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iwlwifi: always check if got h/w access before write
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Before we write to the device registers always check if
iwl_grap_nic_access() was successful.

On the way change return type of grab_nic_access() to bool, and add
likely()/unlikely() statement.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Stanislaw Gruszka authored and John W. Linville committed Mar 8, 2012
1 parent aa5affb commit bfe4b80
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Showing 6 changed files with 35 additions and 30 deletions.
2 changes: 1 addition & 1 deletion drivers/net/wireless/iwlwifi/iwl-agn-tt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -189,7 +189,7 @@ static void iwl_tt_check_exit_ct_kill(unsigned long data)
}
iwl_read32(trans(priv), CSR_UCODE_DRV_GP1);
spin_lock_irqsave(&trans(priv)->reg_lock, flags);
if (!iwl_grab_nic_access(trans(priv)))
if (likely(iwl_grab_nic_access(trans(priv))))
iwl_release_nic_access(trans(priv));
spin_unlock_irqrestore(&trans(priv)->reg_lock, flags);

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2 changes: 1 addition & 1 deletion drivers/net/wireless/iwlwifi/iwl-agn.c
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Original file line number Diff line number Diff line change
Expand Up @@ -327,7 +327,7 @@ static void iwl_print_cont_event_trace(struct iwl_priv *priv, u32 base,

/* Make sure device is powered up for SRAM reads */
spin_lock_irqsave(&trans(priv)->reg_lock, reg_flags);
if (iwl_grab_nic_access(trans(priv))) {
if (unlikely(!iwl_grab_nic_access(trans(priv)))) {
spin_unlock_irqrestore(&trans(priv)->reg_lock, reg_flags);
return;
}
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53 changes: 28 additions & 25 deletions drivers/net/wireless/iwlwifi/iwl-io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,16 +118,17 @@ int iwl_grab_nic_access_silent(struct iwl_trans *trans)
return 0;
}

int iwl_grab_nic_access(struct iwl_trans *trans)
bool iwl_grab_nic_access(struct iwl_trans *trans)
{
int ret = iwl_grab_nic_access_silent(trans);
if (unlikely(ret)) {
u32 val = iwl_read32(trans, CSR_GP_CNTRL);
WARN_ONCE(1, "Timeout waiting for hardware access "
"(CSR_GP_CNTRL 0x%08x)\n", val);
return false;
}

return ret;
return true;
}

void iwl_release_nic_access(struct iwl_trans *trans)
Expand Down Expand Up @@ -156,7 +157,7 @@ void iwl_write_direct32(struct iwl_trans *trans, u32 reg, u32 value)
unsigned long flags;

spin_lock_irqsave(&trans->reg_lock, flags);
if (!iwl_grab_nic_access(trans)) {
if (likely(iwl_grab_nic_access(trans))) {
iwl_write32(trans, reg, value);
iwl_release_nic_access(trans);
}
Expand Down Expand Up @@ -211,7 +212,7 @@ void iwl_write_prph(struct iwl_trans *trans, u32 addr, u32 val)
unsigned long flags;

spin_lock_irqsave(&trans->reg_lock, flags);
if (!iwl_grab_nic_access(trans)) {
if (likely(iwl_grab_nic_access(trans))) {
__iwl_write_prph(trans, addr, val);
iwl_release_nic_access(trans);
}
Expand All @@ -223,9 +224,11 @@ void iwl_set_bits_prph(struct iwl_trans *trans, u32 reg, u32 mask)
unsigned long flags;

spin_lock_irqsave(&trans->reg_lock, flags);
iwl_grab_nic_access(trans);
__iwl_write_prph(trans, reg, __iwl_read_prph(trans, reg) | mask);
iwl_release_nic_access(trans);
if (likely(iwl_grab_nic_access(trans))) {
__iwl_write_prph(trans, reg,
__iwl_read_prph(trans, reg) | mask);
iwl_release_nic_access(trans);
}
spin_unlock_irqrestore(&trans->reg_lock, flags);
}

Expand All @@ -235,10 +238,11 @@ void iwl_set_bits_mask_prph(struct iwl_trans *trans, u32 reg,
unsigned long flags;

spin_lock_irqsave(&trans->reg_lock, flags);
iwl_grab_nic_access(trans);
__iwl_write_prph(trans, reg,
(__iwl_read_prph(trans, reg) & mask) | bits);
iwl_release_nic_access(trans);
if (likely(iwl_grab_nic_access(trans))) {
__iwl_write_prph(trans, reg,
(__iwl_read_prph(trans, reg) & mask) | bits);
iwl_release_nic_access(trans);
}
spin_unlock_irqrestore(&trans->reg_lock, flags);
}

Expand All @@ -248,10 +252,11 @@ void iwl_clear_bits_prph(struct iwl_trans *trans, u32 reg, u32 mask)
u32 val;

spin_lock_irqsave(&trans->reg_lock, flags);
iwl_grab_nic_access(trans);
val = __iwl_read_prph(trans, reg);
__iwl_write_prph(trans, reg, (val & ~mask));
iwl_release_nic_access(trans);
if (likely(iwl_grab_nic_access(trans))) {
val = __iwl_read_prph(trans, reg);
__iwl_write_prph(trans, reg, (val & ~mask));
iwl_release_nic_access(trans);
}
spin_unlock_irqrestore(&trans->reg_lock, flags);
}

Expand All @@ -263,15 +268,13 @@ void _iwl_read_targ_mem_words(struct iwl_trans *trans, u32 addr,
u32 *vals = buf;

spin_lock_irqsave(&trans->reg_lock, flags);
iwl_grab_nic_access(trans);

iwl_write32(trans, HBUS_TARG_MEM_RADDR, addr);
rmb();

for (offs = 0; offs < words; offs++)
vals[offs] = iwl_read32(trans, HBUS_TARG_MEM_RDAT);

iwl_release_nic_access(trans);
if (likely(iwl_grab_nic_access(trans))) {
iwl_write32(trans, HBUS_TARG_MEM_RADDR, addr);
rmb();
for (offs = 0; offs < words; offs++)
vals[offs] = iwl_read32(trans, HBUS_TARG_MEM_RDAT);
iwl_release_nic_access(trans);
}
spin_unlock_irqrestore(&trans->reg_lock, flags);
}

Expand All @@ -292,7 +295,7 @@ int _iwl_write_targ_mem_words(struct iwl_trans *trans, u32 addr,
u32 *vals = buf;

spin_lock_irqsave(&trans->reg_lock, flags);
if (!iwl_grab_nic_access(trans)) {
if (likely(iwl_grab_nic_access(trans))) {
iwl_write32(trans, HBUS_TARG_MEM_WADDR, addr);
wmb();

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2 changes: 1 addition & 1 deletion drivers/net/wireless/iwlwifi/iwl-io.h
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,7 @@ int iwl_poll_direct_bit(struct iwl_trans *trans, u32 addr, u32 mask,
int timeout);

int iwl_grab_nic_access_silent(struct iwl_trans *trans);
int iwl_grab_nic_access(struct iwl_trans *trans);
bool iwl_grab_nic_access(struct iwl_trans *trans);
void iwl_release_nic_access(struct iwl_trans *trans);

u32 iwl_read_direct32(struct iwl_trans *trans, u32 reg);
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2 changes: 1 addition & 1 deletion drivers/net/wireless/iwlwifi/iwl-mac80211.c
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Original file line number Diff line number Diff line change
Expand Up @@ -445,7 +445,7 @@ static int iwlagn_mac_resume(struct ieee80211_hw *hw)
if (iwlagn_hw_valid_rtc_data_addr(base)) {
spin_lock_irqsave(&trans(priv)->reg_lock, flags);
ret = iwl_grab_nic_access_silent(trans(priv));
if (ret == 0) {
if (likely(ret == 0)) {
iwl_write32(trans(priv), HBUS_TARG_MEM_RADDR, base);
status = iwl_read32(trans(priv), HBUS_TARG_MEM_RDAT);
iwl_release_nic_access(trans(priv));
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4 changes: 3 additions & 1 deletion drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -745,7 +745,8 @@ static int iwl_print_event_log(struct iwl_trans *trans, u32 start_idx,

/* Make sure device is powered up for SRAM reads */
spin_lock_irqsave(&trans->reg_lock, reg_flags);
iwl_grab_nic_access(trans);
if (unlikely(!iwl_grab_nic_access(trans)))
goto out_unlock;

/* Set starting address; reads will auto-increment */
iwl_write32(trans, HBUS_TARG_MEM_RADDR, ptr);
Expand Down Expand Up @@ -785,6 +786,7 @@ static int iwl_print_event_log(struct iwl_trans *trans, u32 start_idx,

/* Allow device to power down */
iwl_release_nic_access(trans);
out_unlock:
spin_unlock_irqrestore(&trans->reg_lock, reg_flags);
return pos;
}
Expand Down

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