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[PATCH] zd1211rw: consistent handling of ZD1211 specific rates
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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>
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Ulrich Kunitz authored and David S. Miller committed Oct 10, 2007
1 parent 8e97afe commit 64f222c
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Showing 4 changed files with 126 additions and 132 deletions.
51 changes: 28 additions & 23 deletions drivers/net/wireless/zd1211rw/zd_chip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1009,19 +1009,19 @@ int zd_chip_set_rts_cts_rate_locked(struct zd_chip *chip,
u32 value = 0;

/* Modulation bit */
if (ZD_CS_TYPE(rts_rate) == ZD_CS_OFDM)
if (ZD_MODULATION_TYPE(rts_rate) == ZD_OFDM)
rts_mod = ZD_RX_OFDM;

dev_dbg_f(zd_chip_dev(chip), "rts_rate=%x preamble=%x\n",
rts_rate, preamble);

value |= rts_rate << RTSCTS_SH_RTS_RATE;
value |= ZD_PURE_RATE(rts_rate) << RTSCTS_SH_RTS_RATE;
value |= rts_mod << RTSCTS_SH_RTS_MOD_TYPE;
value |= preamble << RTSCTS_SH_RTS_PMB_TYPE;
value |= preamble << RTSCTS_SH_CTS_PMB_TYPE;

/* We always send 11M self-CTS messages, like the vendor driver. */
value |= ZD_CCK_RATE_11M << RTSCTS_SH_CTS_RATE;
value |= ZD_PURE_RATE(ZD_CCK_RATE_11M) << RTSCTS_SH_CTS_RATE;
value |= ZD_RX_CCK << RTSCTS_SH_CTS_MOD_TYPE;

return zd_iowrite32_locked(chip, value, CR_RTS_CTS_RATE);
Expand Down Expand Up @@ -1328,7 +1328,7 @@ int zd_chip_set_basic_rates_locked(struct zd_chip *chip, u16 cr_rates)
return zd_iowrite32_locked(chip, cr_rates, CR_BASIC_RATE_TBL);
}

static int ofdm_qual_db(u8 status_quality, u8 rate, unsigned int size)
static int ofdm_qual_db(u8 status_quality, u8 zd_rate, unsigned int size)
{
static const u16 constants[] = {
715, 655, 585, 540, 470, 410, 360, 315,
Expand All @@ -1342,7 +1342,7 @@ static int ofdm_qual_db(u8 status_quality, u8 rate, unsigned int size)
/* It seems that their quality parameter is somehow per signal
* and is now transferred per bit.
*/
switch (rate) {
switch (zd_rate) {
case ZD_OFDM_RATE_6M:
case ZD_OFDM_RATE_12M:
case ZD_OFDM_RATE_24M:
Expand All @@ -1369,7 +1369,7 @@ static int ofdm_qual_db(u8 status_quality, u8 rate, unsigned int size)
break;
}

switch (rate) {
switch (zd_rate) {
case ZD_OFDM_RATE_6M:
case ZD_OFDM_RATE_9M:
i += 3;
Expand All @@ -1393,11 +1393,11 @@ static int ofdm_qual_db(u8 status_quality, u8 rate, unsigned int size)
return i;
}

static int ofdm_qual_percent(u8 status_quality, u8 rate, unsigned int size)
static int ofdm_qual_percent(u8 status_quality, u8 zd_rate, unsigned int size)
{
int r;

r = ofdm_qual_db(status_quality, rate, size);
r = ofdm_qual_db(status_quality, zd_rate, size);
ZD_ASSERT(r >= 0);
if (r < 0)
r = 0;
Expand Down Expand Up @@ -1458,12 +1458,17 @@ static int cck_qual_percent(u8 status_quality)
return r <= 100 ? r : 100;
}

static inline u8 zd_rate_from_ofdm_plcp_header(const void *rx_frame)
{
return ZD_OFDM | zd_ofdm_plcp_header_rate(rx_frame);
}

u8 zd_rx_qual_percent(const void *rx_frame, unsigned int size,
const struct rx_status *status)
{
return (status->frame_status&ZD_RX_OFDM) ?
ofdm_qual_percent(status->signal_quality_ofdm,
zd_ofdm_plcp_header_rate(rx_frame),
zd_rate_from_ofdm_plcp_header(rx_frame),
size) :
cck_qual_percent(status->signal_quality_cck);
}
Expand All @@ -1479,32 +1484,32 @@ u8 zd_rx_strength_percent(u8 rssi)
u16 zd_rx_rate(const void *rx_frame, const struct rx_status *status)
{
static const u16 ofdm_rates[] = {
[ZD_OFDM_RATE_6M] = 60,
[ZD_OFDM_RATE_9M] = 90,
[ZD_OFDM_RATE_12M] = 120,
[ZD_OFDM_RATE_18M] = 180,
[ZD_OFDM_RATE_24M] = 240,
[ZD_OFDM_RATE_36M] = 360,
[ZD_OFDM_RATE_48M] = 480,
[ZD_OFDM_RATE_54M] = 540,
[ZD_OFDM_PLCP_RATE_6M] = 60,
[ZD_OFDM_PLCP_RATE_9M] = 90,
[ZD_OFDM_PLCP_RATE_12M] = 120,
[ZD_OFDM_PLCP_RATE_18M] = 180,
[ZD_OFDM_PLCP_RATE_24M] = 240,
[ZD_OFDM_PLCP_RATE_36M] = 360,
[ZD_OFDM_PLCP_RATE_48M] = 480,
[ZD_OFDM_PLCP_RATE_54M] = 540,
};
u16 rate;
if (status->frame_status & ZD_RX_OFDM) {
/* Deals with PLCP OFDM rate (not zd_rates) */
u8 ofdm_rate = zd_ofdm_plcp_header_rate(rx_frame);
rate = ofdm_rates[ofdm_rate & 0xf];
} else {
u8 cck_rate = zd_cck_plcp_header_rate(rx_frame);
switch (cck_rate) {
case ZD_CCK_SIGNAL_1M:
switch (zd_cck_plcp_header_signal(rx_frame)) {
case ZD_CCK_PLCP_SIGNAL_1M:
rate = 10;
break;
case ZD_CCK_SIGNAL_2M:
case ZD_CCK_PLCP_SIGNAL_2M:
rate = 20;
break;
case ZD_CCK_SIGNAL_5M5:
case ZD_CCK_PLCP_SIGNAL_5M5:
rate = 55;
break;
case ZD_CCK_SIGNAL_11M:
case ZD_CCK_PLCP_SIGNAL_11M:
rate = 110;
break;
default:
Expand Down
43 changes: 27 additions & 16 deletions drivers/net/wireless/zd1211rw/zd_ieee80211.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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,
Expand Down
99 changes: 27 additions & 72 deletions drivers/net/wireless/zd1211rw/zd_mac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -610,28 +610,6 @@ u8 zd_mac_get_channel(struct zd_mac *mac)
return channel;
}

/* If wrong rate is given, we are falling back to the slowest rate: 1MBit/s */
static u8 zd_rate_typed(u8 zd_rate)
{
static const u8 typed_rates[16] = {
[ZD_CCK_RATE_1M] = ZD_CS_CCK|ZD_CCK_RATE_1M,
[ZD_CCK_RATE_2M] = ZD_CS_CCK|ZD_CCK_RATE_2M,
[ZD_CCK_RATE_5_5M] = ZD_CS_CCK|ZD_CCK_RATE_5_5M,
[ZD_CCK_RATE_11M] = ZD_CS_CCK|ZD_CCK_RATE_11M,
[ZD_OFDM_RATE_6M] = ZD_CS_OFDM|ZD_OFDM_RATE_6M,
[ZD_OFDM_RATE_9M] = ZD_CS_OFDM|ZD_OFDM_RATE_9M,
[ZD_OFDM_RATE_12M] = ZD_CS_OFDM|ZD_OFDM_RATE_12M,
[ZD_OFDM_RATE_18M] = ZD_CS_OFDM|ZD_OFDM_RATE_18M,
[ZD_OFDM_RATE_24M] = ZD_CS_OFDM|ZD_OFDM_RATE_24M,
[ZD_OFDM_RATE_36M] = ZD_CS_OFDM|ZD_OFDM_RATE_36M,
[ZD_OFDM_RATE_48M] = ZD_CS_OFDM|ZD_OFDM_RATE_48M,
[ZD_OFDM_RATE_54M] = ZD_CS_OFDM|ZD_OFDM_RATE_54M,
};

ZD_ASSERT(ZD_CS_RATE_MASK == 0x0f);
return typed_rates[zd_rate & ZD_CS_RATE_MASK];
}

int zd_mac_set_mode(struct zd_mac *mac, u32 mode)
{
struct ieee80211_device *ieee;
Expand Down Expand Up @@ -739,25 +717,30 @@ int zd_mac_get_range(struct zd_mac *mac, struct iw_range *range)

static int zd_calc_tx_length_us(u8 *service, u8 zd_rate, u16 tx_length)
{
/* ZD_PURE_RATE() must be used to remove the modulation type flag of
* the zd-rate values. */
static const u8 rate_divisor[] = {
[ZD_CCK_RATE_1M] = 1,
[ZD_CCK_RATE_2M] = 2,
[ZD_CCK_RATE_5_5M] = 11, /* bits must be doubled */
[ZD_CCK_RATE_11M] = 11,
[ZD_OFDM_RATE_6M] = 6,
[ZD_OFDM_RATE_9M] = 9,
[ZD_OFDM_RATE_12M] = 12,
[ZD_OFDM_RATE_18M] = 18,
[ZD_OFDM_RATE_24M] = 24,
[ZD_OFDM_RATE_36M] = 36,
[ZD_OFDM_RATE_48M] = 48,
[ZD_OFDM_RATE_54M] = 54,
[ZD_PURE_RATE(ZD_CCK_RATE_1M)] = 1,
[ZD_PURE_RATE(ZD_CCK_RATE_2M)] = 2,

/* bits must be doubled */
[ZD_PURE_RATE(ZD_CCK_RATE_5_5M)] = 11,

[ZD_PURE_RATE(ZD_CCK_RATE_11M)] = 11,
[ZD_PURE_RATE(ZD_OFDM_RATE_6M)] = 6,
[ZD_PURE_RATE(ZD_OFDM_RATE_9M)] = 9,
[ZD_PURE_RATE(ZD_OFDM_RATE_12M)] = 12,
[ZD_PURE_RATE(ZD_OFDM_RATE_18M)] = 18,
[ZD_PURE_RATE(ZD_OFDM_RATE_24M)] = 24,
[ZD_PURE_RATE(ZD_OFDM_RATE_36M)] = 36,
[ZD_PURE_RATE(ZD_OFDM_RATE_48M)] = 48,
[ZD_PURE_RATE(ZD_OFDM_RATE_54M)] = 54,
};

u32 bits = (u32)tx_length * 8;
u32 divisor;

divisor = rate_divisor[zd_rate];
divisor = rate_divisor[ZD_PURE_RATE(zd_rate)];
if (divisor == 0)
return -EINVAL;

Expand All @@ -780,52 +763,24 @@ static int zd_calc_tx_length_us(u8 *service, u8 zd_rate, u16 tx_length)
return bits/divisor;
}

enum {
R2M_SHORT_PREAMBLE = 0x01,
R2M_11A = 0x02,
};

static u8 zd_rate_to_modulation(u8 zd_rate, int flags)
{
u8 modulation;

modulation = zd_rate_typed(zd_rate);
if (flags & R2M_SHORT_PREAMBLE) {
switch (ZD_CS_RATE(modulation)) {
case ZD_CCK_RATE_2M:
case ZD_CCK_RATE_5_5M:
case ZD_CCK_RATE_11M:
modulation |= ZD_CS_CCK_PREA_SHORT;
return modulation;
}
}
if (flags & R2M_11A) {
if (ZD_CS_TYPE(modulation) == ZD_CS_OFDM)
modulation |= ZD_CS_OFDM_MODE_11A;
}
return modulation;
}

static void cs_set_modulation(struct zd_mac *mac, struct zd_ctrlset *cs,
struct ieee80211_hdr_4addr *hdr)
{
struct ieee80211softmac_device *softmac = ieee80211_priv(mac->netdev);
u16 ftype = WLAN_FC_GET_TYPE(le16_to_cpu(hdr->frame_ctl));
u8 rate, zd_rate;
u8 rate;
int is_mgt = (ftype == IEEE80211_FTYPE_MGMT) != 0;
int is_multicast = is_multicast_ether_addr(hdr->addr1);
int short_preamble = ieee80211softmac_short_preamble_ok(softmac,
is_multicast, is_mgt);
int flags = 0;

/* FIXME: 802.11a? */
rate = ieee80211softmac_suggest_txrate(softmac, is_multicast, is_mgt);
cs->modulation = rate_to_zd_rate(rate);

if (short_preamble)
flags |= R2M_SHORT_PREAMBLE;

zd_rate = rate_to_zd_rate(rate);
cs->modulation = zd_rate_to_modulation(zd_rate, flags);
/* Set short preamble bit when appropriate */
if (short_preamble && ZD_MODULATION_TYPE(cs->modulation) == ZD_CCK
&& cs->modulation != ZD_CCK_RATE_1M)
cs->modulation |= ZD_CCK_PREA_SHORT;
}

static void cs_set_control(struct zd_mac *mac, struct zd_ctrlset *cs,
Expand Down Expand Up @@ -864,7 +819,7 @@ static void cs_set_control(struct zd_mac *mac, struct zd_ctrlset *cs,
cs->control |= ZD_CS_RTS;

/* Use CTS-to-self protection if required */
if (ZD_CS_TYPE(cs->modulation) == ZD_CS_OFDM &&
if (ZD_MODULATION_TYPE(cs->modulation) == ZD_OFDM &&
ieee80211softmac_protection_needed(softmac)) {
/* FIXME: avoid sending RTS *and* self-CTS, is that correct? */
cs->control &= ~ZD_CS_RTS;
Expand Down Expand Up @@ -925,7 +880,7 @@ static int fill_ctrlset(struct zd_mac *mac,
* - see line 53 of zdinlinef.h
*/
cs->service = 0;
r = zd_calc_tx_length_us(&cs->service, ZD_CS_RATE(cs->modulation),
r = zd_calc_tx_length_us(&cs->service, ZD_RATE(cs->modulation),
le16_to_cpu(cs->tx_length));
if (r < 0)
return r;
Expand All @@ -934,7 +889,7 @@ static int fill_ctrlset(struct zd_mac *mac,
if (next_frag_len == 0) {
cs->next_frame_length = 0;
} else {
r = zd_calc_tx_length_us(NULL, ZD_CS_RATE(cs->modulation),
r = zd_calc_tx_length_us(NULL, ZD_RATE(cs->modulation),
next_frag_len);
if (r < 0)
return r;
Expand Down
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