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Commit 6158425b authored by Luis R. Rodriguez's avatar Luis R. Rodriguez Committed by John W. Linville
Browse files

ath9k: implement IO serialization 

All 802.11n PCI devices (Cardbus, PCI, mini-PCI) require
serialization of IO when on non-uniprocessor systems. PCI
express devices not not require this.

This should fix our only last standing open ath9k kernel.org
bugzilla bug report:

http://bugzilla.kernel.org/show_bug.cgi?id=12110



A port is probably required to older kernels and I can work on
that.

Cc: stable@kernel.org
Signed-off-by: default avatarLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 6f16bf3b

drivers/net/wireless/ath9k/ath9k.h

+2 −2
Original line number Diff line number Diff line
@@ -587,8 +587,8 @@ struct ath9k_country_entry { 
	u8 iso[3];

};



#define REG_WRITE(_ah, _reg, _val) iowrite32(_val, _ah->ah_sh + _reg)

#define REG_READ(_ah, _reg) ioread32(_ah->ah_sh + _reg)

#define REG_WRITE(_ah, _reg, _val) ath9k_iowrite32((_ah), (_reg), (_val))

#define REG_READ(_ah, _reg) ath9k_ioread32((_ah), (_reg))



#define SM(_v, _f)  (((_v) << _f##_S) & _f)

#define MS(_v, _f)  (((_v) & _f) >> _f##_S)

drivers/net/wireless/ath9k/core.h

+33 −0
Original line number Diff line number Diff line
@@ -701,6 +701,7 @@ struct ath_softc { 
	struct ath_hal *sc_ah;

	void __iomem *mem;

	spinlock_t sc_resetlock;

	spinlock_t sc_serial_rw;

	struct mutex mutex;



	u8 sc_curbssid[ETH_ALEN];
@@ -751,4 +752,36 @@ int ath_get_hal_qnum(u16 queue, struct ath_softc *sc); 
int ath_get_mac80211_qnum(u32 queue, struct ath_softc *sc);

int ath_cabq_update(struct ath_softc *);



/*

 * Read and write, they both share the same lock. We do this to serialize

 * reads and writes on Atheros 802.11n PCI devices only. This is required

 * as the FIFO on these devices can only accept sanely 2 requests. After

 * that the device goes bananas. Serializing the reads/writes prevents this

 * from happening.

 */



static inline void ath9k_iowrite32(struct ath_hal *ah, u32 reg_offset, u32 val)

{

	if (ah->ah_config.serialize_regmode == SER_REG_MODE_ON) {

		unsigned long flags;

		spin_lock_irqsave(&ah->ah_sc->sc_serial_rw, flags);

		iowrite32(val, ah->ah_sc->mem + reg_offset);

		spin_unlock_irqrestore(&ah->ah_sc->sc_serial_rw, flags);

	} else

		iowrite32(val, ah->ah_sc->mem + reg_offset);

}



static inline unsigned int ath9k_ioread32(struct ath_hal *ah, u32 reg_offset)

{

	u32 val;

	if (ah->ah_config.serialize_regmode == SER_REG_MODE_ON) {

		unsigned long flags;

		spin_lock_irqsave(&ah->ah_sc->sc_serial_rw, flags);

		val = ioread32(ah->ah_sc->mem + reg_offset);

		spin_unlock_irqrestore(&ah->ah_sc->sc_serial_rw, flags);

	} else

		val = ioread32(ah->ah_sc->mem + reg_offset);

	return val;

}



#endif /* CORE_H */

drivers/net/wireless/ath9k/hw.c

+19 −0
Original line number Diff line number Diff line
@@ -437,6 +437,25 @@ static void ath9k_hw_set_defaults(struct ath_hal *ah) 
	}



	ah->ah_config.intr_mitigation = 1;



	/*

	 * We need this for PCI devices only (Cardbus, PCI, miniPCI)

	 * _and_ if on non-uniprocessor systems (Multiprocessor/HT).

	 * This means we use it for all AR5416 devices, and the few

	 * minor PCI AR9280 devices out there.

	 *

	 * Serialization is required because these devices do not handle

	 * well the case of two concurrent reads/writes due to the latency

	 * involved. During one read/write another read/write can be issued

	 * on another CPU while the previous read/write may still be working

	 * on our hardware, if we hit this case the hardware poops in a loop.

	 * We prevent this by serializing reads and writes.

	 *

	 * This issue is not present on PCI-Express devices or pre-AR5416

	 * devices (legacy, 802.11abg).

	 */

	if (num_possible_cpus() > 1)

		ah->ah_config.serialize_regmode = SER_REG_MODE_AUTO;

}



static struct ath_hal_5416 *ath9k_hw_newstate(u16 devid,

drivers/net/wireless/ath9k/main.c

+1 −0
Original line number Diff line number Diff line
@@ -1336,6 +1336,7 @@ static int ath_init(u16 devid, struct ath_softc *sc) 
		printk(KERN_ERR "Unable to create debugfs files\n");



	spin_lock_init(&sc->sc_resetlock);

	spin_lock_init(&sc->sc_serial_rw);

	mutex_init(&sc->mutex);

	tasklet_init(&sc->intr_tq, ath9k_tasklet, (unsigned long)sc);

	tasklet_init(&sc->bcon_tasklet, ath9k_beacon_tasklet,