linux/drivers/of/device.c
Robin Murphy d89e2378a9 drivers: flag buses which demand DMA configuration
We do not want the common dma_configure() pathway to apply
indiscriminately to all devices, since there are plenty of buses which
do not have DMA capability, and if their child devices were used for
DMA API calls it would only be indicative of a driver bug. However,
there are a number of buses for which DMA is implicitly expected even
when not described by firmware - those we whitelist with an automatic
opt-in to dma_configure(), assuming that the DMA address space and the
physical address space are equivalent if not otherwise specified.

Commit 7232888366 ("of: restrict DMA configuration") introduced a
short-term fix by comparing explicit bus types, but this approach is far
from pretty, doesn't scale well, and fails to cope at all with bus
drivers which may be built as modules, like host1x. Let's refine things
by making that opt-in a property of the bus type, which neatly addresses
those problems and lets the decision of whether firmware description of
DMA capability should be optional or mandatory stay internal to the bus
drivers themselves.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2017-10-19 16:34:52 +02:00

343 lines
8.1 KiB
C

#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
*
* 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)
{
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 (!dev->bus->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);
}
/*
* Set default coherent_dma_mask to 32 bit. Drivers are expected to
* setup the correct supported mask.
*/
if (!dev->coherent_dma_mask)
dev->coherent_dma_mask = DMA_BIT_MASK(32);
/*
* Set it to coherent_dma_mask by default if the architecture
* code has not set it.
*/
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
if (!size)
size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
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->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);