Re: mac80211 driver for RT3070 wifi card does not work on big-endian platform

[Larry Finger <Larry.Finger@lwfinger.net>]

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On 09/09/2011 12:30 PM, Semigod King wrote:
> I noticed two lines of code:
>                  static const u32 wcid[2] = { 0xffffffff, 0x00ffffff };
>                  rt2800_register_multiwrite(rt2x00dev, MAC_WCID_ENTRY(i),
>                                                wcid, sizeof(wcid));
>
> Do you think the first line should be changed as below to eliminate
> platform difference?
>                  static const u32 wcid[2] = { 0xffffffff,
> cpu_to_le32(0x00ffffff) };

No, that kind of thing should not be done. Internal data that are not 
specifically set to be little- or big-endian should be in cpu order. The 
conversions need to be done when writing to or reading from the device when the 
order differs from that of the cpu.

The changes were minimal. Most of the time it took me were in getting Linux 
running on my Powerbook G4 and getting the code to compile - I had to work 
around a bug in gcc version 4.4.5 on the PowerMac platform. The patch I needed 
is attached. The performance of rt2800usb is not great. With netperf, I'm 
getting about 5 Mbps for the netperf MAERTS, STREAM, and SENDFILE tests.

Larry



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Index: wireless-testing-new/drivers/net/wireless/rt2x00/rt2800lib.c
===================================================================
--- wireless-testing-new.orig/drivers/net/wireless/rt2x00/rt2800lib.c	2011-09-14 15:25:01.595735348 -0500
+++ wireless-testing-new/drivers/net/wireless/rt2x00/rt2800lib.c	2011-09-14 15:25:09.291644646 -0500
@@ -3697,14 +3697,15 @@
 	rt2800_regbusy_read(rt2x00dev, EFUSE_CTRL, EFUSE_CTRL_KICK, &reg);
 
 	/* Apparently the data is read from end to start */
-	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA3,
-					(u32 *)&rt2x00dev->eeprom[i]);
-	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA2,
-					(u32 *)&rt2x00dev->eeprom[i + 2]);
-	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA1,
-					(u32 *)&rt2x00dev->eeprom[i + 4]);
-	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA0,
-					(u32 *)&rt2x00dev->eeprom[i + 6]);
+	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA3, &reg);
+	/* The returned value is in CPU order, but eeprom is le */
+	rt2x00dev->eeprom[i] = cpu_to_le32(reg);
+	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA2, &reg);
+	*(u32 *)&rt2x00dev->eeprom[i + 2] = cpu_to_le32(reg);
+	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA1, &reg);
+	*(u32 *)&rt2x00dev->eeprom[i + 4] = cpu_to_le32(reg);
+	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA0, &reg);
+	*(u32 *)&rt2x00dev->eeprom[i + 6] = cpu_to_le32(reg);
 
 	mutex_unlock(&rt2x00dev->csr_mutex);
 }
@@ -3870,19 +3872,23 @@
 		return -ENODEV;
 	}
 
-	if (!rt2x00_rf(rt2x00dev, RF2820) &&
-	    !rt2x00_rf(rt2x00dev, RF2850) &&
-	    !rt2x00_rf(rt2x00dev, RF2720) &&
-	    !rt2x00_rf(rt2x00dev, RF2750) &&
-	    !rt2x00_rf(rt2x00dev, RF3020) &&
-	    !rt2x00_rf(rt2x00dev, RF2020) &&
-	    !rt2x00_rf(rt2x00dev, RF3021) &&
-	    !rt2x00_rf(rt2x00dev, RF3022) &&
-	    !rt2x00_rf(rt2x00dev, RF3052) &&
-	    !rt2x00_rf(rt2x00dev, RF3320) &&
-	    !rt2x00_rf(rt2x00dev, RF5370) &&
-	    !rt2x00_rf(rt2x00dev, RF5390)) {
-		ERROR(rt2x00dev, "Invalid RF chipset detected.\n");
+	switch (rt2x00dev->chip.rf) {
+	case RF2820:
+	case RF2850:
+	case RF2720:
+	case RF2750:
+	case RF3020:
+	case RF2020:
+	case RF3021:
+	case RF3022:
+	case RF3052:
+	case RF3320:
+	case RF5370:
+	case RF5390:
+		break;
+	default:
+		ERROR(rt2x00dev, "Invalid RF chipset 0x%x detected.\n",
+		      rt2x00dev->chip.rf);
 		return -ENODEV;
 	}