kernel-ark/drivers/uio/uio_pci_generic.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

209 lines
5.7 KiB
C

/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
*
* Copyright (C) 2009 Red Hat, Inc.
* Author: Michael S. Tsirkin <mst@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2.
*
* Since the driver does not declare any device ids, you must allocate
* id and bind the device to the driver yourself. For example:
*
* # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
* # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
* # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
* # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
* .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
*
* Driver won't bind to devices which do not support the Interrupt Disable Bit
* in the command register. All devices compliant to PCI 2.3 (circa 2002) and
* all compliant PCI Express devices should support this bit.
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uio_driver.h>
#include <linux/spinlock.h>
#define DRIVER_VERSION "0.01.0"
#define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>"
#define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices"
struct uio_pci_generic_dev {
struct uio_info info;
struct pci_dev *pdev;
spinlock_t lock; /* guards command register accesses */
};
static inline struct uio_pci_generic_dev *
to_uio_pci_generic_dev(struct uio_info *info)
{
return container_of(info, struct uio_pci_generic_dev, info);
}
/* Interrupt handler. Read/modify/write the command register to disable
* the interrupt. */
static irqreturn_t irqhandler(int irq, struct uio_info *info)
{
struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
struct pci_dev *pdev = gdev->pdev;
irqreturn_t ret = IRQ_NONE;
u32 cmd_status_dword;
u16 origcmd, newcmd, status;
/* We do a single dword read to retrieve both command and status.
* Document assumptions that make this possible. */
BUILD_BUG_ON(PCI_COMMAND % 4);
BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS);
spin_lock_irq(&gdev->lock);
pci_block_user_cfg_access(pdev);
/* Read both command and status registers in a single 32-bit operation.
* Note: we could cache the value for command and move the status read
* out of the lock if there was a way to get notified of user changes
* to command register through sysfs. Should be good for shared irqs. */
pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);
origcmd = cmd_status_dword;
status = cmd_status_dword >> 16;
/* Check interrupt status register to see whether our device
* triggered the interrupt. */
if (!(status & PCI_STATUS_INTERRUPT))
goto done;
/* We triggered the interrupt, disable it. */
newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;
if (newcmd != origcmd)
pci_write_config_word(pdev, PCI_COMMAND, newcmd);
/* UIO core will signal the user process. */
ret = IRQ_HANDLED;
done:
pci_unblock_user_cfg_access(pdev);
spin_unlock_irq(&gdev->lock);
return ret;
}
/* Verify that the device supports Interrupt Disable bit in command register,
* per PCI 2.3, by flipping this bit and reading it back: this bit was readonly
* in PCI 2.2. */
static int __devinit verify_pci_2_3(struct pci_dev *pdev)
{
u16 orig, new;
int err = 0;
pci_block_user_cfg_access(pdev);
pci_read_config_word(pdev, PCI_COMMAND, &orig);
pci_write_config_word(pdev, PCI_COMMAND,
orig ^ PCI_COMMAND_INTX_DISABLE);
pci_read_config_word(pdev, PCI_COMMAND, &new);
/* There's no way to protect against
* hardware bugs or detect them reliably, but as long as we know
* what the value should be, let's go ahead and check it. */
if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE) {
err = -EBUSY;
dev_err(&pdev->dev, "Command changed from 0x%x to 0x%x: "
"driver or HW bug?\n", orig, new);
goto err;
}
if (!((new ^ orig) & PCI_COMMAND_INTX_DISABLE)) {
dev_warn(&pdev->dev, "Device does not support "
"disabling interrupts: unable to bind.\n");
err = -ENODEV;
goto err;
}
/* Now restore the original value. */
pci_write_config_word(pdev, PCI_COMMAND, orig);
err:
pci_unblock_user_cfg_access(pdev);
return err;
}
static int __devinit probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
struct uio_pci_generic_dev *gdev;
int err;
if (!pdev->irq) {
dev_warn(&pdev->dev, "No IRQ assigned to device: "
"no support for interrupts?\n");
return -ENODEV;
}
err = pci_enable_device(pdev);
if (err) {
dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
__func__, err);
return err;
}
err = verify_pci_2_3(pdev);
if (err)
goto err_verify;
gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
if (!gdev) {
err = -ENOMEM;
goto err_alloc;
}
gdev->info.name = "uio_pci_generic";
gdev->info.version = DRIVER_VERSION;
gdev->info.irq = pdev->irq;
gdev->info.irq_flags = IRQF_SHARED;
gdev->info.handler = irqhandler;
gdev->pdev = pdev;
spin_lock_init(&gdev->lock);
if (uio_register_device(&pdev->dev, &gdev->info))
goto err_register;
pci_set_drvdata(pdev, gdev);
return 0;
err_register:
kfree(gdev);
err_alloc:
err_verify:
pci_disable_device(pdev);
return err;
}
static void remove(struct pci_dev *pdev)
{
struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
uio_unregister_device(&gdev->info);
pci_disable_device(pdev);
kfree(gdev);
}
static struct pci_driver driver = {
.name = "uio_pci_generic",
.id_table = NULL, /* only dynamic id's */
.probe = probe,
.remove = remove,
};
static int __init init(void)
{
pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
return pci_register_driver(&driver);
}
static void __exit cleanup(void)
{
pci_unregister_driver(&driver);
}
module_init(init);
module_exit(cleanup);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);