linux/drivers/s390/char/vmur.c

907 lines
20 KiB
C

/*
* Linux driver for System z and s390 unit record devices
* (z/VM virtual punch, reader, printer)
*
* Copyright IBM Corp. 2001, 2007
* Authors: Malcolm Beattie <beattiem@uk.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
* Frank Munzert <munzert@de.ibm.com>
*/
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <asm/cio.h>
#include <asm/ccwdev.h>
#include <asm/debug.h>
#include "vmur.h"
/*
* Driver overview
*
* Unit record device support is implemented as a character device driver.
* We can fit at least 16 bits into a device minor number and use the
* simple method of mapping a character device number with minor abcd
* to the unit record device with devno abcd.
* I/O to virtual unit record devices is handled as follows:
* Reads: Diagnose code 0x14 (input spool file manipulation)
* is used to read spool data page-wise.
* Writes: The CCW used is WRITE_CCW_CMD (0x01). The device's record length
* is available by reading sysfs attr reclen. Each write() to the device
* must specify an integral multiple (maximal 511) of reclen.
*/
static char ur_banner[] = "z/VM virtual unit record device driver";
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("s390 z/VM virtual unit record device driver");
MODULE_LICENSE("GPL");
#define PRINTK_HEADER "vmur: "
static dev_t ur_first_dev_maj_min;
static struct class *vmur_class;
static struct debug_info *vmur_dbf;
/* We put the device's record length (for writes) in the driver_info field */
static struct ccw_device_id ur_ids[] = {
{ CCWDEV_CU_DI(READER_PUNCH_DEVTYPE, 80) },
{ CCWDEV_CU_DI(PRINTER_DEVTYPE, 132) },
{ /* end of list */ }
};
MODULE_DEVICE_TABLE(ccw, ur_ids);
static int ur_probe(struct ccw_device *cdev);
static void ur_remove(struct ccw_device *cdev);
static int ur_set_online(struct ccw_device *cdev);
static int ur_set_offline(struct ccw_device *cdev);
static struct ccw_driver ur_driver = {
.name = "vmur",
.owner = THIS_MODULE,
.ids = ur_ids,
.probe = ur_probe,
.remove = ur_remove,
.set_online = ur_set_online,
.set_offline = ur_set_offline,
};
/*
* Allocation, freeing, getting and putting of urdev structures
*/
static struct urdev *urdev_alloc(struct ccw_device *cdev)
{
struct urdev *urd;
urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
if (!urd)
return NULL;
urd->cdev = cdev;
urd->reclen = cdev->id.driver_info;
ccw_device_get_id(cdev, &urd->dev_id);
mutex_init(&urd->io_mutex);
mutex_init(&urd->open_mutex);
return urd;
}
static void urdev_free(struct urdev *urd)
{
kfree(urd);
}
/*
* This is how the character device driver gets a reference to a
* ur device. When this call returns successfully, a reference has
* been taken (by get_device) on the underlying kobject. The recipient
* of this urdev pointer must eventually drop it with urdev_put(urd)
* which does the corresponding put_device().
*/
static struct urdev *urdev_get_from_devno(u16 devno)
{
char bus_id[16];
struct ccw_device *cdev;
sprintf(bus_id, "0.0.%04x", devno);
cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
if (!cdev)
return NULL;
return cdev->dev.driver_data;
}
static void urdev_put(struct urdev *urd)
{
put_device(&urd->cdev->dev);
}
/*
* Low-level functions to do I/O to a ur device.
* alloc_chan_prog
* do_ur_io
* ur_int_handler
*
* alloc_chan_prog allocates and builds the channel program
*
* do_ur_io issues the channel program to the device and blocks waiting
* on a completion event it publishes at urd->io_done. The function
* serialises itself on the device's mutex so that only one I/O
* is issued at a time (and that I/O is synchronous).
*
* ur_int_handler catches the "I/O done" interrupt, writes the
* subchannel status word into the scsw member of the urdev structure
* and complete()s the io_done to wake the waiting do_ur_io.
*
* The caller of do_ur_io is responsible for kfree()ing the channel program
* address pointer that alloc_chan_prog returned.
*/
/*
* alloc_chan_prog
* The channel program we use is write commands chained together
* with a final NOP CCW command-chained on (which ensures that CE and DE
* are presented together in a single interrupt instead of as separate
* interrupts unless an incorrect length indication kicks in first). The
* data length in each CCW is reclen. The caller must ensure that count
* is an integral multiple of reclen.
* The channel program pointer returned by this function must be freed
* with kfree. The caller is responsible for checking that
* count/reclen is not ridiculously large.
*/
static struct ccw1 *alloc_chan_prog(char *buf, size_t count, size_t reclen)
{
size_t num_ccws;
struct ccw1 *cpa;
int i;
TRACE("alloc_chan_prog(%p, %zu, %zu)\n", buf, count, reclen);
/*
* We chain a NOP onto the writes to force CE+DE together.
* That means we allocate room for CCWs to cover count/reclen
* records plus a NOP.
*/
num_ccws = count / reclen + 1;
cpa = kmalloc(num_ccws * sizeof(struct ccw1), GFP_KERNEL | GFP_DMA);
if (!cpa)
return NULL;
for (i = 0; count; i++) {
cpa[i].cmd_code = WRITE_CCW_CMD;
cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
cpa[i].count = reclen;
cpa[i].cda = __pa(buf);
buf += reclen;
count -= reclen;
}
/* The following NOP CCW forces CE+DE to be presented together */
cpa[i].cmd_code = CCW_CMD_NOOP;
cpa[i].flags = 0;
cpa[i].count = 0;
cpa[i].cda = 0;
return cpa;
}
static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
{
int rc;
struct ccw_device *cdev = urd->cdev;
DECLARE_COMPLETION(event);
TRACE("do_ur_io: cpa=%p\n", cpa);
rc = mutex_lock_interruptible(&urd->io_mutex);
if (rc)
return rc;
urd->io_done = &event;
spin_lock_irq(get_ccwdev_lock(cdev));
rc = ccw_device_start(cdev, cpa, 1, 0, 0);
spin_unlock_irq(get_ccwdev_lock(cdev));
TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
if (rc)
goto out;
wait_for_completion(&event);
TRACE("do_ur_io: I/O complete\n");
rc = 0;
out:
mutex_unlock(&urd->io_mutex);
return rc;
}
/*
* ur interrupt handler, called from the ccw_device layer
*/
static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
struct irb *irb)
{
struct urdev *urd;
TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
intparm, irb->scsw.cstat, irb->scsw.dstat, irb->scsw.count);
if (!intparm) {
TRACE("ur_int_handler: unsolicited interrupt\n");
return;
}
urd = cdev->dev.driver_data;
/* On special conditions irb is an error pointer */
if (IS_ERR(irb))
urd->io_request_rc = PTR_ERR(irb);
else if (irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
urd->io_request_rc = 0;
else
urd->io_request_rc = -EIO;
complete(urd->io_done);
}
/*
* reclen sysfs attribute - The record length to be used for write CCWs
*/
static ssize_t ur_attr_reclen_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct urdev *urd = dev->driver_data;
return sprintf(buf, "%zu\n", urd->reclen);
}
static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
static int ur_create_attributes(struct device *dev)
{
return device_create_file(dev, &dev_attr_reclen);
}
static void ur_remove_attributes(struct device *dev)
{
device_remove_file(dev, &dev_attr_reclen);
}
/*
* diagnose code 0x210 - retrieve device information
* cc=0 normal completion, we have a real device
* cc=1 CP paging error
* cc=2 The virtual device exists, but is not associated with a real device
* cc=3 Invalid device address, or the virtual device does not exist
*/
static int get_urd_class(struct urdev *urd)
{
static struct diag210 ur_diag210;
int cc;
ur_diag210.vrdcdvno = urd->dev_id.devno;
ur_diag210.vrdclen = sizeof(struct diag210);
cc = diag210(&ur_diag210);
switch (cc) {
case 0:
return -ENOTSUPP;
case 2:
return ur_diag210.vrdcvcla; /* virtual device class */
case 3:
return -ENODEV;
default:
return -EIO;
}
}
/*
* Allocation and freeing of urfile structures
*/
static struct urfile *urfile_alloc(struct urdev *urd)
{
struct urfile *urf;
urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
if (!urf)
return NULL;
urf->urd = urd;
TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
urf->dev_reclen);
return urf;
}
static void urfile_free(struct urfile *urf)
{
TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
kfree(urf);
}
/*
* The fops implementation of the character device driver
*/
static ssize_t do_write(struct urdev *urd, const char __user *udata,
size_t count, size_t reclen, loff_t *ppos)
{
struct ccw1 *cpa;
char *buf;
int rc;
/* Data buffer must be under 2GB line for fmt1 CCWs: hence GFP_DMA */
buf = kmalloc(count, GFP_KERNEL | GFP_DMA);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, udata, count)) {
rc = -EFAULT;
goto fail_kfree_buf;
}
cpa = alloc_chan_prog(buf, count, reclen);
if (!cpa) {
rc = -ENOMEM;
goto fail_kfree_buf;
}
rc = do_ur_io(urd, cpa);
if (rc)
goto fail_kfree_cpa;
if (urd->io_request_rc) {
rc = urd->io_request_rc;
goto fail_kfree_cpa;
}
*ppos += count;
rc = count;
fail_kfree_cpa:
kfree(cpa);
fail_kfree_buf:
kfree(buf);
return rc;
}
static ssize_t ur_write(struct file *file, const char __user *udata,
size_t count, loff_t *ppos)
{
struct urfile *urf = file->private_data;
TRACE("ur_write: count=%zu\n", count);
if (count == 0)
return 0;
if (count % urf->dev_reclen)
return -EINVAL; /* count must be a multiple of reclen */
if (count > urf->dev_reclen * MAX_RECS_PER_IO)
count = urf->dev_reclen * MAX_RECS_PER_IO;
return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
}
static int do_diag_14(unsigned long rx, unsigned long ry1,
unsigned long subcode)
{
register unsigned long _ry1 asm("2") = ry1;
register unsigned long _ry2 asm("3") = subcode;
int rc = 0;
asm volatile(
#ifdef CONFIG_64BIT
" sam31\n"
" diag %2,2,0x14\n"
" sam64\n"
#else
" diag %2,2,0x14\n"
#endif
" ipm %0\n"
" srl %0,28\n"
: "=d" (rc), "+d" (_ry2)
: "d" (rx), "d" (_ry1)
: "cc");
TRACE("diag 14: subcode=0x%lx, cc=%i\n", subcode, rc);
return rc;
}
/*
* diagnose code 0x14 subcode 0x0028 - position spool file to designated
* record
* cc=0 normal completion
* cc=2 no file active on the virtual reader or device not ready
* cc=3 record specified is beyond EOF
*/
static int diag_position_to_record(int devno, int record)
{
int cc;
cc = do_diag_14(record, devno, 0x28);
switch (cc) {
case 0:
return 0;
case 2:
return -ENOMEDIUM;
case 3:
return -ENODATA; /* position beyond end of file */
default:
return -EIO;
}
}
/*
* diagnose code 0x14 subcode 0x0000 - read next spool file buffer
* cc=0 normal completion
* cc=1 EOF reached
* cc=2 no file active on the virtual reader, and no file eligible
* cc=3 file already active on the virtual reader or specified virtual
* reader does not exist or is not a reader
*/
static int diag_read_file(int devno, char *buf)
{
int cc;
cc = do_diag_14((unsigned long) buf, devno, 0x00);
switch (cc) {
case 0:
return 0;
case 1:
return -ENODATA;
case 2:
return -ENOMEDIUM;
default:
return -EIO;
}
}
static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
loff_t *offs)
{
size_t len, copied, res;
char *buf;
int rc;
u16 reclen;
struct urdev *urd;
urd = ((struct urfile *) file->private_data)->urd;
reclen = ((struct urfile *) file->private_data)->file_reclen;
rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
if (rc == -ENODATA)
return 0;
if (rc)
return rc;
len = min((size_t) PAGE_SIZE, count);
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
return -ENOMEM;
copied = 0;
res = (size_t) (*offs % PAGE_SIZE);
do {
rc = diag_read_file(urd->dev_id.devno, buf);
if (rc == -ENODATA) {
break;
}
if (rc)
goto fail;
if (reclen)
*((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
len = min(count - copied, PAGE_SIZE - res);
if (copy_to_user(ubuf + copied, buf + res, len)) {
rc = -EFAULT;
goto fail;
}
res = 0;
copied += len;
} while (copied != count);
*offs += copied;
rc = copied;
fail:
kfree(buf);
return rc;
}
static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
loff_t *offs)
{
struct urdev *urd;
int rc;
TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
if (count == 0)
return 0;
urd = ((struct urfile *) file->private_data)->urd;
rc = mutex_lock_interruptible(&urd->io_mutex);
if (rc)
return rc;
rc = diag14_read(file, ubuf, count, offs);
mutex_unlock(&urd->io_mutex);
return rc;
}
/*
* diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
* cc=0 normal completion
* cc=1 no files on reader queue or no subsequent file
* cc=2 spid specified is invalid
*/
static int diag_read_next_file_info(struct file_control_block *buf, int spid)
{
int cc;
cc = do_diag_14((unsigned long) buf, spid, 0xfff);
switch (cc) {
case 0:
return 0;
default:
return -ENODATA;
}
}
static int verify_device(struct urdev *urd)
{
struct file_control_block fcb;
char *buf;
int rc;
switch (urd->class) {
case DEV_CLASS_UR_O:
return 0; /* no check needed here */
case DEV_CLASS_UR_I:
/* check for empty reader device (beginning of chain) */
rc = diag_read_next_file_info(&fcb, 0);
if (rc)
return rc;
/* open file on virtual reader */
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
return -ENOMEM;
rc = diag_read_file(urd->dev_id.devno, buf);
kfree(buf);
if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
return rc;
return 0;
default:
return -ENOTSUPP;
}
}
static int get_file_reclen(struct urdev *urd)
{
struct file_control_block fcb;
int rc;
switch (urd->class) {
case DEV_CLASS_UR_O:
return 0;
case DEV_CLASS_UR_I:
rc = diag_read_next_file_info(&fcb, 0);
if (rc)
return rc;
break;
default:
return -ENOTSUPP;
}
if (fcb.file_stat & FLG_CP_DUMP)
return 0;
return fcb.rec_len;
}
static int ur_open(struct inode *inode, struct file *file)
{
u16 devno;
struct urdev *urd;
struct urfile *urf;
unsigned short accmode;
int rc;
accmode = file->f_flags & O_ACCMODE;
if (accmode == O_RDWR)
return -EACCES;
/*
* We treat the minor number as the devno of the ur device
* to find in the driver tree.
*/
devno = MINOR(file->f_dentry->d_inode->i_rdev);
urd = urdev_get_from_devno(devno);
if (!urd)
return -ENXIO;
if (file->f_flags & O_NONBLOCK) {
if (!mutex_trylock(&urd->open_mutex)) {
rc = -EBUSY;
goto fail_put;
}
} else {
if (mutex_lock_interruptible(&urd->open_mutex)) {
rc = -ERESTARTSYS;
goto fail_put;
}
}
TRACE("ur_open\n");
if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
rc = -EACCES;
goto fail_unlock;
}
rc = verify_device(urd);
if (rc)
goto fail_unlock;
urf = urfile_alloc(urd);
if (!urf) {
rc = -ENOMEM;
goto fail_unlock;
}
urf->dev_reclen = urd->reclen;
rc = get_file_reclen(urd);
if (rc < 0)
goto fail_urfile_free;
urf->file_reclen = rc;
file->private_data = urf;
return 0;
fail_urfile_free:
urfile_free(urf);
fail_unlock:
mutex_unlock(&urd->open_mutex);
fail_put:
urdev_put(urd);
return rc;
}
static int ur_release(struct inode *inode, struct file *file)
{
struct urfile *urf = file->private_data;
TRACE("ur_release\n");
mutex_unlock(&urf->urd->open_mutex);
urdev_put(urf->urd);
urfile_free(urf);
return 0;
}
static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
{
loff_t newpos;
if ((file->f_flags & O_ACCMODE) != O_RDONLY)
return -ESPIPE; /* seek allowed only for reader */
if (offset % PAGE_SIZE)
return -ESPIPE; /* only multiples of 4K allowed */
switch (whence) {
case 0: /* SEEK_SET */
newpos = offset;
break;
case 1: /* SEEK_CUR */
newpos = file->f_pos + offset;
break;
default:
return -EINVAL;
}
file->f_pos = newpos;
return newpos;
}
static struct file_operations ur_fops = {
.owner = THIS_MODULE,
.open = ur_open,
.release = ur_release,
.read = ur_read,
.write = ur_write,
.llseek = ur_llseek,
};
/*
* ccw_device infrastructure:
* ur_probe gets its own ref to the device (i.e. get_device),
* creates the struct urdev, the device attributes, sets up
* the interrupt handler and validates the virtual unit record device.
* ur_remove removes the device attributes, frees the struct urdev
* and drops (put_device) the ref to the device we got in ur_probe.
*/
static int ur_probe(struct ccw_device *cdev)
{
struct urdev *urd;
int rc;
TRACE("ur_probe: cdev=%p state=%d\n", cdev, *(int *) cdev->private);
if (!get_device(&cdev->dev))
return -ENODEV;
urd = urdev_alloc(cdev);
if (!urd) {
rc = -ENOMEM;
goto fail;
}
rc = ur_create_attributes(&cdev->dev);
if (rc) {
rc = -ENOMEM;
goto fail;
}
cdev->dev.driver_data = urd;
cdev->handler = ur_int_handler;
/* validate virtual unit record device */
urd->class = get_urd_class(urd);
if (urd->class < 0) {
rc = urd->class;
goto fail;
}
if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
rc = -ENOTSUPP;
goto fail;
}
return 0;
fail:
urdev_free(urd);
put_device(&cdev->dev);
return rc;
}
static void ur_remove(struct ccw_device *cdev)
{
struct urdev *urd = cdev->dev.driver_data;
TRACE("ur_remove\n");
if (cdev->online)
ur_set_offline(cdev);
ur_remove_attributes(&cdev->dev);
urdev_free(urd);
put_device(&cdev->dev);
}
static int ur_set_online(struct ccw_device *cdev)
{
struct urdev *urd;
int minor, major, rc;
char node_id[16];
TRACE("ur_set_online: cdev=%p state=%d\n", cdev,
*(int *) cdev->private);
if (!try_module_get(ur_driver.owner))
return -EINVAL;
urd = (struct urdev *) cdev->dev.driver_data;
minor = urd->dev_id.devno;
major = MAJOR(ur_first_dev_maj_min);
urd->char_device = cdev_alloc();
if (!urd->char_device) {
rc = -ENOMEM;
goto fail_module_put;
}
cdev_init(urd->char_device, &ur_fops);
urd->char_device->dev = MKDEV(major, minor);
urd->char_device->owner = ur_fops.owner;
rc = cdev_add(urd->char_device, urd->char_device->dev, 1);
if (rc)
goto fail_free_cdev;
if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
if (urd->class == DEV_CLASS_UR_I)
sprintf(node_id, "vmrdr-%s", cdev->dev.bus_id);
if (urd->class == DEV_CLASS_UR_O)
sprintf(node_id, "vmpun-%s", cdev->dev.bus_id);
} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
sprintf(node_id, "vmprt-%s", cdev->dev.bus_id);
} else {
rc = -ENOTSUPP;
goto fail_free_cdev;
}
urd->device = device_create(vmur_class, NULL, urd->char_device->dev,
"%s", node_id);
if (IS_ERR(urd->device)) {
rc = PTR_ERR(urd->device);
TRACE("ur_set_online: device_create rc=%d\n", rc);
goto fail_free_cdev;
}
return 0;
fail_free_cdev:
cdev_del(urd->char_device);
fail_module_put:
module_put(ur_driver.owner);
return rc;
}
static int ur_set_offline(struct ccw_device *cdev)
{
struct urdev *urd;
TRACE("ur_set_offline: cdev=%p cdev->private=%p state=%d\n",
cdev, cdev->private, *(int *) cdev->private);
urd = (struct urdev *) cdev->dev.driver_data;
device_destroy(vmur_class, urd->char_device->dev);
cdev_del(urd->char_device);
module_put(ur_driver.owner);
return 0;
}
/*
* Module initialisation and cleanup
*/
static int __init ur_init(void)
{
int rc;
dev_t dev;
if (!MACHINE_IS_VM) {
PRINT_ERR("%s is only available under z/VM.\n", ur_banner);
return -ENODEV;
}
vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
if (!vmur_dbf)
return -ENOMEM;
rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
if (rc)
goto fail_free_dbf;
debug_set_level(vmur_dbf, 6);
rc = ccw_driver_register(&ur_driver);
if (rc)
goto fail_free_dbf;
rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
if (rc) {
PRINT_ERR("alloc_chrdev_region failed: err = %d\n", rc);
goto fail_unregister_driver;
}
ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);
vmur_class = class_create(THIS_MODULE, "vmur");
if (IS_ERR(vmur_class)) {
rc = PTR_ERR(vmur_class);
goto fail_unregister_region;
}
PRINT_INFO("%s loaded.\n", ur_banner);
return 0;
fail_unregister_region:
unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
fail_unregister_driver:
ccw_driver_unregister(&ur_driver);
fail_free_dbf:
debug_unregister(vmur_dbf);
return rc;
}
static void __exit ur_exit(void)
{
class_destroy(vmur_class);
unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
ccw_driver_unregister(&ur_driver);
debug_unregister(vmur_dbf);
PRINT_INFO("%s unloaded.\n", ur_banner);
}
module_init(ur_init);
module_exit(ur_exit);