/*
* Interfaces to retrieve and set PDC Stable options (firmware)
*
- * Copyright (C) 2005 Thibaut VARENE <varenet@parisc-linux.org>
+ * Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
*
* Since locations between 96 and 192 are the various paths, most (if not
* all) PA-RISC machines should have them. Anyway, for safety reasons, the
- * following code can deal with only 96 bytes of Stable Storage, and all
+ * following code can deal with just 96 bytes of Stable Storage, and all
* sizes between 96 and 192 bytes (provided they are multiple of struct
* device_path size, eg: 128, 160 and 192) to provide full information.
* The code makes no use of data above 192 bytes. One last word: there's one
* path we can always count on: the primary path.
+ *
+ * The current policy wrt file permissions is:
+ * - write: root only
+ * - read: (reading triggers PDC calls) ? root only : everyone
+ * The rationale is that PDC calls could hog (DoS) the machine.
+ *
+ * TODO:
+ * - timer/fastsize write calls
*/
#undef PDCS_DEBUG
#include <linux/kobject.h>
#include <linux/device.h>
#include <linux/errno.h>
+#include <linux/spinlock.h>
#include <asm/pdc.h>
#include <asm/page.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
-#define PDCS_VERSION "0.10"
+#define PDCS_VERSION "0.22"
+#define PDCS_PREFIX "PDC Stable Storage"
#define PDCS_ADDR_PPRI 0x00
#define PDCS_ADDR_OSID 0x40
MODULE_LICENSE("GPL");
MODULE_VERSION(PDCS_VERSION);
+/* holds Stable Storage size. Initialized once and for all, no lock needed */
static unsigned long pdcs_size __read_mostly;
/* This struct defines what we need to deal with a parisc pdc path entry */
struct pdcspath_entry {
+ rwlock_t rw_lock; /* to protect path entry access */
short ready; /* entry record is valid if != 0 */
unsigned long addr; /* entry address in stable storage */
char *name; /* entry name */
* 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)
* pointer, from which it'll find out the corresponding hardware path.
* For now we do not handle the case where there's an error in writing to the
* Stable Storage area, so you'd better not mess up the data :P
+ *
+ * This function expects to be called with @entry->rw_lock write-hold.
*/
-static int
+static void
pdcspath_store(struct pdcspath_entry *entry)
{
struct device_path *devpath;
- if (!entry)
- return -EINVAL;
+ BUG_ON(!entry);
devpath = &entry->devpath;
First case, we don't have a preset hwpath... */
if (!entry->ready) {
/* ...but we have a device, map it */
- if (entry->dev)
- device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
- else
- return -EINVAL;
+ BUG_ON(!entry->dev);
+ device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
}
/* else, we expect the provided hwpath to be valid. */
printk(KERN_ERR "%s: an error occured when writing to PDC.\n"
"It is likely that the Stable Storage data has been corrupted.\n"
"Please check it carefully upon next reboot.\n", __func__);
- return -EIO;
+ WARN_ON(1);
}
/* kobject is already registered */
entry->ready = 2;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
-
- return 0;
}
/**
{
char *out = buf;
struct device_path *devpath;
- unsigned short i;
+ short i;
if (!entry || !buf)
return -EINVAL;
+ read_lock(&entry->rw_lock);
devpath = &entry->devpath;
+ i = entry->ready;
+ read_unlock(&entry->rw_lock);
- if (!entry->ready)
+ if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; i < 6; i++) {
*
* We will call this function to change the current hardware path.
* Hardware paths are to be given '/'-delimited, without brackets.
- * We take care to make sure that the provided path actually maps to an existing
+ * 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
}
/* 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 */
- WARN_ON(pdcspath_store(entry)); /* this warn should *NEVER* happen */
+ pdcspath_store(entry);
/* Update the symlink to the real device */
sysfs_remove_link(&entry->kobj, "device");
sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
+ write_unlock(&entry->rw_lock);
- printk(KERN_INFO "PDC Stable Storage: changed \"%s\" path to \"%s\"\n",
+ printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
entry->name, buf);
return count;
{
char *out = buf;
struct device_path *devpath;
- unsigned short i;
+ short i;
if (!entry || !buf)
return -EINVAL;
+ read_lock(&entry->rw_lock);
devpath = &entry->devpath;
+ i = entry->ready;
+ read_unlock(&entry->rw_lock);
- if (!entry->ready)
+ if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; devpath->layers[i] && (likely(i < 6)); i++)
}
/* So far so good, let's get in deep */
+ write_lock(&entry->rw_lock);
/* First, overwrite the current layers with the new ones, not touching
the hardware path. */
memcpy(&entry->devpath.layers, &layers, sizeof(layers));
/* Now, dive in. Write back to the hardware */
- WARN_ON(pdcspath_store(entry)); /* this warn should *NEVER* happen */
+ pdcspath_store(entry);
+ write_unlock(&entry->rw_lock);
- printk(KERN_INFO "PDC Stable Storage: changed \"%s\" layers to \"%s\"\n",
+ printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n",
entry->name, buf);
return count;
struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
ssize_t ret = 0;
- if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
-
if (pdcs_attr->show)
ret = pdcs_attr->show(entry, buf);
};
/* These are the two attributes of any PDC path. */
-static PATHS_ATTR(hwpath, 0600, pdcspath_hwpath_read, pdcspath_hwpath_write);
-static PATHS_ATTR(layer, 0600, pdcspath_layer_read, pdcspath_layer_write);
+static PATHS_ATTR(hwpath, 0644, pdcspath_hwpath_read, pdcspath_hwpath_write);
+static PATHS_ATTR(layer, 0644, pdcspath_layer_read, pdcspath_layer_write);
static struct attribute *paths_subsys_attrs[] = {
&paths_attr_hwpath.attr,
NULL,
};
+
+/* For more insight of what's going on here, refer to PDC Procedures doc,
+ * Section PDC_STABLE */
+
/**
- * pdcs_info_read - Pretty printing of the remaining useful data.
+ * pdcs_size_read - Stable Storage size output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
- *
- * We will call this function to format the output of the 'info' attribute file.
- * Please refer to PDC Procedures documentation, section PDC_STABLE to get a
- * better insight of what we're doing here.
*/
static ssize_t
-pdcs_info_read(struct subsystem *entry, char *buf)
+pdcs_size_read(struct subsystem *entry, char *buf)
{
char *out = buf;
- __u32 result;
- struct device_path devpath;
- char *tmpstr = NULL;
if (!entry || !buf)
return -EINVAL;
/* show the size of the stable storage */
- out += sprintf(out, "Stable Storage size: %ld bytes\n", pdcs_size);
+ out += sprintf(out, "%ld\n", pdcs_size);
- /* deal with flags */
- if (pdc_stable_read(PDCS_ADDR_PPRI, &devpath, sizeof(devpath)) != PDC_OK)
- return -EIO;
+ return out - buf;
+}
+
+/**
+ * pdcs_auto_read - Stable Storage autoboot/search flag output.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
+ */
+static ssize_t
+pdcs_auto_read(struct subsystem *entry, char *buf, int knob)
+{
+ char *out = buf;
+ struct pdcspath_entry *pathentry;
- out += sprintf(out, "Autoboot: %s\n", (devpath.flags & PF_AUTOBOOT) ? "On" : "Off");
- out += sprintf(out, "Autosearch: %s\n", (devpath.flags & PF_AUTOSEARCH) ? "On" : "Off");
- out += sprintf(out, "Timer: %u s\n", (devpath.flags & PF_TIMER) ? (1 << (devpath.flags & PF_TIMER)) : 0);
+ if (!entry || !buf)
+ return -EINVAL;
+
+ /* Current flags are stored in primary boot path entry */
+ pathentry = &pdcspath_entry_primary;
+
+ read_lock(&pathentry->rw_lock);
+ out += sprintf(out, "%s\n", (pathentry->devpath.flags & knob) ?
+ "On" : "Off");
+ read_unlock(&pathentry->rw_lock);
+
+ return out - buf;
+}
+
+/**
+ * pdcs_autoboot_read - Stable Storage autoboot flag output.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ */
+static inline ssize_t
+pdcs_autoboot_read(struct subsystem *entry, char *buf)
+{
+ return pdcs_auto_read(entry, buf, PF_AUTOBOOT);
+}
+
+/**
+ * pdcs_autosearch_read - Stable Storage autoboot flag output.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ */
+static inline ssize_t
+pdcs_autosearch_read(struct subsystem *entry, char *buf)
+{
+ return pdcs_auto_read(entry, buf, PF_AUTOSEARCH);
+}
+
+/**
+ * pdcs_timer_read - Stable Storage timer count output (in seconds).
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ *
+ * The value of the timer field correponds to a number of seconds in powers of 2.
+ */
+static ssize_t
+pdcs_timer_read(struct subsystem *entry, char *buf)
+{
+ char *out = buf;
+ struct pdcspath_entry *pathentry;
+
+ if (!entry || !buf)
+ return -EINVAL;
+
+ /* Current flags are stored in primary boot path entry */
+ pathentry = &pdcspath_entry_primary;
+
+ /* print the timer value in seconds */
+ read_lock(&pathentry->rw_lock);
+ out += sprintf(out, "%u\n", (pathentry->devpath.flags & PF_TIMER) ?
+ (1 << (pathentry->devpath.flags & PF_TIMER)) : 0);
+ read_unlock(&pathentry->rw_lock);
+
+ return out - buf;
+}
+
+/**
+ * pdcs_osid_read - Stable Storage OS ID register output.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ */
+static ssize_t
+pdcs_osid_read(struct subsystem *entry, char *buf)
+{
+ char *out = buf;
+ __u32 result;
+ char *tmpstr = NULL;
+
+ if (!entry || !buf)
+ return -EINVAL;
/* get OSID */
if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK)
case 0x0005: tmpstr = "Novell Netware dependent data"; break;
default: tmpstr = "Unknown"; break;
}
- out += sprintf(out, "OS ID: %s (0x%.4x)\n", tmpstr, (result >> 16));
+ out += sprintf(out, "%s (0x%.4x)\n", tmpstr, (result >> 16));
+
+ return out - buf;
+}
+
+/**
+ * pdcs_fastsize_read - Stable Storage FastSize register output.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The output buffer to write to.
+ *
+ * This register holds the amount of system RAM to be tested during boot sequence.
+ */
+static ssize_t
+pdcs_fastsize_read(struct subsystem *entry, char *buf)
+{
+ char *out = buf;
+ __u32 result;
+
+ if (!entry || !buf)
+ return -EINVAL;
/* get fast-size */
if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK)
return -EIO;
- out += sprintf(out, "Memory tested: ");
if ((result & 0x0F) < 0x0E)
out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256);
else
}
/**
- * pdcs_info_write - This function handles boot flag modifying.
+ * pdcs_auto_write - This function handles autoboot/search flag modifying.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
+ * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
*
- * We will call this function to change the current boot flags.
+ * We will call this function to change the current autoboot flag.
* We expect a precise syntax:
- * \"n n\" (n == 0 or 1) to toggle respectively AutoBoot and AutoSearch
- *
- * As of now there is no incentive on my side to provide more "knobs" to that
- * interface, since modifying the rest of the data is pretty meaningless when
- * the machine is running and for the expected use of that facility, such as
- * PALO setting up the boot disk when installing a Linux distribution...
+ * \"n\" (n == 0 or 1) to toggle AutoBoot Off or On
*/
static ssize_t
-pdcs_info_write(struct subsystem *entry, const char *buf, size_t count)
+pdcs_auto_write(struct subsystem *entry, const char *buf, size_t count, int knob)
{
struct pdcspath_entry *pathentry;
unsigned char flags;
pathentry = &pdcspath_entry_primary;
/* Be nice to the existing flag record */
+ read_lock(&pathentry->rw_lock);
flags = pathentry->devpath.flags;
+ read_unlock(&pathentry->rw_lock);
DPRINTK("%s: flags before: 0x%X\n", __func__, flags);
if ((c != 0) && (c != 1))
goto parse_error;
if (c == 0)
- flags &= ~PF_AUTOBOOT;
+ flags &= ~knob;
else
- flags |= PF_AUTOBOOT;
-
- if (*temp++ != ' ')
- goto parse_error;
-
- c = *temp++ - '0';
- if ((c != 0) && (c != 1))
- goto parse_error;
- if (c == 0)
- flags &= ~PF_AUTOSEARCH;
- else
- flags |= PF_AUTOSEARCH;
+ flags |= knob;
DPRINTK("%s: flags after: 0x%X\n", __func__, flags);
/* So far so good, let's get in deep */
+ write_lock(&pathentry->rw_lock);
/* Change the path entry flags first */
pathentry->devpath.flags = flags;
/* Now, dive in. Write back to the hardware */
- WARN_ON(pdcspath_store(pathentry)); /* this warn should *NEVER* happen */
+ pdcspath_store(pathentry);
+ write_unlock(&pathentry->rw_lock);
- printk(KERN_INFO "PDC Stable Storage: changed flags to \"%s\"\n", buf);
+ printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n",
+ (knob & PF_AUTOBOOT) ? "autoboot" : "autosearch",
+ (flags & knob) ? "On" : "Off");
return count;
parse_error:
- printk(KERN_WARNING "%s: Parse error: expect \"n n\" (n == 0 or 1) for AB and AS\n", __func__);
+ printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__);
return -EINVAL;
}
-/* The last attribute (the 'root' one actually) with all remaining data. */
-static PDCS_ATTR(info, 0600, pdcs_info_read, pdcs_info_write);
+/**
+ * pdcs_autoboot_write - This function handles autoboot flag modifying.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The input buffer to read from.
+ * @count: The number of bytes to be read.
+ *
+ * We will call this function to change the current boot flags.
+ * We expect a precise syntax:
+ * \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
+ */
+static inline ssize_t
+pdcs_autoboot_write(struct subsystem *entry, const char *buf, size_t count)
+{
+ return pdcs_auto_write(entry, buf, count, PF_AUTOBOOT);
+}
+
+/**
+ * pdcs_autosearch_write - This function handles autosearch flag modifying.
+ * @entry: An allocated and populated subsytem struct. We don't use it tho.
+ * @buf: The input buffer to read from.
+ * @count: The number of bytes to be read.
+ *
+ * We will call this function to change the current boot flags.
+ * We expect a precise syntax:
+ * \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
+ */
+static inline ssize_t
+pdcs_autosearch_write(struct subsystem *entry, const char *buf, size_t count)
+{
+ return pdcs_auto_write(entry, buf, count, PF_AUTOSEARCH);
+}
+
+/* The remaining attributes. */
+static PDCS_ATTR(size, 0444, pdcs_size_read, NULL);
+static PDCS_ATTR(autoboot, 0644, pdcs_autoboot_read, pdcs_autoboot_write);
+static PDCS_ATTR(autosearch, 0644, pdcs_autosearch_read, pdcs_autosearch_write);
+static PDCS_ATTR(timer, 0444, pdcs_timer_read, NULL);
+static PDCS_ATTR(osid, 0400, pdcs_osid_read, NULL);
+static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL);
static struct subsys_attribute *pdcs_subsys_attrs[] = {
- &pdcs_attr_info,
- NULL, /* maybe more in the future? */
+ &pdcs_attr_size,
+ &pdcs_attr_autoboot,
+ &pdcs_attr_autosearch,
+ &pdcs_attr_timer,
+ &pdcs_attr_osid,
+ &pdcs_attr_fastsize,
+ NULL,
};
static decl_subsys(paths, &ktype_pdcspath, NULL);
-static decl_subsys(pdc, NULL, NULL);
+static decl_subsys(stable, NULL, NULL);
/**
* pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage.
struct pdcspath_entry *entry;
int err;
+ /* Initialize the entries rw_lock before anything else */
+ for (i = 0; (entry = pdcspath_entries[i]); i++)
+ rwlock_init(&entry->rw_lock);
+
for (i = 0; (entry = pdcspath_entries[i]); i++) {
- if (pdcspath_fetch(entry) < 0)
+ write_lock(&entry->rw_lock);
+ err = pdcspath_fetch(entry);
+ write_unlock(&entry->rw_lock);
+
+ if (err < 0)
continue;
if ((err = kobject_set_name(&entry->kobj, "%s", entry->name)))
return err;
/* kobject is now registered */
+ write_lock(&entry->rw_lock);
entry->ready = 2;
- if (!entry->dev)
- continue;
-
/* Add a nice symlink to the real device */
- sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
+ if (entry->dev)
+ sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
+
+ write_unlock(&entry->rw_lock);
}
return 0;
unsigned short i;
struct pdcspath_entry *entry;
- for (i = 0; (entry = pdcspath_entries[i]); i++)
+ for (i = 0; (entry = pdcspath_entries[i]); i++) {
+ read_lock(&entry->rw_lock);
if (entry->ready >= 2)
- kobject_unregister(&entry->kobj);
+ kobject_unregister(&entry->kobj);
+ read_unlock(&entry->rw_lock);
+ }
}
/*
- * For now we register the pdc subsystem with the firmware subsystem
- * and the paths subsystem with the pdc subsystem
+ * For now we register the stable subsystem with the firmware subsystem
+ * and the paths subsystem with the stable subsystem
*/
static int __init
pdc_stable_init(void)
if (pdc_stable_get_size(&pdcs_size) != PDC_OK)
return -ENODEV;
- printk(KERN_INFO "PDC Stable Storage facility v%s\n", PDCS_VERSION);
+ /* make sure we have enough data */
+ if (pdcs_size < 96)
+ return -ENODATA;
+
+ printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION);
- /* For now we'll register the pdc subsys within this driver */
- if ((rc = firmware_register(&pdc_subsys)))
+ /* For now we'll register the stable subsys within this driver */
+ if ((rc = firmware_register(&stable_subsys)))
goto fail_firmreg;
- /* Don't forget the info entry */
+ /* Don't forget the root entries */
for (i = 0; (attr = pdcs_subsys_attrs[i]) && !error; i++)
if (attr->show)
- error = subsys_create_file(&pdc_subsys, attr);
+ error = subsys_create_file(&stable_subsys, attr);
- /* register the paths subsys as a subsystem of pdc subsys */
- kset_set_kset_s(&paths_subsys, pdc_subsys);
+ /* register the paths subsys as a subsystem of stable subsys */
+ kset_set_kset_s(&paths_subsys, stable_subsys);
if ((rc= subsystem_register(&paths_subsys)))
goto fail_subsysreg;
subsystem_unregister(&paths_subsys);
fail_subsysreg:
- firmware_unregister(&pdc_subsys);
+ firmware_unregister(&stable_subsys);
fail_firmreg:
- printk(KERN_INFO "PDC Stable Storage bailing out\n");
+ printk(KERN_INFO PDCS_PREFIX " bailing out\n");
return rc;
}
pdcs_unregister_pathentries();
subsystem_unregister(&paths_subsys);
- firmware_unregister(&pdc_subsys);
+ firmware_unregister(&stable_subsys);
}
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff