linux-stable/drivers/macintosh/adb.c
Linus Torvalds b6a7828502 modules-6.4-rc1
The summary of the changes for this pull requests is:
 
  * Song Liu's new struct module_memory replacement
  * Nick Alcock's MODULE_LICENSE() removal for non-modules
  * My cleanups and enhancements to reduce the areas where we vmalloc
    module memory for duplicates, and the respective debug code which
    proves the remaining vmalloc pressure comes from userspace.
 
 Most of the changes have been in linux-next for quite some time except
 the minor fixes I made to check if a module was already loaded
 prior to allocating the final module memory with vmalloc and the
 respective debug code it introduces to help clarify the issue. Although
 the functional change is small it is rather safe as it can only *help*
 reduce vmalloc space for duplicates and is confirmed to fix a bootup
 issue with over 400 CPUs with KASAN enabled. I don't expect stable
 kernels to pick up that fix as the cleanups would have also had to have
 been picked up. Folks on larger CPU systems with modules will want to
 just upgrade if vmalloc space has been an issue on bootup.
 
 Given the size of this request, here's some more elaborate details
 on this pull request.
 
 The functional change change in this pull request is the very first
 patch from Song Liu which replaces the struct module_layout with a new
 struct module memory. The old data structure tried to put together all
 types of supported module memory types in one data structure, the new
 one abstracts the differences in memory types in a module to allow each
 one to provide their own set of details. This paves the way in the
 future so we can deal with them in a cleaner way. If you look at changes
 they also provide a nice cleanup of how we handle these different memory
 areas in a module. This change has been in linux-next since before the
 merge window opened for v6.3 so to provide more than a full kernel cycle
 of testing. It's a good thing as quite a bit of fixes have been found
 for it.
 
 Jason Baron then made dynamic debug a first class citizen module user by
 using module notifier callbacks to allocate / remove module specific
 dynamic debug information.
 
 Nick Alcock has done quite a bit of work cross-tree to remove module
 license tags from things which cannot possibly be module at my request
 so to:
 
   a) help him with his longer term tooling goals which require a
      deterministic evaluation if a piece a symbol code could ever be
      part of a module or not. But quite recently it is has been made
      clear that tooling is not the only one that would benefit.
      Disambiguating symbols also helps efforts such as live patching,
      kprobes and BPF, but for other reasons and R&D on this area
      is active with no clear solution in sight.
 
   b) help us inch closer to the now generally accepted long term goal
      of automating all the MODULE_LICENSE() tags from SPDX license tags
 
 In so far as a) is concerned, although module license tags are a no-op
 for non-modules, tools which would want create a mapping of possible
 modules can only rely on the module license tag after the commit
 8b41fc4454 ("kbuild: create modules.builtin without Makefile.modbuiltin
 or tristate.conf").  Nick has been working on this *for years* and
 AFAICT I was the only one to suggest two alternatives to this approach
 for tooling. The complexity in one of my suggested approaches lies in
 that we'd need a possible-obj-m and a could-be-module which would check
 if the object being built is part of any kconfig build which could ever
 lead to it being part of a module, and if so define a new define
 -DPOSSIBLE_MODULE [0]. A more obvious yet theoretical approach I've
 suggested would be to have a tristate in kconfig imply the same new
 -DPOSSIBLE_MODULE as well but that means getting kconfig symbol names
 mapping to modules always, and I don't think that's the case today. I am
 not aware of Nick or anyone exploring either of these options. Quite
 recently Josh Poimboeuf has pointed out that live patching, kprobes and
 BPF would benefit from resolving some part of the disambiguation as
 well but for other reasons. The function granularity KASLR (fgkaslr)
 patches were mentioned but Joe Lawrence has clarified this effort has
 been dropped with no clear solution in sight [1].
 
 In the meantime removing module license tags from code which could never
 be modules is welcomed for both objectives mentioned above. Some
 developers have also welcomed these changes as it has helped clarify
 when a module was never possible and they forgot to clean this up,
 and so you'll see quite a bit of Nick's patches in other pull
 requests for this merge window. I just picked up the stragglers after
 rc3. LWN has good coverage on the motivation behind this work [2] and
 the typical cross-tree issues he ran into along the way. The only
 concrete blocker issue he ran into was that we should not remove the
 MODULE_LICENSE() tags from files which have no SPDX tags yet, even if
 they can never be modules. Nick ended up giving up on his efforts due
 to having to do this vetting and backlash he ran into from folks who
 really did *not understand* the core of the issue nor were providing
 any alternative / guidance. I've gone through his changes and dropped
 the patches which dropped the module license tags where an SPDX
 license tag was missing, it only consisted of 11 drivers.  To see
 if a pull request deals with a file which lacks SPDX tags you
 can just use:
 
   ./scripts/spdxcheck.py -f \
 	$(git diff --name-only commid-id | xargs echo)
 
 You'll see a core module file in this pull request for the above,
 but that's not related to his changes. WE just need to add the SPDX
 license tag for the kernel/module/kmod.c file in the future but
 it demonstrates the effectiveness of the script.
 
 Most of Nick's changes were spread out through different trees,
 and I just picked up the slack after rc3 for the last kernel was out.
 Those changes have been in linux-next for over two weeks.
 
 The cleanups, debug code I added and final fix I added for modules
 were motivated by David Hildenbrand's report of boot failing on
 a systems with over 400 CPUs when KASAN was enabled due to running
 out of virtual memory space. Although the functional change only
 consists of 3 lines in the patch "module: avoid allocation if module is
 already present and ready", proving that this was the best we can
 do on the modules side took quite a bit of effort and new debug code.
 
 The initial cleanups I did on the modules side of things has been
 in linux-next since around rc3 of the last kernel, the actual final
 fix for and debug code however have only been in linux-next for about a
 week or so but I think it is worth getting that code in for this merge
 window as it does help fix / prove / evaluate the issues reported
 with larger number of CPUs. Userspace is not yet fixed as it is taking
 a bit of time for folks to understand the crux of the issue and find a
 proper resolution. Worst come to worst, I have a kludge-of-concept [3]
 of how to make kernel_read*() calls for modules unique / converge them,
 but I'm currently inclined to just see if userspace can fix this
 instead.
 
 [0] https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/
 [1] https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com
 [2] https://lwn.net/Articles/927569/
 [3] https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org
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Merge tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull module updates from Luis Chamberlain:
 "The summary of the changes for this pull requests is:

   - Song Liu's new struct module_memory replacement

   - Nick Alcock's MODULE_LICENSE() removal for non-modules

   - My cleanups and enhancements to reduce the areas where we vmalloc
     module memory for duplicates, and the respective debug code which
     proves the remaining vmalloc pressure comes from userspace.

  Most of the changes have been in linux-next for quite some time except
  the minor fixes I made to check if a module was already loaded prior
  to allocating the final module memory with vmalloc and the respective
  debug code it introduces to help clarify the issue. Although the
  functional change is small it is rather safe as it can only *help*
  reduce vmalloc space for duplicates and is confirmed to fix a bootup
  issue with over 400 CPUs with KASAN enabled. I don't expect stable
  kernels to pick up that fix as the cleanups would have also had to
  have been picked up. Folks on larger CPU systems with modules will
  want to just upgrade if vmalloc space has been an issue on bootup.

  Given the size of this request, here's some more elaborate details:

  The functional change change in this pull request is the very first
  patch from Song Liu which replaces the 'struct module_layout' with a
  new 'struct module_memory'. The old data structure tried to put
  together all types of supported module memory types in one data
  structure, the new one abstracts the differences in memory types in a
  module to allow each one to provide their own set of details. This
  paves the way in the future so we can deal with them in a cleaner way.
  If you look at changes they also provide a nice cleanup of how we
  handle these different memory areas in a module. This change has been
  in linux-next since before the merge window opened for v6.3 so to
  provide more than a full kernel cycle of testing. It's a good thing as
  quite a bit of fixes have been found for it.

  Jason Baron then made dynamic debug a first class citizen module user
  by using module notifier callbacks to allocate / remove module
  specific dynamic debug information.

  Nick Alcock has done quite a bit of work cross-tree to remove module
  license tags from things which cannot possibly be module at my request
  so to:

   a) help him with his longer term tooling goals which require a
      deterministic evaluation if a piece a symbol code could ever be
      part of a module or not. But quite recently it is has been made
      clear that tooling is not the only one that would benefit.
      Disambiguating symbols also helps efforts such as live patching,
      kprobes and BPF, but for other reasons and R&D on this area is
      active with no clear solution in sight.

   b) help us inch closer to the now generally accepted long term goal
      of automating all the MODULE_LICENSE() tags from SPDX license tags

  In so far as a) is concerned, although module license tags are a no-op
  for non-modules, tools which would want create a mapping of possible
  modules can only rely on the module license tag after the commit
  8b41fc4454 ("kbuild: create modules.builtin without
  Makefile.modbuiltin or tristate.conf").

  Nick has been working on this *for years* and AFAICT I was the only
  one to suggest two alternatives to this approach for tooling. The
  complexity in one of my suggested approaches lies in that we'd need a
  possible-obj-m and a could-be-module which would check if the object
  being built is part of any kconfig build which could ever lead to it
  being part of a module, and if so define a new define
  -DPOSSIBLE_MODULE [0].

  A more obvious yet theoretical approach I've suggested would be to
  have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
  well but that means getting kconfig symbol names mapping to modules
  always, and I don't think that's the case today. I am not aware of
  Nick or anyone exploring either of these options. Quite recently Josh
  Poimboeuf has pointed out that live patching, kprobes and BPF would
  benefit from resolving some part of the disambiguation as well but for
  other reasons. The function granularity KASLR (fgkaslr) patches were
  mentioned but Joe Lawrence has clarified this effort has been dropped
  with no clear solution in sight [1].

  In the meantime removing module license tags from code which could
  never be modules is welcomed for both objectives mentioned above. Some
  developers have also welcomed these changes as it has helped clarify
  when a module was never possible and they forgot to clean this up, and
  so you'll see quite a bit of Nick's patches in other pull requests for
  this merge window. I just picked up the stragglers after rc3. LWN has
  good coverage on the motivation behind this work [2] and the typical
  cross-tree issues he ran into along the way. The only concrete blocker
  issue he ran into was that we should not remove the MODULE_LICENSE()
  tags from files which have no SPDX tags yet, even if they can never be
  modules. Nick ended up giving up on his efforts due to having to do
  this vetting and backlash he ran into from folks who really did *not
  understand* the core of the issue nor were providing any alternative /
  guidance. I've gone through his changes and dropped the patches which
  dropped the module license tags where an SPDX license tag was missing,
  it only consisted of 11 drivers. To see if a pull request deals with a
  file which lacks SPDX tags you can just use:

    ./scripts/spdxcheck.py -f \
	$(git diff --name-only commid-id | xargs echo)

  You'll see a core module file in this pull request for the above, but
  that's not related to his changes. WE just need to add the SPDX
  license tag for the kernel/module/kmod.c file in the future but it
  demonstrates the effectiveness of the script.

  Most of Nick's changes were spread out through different trees, and I
  just picked up the slack after rc3 for the last kernel was out. Those
  changes have been in linux-next for over two weeks.

  The cleanups, debug code I added and final fix I added for modules
  were motivated by David Hildenbrand's report of boot failing on a
  systems with over 400 CPUs when KASAN was enabled due to running out
  of virtual memory space. Although the functional change only consists
  of 3 lines in the patch "module: avoid allocation if module is already
  present and ready", proving that this was the best we can do on the
  modules side took quite a bit of effort and new debug code.

  The initial cleanups I did on the modules side of things has been in
  linux-next since around rc3 of the last kernel, the actual final fix
  for and debug code however have only been in linux-next for about a
  week or so but I think it is worth getting that code in for this merge
  window as it does help fix / prove / evaluate the issues reported with
  larger number of CPUs. Userspace is not yet fixed as it is taking a
  bit of time for folks to understand the crux of the issue and find a
  proper resolution. Worst come to worst, I have a kludge-of-concept [3]
  of how to make kernel_read*() calls for modules unique / converge
  them, but I'm currently inclined to just see if userspace can fix this
  instead"

Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]

* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
  module: add debugging auto-load duplicate module support
  module: stats: fix invalid_mod_bytes typo
  module: remove use of uninitialized variable len
  module: fix building stats for 32-bit targets
  module: stats: include uapi/linux/module.h
  module: avoid allocation if module is already present and ready
  module: add debug stats to help identify memory pressure
  module: extract patient module check into helper
  modules/kmod: replace implementation with a semaphore
  Change DEFINE_SEMAPHORE() to take a number argument
  module: fix kmemleak annotations for non init ELF sections
  module: Ignore L0 and rename is_arm_mapping_symbol()
  module: Move is_arm_mapping_symbol() to module_symbol.h
  module: Sync code of is_arm_mapping_symbol()
  scripts/gdb: use mem instead of core_layout to get the module address
  interconnect: remove module-related code
  interconnect: remove MODULE_LICENSE in non-modules
  zswap: remove MODULE_LICENSE in non-modules
  zpool: remove MODULE_LICENSE in non-modules
  x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
  ...
2023-04-27 16:36:55 -07:00

898 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Device driver for the Apple Desktop Bus
* and the /dev/adb device on macintoshes.
*
* Copyright (C) 1996 Paul Mackerras.
*
* Modified to declare controllers as structures, added
* client notification of bus reset and handles PowerBook
* sleep, by Benjamin Herrenschmidt.
*
* To do:
*
* - /sys/bus/adb to list the devices and infos
* - more /dev/adb to allow userland to receive the
* flow of auto-polling datas from a given device.
* - move bus probe to a kernel thread
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/pmu.h>
#include <linux/notifier.h>
#include <linux/wait.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/kthread.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/uaccess.h>
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif
EXPORT_SYMBOL(adb_client_list);
extern struct adb_driver via_macii_driver;
extern struct adb_driver via_cuda_driver;
extern struct adb_driver adb_iop_driver;
extern struct adb_driver via_pmu_driver;
extern struct adb_driver macio_adb_driver;
static DEFINE_MUTEX(adb_mutex);
static struct adb_driver *adb_driver_list[] = {
#ifdef CONFIG_ADB_MACII
&via_macii_driver,
#endif
#ifdef CONFIG_ADB_CUDA
&via_cuda_driver,
#endif
#ifdef CONFIG_ADB_IOP
&adb_iop_driver,
#endif
#ifdef CONFIG_ADB_PMU
&via_pmu_driver,
#endif
#ifdef CONFIG_ADB_MACIO
&macio_adb_driver,
#endif
NULL
};
static struct class *adb_dev_class;
static struct adb_driver *adb_controller;
BLOCKING_NOTIFIER_HEAD(adb_client_list);
static int adb_got_sleep;
static int adb_inited;
static DEFINE_SEMAPHORE(adb_probe_mutex, 1);
static int sleepy_trackpad;
static int autopoll_devs;
int __adb_probe_sync;
static int adb_scan_bus(void);
static int do_adb_reset_bus(void);
static void adbdev_init(void);
static int try_handler_change(int, int);
static struct adb_handler {
void (*handler)(unsigned char *, int, int);
int original_address;
int handler_id;
int busy;
} adb_handler[16];
/*
* The adb_handler_mutex mutex protects all accesses to the original_address
* and handler_id fields of adb_handler[i] for all i, and changes to the
* handler field.
* Accesses to the handler field are protected by the adb_handler_lock
* rwlock. It is held across all calls to any handler, so that by the
* time adb_unregister returns, we know that the old handler isn't being
* called.
*/
static DEFINE_MUTEX(adb_handler_mutex);
static DEFINE_RWLOCK(adb_handler_lock);
#if 0
static void printADBreply(struct adb_request *req)
{
int i;
printk("adb reply (%d)", req->reply_len);
for(i = 0; i < req->reply_len; i++)
printk(" %x", req->reply[i]);
printk("\n");
}
#endif
static int adb_scan_bus(void)
{
int i, highFree=0, noMovement;
int devmask = 0;
struct adb_request req;
/* assumes adb_handler[] is all zeroes at this point */
for (i = 1; i < 16; i++) {
/* see if there is anything at address i */
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
(i << 4) | 0xf);
if (req.reply_len > 1)
/* one or more devices at this address */
adb_handler[i].original_address = i;
else if (i > highFree)
highFree = i;
}
/* Note we reset noMovement to 0 each time we move a device */
for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
for (i = 1; i < 16; i++) {
if (adb_handler[i].original_address == 0)
continue;
/*
* Send a "talk register 3" command to address i
* to provoke a collision if there is more than
* one device at this address.
*/
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
(i << 4) | 0xf);
/*
* Move the device(s) which didn't detect a
* collision to address `highFree'. Hopefully
* this only moves one device.
*/
adb_request(&req, NULL, ADBREQ_SYNC, 3,
(i<< 4) | 0xb, (highFree | 0x60), 0xfe);
/*
* See if anybody actually moved. This is suggested
* by HW TechNote 01:
*
* https://developer.apple.com/technotes/hw/hw_01.html
*/
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
(highFree << 4) | 0xf);
if (req.reply_len <= 1) continue;
/*
* Test whether there are any device(s) left
* at address i.
*/
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
(i << 4) | 0xf);
if (req.reply_len > 1) {
/*
* There are still one or more devices
* left at address i. Register the one(s)
* we moved to `highFree', and find a new
* value for highFree.
*/
adb_handler[highFree].original_address =
adb_handler[i].original_address;
while (highFree > 0 &&
adb_handler[highFree].original_address)
highFree--;
if (highFree <= 0)
break;
noMovement = 0;
} else {
/*
* No devices left at address i; move the
* one(s) we moved to `highFree' back to i.
*/
adb_request(&req, NULL, ADBREQ_SYNC, 3,
(highFree << 4) | 0xb,
(i | 0x60), 0xfe);
}
}
}
/* Now fill in the handler_id field of the adb_handler entries. */
for (i = 1; i < 16; i++) {
if (adb_handler[i].original_address == 0)
continue;
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
(i << 4) | 0xf);
adb_handler[i].handler_id = req.reply[2];
printk(KERN_DEBUG "adb device [%d]: %d 0x%X\n", i,
adb_handler[i].original_address,
adb_handler[i].handler_id);
devmask |= 1 << i;
}
return devmask;
}
/*
* This kernel task handles ADB probing. It dies once probing is
* completed.
*/
static int
adb_probe_task(void *x)
{
pr_debug("adb: starting probe task...\n");
do_adb_reset_bus();
pr_debug("adb: finished probe task...\n");
up(&adb_probe_mutex);
return 0;
}
static void
__adb_probe_task(struct work_struct *bullshit)
{
kthread_run(adb_probe_task, NULL, "kadbprobe");
}
static DECLARE_WORK(adb_reset_work, __adb_probe_task);
int
adb_reset_bus(void)
{
if (__adb_probe_sync) {
do_adb_reset_bus();
return 0;
}
down(&adb_probe_mutex);
schedule_work(&adb_reset_work);
return 0;
}
#ifdef CONFIG_PM
/*
* notify clients before sleep
*/
static int __adb_suspend(struct platform_device *dev, pm_message_t state)
{
adb_got_sleep = 1;
/* We need to get a lock on the probe thread */
down(&adb_probe_mutex);
/* Stop autopoll */
if (adb_controller->autopoll)
adb_controller->autopoll(0);
blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
return 0;
}
static int adb_suspend(struct device *dev)
{
return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
}
static int adb_freeze(struct device *dev)
{
return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
}
static int adb_poweroff(struct device *dev)
{
return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
}
/*
* reset bus after sleep
*/
static int __adb_resume(struct platform_device *dev)
{
adb_got_sleep = 0;
up(&adb_probe_mutex);
adb_reset_bus();
return 0;
}
static int adb_resume(struct device *dev)
{
return __adb_resume(to_platform_device(dev));
}
#endif /* CONFIG_PM */
static int __init adb_init(void)
{
struct adb_driver *driver;
int i;
#ifdef CONFIG_PPC32
if (!machine_is(chrp) && !machine_is(powermac))
return 0;
#endif
#ifdef CONFIG_MAC
if (!MACH_IS_MAC)
return 0;
#endif
/* xmon may do early-init */
if (adb_inited)
return 0;
adb_inited = 1;
adb_controller = NULL;
i = 0;
while ((driver = adb_driver_list[i++]) != NULL) {
if (!driver->probe()) {
adb_controller = driver;
break;
}
}
if (adb_controller != NULL && adb_controller->init &&
adb_controller->init())
adb_controller = NULL;
if (adb_controller == NULL) {
pr_warn("Warning: no ADB interface detected\n");
} else {
#ifdef CONFIG_PPC
if (of_machine_is_compatible("AAPL,PowerBook1998") ||
of_machine_is_compatible("PowerBook1,1"))
sleepy_trackpad = 1;
#endif /* CONFIG_PPC */
adbdev_init();
adb_reset_bus();
}
return 0;
}
device_initcall(adb_init);
static int
do_adb_reset_bus(void)
{
int ret;
if (adb_controller == NULL)
return -ENXIO;
if (adb_controller->autopoll)
adb_controller->autopoll(0);
blocking_notifier_call_chain(&adb_client_list,
ADB_MSG_PRE_RESET, NULL);
if (sleepy_trackpad) {
/* Let the trackpad settle down */
msleep(500);
}
mutex_lock(&adb_handler_mutex);
write_lock_irq(&adb_handler_lock);
memset(adb_handler, 0, sizeof(adb_handler));
write_unlock_irq(&adb_handler_lock);
/* That one is still a bit synchronous, oh well... */
if (adb_controller->reset_bus)
ret = adb_controller->reset_bus();
else
ret = 0;
if (sleepy_trackpad) {
/* Let the trackpad settle down */
msleep(1500);
}
if (!ret) {
autopoll_devs = adb_scan_bus();
if (adb_controller->autopoll)
adb_controller->autopoll(autopoll_devs);
}
mutex_unlock(&adb_handler_mutex);
blocking_notifier_call_chain(&adb_client_list,
ADB_MSG_POST_RESET, NULL);
return ret;
}
void
adb_poll(void)
{
if ((adb_controller == NULL)||(adb_controller->poll == NULL))
return;
adb_controller->poll();
}
EXPORT_SYMBOL(adb_poll);
static void adb_sync_req_done(struct adb_request *req)
{
struct completion *comp = req->arg;
complete(comp);
}
int
adb_request(struct adb_request *req, void (*done)(struct adb_request *),
int flags, int nbytes, ...)
{
va_list list;
int i;
int rc;
struct completion comp;
if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
return -ENXIO;
if (nbytes < 1)
return -EINVAL;
req->nbytes = nbytes+1;
req->done = done;
req->reply_expected = flags & ADBREQ_REPLY;
req->data[0] = ADB_PACKET;
va_start(list, nbytes);
for (i = 0; i < nbytes; ++i)
req->data[i+1] = va_arg(list, int);
va_end(list);
if (flags & ADBREQ_NOSEND)
return 0;
/* Synchronous requests block using an on-stack completion */
if (flags & ADBREQ_SYNC) {
WARN_ON(done);
req->done = adb_sync_req_done;
req->arg = &comp;
init_completion(&comp);
}
rc = adb_controller->send_request(req, 0);
if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
wait_for_completion(&comp);
return rc;
}
EXPORT_SYMBOL(adb_request);
/* Ultimately this should return the number of devices with
the given default id.
And it does it now ! Note: changed behaviour: This function
will now register if default_id _and_ handler_id both match
but handler_id can be left to 0 to match with default_id only.
When handler_id is set, this function will try to adjust
the handler_id id it doesn't match. */
int
adb_register(int default_id, int handler_id, struct adb_ids *ids,
void (*handler)(unsigned char *, int, int))
{
int i;
mutex_lock(&adb_handler_mutex);
ids->nids = 0;
for (i = 1; i < 16; i++) {
if ((adb_handler[i].original_address == default_id) &&
(!handler_id || (handler_id == adb_handler[i].handler_id) ||
try_handler_change(i, handler_id))) {
if (adb_handler[i].handler) {
pr_err("Two handlers for ADB device %d\n",
default_id);
continue;
}
write_lock_irq(&adb_handler_lock);
adb_handler[i].handler = handler;
write_unlock_irq(&adb_handler_lock);
ids->id[ids->nids++] = i;
}
}
mutex_unlock(&adb_handler_mutex);
return ids->nids;
}
EXPORT_SYMBOL(adb_register);
int
adb_unregister(int index)
{
int ret = -ENODEV;
mutex_lock(&adb_handler_mutex);
write_lock_irq(&adb_handler_lock);
if (adb_handler[index].handler) {
while(adb_handler[index].busy) {
write_unlock_irq(&adb_handler_lock);
yield();
write_lock_irq(&adb_handler_lock);
}
ret = 0;
adb_handler[index].handler = NULL;
}
write_unlock_irq(&adb_handler_lock);
mutex_unlock(&adb_handler_mutex);
return ret;
}
EXPORT_SYMBOL(adb_unregister);
void
adb_input(unsigned char *buf, int nb, int autopoll)
{
int i, id;
static int dump_adb_input;
unsigned long flags;
void (*handler)(unsigned char *, int, int);
/* We skip keystrokes and mouse moves when the sleep process
* has been started. We stop autopoll, but this is another security
*/
if (adb_got_sleep)
return;
id = buf[0] >> 4;
if (dump_adb_input) {
pr_info("adb packet: ");
for (i = 0; i < nb; ++i)
pr_cont(" %x", buf[i]);
pr_cont(", id = %d\n", id);
}
write_lock_irqsave(&adb_handler_lock, flags);
handler = adb_handler[id].handler;
if (handler != NULL)
adb_handler[id].busy = 1;
write_unlock_irqrestore(&adb_handler_lock, flags);
if (handler != NULL) {
(*handler)(buf, nb, autopoll);
wmb();
adb_handler[id].busy = 0;
}
}
/* Try to change handler to new_id. Will return 1 if successful. */
static int try_handler_change(int address, int new_id)
{
struct adb_request req;
if (adb_handler[address].handler_id == new_id)
return 1;
adb_request(&req, NULL, ADBREQ_SYNC, 3,
ADB_WRITEREG(address, 3), address | 0x20, new_id);
adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
ADB_READREG(address, 3));
if (req.reply_len < 2)
return 0;
if (req.reply[2] != new_id)
return 0;
adb_handler[address].handler_id = req.reply[2];
return 1;
}
int
adb_try_handler_change(int address, int new_id)
{
int ret;
mutex_lock(&adb_handler_mutex);
ret = try_handler_change(address, new_id);
mutex_unlock(&adb_handler_mutex);
if (ret)
pr_debug("adb handler change: [%d] 0x%X\n", address, new_id);
return ret;
}
EXPORT_SYMBOL(adb_try_handler_change);
int
adb_get_infos(int address, int *original_address, int *handler_id)
{
mutex_lock(&adb_handler_mutex);
*original_address = adb_handler[address].original_address;
*handler_id = adb_handler[address].handler_id;
mutex_unlock(&adb_handler_mutex);
return (*original_address != 0);
}
/*
* /dev/adb device driver.
*/
#define ADB_MAJOR 56 /* major number for /dev/adb */
struct adbdev_state {
spinlock_t lock;
atomic_t n_pending;
struct adb_request *completed;
wait_queue_head_t wait_queue;
int inuse;
};
static void adb_write_done(struct adb_request *req)
{
struct adbdev_state *state = (struct adbdev_state *) req->arg;
unsigned long flags;
if (!req->complete) {
req->reply_len = 0;
req->complete = 1;
}
spin_lock_irqsave(&state->lock, flags);
atomic_dec(&state->n_pending);
if (!state->inuse) {
kfree(req);
if (atomic_read(&state->n_pending) == 0) {
spin_unlock_irqrestore(&state->lock, flags);
kfree(state);
return;
}
} else {
struct adb_request **ap = &state->completed;
while (*ap != NULL)
ap = &(*ap)->next;
req->next = NULL;
*ap = req;
wake_up_interruptible(&state->wait_queue);
}
spin_unlock_irqrestore(&state->lock, flags);
}
static int
do_adb_query(struct adb_request *req)
{
int ret = -EINVAL;
switch(req->data[1]) {
case ADB_QUERY_GETDEVINFO:
if (req->nbytes < 3 || req->data[2] >= 16)
break;
mutex_lock(&adb_handler_mutex);
req->reply[0] = adb_handler[req->data[2]].original_address;
req->reply[1] = adb_handler[req->data[2]].handler_id;
mutex_unlock(&adb_handler_mutex);
req->complete = 1;
req->reply_len = 2;
adb_write_done(req);
ret = 0;
break;
}
return ret;
}
static int adb_open(struct inode *inode, struct file *file)
{
struct adbdev_state *state;
int ret = 0;
mutex_lock(&adb_mutex);
if (iminor(inode) > 0 || adb_controller == NULL) {
ret = -ENXIO;
goto out;
}
state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
if (!state) {
ret = -ENOMEM;
goto out;
}
file->private_data = state;
spin_lock_init(&state->lock);
atomic_set(&state->n_pending, 0);
state->completed = NULL;
init_waitqueue_head(&state->wait_queue);
state->inuse = 1;
out:
mutex_unlock(&adb_mutex);
return ret;
}
static int adb_release(struct inode *inode, struct file *file)
{
struct adbdev_state *state = file->private_data;
unsigned long flags;
mutex_lock(&adb_mutex);
if (state) {
file->private_data = NULL;
spin_lock_irqsave(&state->lock, flags);
if (atomic_read(&state->n_pending) == 0
&& state->completed == NULL) {
spin_unlock_irqrestore(&state->lock, flags);
kfree(state);
} else {
state->inuse = 0;
spin_unlock_irqrestore(&state->lock, flags);
}
}
mutex_unlock(&adb_mutex);
return 0;
}
static ssize_t adb_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
int ret = 0;
struct adbdev_state *state = file->private_data;
struct adb_request *req;
DECLARE_WAITQUEUE(wait, current);
unsigned long flags;
if (count < 2)
return -EINVAL;
if (count > sizeof(req->reply))
count = sizeof(req->reply);
req = NULL;
spin_lock_irqsave(&state->lock, flags);
add_wait_queue(&state->wait_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
for (;;) {
req = state->completed;
if (req != NULL)
state->completed = req->next;
else if (atomic_read(&state->n_pending) == 0)
ret = -EIO;
if (req != NULL || ret != 0)
break;
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
spin_unlock_irqrestore(&state->lock, flags);
schedule();
spin_lock_irqsave(&state->lock, flags);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&state->wait_queue, &wait);
spin_unlock_irqrestore(&state->lock, flags);
if (ret)
return ret;
ret = req->reply_len;
if (ret > count)
ret = count;
if (ret > 0 && copy_to_user(buf, req->reply, ret))
ret = -EFAULT;
kfree(req);
return ret;
}
static ssize_t adb_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
int ret/*, i*/;
struct adbdev_state *state = file->private_data;
struct adb_request *req;
if (count < 2 || count > sizeof(req->data))
return -EINVAL;
if (adb_controller == NULL)
return -ENXIO;
req = kmalloc(sizeof(struct adb_request),
GFP_KERNEL);
if (req == NULL)
return -ENOMEM;
req->nbytes = count;
req->done = adb_write_done;
req->arg = (void *) state;
req->complete = 0;
ret = -EFAULT;
if (copy_from_user(req->data, buf, count))
goto out;
atomic_inc(&state->n_pending);
/* If a probe is in progress or we are sleeping, wait for it to complete */
down(&adb_probe_mutex);
/* Queries are special requests sent to the ADB driver itself */
if (req->data[0] == ADB_QUERY) {
if (count > 1)
ret = do_adb_query(req);
else
ret = -EINVAL;
up(&adb_probe_mutex);
}
/* Special case for ADB_BUSRESET request, all others are sent to
the controller */
else if ((req->data[0] == ADB_PACKET) && (count > 1)
&& (req->data[1] == ADB_BUSRESET)) {
ret = do_adb_reset_bus();
up(&adb_probe_mutex);
atomic_dec(&state->n_pending);
if (ret == 0)
ret = count;
goto out;
} else {
req->reply_expected = ((req->data[1] & 0xc) == 0xc);
if (adb_controller && adb_controller->send_request)
ret = adb_controller->send_request(req, 0);
else
ret = -ENXIO;
up(&adb_probe_mutex);
}
if (ret != 0) {
atomic_dec(&state->n_pending);
goto out;
}
return count;
out:
kfree(req);
return ret;
}
static const struct file_operations adb_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = adb_read,
.write = adb_write,
.open = adb_open,
.release = adb_release,
};
#ifdef CONFIG_PM
static const struct dev_pm_ops adb_dev_pm_ops = {
.suspend = adb_suspend,
.resume = adb_resume,
/* Hibernate hooks */
.freeze = adb_freeze,
.thaw = adb_resume,
.poweroff = adb_poweroff,
.restore = adb_resume,
};
#endif
static struct platform_driver adb_pfdrv = {
.driver = {
.name = "adb",
#ifdef CONFIG_PM
.pm = &adb_dev_pm_ops,
#endif
},
};
static struct platform_device adb_pfdev = {
.name = "adb",
};
static int __init
adb_dummy_probe(struct platform_device *dev)
{
if (dev == &adb_pfdev)
return 0;
return -ENODEV;
}
static void __init
adbdev_init(void)
{
if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
pr_err("adb: unable to get major %d\n", ADB_MAJOR);
return;
}
adb_dev_class = class_create("adb");
if (IS_ERR(adb_dev_class))
return;
device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
platform_device_register(&adb_pfdev);
platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
}