/**
* pdcspath_fetch - This function populates the path entry structs.
* @entry: A pointer to an allocated pdcspath_entry.
*
* The general idea is that you don't read from the Stable Storage every time
* you access the files provided by the facilites. We store a copy of the
* content of the stable storage WRT various paths in these structs. We read
* these structs when reading the files, and we will write to these structs when
* writing to the files, and only then write them back to the Stable Storage.
*
* This function expects to be called with @entry->rw_lock write-hold.
*/
static int
pdcspath_fetch(struct pdcspath_entry *entry)
{
struct device_path *devpath;
if (!entry)
return -EINVAL;
devpath = &entry->devpath;
DPRINTK("%s: fetch: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
entry, devpath, entry->addr);
/* addr, devpath and count must be word aligned */
if (pdc_stable_read(entry->addr, devpath, sizeof(*devpath)) != PDC_OK)
return -EIO;
/* Find the matching device.
NOTE: hardware_path overlays with device_path, so the nice cast can
be used */
entry->dev = hwpath_to_device((struct hardware_path *)devpath);
entry->ready = 1;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
return 0;
}
static int
pdcspath_fetch(struct pdcspath_entry *entry)
{
struct device_path *devpath;
if (!entry)
return -EINVAL;
devpath = &entry->devpath;
DPRINTK("%s: fetch: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
entry, devpath, entry->addr);
if (pdc_stable_read(entry->addr, devpath, sizeof(*devpath)) != PDC_OK)
return -EIO;
entry->dev = hwpath_to_device((struct hardware_path *)devpath);
entry->ready = 1;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
return 0;
}
/**
* pdcspath_hwpath_write - This function handles hardware path modifying.
* @entry: An allocated and populated pdscpath_entry struct.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current hardware path.
* Hardware paths are to be given '/'-delimited, without brackets.
* We make sure that the provided path actually maps to an existing
* device, BUT nothing would prevent some foolish user to set the path to some
* PCI bridge or even a CPU...
* A better work around would be to make sure we are at the end of a device tree
* for instance, but it would be IMHO beyond the simple scope of that driver.
* The aim is to provide a facility. Data correctness is left to userland.
*/
static ssize_t
pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t count)
{
struct hardware_path hwpath;
unsigned short i;
char in[count+1], *temp;
struct device *dev;
int ret;
if (!entry || !buf || !count)
return -EINVAL;
/* We'll use a local copy of buf */
memset(in, 0, count+1);
strncpy(in, buf, count);
/* Let's clean up the target. 0xff is a blank pattern */
memset(&hwpath, 0xff, sizeof(hwpath));
/* First, pick the mod field (the last one of the input string) */
if (!(temp = strrchr(in, '/')))
return -EINVAL;
hwpath.mod = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0'; /* truncate the remaining string. just precaution */
DPRINTK("%s: mod: %d\n", __func__, hwpath.mod);
/* Then, loop for each delimiter, making sure we don't have too many.
we write the bc fields in a down-top way. No matter what, we stop
before writing the last field. If there are too many fields anyway,
then the user is a moron and it'll be caught up later when we'll
check the consistency of the given hwpath. */
for (i=5; ((temp = strrchr(in, '/'))) && (temp-in > 0) && (likely(i)); i--) {
hwpath.bc[i] = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0';
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
}
/* Store the final field */
hwpath.bc[i] = simple_strtoul(in, NULL, 10);
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
/* Now we check that the user isn't trying to lure us */
if (!(dev = hwpath_to_device((struct hardware_path *)&hwpath))) {
printk(KERN_WARNING "%s: attempt to set invalid \"%s\" "
"hardware path: %s\n", __func__, entry->name, buf);
return -EINVAL;
}
/* So far so good, let's get in deep */
write_lock(&entry->rw_lock);
entry->ready = 0;
entry->dev = dev;
/* Now, dive in. Write back to the hardware */
pdcspath_store(entry);
/* Update the symlink to the real device */
sysfs_remove_link(&entry->kobj, "device");
ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
WARN_ON(ret);
write_unlock(&entry->rw_lock);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
entry->name, buf);
return count;
}
static ssize_t
pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t count)
{
struct hardware_path hwpath;
unsigned short i;
char in[count+1], *temp;
struct device *dev;
int ret;
if (!entry || !buf || !count)
return -EINVAL;
memset(in, 0, count+1);
strncpy(in, buf, count);
memset(&hwpath, 0xff, sizeof(hwpath));
if (!(temp = strrchr(in, '/')))
return -EINVAL;
hwpath.mod = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0';
DPRINTK("%s: mod: %d\n", __func__, hwpath.mod);
for (i=5; ((temp = strrchr(in, '/'))) && (temp-in > 0) && (likely(i)); i--) {
hwpath.bc[i] = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0';
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
}
hwpath.bc[i] = simple_strtoul(in, NULL, 10);
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
if (!(dev = hwpath_to_device((struct hardware_path *)&hwpath))) {
printk(KERN_WARNING "%s: attempt to set invalid \"%s\" "
"hardware path: %s\n", __func__, entry->name, buf);
return -EINVAL;
}
write_lock(&entry->rw_lock);
entry->ready = 0;
entry->dev = dev;
pdcspath_store(entry);
sysfs_remove_link(&entry->kobj, "device");
ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
WARN_ON(ret);
write_unlock(&entry->rw_lock);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
entry->name, buf);
return count;
}