linux-kernel - [PATCH 4.7 057/186] iwlwifi: pcie: enable interrupts before releasing the NICs CPU

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Date:	Thu, 18 Aug 2016 15:57:54 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
	Luca Coelho <luciano.coelho@...el.com>
Subject: [PATCH 4.7 057/186] iwlwifi: pcie: enable interrupts before releasing the NICs CPU

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Emmanuel Grumbach <emmanuel.grumbach@...el.com>

commit 2aabdbdc17b7c53490337bfc58de3409c84d85d2 upstream.

The NIC's CPU gets started after the firmware has been
written to its memory. The first thing it does is to
send an interrupt to let the driver know that it is
running. In order to get that interrupt, the driver needs
to make sure it is not masked. Of course, the interrupt
needs to be enabled in the driver before the CPU starts to
run.
I mistakenly inversed those two steps leading to races
which prevented the driver from getting the alive interrupt
from the firmware.
Fix that.

Fixes: a6bd005fe92 ("iwlwifi: pcie: fix RF-Kill vs. firmware load race")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@...el.com>
Signed-off-by: Luca Coelho <luciano.coelho@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/wireless/intel/iwlwifi/pcie/trans.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -801,6 +801,8 @@ static int iwl_pcie_load_cpu_sections_80

 	*first_ucode_section = last_read_idx;

+	iwl_enable_interrupts(trans);
+
 	if (cpu == 1)
 		iwl_write_direct32(trans, FH_UCODE_LOAD_STATUS, 0xFFFF);
 	else
@@ -980,6 +982,8 @@ static int iwl_pcie_load_given_ucode(str
 		iwl_pcie_apply_destination(trans);
 	}

+	iwl_enable_interrupts(trans);
+
 	/* release CPU reset */
 	iwl_write32(trans, CSR_RESET, 0);

@@ -1215,7 +1219,6 @@ static int iwl_trans_pcie_start_fw(struc
 		ret = iwl_pcie_load_given_ucode_8000(trans, fw);
 	else
 		ret = iwl_pcie_load_given_ucode(trans, fw);
-	iwl_enable_interrupts(trans);

 	/* re-check RF-Kill state since we may have missed the interrupt */
 	hw_rfkill = iwl_is_rfkill_set(trans);