On 26-2-2018 18:42, Dan Williams wrote:
On Mon, 2018-02-26 at 17:44 +0100, Bas Vermeulen wrote:
On 26-02-18 17:32, Larry Finger wrote:
On 02/26/2018 04:07 AM, Bas Vermeulen wrote:
On 26-02-18 10:54, Kalle Valo wrote:
Bas Vermeulen <bvermeul@xxxxxxxxxxxx> writes:
A random (little endian eeprom'd) ar9278 card didn't work on
my
PowerMac G5 without allowing the driver to byte-swap the
eeprom.
Introduce a module parameter endian_check to allow this to
happen,
and the PCIe card to function correctly on BE powerpc.
Signed-off-by: Bas Vermeulen <bvermeul@xxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath9k/init.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath9k/init.c
b/drivers/net/wireless/ath/ath9k/init.c
index fa58a32227f5..421039dc060a 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -67,6 +67,9 @@ static int ath9k_ps_enable;
module_param_named(ps_enable, ath9k_ps_enable, int, 0444);
MODULE_PARM_DESC(ps_enable, "Enable WLAN PowerSave");
+static int ath9k_endian_check;
+module_param_named(endian_check, ath9k_endian_check, int,
0444);
+MODULE_PARM_DESC(endian_check, "Check EEPROM for endianness
compatibility");
#ifdef CONFIG_ATH9K_CHANNEL_CONTEXT
int ath9k_use_chanctx;
@@ -587,7 +590,8 @@ static int ath9k_of_init(struct ath_softc
*sc)
ether_addr_copy(common->macaddr, mac);
ah->ah_flags &= ~AH_USE_EEPROM;
- ah->ah_flags |= AH_NO_EEP_SWAP;
+ if (!ath9k_endian_check)
+ ah->ah_flags |= AH_NO_EEP_SWAP;
A bit annoying to have a module parameter, isn't there any
automatic
way
to detect/try this? But on the other hand I guess this isn't a
common
problem as nobody has reported this before?
There is an automatic way to detect this, but that is disabled by
the
AH_NO_EEP_SWAP flag.
The platform initialisation does not set this flag if the
endian_check member of pdata is set
to true, but there is no way to not set this when using a device
tree. I used a module
parameter instead of a device tree variable because I don't know
of a
way to modify the
device tree my PowerMac boots with.
Shouldn't you be able to set ath9k_endian_check inside #ifdef
__BIG_ENDIAN ... #endif in the initialization? I think that would
achieve the same functionality without requiring the user to set a
module parameter.
I could have done that, but didn't want to change the default
behaviour.
This patch keeps the
current behaviour on all platforms if the module parameter is not
set. I
don't have the means
to test mips and other platforms this could be used on. I don't mind
having to set a module
parameter, I mind not being able to change the behaviour
Still, module parameters are an awful user experience because you need
to know that they exist, what they do, and whether you need it or not.
It doesn't just work.
Is there no way to autodetect the endian-ness of the firmware itself,
and if the known machine endian-ness isn't the same then swap? This
seems like a solvable problem.
The problem is already solved, but the solution is disabled by the
AH_NO_EEP_SWAP
flag set in both initialization functions. See ath9k/init.c and
ath9k/eeprom.c.
My patch just disables the flag when a module parameter is set, which
enables the solution.
I can disable the flag without a problem, but that might have unintended
side effects
on some platforms. If the consensus is that's the better solution I can
prepare a patch,
but that would have to come from someone more knowledgeable than me.
Bas Vermeulen
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