}
/*
* If @dev is expected to be DMA-capable then the bus code that created
* it should have initialised its dma_mask pointer by this point. For
* now, we'll continue the legacy behaviour of coercing it to the
* coherent mask if not, but we'll no longer do so quietly.
*/
if (!dev->dma_mask) {
dev_warn(dev, "DMA mask not set\n");
dev->dma_mask = &dev->coherent_dma_mask;
}
if (!size && dev->coherent_dma_mask)
size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
else if (!size)
size = 1ULL << 32;
dev->dma_pfn_offset = offset;
/*
* Limit coherent and dma mask based on size and default mask
* set by the driver.
*/
mask = DMA_BIT_MASK(ilog2(dma_addr + size - 1) + 1);
dev->bus_dma_mask = mask;
dev->coherent_dma_mask &= mask;
*dev->dma_mask &= mask;
coherent = of_dma_is_coherent(np);
dev_dbg(dev, "device is%sdma coherent\n",
coherent ? " " : " not ");
iommu = of_iommu_configure(dev, np);
if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
return -EPROBE_DEFER;
dev_dbg(dev, "device is%sbehind an iommu\n",
iommu ? " " : " not ");
arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
return 0;
}
EXPORT_SYMBOL_GPL(of_dma_configure);
/**
* of_dma_deconfigure - Clean up DMA configuration
* @dev: Device for which to clean up DMA configuration
*
* Clean up all configuration performed by of_dma_configure_ops() and free all
* resources that have been allocated.
*/
void of_dma_deconfigure(struct device *dev)
{
arch_teardown_dma_ops(dev);
}
int of_device_register(struct platform_device *pdev)
{
device_initialize(&pdev->dev);
return of_device_add(pdev);
}
EXPORT_SYMBOL(of_device_register);
void of_device_unregister(struct platform_device *ofdev)
{
device_unregister(&ofdev->dev);
}
EXPORT_SYMBOL(of_device_unregister);
const void *of_device_get_match_data(const struct device *dev)
{
const struct of_device_id *match;
match = of_match_device(dev->driver->of_match_table, dev);
if (!match)
return NULL;
return match->data;
}
EXPORT_SYMBOL(of_device_get_match_data);
static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
{
const char *compat;
char *c;
struct property *p;
ssize_t csize;
ssize_t tsize;
if ((!dev) || (!dev->of_node))
return -ENODEV;
/* Name & Type */
csize = snprintf(str, len, "of:N%sT%s", dev->of_node->name,
dev->of_node->type);
tsize = csize;
len -= csize;
if (str)
str += csize;
of_property_for_each_string(dev->of_node, "compatible", p, compat) {
csize = strlen(compat) + 1;
tsize += csize;
if (csize > len)
continue;
csize = snprintf(str, len, "C%s", compat);
for (c = str; c; ) {
c = strchr(c, ' ');
if (c)
*c++ = '_';
}
len -= csize;
str += csize;
}
return tsize;
}
int of_device_request_module(struct device *dev)
{
char *str;
ssize_t size;
int ret;
size = of_device_get_modalias(dev, NULL, 0);
if (size < 0)
return size;
str = kmalloc(size + 1, GFP_KERNEL);
if (!str)
return -ENOMEM;
of_device_get_modalias(dev, str, size);
str[size] = '\0';
ret = request_module(str);
kfree(str);
return ret;
}
EXPORT_SYMBOL_GPL(of_device_request_module);
/**
* of_device_modalias - Fill buffer with newline terminated modalias string
*/
ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
{
ssize_t sl = of_device_get_modalias(dev, str, len - 2);
if (sl < 0)
return sl;
if (sl > len - 2)
return -ENOMEM;
str[sl++] = '\n';
str[sl] = 0;
return sl;
}
EXPORT_SYMBOL_GPL(of_device_modalias);
/**
* of_device_uevent - Display OF related uevent information
*/
void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
const char *compat;
struct alias_prop *app;
struct property *p;
int seen = 0;
if ((!dev) || (!dev->of_node))
return;
add_uevent_var(env, "OF_NAME=%s", dev->of_node->name);
add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
if (dev->of_node->type && strcmp("<NULL>", dev->of_node->type) != 0)
add_uevent_var(env, "OF_TYPE=%s", dev->of_node->type);
/* Since the compatible field can contain pretty much anything
* it's not really legal to split it out with commas. We split it
* up using a number of environment variables instead. */
of_property_for_each_string(dev->of_node, "compatible", p, compat) {
add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
seen++;
}
add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
seen = 0;
mutex_lock(&of_mutex);
list_for_each_entry(app, &aliases_lookup, link) {
if (dev->of_node == app->np) {
add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
app->alias);
seen++;
}
}
mutex_unlock(&of_mutex);
}
int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
{
int sl;
if ((!dev) || (!dev->of_node))
return -ENODEV;
/* Devicetree modalias is tricky, we add it in 2 steps */
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
sizeof(env->buf) - env->buflen);
if (sl >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += sl;
return 0;
}
EXPORT_SYMBOL_GPL(of_device_uevent_modalias);