diff options
Diffstat (limited to 'drivers/parisc/pdc_stable.c')
| -rw-r--r-- | drivers/parisc/pdc_stable.c | 1094 |
1 files changed, 1094 insertions, 0 deletions
diff --git a/drivers/parisc/pdc_stable.c b/drivers/parisc/pdc_stable.c new file mode 100644 index 000000000..d6af5726d --- /dev/null +++ b/drivers/parisc/pdc_stable.c @@ -0,0 +1,1094 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Interfaces to retrieve and set PDC Stable options (firmware) + * + * Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org> + * + * DEV NOTE: the PDC Procedures reference states that: + * "A minimum of 96 bytes of Stable Storage is required. Providing more than + * 96 bytes of Stable Storage is optional [...]. Failure to provide the + * optional locations from 96 to 192 results in the loss of certain + * functionality during boot." + * + * 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 just 96 bytes of Stable Storage, and all + * sizes between 96 and 192 bytes (provided they are multiple of struct + * pdc_module_path size, eg: 128, 160 and 192) to provide full information. + * One last word: there's one path we can always count on: the primary path. + * Anything above 224 bytes is used for 'osdep2' OS-dependent storage area. + * + * The first OS-dependent area should always be available. Obviously, this is + * not true for the other one. Also bear in mind that reading/writing from/to + * osdep2 is much more expensive than from/to osdep1. + * NOTE: We do not handle the 2 bytes OS-dep area at 0x5D, nor the first + * 2 bytes of storage available right after OSID. That's a total of 4 bytes + * sacrificed: -ETOOLAZY :P + * + * 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 +#ifdef PDCS_DEBUG +#define DPRINTK(fmt, args...) printk(KERN_DEBUG fmt, ## args) +#else +#define DPRINTK(fmt, args...) +#endif + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/capability.h> +#include <linux/ctype.h> +#include <linux/sysfs.h> +#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 <linux/uaccess.h> +#include <asm/hardware.h> + +#define PDCS_VERSION "0.30" +#define PDCS_PREFIX "PDC Stable Storage" + +#define PDCS_ADDR_PPRI 0x00 +#define PDCS_ADDR_OSID 0x40 +#define PDCS_ADDR_OSD1 0x48 +#define PDCS_ADDR_DIAG 0x58 +#define PDCS_ADDR_FSIZ 0x5C +#define PDCS_ADDR_PCON 0x60 +#define PDCS_ADDR_PALT 0x80 +#define PDCS_ADDR_PKBD 0xA0 +#define PDCS_ADDR_OSD2 0xE0 + +MODULE_AUTHOR("Thibaut VARENE <varenet@parisc-linux.org>"); +MODULE_DESCRIPTION("sysfs interface to HP PDC Stable Storage data"); +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; + +/* holds OS ID. Initialized once and for all, hopefully to 0x0006 */ +static u16 pdcs_osid __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 */ + struct pdc_module_path devpath; /* device path in parisc representation */ + struct device *dev; /* corresponding device */ + struct kobject kobj; +}; + +struct pdcspath_attribute { + struct attribute attr; + ssize_t (*show)(struct pdcspath_entry *entry, char *buf); + ssize_t (*store)(struct pdcspath_entry *entry, const char *buf, size_t count); +}; + +#define PDCSPATH_ENTRY(_addr, _name) \ +struct pdcspath_entry pdcspath_entry_##_name = { \ + .ready = 0, \ + .addr = _addr, \ + .name = __stringify(_name), \ +}; + +#define PDCS_ATTR(_name, _mode, _show, _store) \ +struct kobj_attribute pdcs_attr_##_name = { \ + .attr = {.name = __stringify(_name), .mode = _mode}, \ + .show = _show, \ + .store = _store, \ +}; + +#define PATHS_ATTR(_name, _mode, _show, _store) \ +struct pdcspath_attribute paths_attr_##_name = { \ + .attr = {.name = __stringify(_name), .mode = _mode}, \ + .show = _show, \ + .store = _store, \ +}; + +#define to_pdcspath_attribute(_attr) container_of(_attr, struct pdcspath_attribute, attr) +#define to_pdcspath_entry(obj) container_of(obj, struct pdcspath_entry, kobj) + +/** + * 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 facilities. 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 pdc_module_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 pdc_module_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; +} + +/** + * pdcspath_store - This function writes a path to stable storage. + * @entry: A pointer to an allocated pdcspath_entry. + * + * It can be used in two ways: either by passing it a preset devpath struct + * containing an already computed hardware path, or by passing it a device + * 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 void +pdcspath_store(struct pdcspath_entry *entry) +{ + struct pdc_module_path *devpath; + + BUG_ON(!entry); + + devpath = &entry->devpath; + + /* We expect the caller to set the ready flag to 0 if the hardware + path struct provided is invalid, so that we know we have to fill it. + First case, we don't have a preset hwpath... */ + if (!entry->ready) { + /* ...but we have a device, map it */ + BUG_ON(!entry->dev); + device_to_hwpath(entry->dev, (struct hardware_path *)devpath); + } + /* else, we expect the provided hwpath to be valid. */ + + DPRINTK("%s: store: 0x%p, 0x%p, addr: 0x%lx\n", __func__, + entry, devpath, entry->addr); + + /* addr, devpath and count must be word aligned */ + if (pdc_stable_write(entry->addr, devpath, sizeof(*devpath)) != PDC_OK) + WARN(1, KERN_ERR "%s: an error occurred 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__); + + /* kobject is already registered */ + entry->ready = 2; + + DPRINTK("%s: device: 0x%p\n", __func__, entry->dev); +} + +/** + * pdcspath_hwpath_read - This function handles hardware path pretty printing. + * @entry: An allocated and populated pdscpath_entry struct. + * @buf: The output buffer to write to. + * + * We will call this function to format the output of the hwpath attribute file. + */ +static ssize_t +pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf) +{ + char *out = buf; + struct pdc_module_path *devpath; + short i; + + if (!entry || !buf) + return -EINVAL; + + read_lock(&entry->rw_lock); + devpath = &entry->devpath; + i = entry->ready; + read_unlock(&entry->rw_lock); + + if (!i) /* entry is not ready */ + return -ENODATA; + + for (i = 0; i < 6; i++) { + if (devpath->path.bc[i] < 0) + continue; + out += sprintf(out, "%d/", devpath->path.bc[i]); + } + out += sprintf(out, "%u\n", (unsigned char)devpath->path.mod); + + return out - buf; +} + +/** + * 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[64], *temp; + struct device *dev; + int ret; + + if (!entry || !buf || !count) + return -EINVAL; + + /* We'll use a local copy of buf */ + count = min_t(size_t, count, sizeof(in)-1); + strncpy(in, buf, count); + in[count] = '\0'; + + /* 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.path.bc[i]); + } + + /* Store the final field */ + hwpath.bc[i] = simple_strtoul(in, NULL, 10); + DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.path.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"); + write_unlock(&entry->rw_lock); + + ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device"); + WARN_ON(ret); + + printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n", + entry->name, buf); + + return count; +} + +/** + * pdcspath_layer_read - Extended layer (eg. SCSI ids) pretty printing. + * @entry: An allocated and populated pdscpath_entry struct. + * @buf: The output buffer to write to. + * + * We will call this function to format the output of the layer attribute file. + */ +static ssize_t +pdcspath_layer_read(struct pdcspath_entry *entry, char *buf) +{ + char *out = buf; + struct pdc_module_path *devpath; + short i; + + if (!entry || !buf) + return -EINVAL; + + read_lock(&entry->rw_lock); + devpath = &entry->devpath; + i = entry->ready; + read_unlock(&entry->rw_lock); + + if (!i) /* entry is not ready */ + return -ENODATA; + + for (i = 0; i < 6 && devpath->layers[i]; i++) + out += sprintf(out, "%u ", devpath->layers[i]); + + out += sprintf(out, "\n"); + + return out - buf; +} + +/** + * pdcspath_layer_write - This function handles extended layer 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 layer value. + * Layers are to be given '.'-delimited, without brackets. + * XXX beware we are far less checky WRT input data provided than for hwpath. + * Potential harm can be done, since there's no way to check the validity of + * the layer fields. + */ +static ssize_t +pdcspath_layer_write(struct pdcspath_entry *entry, const char *buf, size_t count) +{ + unsigned int layers[6]; /* device-specific info (ctlr#, unit#, ...) */ + unsigned short i; + char in[64], *temp; + + if (!entry || !buf || !count) + return -EINVAL; + + /* We'll use a local copy of buf */ + count = min_t(size_t, count, sizeof(in)-1); + strncpy(in, buf, count); + in[count] = '\0'; + + /* Let's clean up the target. 0 is a blank pattern */ + memset(&layers, 0, sizeof(layers)); + + /* First, pick the first layer */ + if (unlikely(!isdigit(*in))) + return -EINVAL; + layers[0] = simple_strtoul(in, NULL, 10); + DPRINTK("%s: layer[0]: %d\n", __func__, layers[0]); + + temp = in; + for (i=1; ((temp = strchr(temp, '.'))) && (likely(i<6)); i++) { + if (unlikely(!isdigit(*(++temp)))) + return -EINVAL; + layers[i] = simple_strtoul(temp, NULL, 10); + DPRINTK("%s: layer[%d]: %d\n", __func__, i, layers[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 */ + pdcspath_store(entry); + write_unlock(&entry->rw_lock); + + printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n", + entry->name, buf); + + return count; +} + +/** + * pdcspath_attr_show - Generic read function call wrapper. + * @kobj: The kobject to get info from. + * @attr: The attribute looked upon. + * @buf: The output buffer. + */ +static ssize_t +pdcspath_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) +{ + struct pdcspath_entry *entry = to_pdcspath_entry(kobj); + struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr); + ssize_t ret = 0; + + if (pdcs_attr->show) + ret = pdcs_attr->show(entry, buf); + + return ret; +} + +/** + * pdcspath_attr_store - Generic write function call wrapper. + * @kobj: The kobject to write info to. + * @attr: The attribute to be modified. + * @buf: The input buffer. + * @count: The size of the buffer. + */ +static ssize_t +pdcspath_attr_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct pdcspath_entry *entry = to_pdcspath_entry(kobj); + struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr); + ssize_t ret = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (pdcs_attr->store) + ret = pdcs_attr->store(entry, buf, count); + + return ret; +} + +static const struct sysfs_ops pdcspath_attr_ops = { + .show = pdcspath_attr_show, + .store = pdcspath_attr_store, +}; + +/* These are the two attributes of any PDC path. */ +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, + &paths_attr_layer.attr, + NULL, +}; +ATTRIBUTE_GROUPS(paths_subsys); + +/* Specific kobject type for our PDC paths */ +static struct kobj_type ktype_pdcspath = { + .sysfs_ops = &pdcspath_attr_ops, + .default_groups = paths_subsys_groups, +}; + +/* We hard define the 4 types of path we expect to find */ +static PDCSPATH_ENTRY(PDCS_ADDR_PPRI, primary); +static PDCSPATH_ENTRY(PDCS_ADDR_PCON, console); +static PDCSPATH_ENTRY(PDCS_ADDR_PALT, alternative); +static PDCSPATH_ENTRY(PDCS_ADDR_PKBD, keyboard); + +/* An array containing all PDC paths we will deal with */ +static struct pdcspath_entry *pdcspath_entries[] = { + &pdcspath_entry_primary, + &pdcspath_entry_alternative, + &pdcspath_entry_console, + &pdcspath_entry_keyboard, + NULL, +}; + + +/* For more insight of what's going on here, refer to PDC Procedures doc, + * Section PDC_STABLE */ + +/** + * pdcs_size_read - Stable Storage size output. + * @buf: The output buffer to write to. + */ +static ssize_t pdcs_size_read(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + char *out = buf; + + if (!buf) + return -EINVAL; + + /* show the size of the stable storage */ + out += sprintf(out, "%ld\n", pdcs_size); + + return out - buf; +} + +/** + * pdcs_auto_read - Stable Storage autoboot/search flag output. + * @buf: The output buffer to write to. + * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag + */ +static ssize_t pdcs_auto_read(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf, int knob) +{ + char *out = buf; + struct pdcspath_entry *pathentry; + + if (!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.path.flags & knob) ? + "On" : "Off"); + read_unlock(&pathentry->rw_lock); + + return out - buf; +} + +/** + * pdcs_autoboot_read - Stable Storage autoboot flag output. + * @buf: The output buffer to write to. + */ +static ssize_t pdcs_autoboot_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return pdcs_auto_read(kobj, attr, buf, PF_AUTOBOOT); +} + +/** + * pdcs_autosearch_read - Stable Storage autoboot flag output. + * @buf: The output buffer to write to. + */ +static ssize_t pdcs_autosearch_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return pdcs_auto_read(kobj, attr, buf, PF_AUTOSEARCH); +} + +/** + * pdcs_timer_read - Stable Storage timer count output (in seconds). + * @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 kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + struct pdcspath_entry *pathentry; + + if (!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.path.flags & PF_TIMER) ? + (1 << (pathentry->devpath.path.flags & PF_TIMER)) : 0); + read_unlock(&pathentry->rw_lock); + + return out - buf; +} + +/** + * pdcs_osid_read - Stable Storage OS ID register output. + * @buf: The output buffer to write to. + */ +static ssize_t pdcs_osid_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + + if (!buf) + return -EINVAL; + + out += sprintf(out, "%s dependent data (0x%.4x)\n", + os_id_to_string(pdcs_osid), pdcs_osid); + + return out - buf; +} + +/** + * pdcs_osdep1_read - Stable Storage OS-Dependent data area 1 output. + * @buf: The output buffer to write to. + * + * This can hold 16 bytes of OS-Dependent data. + */ +static ssize_t pdcs_osdep1_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + u32 result[4]; + + if (!buf) + return -EINVAL; + + if (pdc_stable_read(PDCS_ADDR_OSD1, &result, sizeof(result)) != PDC_OK) + return -EIO; + + out += sprintf(out, "0x%.8x\n", result[0]); + out += sprintf(out, "0x%.8x\n", result[1]); + out += sprintf(out, "0x%.8x\n", result[2]); + out += sprintf(out, "0x%.8x\n", result[3]); + + return out - buf; +} + +/** + * pdcs_diagnostic_read - Stable Storage Diagnostic register output. + * @buf: The output buffer to write to. + * + * I have NFC how to interpret the content of that register ;-). + */ +static ssize_t pdcs_diagnostic_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + u32 result; + + if (!buf) + return -EINVAL; + + /* get diagnostic */ + if (pdc_stable_read(PDCS_ADDR_DIAG, &result, sizeof(result)) != PDC_OK) + return -EIO; + + out += sprintf(out, "0x%.4x\n", (result >> 16)); + + return out - buf; +} + +/** + * pdcs_fastsize_read - Stable Storage FastSize register output. + * @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 kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + u32 result; + + if (!buf) + return -EINVAL; + + /* get fast-size */ + if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK) + return -EIO; + + if ((result & 0x0F) < 0x0E) + out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256); + else + out += sprintf(out, "All"); + out += sprintf(out, "\n"); + + return out - buf; +} + +/** + * pdcs_osdep2_read - Stable Storage OS-Dependent data area 2 output. + * @buf: The output buffer to write to. + * + * This can hold pdcs_size - 224 bytes of OS-Dependent data, when available. + */ +static ssize_t pdcs_osdep2_read(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *out = buf; + unsigned long size; + unsigned short i; + u32 result; + + if (unlikely(pdcs_size <= 224)) + return -ENODATA; + + size = pdcs_size - 224; + + if (!buf) + return -EINVAL; + + for (i=0; i<size; i+=4) { + if (unlikely(pdc_stable_read(PDCS_ADDR_OSD2 + i, &result, + sizeof(result)) != PDC_OK)) + return -EIO; + out += sprintf(out, "0x%.8x\n", result); + } + + return out - buf; +} + +/** + * pdcs_auto_write - This function handles autoboot/search flag modifying. + * @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 autoboot flag. + * We expect a precise syntax: + * \"n\" (n == 0 or 1) to toggle AutoBoot Off or On + */ +static ssize_t pdcs_auto_write(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, + size_t count, int knob) +{ + struct pdcspath_entry *pathentry; + unsigned char flags; + char in[8], *temp; + char c; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (!buf || !count) + return -EINVAL; + + /* We'll use a local copy of buf */ + count = min_t(size_t, count, sizeof(in)-1); + strncpy(in, buf, count); + in[count] = '\0'; + + /* Current flags are stored in primary boot path entry */ + pathentry = &pdcspath_entry_primary; + + /* Be nice to the existing flag record */ + read_lock(&pathentry->rw_lock); + flags = pathentry->devpath.path.flags; + read_unlock(&pathentry->rw_lock); + + DPRINTK("%s: flags before: 0x%X\n", __func__, flags); + + temp = skip_spaces(in); + + c = *temp++ - '0'; + if ((c != 0) && (c != 1)) + goto parse_error; + if (c == 0) + flags &= ~knob; + else + 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.path.flags = flags; + + /* Now, dive in. Write back to the hardware */ + pdcspath_store(pathentry); + write_unlock(&pathentry->rw_lock); + + 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 == 0 or 1)\n", __func__); + return -EINVAL; +} + +/** + * pdcs_autoboot_write - This function handles autoboot flag modifying. + * @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 ssize_t pdcs_autoboot_write(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOBOOT); +} + +/** + * pdcs_autosearch_write - This function handles autosearch flag modifying. + * @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 ssize_t pdcs_autosearch_write(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOSEARCH); +} + +/** + * pdcs_osdep1_write - Stable Storage OS-Dependent data area 1 input. + * @buf: The input buffer to read from. + * @count: The number of bytes to be read. + * + * This can store 16 bytes of OS-Dependent data. We use a byte-by-byte + * write approach. It's up to userspace to deal with it when constructing + * its input buffer. + */ +static ssize_t pdcs_osdep1_write(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + u8 in[16]; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (!buf || !count) + return -EINVAL; + + if (unlikely(pdcs_osid != OS_ID_LINUX)) + return -EPERM; + + if (count > 16) + return -EMSGSIZE; + + /* We'll use a local copy of buf */ + memset(in, 0, 16); + memcpy(in, buf, count); + + if (pdc_stable_write(PDCS_ADDR_OSD1, &in, sizeof(in)) != PDC_OK) + return -EIO; + + return count; +} + +/** + * pdcs_osdep2_write - Stable Storage OS-Dependent data area 2 input. + * @buf: The input buffer to read from. + * @count: The number of bytes to be read. + * + * This can store pdcs_size - 224 bytes of OS-Dependent data. We use a + * byte-by-byte write approach. It's up to userspace to deal with it when + * constructing its input buffer. + */ +static ssize_t pdcs_osdep2_write(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long size; + unsigned short i; + u8 in[4]; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (!buf || !count) + return -EINVAL; + + if (unlikely(pdcs_size <= 224)) + return -ENOSYS; + + if (unlikely(pdcs_osid != OS_ID_LINUX)) + return -EPERM; + + size = pdcs_size - 224; + + if (count > size) + return -EMSGSIZE; + + /* We'll use a local copy of buf */ + + for (i=0; i<count; i+=4) { + memset(in, 0, 4); + memcpy(in, buf+i, (count-i < 4) ? count-i : 4); + if (unlikely(pdc_stable_write(PDCS_ADDR_OSD2 + i, &in, + sizeof(in)) != PDC_OK)) + return -EIO; + } + + return count; +} + +/* 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, 0444, pdcs_osid_read, NULL); +static PDCS_ATTR(osdep1, 0600, pdcs_osdep1_read, pdcs_osdep1_write); +static PDCS_ATTR(diagnostic, 0400, pdcs_diagnostic_read, NULL); +static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL); +static PDCS_ATTR(osdep2, 0600, pdcs_osdep2_read, pdcs_osdep2_write); + +static struct attribute *pdcs_subsys_attrs[] = { + &pdcs_attr_size.attr, + &pdcs_attr_autoboot.attr, + &pdcs_attr_autosearch.attr, + &pdcs_attr_timer.attr, + &pdcs_attr_osid.attr, + &pdcs_attr_osdep1.attr, + &pdcs_attr_diagnostic.attr, + &pdcs_attr_fastsize.attr, + &pdcs_attr_osdep2.attr, + NULL, +}; + +static const struct attribute_group pdcs_attr_group = { + .attrs = pdcs_subsys_attrs, +}; + +static struct kobject *stable_kobj; +static struct kset *paths_kset; + +/** + * pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage. + * + * It creates kobjects corresponding to each path entry with nice sysfs + * links to the real device. This is where the magic takes place: when + * registering the subsystem attributes during module init, each kobject hereby + * created will show in the sysfs tree as a folder containing files as defined + * by path_subsys_attr[]. + */ +static inline int __init +pdcs_register_pathentries(void) +{ + unsigned short i; + 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++) { + write_lock(&entry->rw_lock); + err = pdcspath_fetch(entry); + write_unlock(&entry->rw_lock); + + if (err < 0) + continue; + + entry->kobj.kset = paths_kset; + err = kobject_init_and_add(&entry->kobj, &ktype_pdcspath, NULL, + "%s", entry->name); + if (err) { + kobject_put(&entry->kobj); + return err; + } + + /* kobject is now registered */ + write_lock(&entry->rw_lock); + entry->ready = 2; + write_unlock(&entry->rw_lock); + + /* Add a nice symlink to the real device */ + if (entry->dev) { + err = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device"); + WARN_ON(err); + } + + kobject_uevent(&entry->kobj, KOBJ_ADD); + } + + return 0; +} + +/** + * pdcs_unregister_pathentries - Routine called when unregistering the module. + */ +static inline void +pdcs_unregister_pathentries(void) +{ + unsigned short i; + struct pdcspath_entry *entry; + + for (i = 0; (entry = pdcspath_entries[i]); i++) { + read_lock(&entry->rw_lock); + if (entry->ready >= 2) + kobject_put(&entry->kobj); + read_unlock(&entry->rw_lock); + } +} + +/* + * 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) +{ + int rc = 0, error = 0; + u32 result; + + /* find the size of the stable storage */ + if (pdc_stable_get_size(&pdcs_size) != PDC_OK) + return -ENODEV; + + /* make sure we have enough data */ + if (pdcs_size < 96) + return -ENODATA; + + printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION); + + /* get OSID */ + if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK) + return -EIO; + + /* the actual result is 16 bits away */ + pdcs_osid = (u16)(result >> 16); + + /* For now we'll register the directory at /sys/firmware/stable */ + stable_kobj = kobject_create_and_add("stable", firmware_kobj); + if (!stable_kobj) { + rc = -ENOMEM; + goto fail_firmreg; + } + + /* Don't forget the root entries */ + error = sysfs_create_group(stable_kobj, &pdcs_attr_group); + + /* register the paths kset as a child of the stable kset */ + paths_kset = kset_create_and_add("paths", NULL, stable_kobj); + if (!paths_kset) { + rc = -ENOMEM; + goto fail_ksetreg; + } + + /* now we create all "files" for the paths kset */ + if ((rc = pdcs_register_pathentries())) + goto fail_pdcsreg; + + return rc; + +fail_pdcsreg: + pdcs_unregister_pathentries(); + kset_unregister(paths_kset); + +fail_ksetreg: + kobject_put(stable_kobj); + +fail_firmreg: + printk(KERN_INFO PDCS_PREFIX " bailing out\n"); + return rc; +} + +static void __exit +pdc_stable_exit(void) +{ + pdcs_unregister_pathentries(); + kset_unregister(paths_kset); + kobject_put(stable_kobj); +} + + +module_init(pdc_stable_init); +module_exit(pdc_stable_exit); |