[PATCH 4.4 005/158] ath9k: Check for errors when reading SREV register

Greg Kroah-Hartman
2019-08-02T09:30:13Z

[ Upstream commit 2f90c7e5d09437a4d8d5546feaae9f1cf48cfbe1 ]

Right now, if an error is encountered during the SREV register
read (i.e. an EIO in ath9k_regread()), that error code gets
passed all the way to __ath9k_hw_init(), where it is visible
during the "Chip rev not supported" message.

ath9k_htc 1-1.4:1.0: ath9k_htc: HTC initialized with 33 credits
ath: phy2: Mac Chip Rev 0x0f.3 is not supported by this driver
ath: phy2: Unable to initialize hardware; initialization status: -95
ath: phy2: Unable to initialize hardware; initialization status: -95
ath9k_htc: Failed to initialize the device

Check for -EIO explicitly in ath9k_hw_read_revisions() and return
a boolean based on the success of the operation. Check for that in
__ath9k_hw_init() and abort with a more debugging-friendly message
if reading the revisions wasn't successful.

ath9k_htc 1-1.4:1.0: ath9k_htc: HTC initialized with 33 credits
ath: phy2: Failed to read SREV register
ath: phy2: Could not read hardware revision
ath: phy2: Unable to initialize hardware; initialization status: -95
ath: phy2: Unable to initialize hardware; initialization status: -95
ath9k_htc: Failed to initialize the device

This helps when debugging by directly showing the first point of
failure and it could prevent possible errors if a 0x0f.3 revision
is ever supported.

Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/ath9k/hw.c | 32 +++++++++++++++++++++--------
1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 4435c7bbb625..d50e2e8bd998 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -250,8 +250,9 @@ void ath9k_hw_get_channel_centers(struct ath_hw *ah,
/* Chip Revisions */
/******************/

-static void ath9k_hw_read_revisions(struct ath_hw *ah)
+static bool ath9k_hw_read_revisions(struct ath_hw *ah)
{
+ u32 srev;
u32 val;

if (ah->get_mac_revision)
@@ -267,25 +268,33 @@ static void ath9k_hw_read_revisions(struct ath_hw *ah)
val = REG_READ(ah, AR_SREV);
ah->hw_version.macRev = MS(val, AR_SREV_REVISION2);
}
- return;
+ return true;
case AR9300_DEVID_AR9340:
ah->hw_version.macVersion = AR_SREV_VERSION_9340;
- return;
+ return true;
case AR9300_DEVID_QCA955X:
ah->hw_version.macVersion = AR_SREV_VERSION_9550;
- return;
+ return true;
case AR9300_DEVID_AR953X:
ah->hw_version.macVersion = AR_SREV_VERSION_9531;
- return;
+ return true;
case AR9300_DEVID_QCA956X:
ah->hw_version.macVersion = AR_SREV_VERSION_9561;
- return;
+ return true;
}

- val = REG_READ(ah, AR_SREV) & AR_SREV_ID;
+ srev = REG_READ(ah, AR_SREV);
+
+ if (srev == -EIO) {
+ ath_err(ath9k_hw_common(ah),
+ "Failed to read SREV register");
+ return false;
+ }
+
+ val = srev & AR_SREV_ID;

if (val == 0xFF) {
- val = REG_READ(ah, AR_SREV);
+ val = srev;
ah->hw_version.macVersion =
(val & AR_SREV_VERSION2) >> AR_SREV_TYPE2_S;
ah->hw_version.macRev = MS(val, AR_SREV_REVISION2);
@@ -304,6 +313,8 @@ static void ath9k_hw_read_revisions(struct ath_hw *ah)
if (ah->hw_version.macVersion == AR_SREV_VERSION_5416_PCIE)
ah->is_pciexpress = true;
}
+
+ return true;
}

/************************************/
@@ -556,7 +567,10 @@ static int __ath9k_hw_init(struct ath_hw *ah)
struct ath_common *common = ath9k_hw_common(ah);
int r = 0;

- ath9k_hw_read_revisions(ah);
+ if (!ath9k_hw_read_revisions(ah)) {
+ ath_err(common, "Could not read hardware revisions");
+ return -EOPNOTSUPP;
+ }

switch (ah->hw_version.macVersion) {
case AR_SREV_VERSION_5416_PCI:
--
2.20.1