Commit 6f246714 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 platform update from Ingo Molnar:
 "The biggest change is the rework of the intel/iosf_mbi locking code
  which used a few non-standard locking patterns, to make it work under
  lockdep"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/uv: Fix kmalloc() NULL check routine
  x86/platform/intel/iosf_mbi Rewrite locking
parents ac51667b 864b23f0
......@@ -17,6 +17,7 @@
#include <linux/debugfs.h>
#include <linux/capability.h>
#include <linux/pm_qos.h>
#include <linux/wait.h>
#include <asm/iosf_mbi.h>
......@@ -201,23 +202,45 @@ EXPORT_SYMBOL(iosf_mbi_available);
#define PUNIT_SEMAPHORE_BIT BIT(0)
#define PUNIT_SEMAPHORE_ACQUIRE BIT(1)
static DEFINE_MUTEX(iosf_mbi_punit_mutex);
static DEFINE_MUTEX(iosf_mbi_block_punit_i2c_access_count_mutex);
static DEFINE_MUTEX(iosf_mbi_pmic_access_mutex);
static BLOCKING_NOTIFIER_HEAD(iosf_mbi_pmic_bus_access_notifier);
static u32 iosf_mbi_block_punit_i2c_access_count;
static DECLARE_WAIT_QUEUE_HEAD(iosf_mbi_pmic_access_waitq);
static u32 iosf_mbi_pmic_punit_access_count;
static u32 iosf_mbi_pmic_i2c_access_count;
static u32 iosf_mbi_sem_address;
static unsigned long iosf_mbi_sem_acquired;
static struct pm_qos_request iosf_mbi_pm_qos;
void iosf_mbi_punit_acquire(void)
{
mutex_lock(&iosf_mbi_punit_mutex);
/* Wait for any I2C PMIC accesses from in kernel drivers to finish. */
mutex_lock(&iosf_mbi_pmic_access_mutex);
while (iosf_mbi_pmic_i2c_access_count != 0) {
mutex_unlock(&iosf_mbi_pmic_access_mutex);
wait_event(iosf_mbi_pmic_access_waitq,
iosf_mbi_pmic_i2c_access_count == 0);
mutex_lock(&iosf_mbi_pmic_access_mutex);
}
/*
* We do not need to do anything to allow the PUNIT to safely access
* the PMIC, other then block in kernel accesses to the PMIC.
*/
iosf_mbi_pmic_punit_access_count++;
mutex_unlock(&iosf_mbi_pmic_access_mutex);
}
EXPORT_SYMBOL(iosf_mbi_punit_acquire);
void iosf_mbi_punit_release(void)
{
mutex_unlock(&iosf_mbi_punit_mutex);
bool do_wakeup;
mutex_lock(&iosf_mbi_pmic_access_mutex);
iosf_mbi_pmic_punit_access_count--;
do_wakeup = iosf_mbi_pmic_punit_access_count == 0;
mutex_unlock(&iosf_mbi_pmic_access_mutex);
if (do_wakeup)
wake_up(&iosf_mbi_pmic_access_waitq);
}
EXPORT_SYMBOL(iosf_mbi_punit_release);
......@@ -256,34 +279,32 @@ static void iosf_mbi_reset_semaphore(void)
* already blocked P-Unit accesses because it wants them blocked over multiple
* i2c-transfers, for e.g. read-modify-write of an I2C client register.
*
* The P-Unit accesses already being blocked is tracked through the
* iosf_mbi_block_punit_i2c_access_count variable which is protected by the
* iosf_mbi_block_punit_i2c_access_count_mutex this mutex is hold for the
* entire duration of the function.
*
* If access is not blocked yet, this function takes the following steps:
* To allow safe PMIC i2c bus accesses this function takes the following steps:
*
* 1) Some code sends request to the P-Unit which make it access the PMIC
* I2C bus. Testing has shown that the P-Unit does not check its internal
* PMIC bus semaphore for these requests. Callers of these requests call
* iosf_mbi_punit_acquire()/_release() around their P-Unit accesses, these
* functions lock/unlock the iosf_mbi_punit_mutex.
* As the first step we lock the iosf_mbi_punit_mutex, to wait for any in
* flight requests to finish and to block any new requests.
* functions increase/decrease iosf_mbi_pmic_punit_access_count, so first
* we wait for iosf_mbi_pmic_punit_access_count to become 0.
*
* 2) Check iosf_mbi_pmic_i2c_access_count, if access has already
* been blocked by another caller, we only need to increment
* iosf_mbi_pmic_i2c_access_count and we can skip the other steps.
*
* 2) Some code makes such P-Unit requests from atomic contexts where it
* 3) Some code makes such P-Unit requests from atomic contexts where it
* cannot call iosf_mbi_punit_acquire() as that may sleep.
* As the second step we call a notifier chain which allows any code
* needing P-Unit resources from atomic context to acquire them before
* we take control over the PMIC I2C bus.
*
* 3) When CPU cores enter C6 or C7 the P-Unit needs to talk to the PMIC
* 4) When CPU cores enter C6 or C7 the P-Unit needs to talk to the PMIC
* if this happens while the kernel itself is accessing the PMIC I2C bus
* the SoC hangs.
* As the third step we call pm_qos_update_request() to disallow the CPU
* to enter C6 or C7.
*
* 4) The P-Unit has a PMIC bus semaphore which we can request to stop
* 5) The P-Unit has a PMIC bus semaphore which we can request to stop
* autonomous P-Unit tasks from accessing the PMIC I2C bus while we hold it.
* As the fourth and final step we request this semaphore and wait for our
* request to be acknowledged.
......@@ -297,12 +318,18 @@ int iosf_mbi_block_punit_i2c_access(void)
if (WARN_ON(!mbi_pdev || !iosf_mbi_sem_address))
return -ENXIO;
mutex_lock(&iosf_mbi_block_punit_i2c_access_count_mutex);
mutex_lock(&iosf_mbi_pmic_access_mutex);
if (iosf_mbi_block_punit_i2c_access_count > 0)
while (iosf_mbi_pmic_punit_access_count != 0) {
mutex_unlock(&iosf_mbi_pmic_access_mutex);
wait_event(iosf_mbi_pmic_access_waitq,
iosf_mbi_pmic_punit_access_count == 0);
mutex_lock(&iosf_mbi_pmic_access_mutex);
}
if (iosf_mbi_pmic_i2c_access_count > 0)
goto success;
mutex_lock(&iosf_mbi_punit_mutex);
blocking_notifier_call_chain(&iosf_mbi_pmic_bus_access_notifier,
MBI_PMIC_BUS_ACCESS_BEGIN, NULL);
......@@ -330,10 +357,6 @@ int iosf_mbi_block_punit_i2c_access(void)
iosf_mbi_sem_acquired = jiffies;
dev_dbg(&mbi_pdev->dev, "P-Unit semaphore acquired after %ums\n",
jiffies_to_msecs(jiffies - start));
/*
* Success, keep iosf_mbi_punit_mutex locked till
* iosf_mbi_unblock_punit_i2c_access() gets called.
*/
goto success;
}
......@@ -344,15 +367,13 @@ int iosf_mbi_block_punit_i2c_access(void)
dev_err(&mbi_pdev->dev, "Error P-Unit semaphore timed out, resetting\n");
error:
iosf_mbi_reset_semaphore();
mutex_unlock(&iosf_mbi_punit_mutex);
if (!iosf_mbi_get_sem(&sem))
dev_err(&mbi_pdev->dev, "P-Unit semaphore: %d\n", sem);
success:
if (!WARN_ON(ret))
iosf_mbi_block_punit_i2c_access_count++;
iosf_mbi_pmic_i2c_access_count++;
mutex_unlock(&iosf_mbi_block_punit_i2c_access_count_mutex);
mutex_unlock(&iosf_mbi_pmic_access_mutex);
return ret;
}
......@@ -360,17 +381,20 @@ EXPORT_SYMBOL(iosf_mbi_block_punit_i2c_access);
void iosf_mbi_unblock_punit_i2c_access(void)
{
mutex_lock(&iosf_mbi_block_punit_i2c_access_count_mutex);
bool do_wakeup = false;
iosf_mbi_block_punit_i2c_access_count--;
if (iosf_mbi_block_punit_i2c_access_count == 0) {
mutex_lock(&iosf_mbi_pmic_access_mutex);
iosf_mbi_pmic_i2c_access_count--;
if (iosf_mbi_pmic_i2c_access_count == 0) {
iosf_mbi_reset_semaphore();
mutex_unlock(&iosf_mbi_punit_mutex);
dev_dbg(&mbi_pdev->dev, "punit semaphore held for %ums\n",
jiffies_to_msecs(jiffies - iosf_mbi_sem_acquired));
do_wakeup = true;
}
mutex_unlock(&iosf_mbi_pmic_access_mutex);
mutex_unlock(&iosf_mbi_block_punit_i2c_access_count_mutex);
if (do_wakeup)
wake_up(&iosf_mbi_pmic_access_waitq);
}
EXPORT_SYMBOL(iosf_mbi_unblock_punit_i2c_access);
......@@ -379,10 +403,10 @@ int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
int ret;
/* Wait for the bus to go inactive before registering */
mutex_lock(&iosf_mbi_punit_mutex);
iosf_mbi_punit_acquire();
ret = blocking_notifier_chain_register(
&iosf_mbi_pmic_bus_access_notifier, nb);
mutex_unlock(&iosf_mbi_punit_mutex);
iosf_mbi_punit_release();
return ret;
}
......@@ -403,9 +427,9 @@ int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
int ret;
/* Wait for the bus to go inactive before unregistering */
mutex_lock(&iosf_mbi_punit_mutex);
iosf_mbi_punit_acquire();
ret = iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(nb);
mutex_unlock(&iosf_mbi_punit_mutex);
iosf_mbi_punit_release();
return ret;
}
......@@ -413,7 +437,7 @@ EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier);
void iosf_mbi_assert_punit_acquired(void)
{
WARN_ON(!mutex_is_locked(&iosf_mbi_punit_mutex));
WARN_ON(iosf_mbi_pmic_punit_access_count == 0);
}
EXPORT_SYMBOL(iosf_mbi_assert_punit_acquired);
......
......@@ -1804,9 +1804,9 @@ static void pq_init(int node, int pnode)
plsize = (DEST_Q_SIZE + 1) * sizeof(struct bau_pq_entry);
vp = kmalloc_node(plsize, GFP_KERNEL, node);
pqp = (struct bau_pq_entry *)vp;
BUG_ON(!pqp);
BUG_ON(!vp);
pqp = (struct bau_pq_entry *)vp;
cp = (char *)pqp + 31;
pqp = (struct bau_pq_entry *)(((unsigned long)cp >> 5) << 5);
......
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