zd1211rw firmware loading timeout

[Florian Fainelli <florian@openwrt.org>]

Hello,

I am running Debian testing kernel 3.1.0-1-amd64, using a 079b:0062 Sagem 
XG-76NA 802.11bg stick.

Upon zd1211rw interface 
bringup (ifconfig wlan0 up) I get the following timeout:

[  950.330573] zd1211rw 1-3:1.0: phy2
[  955.108510] zd1211rw 1-3:1.0: firmware version 4725
[  955.148532] zd1211rw 1-3:1.0: zd1211b chip 079b:0062 v4810 high 00-19-70 
AL2230_RF pa0 g--NS
[snip]
[  955.204072] zd1211rw 1-3:1.0: error ioread32(CR_REG1): -110

A second ifconfig wlan0 up brings the interface up without problems.

After a bit more debugging, the call trace is the following:

[10241.028130] zd1211rw 1-3:1.0: zd_chip_lock_phy_regs: error 
ioread32(CR_REG1): -110
[10241.028140] zd1211rw 1-3:1.0: zd_switch_radio_on: failed to lock PHY regs
[10241.028148] zd1211rw 1-3:1.0: zd_op_start: failed to set radio on

The following small modification works around the issue:

diff --git a/zd_mac.c b/zd_mac.c
index cabfae1..6bfb673 100644
--- a/zd_mac.c
+++ b/zd_mac.c
@@ -306,9 +306,14 @@ int zd_op_start(struct ieee80211_hw *hw)
        r = set_mc_hash(mac);
        if (r)
                goto disable_int;
+
+       msleep(10);
+
        r = zd_chip_switch_radio_on(chip);
-       if (r < 0)
+       if (r < 0) {
+               dev_err(zd_chip_dev(chip), "%s: failed to set radio on\n", 
__func__);
                goto disable_int;
+       }
        r = zd_chip_enable_rxtx(chip);
        if (r < 0)
                goto disable_radio;

Is it possible that some chips require more time between a set_mc_hash and a 
radio on? Or in general that consequent writes to the PHY regs should be timed 
appropriately?

When I googled for this timeout issue, I could see quite some reports of other 
people having this error while the chip was already operating.

Thanks
-- 
Florian