[PATCH] zd1211rw: consistent handling of ZD1211 specific rates

As pointed out by Daniel Drake, the zd1211rw driver used several
different rate values and names throughout the driver. He has
written a patch to change it and tweaked it after some pretty wild
ideas from my side. But the discussion helped me to understand the
problem better and I think I have nailed it down with this patch.

A zd-rate will consist from now on of a four-bit "pure" rate value
and a modulation type flag as used in the ZD1211 control set used
for packet transmission. This is consistent with the usage in the
zd_rates table. If possible these zd-rates should be used in the
code.

Signed-off-by: Ulrich Kunitz <kune@deine-taler.de>
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 27 insertions, 16 deletions

diff --git a/drivers/net/wireless/zd1211rw/zd_ieee80211.h b/drivers/net/wireless/zd1211rw/zd_ieee80211.h
index c4f36d39642..fbf6491dce7 100644
--- a/drivers/net/wireless/zd1211rw/zd_ieee80211.h
+++ b/drivers/net/wireless/zd1211rw/zd_ieee80211.h
@@ -43,21 +43,25 @@ struct ofdm_plcp_header {
 	__le16 service;
 } __attribute__((packed));
 
-static inline u8 zd_ofdm_plcp_header_rate(
-	const struct ofdm_plcp_header *header)
+static inline u8 zd_ofdm_plcp_header_rate(const struct ofdm_plcp_header *header)
 {
 	return header->prefix[0] & 0xf;
 }
 
-/* These are referred to as zd_rates */
-#define ZD_OFDM_RATE_6M		0xb
-#define ZD_OFDM_RATE_9M		0xf
-#define ZD_OFDM_RATE_12M	0xa
-#define ZD_OFDM_RATE_18M	0xe
-#define ZD_OFDM_RATE_24M	0x9
-#define ZD_OFDM_RATE_36M	0xd
-#define ZD_OFDM_RATE_48M	0x8
-#define ZD_OFDM_RATE_54M	0xc
+/* The following defines give the encoding of the 4-bit rate field in the
+ * OFDM (802.11a/802.11g) PLCP header. Notify that these values are used to
+ * define the zd-rate values for OFDM.
+ *
+ * See the struct zd_ctrlset definition in zd_mac.h.
+ */
+#define ZD_OFDM_PLCP_RATE_6M		0xb
+#define ZD_OFDM_PLCP_RATE_9M		0xf
+#define ZD_OFDM_PLCP_RATE_12M	0xa
+#define ZD_OFDM_PLCP_RATE_18M	0xe
+#define ZD_OFDM_PLCP_RATE_24M	0x9
+#define ZD_OFDM_PLCP_RATE_36M	0xd
+#define ZD_OFDM_PLCP_RATE_48M	0x8
+#define ZD_OFDM_PLCP_RATE_54M	0xc
 
 struct cck_plcp_header {
 	u8 signal;
@@ -66,15 +70,22 @@ struct cck_plcp_header {
 	__le16 crc16;
 } __attribute__((packed));
 
-static inline u8 zd_cck_plcp_header_rate(const struct cck_plcp_header *header)
+static inline u8 zd_cck_plcp_header_signal(const struct cck_plcp_header *header)
 {
 	return header->signal;
 }
 
-#define ZD_CCK_SIGNAL_1M	0x0a
-#define ZD_CCK_SIGNAL_2M	0x14
-#define ZD_CCK_SIGNAL_5M5	0x37
-#define ZD_CCK_SIGNAL_11M	0x6e
+/* These defines give the encodings of the signal field in the 802.11b PLCP
+ * header. The signal field gives the bit rate of the following packet. Even
+ * if technically wrong we use CCK here also for the 1 MBit/s and 2 MBit/s
+ * rate to stay consistent with Zydas and our use of the term.
+ *
+ * Notify that these values are *not* used in the zd-rates.
+ */
+#define ZD_CCK_PLCP_SIGNAL_1M	0x0a
+#define ZD_CCK_PLCP_SIGNAL_2M	0x14
+#define ZD_CCK_PLCP_SIGNAL_5M5	0x37
+#define ZD_CCK_PLCP_SIGNAL_11M	0x6e
 
 enum ieee80211_std {
 	IEEE80211B = 0x01,