Commit 78ff56a0 authored by Michael Buesch's avatar Michael Buesch Committed by John W. Linville

[PATCH] bcm43xx: redesign locking

Redesign the bcm43xx locking.
This is pre-work to get a preemptible periodic work handler.
Signed-off-by: default avatarMichael Buesch <mb@bu3sch.de>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 74f49033
......@@ -636,6 +636,17 @@ struct bcm43xx_key {
u8 algorithm;
};
/* Driver initialization status. */
enum {
BCM43xx_STAT_UNINIT, /* Uninitialized. */
BCM43xx_STAT_INITIALIZING, /* init_board() in progress. */
BCM43xx_STAT_INITIALIZED, /* Fully operational. */
BCM43xx_STAT_SHUTTINGDOWN, /* free_board() in progress. */
BCM43xx_STAT_RESTARTING, /* controller_restart() called. */
};
#define bcm43xx_status(bcm) atomic_read(&(bcm)->init_status)
#define bcm43xx_set_status(bcm, stat) atomic_set(&(bcm)->init_status, (stat))
struct bcm43xx_private {
struct ieee80211_device *ieee;
struct ieee80211softmac_device *softmac;
......@@ -646,18 +657,17 @@ struct bcm43xx_private {
void __iomem *mmio_addr;
/* Do not use the lock directly. Use the bcm43xx_lock* helper
* functions, to be MMIO-safe. */
spinlock_t _lock;
/* Locking, see "theory of locking" text below. */
spinlock_t irq_lock;
struct mutex mutex;
/* Driver status flags. */
u32 initialized:1, /* init_board() succeed */
was_initialized:1, /* for PCI suspend/resume. */
shutting_down:1, /* free_board() in progress */
/* Driver initialization status BCM43xx_STAT_*** */
atomic_t init_status;
u16 was_initialized:1, /* for PCI suspend/resume. */
__using_pio:1, /* Internal, use bcm43xx_using_pio(). */
bad_frames_preempt:1, /* Use "Bad Frames Preemption" (default off) */
reg124_set_0x4:1, /* Some variable to keep track of IRQ stuff. */
powersaving:1, /* TRUE if we are in PowerSaving mode. FALSE otherwise. */
short_preamble:1, /* TRUE, if short preamble is enabled. */
firmware_norelease:1; /* Do not release the firmware. Used on suspend. */
......@@ -721,7 +731,7 @@ struct bcm43xx_private {
struct tasklet_struct isr_tasklet;
/* Periodic tasks */
struct timer_list periodic_tasks;
struct work_struct periodic_work;
unsigned int periodic_state;
struct work_struct restart_work;
......@@ -746,21 +756,55 @@ struct bcm43xx_private {
#endif
};
/* bcm43xx_(un)lock() protect struct bcm43xx_private.
* Note that _NO_ MMIO writes are allowed. If you want to
* write to the device through MMIO in the critical section, use
* the *_mmio lock functions.
* MMIO read-access is allowed, though.
*/
#define bcm43xx_lock(bcm, flags) spin_lock_irqsave(&(bcm)->_lock, flags)
#define bcm43xx_unlock(bcm, flags) spin_unlock_irqrestore(&(bcm)->_lock, flags)
/* bcm43xx_(un)lock_mmio() protect struct bcm43xx_private and MMIO.
* MMIO write-access to the device is allowed.
* All MMIO writes are flushed on unlock, so it is guaranteed to not
* interfere with other threads writing MMIO registers.
/* *** THEORY OF LOCKING ***
*
* We have two different locks in the bcm43xx driver.
* => bcm->mutex: General sleeping mutex. Protects struct bcm43xx_private
* and the device registers.
* => bcm->irq_lock: IRQ spinlock. Protects against IRQ handler concurrency.
*
* We have three types of helper function pairs to utilize these locks.
* (Always use the helper functions.)
* 1) bcm43xx_{un}lock_noirq():
* Takes bcm->mutex. Does _not_ protect against IRQ concurrency,
* so it is almost always unsafe, if device IRQs are enabled.
* So only use this, if device IRQs are masked.
* Locking may sleep.
* You can sleep within the critical section.
* 2) bcm43xx_{un}lock_irqonly():
* Takes bcm->irq_lock. Does _not_ protect against
* bcm43xx_lock_noirq() critical sections.
* Does only protect against the IRQ handler path and other
* irqonly() critical sections.
* Locking does not sleep.
* You must not sleep within the critical section.
* 3) bcm43xx_{un}lock_irqsafe():
* This is the cummulative lock and takes both, mutex and irq_lock.
* Protects against noirq() and irqonly() critical sections (and
* the IRQ handler path).
* Locking may sleep.
* You must not sleep within the critical section.
*/
#define bcm43xx_lock_mmio(bcm, flags) bcm43xx_lock(bcm, flags)
#define bcm43xx_unlock_mmio(bcm, flags) do { mmiowb(); bcm43xx_unlock(bcm, flags); } while (0)
/* Lock type 1 */
#define bcm43xx_lock_noirq(bcm) mutex_lock(&(bcm)->mutex)
#define bcm43xx_unlock_noirq(bcm) mutex_unlock(&(bcm)->mutex)
/* Lock type 2 */
#define bcm43xx_lock_irqonly(bcm, flags) \
spin_lock_irqsave(&(bcm)->irq_lock, flags)
#define bcm43xx_unlock_irqonly(bcm, flags) \
spin_unlock_irqrestore(&(bcm)->irq_lock, flags)
/* Lock type 3 */
#define bcm43xx_lock_irqsafe(bcm, flags) do { \
bcm43xx_lock_noirq(bcm); \
bcm43xx_lock_irqonly(bcm, flags); \
} while (0)
#define bcm43xx_unlock_irqsafe(bcm, flags) do { \
bcm43xx_unlock_irqonly(bcm, flags); \
bcm43xx_unlock_noirq(bcm); \
} while (0)
static inline
struct bcm43xx_private * bcm43xx_priv(struct net_device *dev)
......@@ -843,16 +887,6 @@ struct bcm43xx_radioinfo * bcm43xx_current_radio(struct bcm43xx_private *bcm)
return &(bcm->core_80211_ext[bcm->current_80211_core_idx].radio);
}
/* Are we running in init_board() context? */
static inline
int bcm43xx_is_initializing(struct bcm43xx_private *bcm)
{
if (bcm->initialized)
return 0;
if (bcm->shutting_down)
return 0;
return 1;
}
static inline
struct bcm43xx_lopair * bcm43xx_get_lopair(struct bcm43xx_phyinfo *phy,
......
......@@ -77,8 +77,8 @@ static ssize_t devinfo_read_file(struct file *file, char __user *userbuf,
down(&big_buffer_sem);
bcm43xx_lock_mmio(bcm, flags);
if (!bcm->initialized) {
bcm43xx_lock_irqsafe(bcm, flags);
if (bcm43xx_status(bcm) != BCM43xx_STAT_INITIALIZED) {
fappend("Board not initialized.\n");
goto out;
}
......@@ -121,7 +121,7 @@ static ssize_t devinfo_read_file(struct file *file, char __user *userbuf,
fappend("\n");
out:
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
up(&big_buffer_sem);
return res;
......@@ -159,8 +159,8 @@ static ssize_t spromdump_read_file(struct file *file, char __user *userbuf,
unsigned long flags;
down(&big_buffer_sem);
bcm43xx_lock_mmio(bcm, flags);
if (!bcm->initialized) {
bcm43xx_lock_irqsafe(bcm, flags);
if (bcm43xx_status(bcm) != BCM43xx_STAT_INITIALIZED) {
fappend("Board not initialized.\n");
goto out;
}
......@@ -169,7 +169,7 @@ static ssize_t spromdump_read_file(struct file *file, char __user *userbuf,
fappend("boardflags: 0x%04x\n", bcm->sprom.boardflags);
out:
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
up(&big_buffer_sem);
return res;
......@@ -188,8 +188,8 @@ static ssize_t tsf_read_file(struct file *file, char __user *userbuf,
u64 tsf;
down(&big_buffer_sem);
bcm43xx_lock_mmio(bcm, flags);
if (!bcm->initialized) {
bcm43xx_lock_irqsafe(bcm, flags);
if (bcm43xx_status(bcm) != BCM43xx_STAT_INITIALIZED) {
fappend("Board not initialized.\n");
goto out;
}
......@@ -199,7 +199,7 @@ static ssize_t tsf_read_file(struct file *file, char __user *userbuf,
(unsigned int)(tsf & 0xFFFFFFFFULL));
out:
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
up(&big_buffer_sem);
return res;
......@@ -221,8 +221,8 @@ static ssize_t tsf_write_file(struct file *file, const char __user *user_buf,
res = -EFAULT;
goto out_up;
}
bcm43xx_lock_mmio(bcm, flags);
if (!bcm->initialized) {
bcm43xx_lock_irqsafe(bcm, flags);
if (bcm43xx_status(bcm) != BCM43xx_STAT_INITIALIZED) {
printk(KERN_INFO PFX "debugfs: Board not initialized.\n");
res = -EFAULT;
goto out_unlock;
......@@ -233,10 +233,11 @@ static ssize_t tsf_write_file(struct file *file, const char __user *user_buf,
goto out_unlock;
}
bcm43xx_tsf_write(bcm, tsf);
mmiowb();
res = buf_size;
out_unlock:
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
out_up:
up(&big_buffer_sem);
return res;
......@@ -257,7 +258,7 @@ static ssize_t txstat_read_file(struct file *file, char __user *userbuf,
int i, cnt, j = 0;
down(&big_buffer_sem);
bcm43xx_lock(bcm, flags);
bcm43xx_lock_irqsafe(bcm, flags);
fappend("Last %d logged xmitstatus blobs (Latest first):\n\n",
BCM43xx_NR_LOGGED_XMITSTATUS);
......@@ -293,14 +294,14 @@ static ssize_t txstat_read_file(struct file *file, char __user *userbuf,
i = BCM43xx_NR_LOGGED_XMITSTATUS - 1;
}
bcm43xx_unlock(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
bcm43xx_lock(bcm, flags);
bcm43xx_lock_irqsafe(bcm, flags);
if (*ppos == pos) {
/* Done. Drop the copied data. */
e->xmitstatus_printing = 0;
}
bcm43xx_unlock(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
up(&big_buffer_sem);
return res;
}
......
......@@ -51,12 +51,12 @@ static void bcm43xx_led_blink(unsigned long d)
struct bcm43xx_private *bcm = led->bcm;
unsigned long flags;
bcm43xx_lock_mmio(bcm, flags);
bcm43xx_lock_irqonly(bcm, flags);
if (led->blink_interval) {
bcm43xx_led_changestate(led);
mod_timer(&led->blink_timer, jiffies + led->blink_interval);
}
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqonly(bcm, flags);
}
static void bcm43xx_led_blink_start(struct bcm43xx_led *led,
......
This diff is collapsed.
......@@ -1648,7 +1648,7 @@ void bcm43xx_phy_set_baseband_attenuation(struct bcm43xx_private *bcm,
void bcm43xx_phy_lo_g_measure(struct bcm43xx_private *bcm)
{
static const u8 pairorder[10] = { 3, 1, 5, 7, 9, 2, 0, 4, 6, 8 };
const int is_initializing = bcm43xx_is_initializing(bcm);
const int is_initializing = (bcm43xx_status(bcm) == BCM43xx_STAT_INITIALIZING);
struct bcm43xx_phyinfo *phy = bcm43xx_current_phy(bcm);
struct bcm43xx_radioinfo *radio = bcm43xx_current_radio(bcm);
u16 h, i, oldi = 0, j;
......
......@@ -262,7 +262,7 @@ static void tx_tasklet(unsigned long d)
int err;
u16 txctl;
bcm43xx_lock_mmio(bcm, flags);
bcm43xx_lock_irqonly(bcm, flags);
txctl = bcm43xx_pio_read(queue, BCM43xx_PIO_TXCTL);
if (txctl & BCM43xx_PIO_TXCTL_SUSPEND)
......@@ -298,7 +298,7 @@ static void tx_tasklet(unsigned long d)
continue;
}
out_unlock:
bcm43xx_unlock_mmio(bcm, flags);
bcm43xx_unlock_irqonly(bcm, flags);
}
static void setup_txqueues(struct bcm43xx_pioqueue *queue)
......@@ -374,7 +374,6 @@ static void cancel_transfers(struct bcm43xx_pioqueue *queue)
struct bcm43xx_pio_txpacket *packet, *tmp_packet;
netif_tx_disable(queue->bcm->net_dev);
assert(queue->bcm->shutting_down);
tasklet_disable(&queue->txtask);
list_for_each_entry_safe(packet, tmp_packet, &queue->txrunning, list)
......
......@@ -120,12 +120,12 @@ static ssize_t bcm43xx_attr_sprom_show(struct device *dev,
GFP_KERNEL);
if (!sprom)
return -ENOMEM;
bcm43xx_lock_mmio(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_irqsafe(bcm, flags);
err = bcm43xx_sprom_read(bcm, sprom);
if (!err)
err = sprom2hex(sprom, buf, PAGE_SIZE);
bcm43xx_unlock_mmio(bcm, flags);
mmiowb();
bcm43xx_unlock_irqsafe(bcm, flags);
kfree(sprom);
return err;
......@@ -150,10 +150,10 @@ static ssize_t bcm43xx_attr_sprom_store(struct device *dev,
err = hex2sprom(sprom, buf, count);
if (err)
goto out_kfree;
bcm43xx_lock_mmio(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_irqsafe(bcm, flags);
err = bcm43xx_sprom_write(bcm, sprom);
bcm43xx_unlock_mmio(bcm, flags);
mmiowb();
bcm43xx_unlock_irqsafe(bcm, flags);
out_kfree:
kfree(sprom);
......@@ -170,15 +170,13 @@ static ssize_t bcm43xx_attr_interfmode_show(struct device *dev,
char *buf)
{
struct bcm43xx_private *bcm = dev_to_bcm(dev);
unsigned long flags;
int err;
ssize_t count = 0;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
bcm43xx_lock(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_noirq(bcm);
switch (bcm43xx_current_radio(bcm)->interfmode) {
case BCM43xx_RADIO_INTERFMODE_NONE:
......@@ -195,7 +193,7 @@ static ssize_t bcm43xx_attr_interfmode_show(struct device *dev,
}
err = 0;
bcm43xx_unlock(bcm, flags);
bcm43xx_unlock_noirq(bcm);
return err ? err : count;
......@@ -231,16 +229,15 @@ static ssize_t bcm43xx_attr_interfmode_store(struct device *dev,
return -EINVAL;
}
bcm43xx_lock_mmio(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_irqsafe(bcm, flags);
err = bcm43xx_radio_set_interference_mitigation(bcm, mode);
if (err) {
printk(KERN_ERR PFX "Interference Mitigation not "
"supported by device\n");
}
bcm43xx_unlock_mmio(bcm, flags);
mmiowb();
bcm43xx_unlock_irqsafe(bcm, flags);
return err ? err : count;
}
......@@ -254,15 +251,13 @@ static ssize_t bcm43xx_attr_preamble_show(struct device *dev,
char *buf)
{
struct bcm43xx_private *bcm = dev_to_bcm(dev);
unsigned long flags;
int err;
ssize_t count;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
bcm43xx_lock(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_noirq(bcm);
if (bcm->short_preamble)
count = snprintf(buf, PAGE_SIZE, "1 (Short Preamble enabled)\n");
......@@ -270,7 +265,7 @@ static ssize_t bcm43xx_attr_preamble_show(struct device *dev,
count = snprintf(buf, PAGE_SIZE, "0 (Short Preamble disabled)\n");
err = 0;
bcm43xx_unlock(bcm, flags);
bcm43xx_unlock_noirq(bcm);
return err ? err : count;
}
......@@ -290,13 +285,12 @@ static ssize_t bcm43xx_attr_preamble_store(struct device *dev,
value = get_boolean(buf, count);
if (value < 0)
return value;
bcm43xx_lock(bcm, flags);
assert(bcm->initialized);
bcm43xx_lock_irqsafe(bcm, flags);
bcm->short_preamble = !!value;
err = 0;
bcm43xx_unlock(bcm, flags);
bcm43xx_unlock_irqsafe(bcm, flags);
return err ? err : count;
}
......@@ -310,7 +304,7 @@ int bcm43xx_sysfs_register(struct bcm43xx_private *bcm)
struct device *dev = &bcm->pci_dev->dev;
int err;
assert(bcm->initialized);
assert(bcm43xx_status(bcm) == BCM43xx_STAT_INITIALIZED);
err = device_create_file(dev, &dev_attr_sprom);
if (err)
......
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