Upon CPU Hotplug the number of CPUs can change and we can tweak
our driver configuration as such. Keep in mind CPU hotplug also
occurs during suspend/resume.
Since we have a notifier now we can rely on num_present_cpus()
rather than num_possible_cpus() to enable/disable serialization.
Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
---
drivers/net/wireless/ath9k/ath9k.h | 7 +++++
drivers/net/wireless/ath9k/hw.c | 49 ++++++++++++++++++++++-------------
drivers/net/wireless/ath9k/hw.h | 3 ++
drivers/net/wireless/ath9k/main.c | 29 +++++++++++++++++++++
drivers/net/wireless/ath9k/pci.c | 4 +++
5 files changed, 74 insertions(+), 18 deletions(-)
diff --git a/drivers/net/wireless/ath9k/ath9k.h b/drivers/net/wireless/ath9k/ath9k.h
index 90ee2e3..a2e9b1e 100644
--- a/drivers/net/wireless/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath9k/ath9k.h
@@ -22,6 +22,7 @@
#include <net/mac80211.h>
#include <linux/leds.h>
#include <linux/rfkill.h>
+#include <linux/cpu.h>
#include "hw.h"
#include "rc.h"
@@ -554,6 +555,9 @@ struct ath_bus_ops {
struct ath_wiphy;
+int ath9k_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu);
+
struct ath_softc {
struct ieee80211_hw *hw;
struct device *dev;
@@ -573,6 +577,9 @@ struct ath_softc {
unsigned long wiphy_scheduler_int;
int wiphy_scheduler_index;
+ /* This should or _needs_ to be __cpuinit (?) */
+ struct notifier_block cpu_notifer;
+
struct tasklet_struct intr_tq;
struct tasklet_struct bcon_tasklet;
struct ath_hw *sc_ah;
diff --git a/drivers/net/wireless/ath9k/hw.c b/drivers/net/wireless/ath9k/hw.c
index 05df570..3bbc257 100644
--- a/drivers/net/wireless/ath9k/hw.c
+++ b/drivers/net/wireless/ath9k/hw.c
@@ -16,6 +16,7 @@
#include <linux/io.h>
#include <asm/unaligned.h>
+#include <linux/cpu.h>
#include "ath9k.h"
#include "initvals.h"
@@ -385,6 +386,35 @@ static const char *ath9k_hw_devname(u16 devid)
return NULL;
}
+/*
+ * We can slap on to here things we need to tune depending
+ * on the number of CPUs. This will happen on CPU hotplug
+ * which is also used for suspend/resume.
+ */
+void ath9k_hw_config_for_cpus(struct ath_hw *ah)
+{
+ /*
+ * 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_present_cpus() > 1)
+ ah->config.serialize_regmode = SER_REG_MODE_AUTO;
+ else
+ ah->config.serialize_regmode = SER_REG_MODE_OFF;
+}
+
static void ath9k_hw_set_defaults(struct ath_hw *ah)
{
int i;
@@ -424,24 +454,7 @@ static void ath9k_hw_set_defaults(struct ath_hw *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->config.serialize_regmode = SER_REG_MODE_AUTO;
+ ath9k_hw_config_for_cpus(ah);
}
static struct ath_hw *ath9k_hw_newstate(u16 devid, struct ath_softc *sc,
diff --git a/drivers/net/wireless/ath9k/hw.h b/drivers/net/wireless/ath9k/hw.h
index 790bfa9..c2d32bb 100644
--- a/drivers/net/wireless/ath9k/hw.h
+++ b/drivers/net/wireless/ath9k/hw.h
@@ -570,6 +570,9 @@ struct ath_hw {
void ath9k_iowrite32(struct ath_hw *ah, u32 reg_offset, u32 val);
unsigned int ath9k_ioread32(struct ath_hw *ah, u32 reg_offset);
+/* Lets us tweak the device per CPU changes */
+void ath9k_hw_config_for_cpus(struct ath_hw *ah);
+
/* Attach, Detach, Reset */
const char *ath9k_hw_probe(u16 vendorid, u16 devid);
void ath9k_hw_detach(struct ath_hw *ah);
diff --git a/drivers/net/wireless/ath9k/main.c b/drivers/net/wireless/ath9k/main.c
index 2ad6414..94ea72a 100644
--- a/drivers/net/wireless/ath9k/main.c
+++ b/drivers/net/wireless/ath9k/main.c
@@ -2787,6 +2787,35 @@ struct ieee80211_ops ath9k_ops = {
.sw_scan_complete = ath9k_sw_scan_complete,
};
+int ath9k_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ struct ath_softc *sc = container_of(nfb, struct ath_softc, cpu_notifer);
+ int old_serial_mode;
+
+ old_serial_mode = sc->sc_ah->config.serialize_regmode;
+
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ ath9k_hw_config_for_cpus(sc->sc_ah);
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ ath9k_hw_config_for_cpus(sc->sc_ah);
+ break;
+ }
+
+ if (unlikely(old_serial_mode != sc->sc_ah->config.serialize_regmode)) {
+ DPRINTF(sc, ATH_DBG_RESET,
+ "serialize_regmode has changed due to CPU "
+ "count to %d\n",
+ sc->sc_ah->config.serialize_regmode);
+ }
+
+ return NOTIFY_OK;
+}
+
static struct {
u32 version;
const char * name;
diff --git a/drivers/net/wireless/ath9k/pci.c b/drivers/net/wireless/ath9k/pci.c
index 9a58baa..c1ba207 100644
--- a/drivers/net/wireless/ath9k/pci.c
+++ b/drivers/net/wireless/ath9k/pci.c
@@ -181,6 +181,9 @@ static int ath_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
goto bad3;
}
+ sc->cpu_notifer.notifier_call = ath9k_cpu_callback;
+ register_hotcpu_notifier(&sc->cpu_notifer);
+
/* setup interrupt service routine */
if (request_irq(pdev->irq, ath_isr, IRQF_SHARED, "ath", sc)) {
@@ -223,6 +226,7 @@ static void ath_pci_remove(struct pci_dev *pdev)
struct ath_wiphy *aphy = hw->priv;
struct ath_softc *sc = aphy->sc;
+ unregister_hotcpu_notifier(&sc->cpu_notifer);
ath_cleanup(sc);
}
--
1.6.0.6
--
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