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rt2x00: Optimize get_duration / get_duration_res
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We can optimize get_duration and get_duration_res
by making them a macro. They are really simple
calculation handlers so this doesn't matter much.

Often (especially in rt2400pci and rt2500pci,
the arguments are hardcoded, and the result value
is passed into other hardcoded values.

By making the functions a macro GCC can
optimize the entire thing much better.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Ivo van Doorn authored and John W. Linville committed Nov 21, 2008
1 parent 87c1687 commit bad1363
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Showing 6 changed files with 27 additions and 34 deletions.
10 changes: 5 additions & 5 deletions drivers/net/wireless/rt2x00/rt2400pci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -322,7 +322,7 @@ static void rt2400pci_config_intf(struct rt2x00_dev *rt2x00dev,
/*
* Enable beacon config
*/
bcn_preload = PREAMBLE + get_duration(IEEE80211_HEADER, 20);
bcn_preload = PREAMBLE + GET_DURATION(IEEE80211_HEADER, 20);
rt2x00pci_register_read(rt2x00dev, BCNCSR1, &reg);
rt2x00_set_field32(&reg, BCNCSR1_PRELOAD, bcn_preload);
rt2x00pci_register_write(rt2x00dev, BCNCSR1, reg);
Expand Down Expand Up @@ -367,25 +367,25 @@ static void rt2400pci_config_erp(struct rt2x00_dev *rt2x00dev,
rt2x00pci_register_read(rt2x00dev, ARCSR2, &reg);
rt2x00_set_field32(&reg, ARCSR2_SIGNAL, 0x00);
rt2x00_set_field32(&reg, ARCSR2_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 10));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 10));
rt2x00pci_register_write(rt2x00dev, ARCSR2, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR3, &reg);
rt2x00_set_field32(&reg, ARCSR3_SIGNAL, 0x01 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR3_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 20));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 20));
rt2x00pci_register_write(rt2x00dev, ARCSR3, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR4, &reg);
rt2x00_set_field32(&reg, ARCSR4_SIGNAL, 0x02 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR4_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 55));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 55));
rt2x00pci_register_write(rt2x00dev, ARCSR4, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR5, &reg);
rt2x00_set_field32(&reg, ARCSR5_SIGNAL, 0x03 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR5_SERVICE, 0x84);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 110));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 110));
rt2x00pci_register_write(rt2x00dev, ARCSR5, reg);

rt2x00pci_register_write(rt2x00dev, ARCSR1, erp->basic_rates);
Expand Down
10 changes: 5 additions & 5 deletions drivers/net/wireless/rt2x00/rt2500pci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -327,7 +327,7 @@ static void rt2500pci_config_intf(struct rt2x00_dev *rt2x00dev,
/*
* Enable beacon config
*/
bcn_preload = PREAMBLE + get_duration(IEEE80211_HEADER, 20);
bcn_preload = PREAMBLE + GET_DURATION(IEEE80211_HEADER, 20);
rt2x00pci_register_read(rt2x00dev, BCNCSR1, &reg);
rt2x00_set_field32(&reg, BCNCSR1_PRELOAD, bcn_preload);
rt2x00_set_field32(&reg, BCNCSR1_BEACON_CWMIN, queue->cw_min);
Expand Down Expand Up @@ -373,25 +373,25 @@ static void rt2500pci_config_erp(struct rt2x00_dev *rt2x00dev,
rt2x00pci_register_read(rt2x00dev, ARCSR2, &reg);
rt2x00_set_field32(&reg, ARCSR2_SIGNAL, 0x00);
rt2x00_set_field32(&reg, ARCSR2_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 10));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 10));
rt2x00pci_register_write(rt2x00dev, ARCSR2, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR3, &reg);
rt2x00_set_field32(&reg, ARCSR3_SIGNAL, 0x01 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR3_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 20));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 20));
rt2x00pci_register_write(rt2x00dev, ARCSR3, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR4, &reg);
rt2x00_set_field32(&reg, ARCSR4_SIGNAL, 0x02 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR4_SERVICE, 0x04);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 55));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 55));
rt2x00pci_register_write(rt2x00dev, ARCSR4, reg);

rt2x00pci_register_read(rt2x00dev, ARCSR5, &reg);
rt2x00_set_field32(&reg, ARCSR5_SIGNAL, 0x03 | preamble_mask);
rt2x00_set_field32(&reg, ARCSR5_SERVICE, 0x84);
rt2x00_set_field32(&reg, ARCSR2_LENGTH, get_duration(ACK_SIZE, 110));
rt2x00_set_field32(&reg, ARCSR2_LENGTH, GET_DURATION(ACK_SIZE, 110));
rt2x00pci_register_write(rt2x00dev, ARCSR5, reg);

rt2x00pci_register_write(rt2x00dev, ARCSR1, erp->basic_rates);
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/wireless/rt2x00/rt2500usb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -385,7 +385,7 @@ static void rt2500usb_config_intf(struct rt2x00_dev *rt2x00dev,
/*
* Enable beacon config
*/
bcn_preload = PREAMBLE + get_duration(IEEE80211_HEADER, 20);
bcn_preload = PREAMBLE + GET_DURATION(IEEE80211_HEADER, 20);
rt2500usb_register_read(rt2x00dev, TXRX_CSR20, &reg);
rt2x00_set_field16(&reg, TXRX_CSR20_OFFSET, bcn_preload >> 6);
rt2x00_set_field16(&reg, TXRX_CSR20_BCN_EXPECT_WINDOW,
Expand Down
31 changes: 12 additions & 19 deletions drivers/net/wireless/rt2x00/rt2x00.h
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,16 @@
#define EEPROM(__dev, __msg, __args...) \
DEBUG_PRINTK(__dev, KERN_DEBUG, "EEPROM recovery", __msg, ##__args)

/*
* Duration calculations
* The rate variable passed is: 100kbs.
* To convert from bytes to bits we multiply size with 8,
* then the size is multiplied with 10 to make the
* real rate -> rate argument correction.
*/
#define GET_DURATION(__size, __rate) (((__size) * 8 * 10) / (__rate))
#define GET_DURATION_RES(__size, __rate)(((__size) * 8 * 10) % (__rate))

/*
* Standard timing and size defines.
* These values should follow the ieee80211 specifications.
Expand All @@ -109,9 +119,9 @@
#define DIFS ( PIFS + SLOT_TIME )
#define SHORT_DIFS ( SHORT_PIFS + SHORT_SLOT_TIME )
#define EIFS ( SIFS + DIFS + \
(8 * (IEEE80211_HEADER + ACK_SIZE)) )
GET_DURATION(IEEE80211_HEADER + ACK_SIZE, 10) )
#define SHORT_EIFS ( SIFS + SHORT_DIFS + \
(8 * (IEEE80211_HEADER + ACK_SIZE)) )
GET_DURATION(IEEE80211_HEADER + ACK_SIZE, 10) )

/*
* Chipset identification
Expand Down Expand Up @@ -920,23 +930,6 @@ static inline u16 rt2x00_check_rev(const struct rt2x00_chip *chipset,
!!(chipset->rev & 0x0000f));
}

/*
* Duration calculations
* The rate variable passed is: 100kbs.
* To convert from bytes to bits we multiply size with 8,
* then the size is multiplied with 10 to make the
* real rate -> rate argument correction.
*/
static inline u16 get_duration(const unsigned int size, const u8 rate)
{
return ((size * 8 * 10) / rate);
}

static inline u16 get_duration_res(const unsigned int size, const u8 rate)
{
return ((size * 8 * 10) % rate);
}

/**
* rt2x00queue_map_txskb - Map a skb into DMA for TX purposes.
* @rt2x00dev: Pointer to &struct rt2x00_dev.
Expand Down
4 changes: 2 additions & 2 deletions drivers/net/wireless/rt2x00/rt2x00config.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,8 +92,8 @@ void rt2x00lib_config_erp(struct rt2x00_dev *rt2x00dev,
erp.difs = bss_conf->use_short_slot ? SHORT_DIFS : DIFS;
erp.eifs = bss_conf->use_short_slot ? SHORT_EIFS : EIFS;

erp.ack_timeout = PLCP + erp.difs + get_duration(ACK_SIZE, 10);
erp.ack_consume_time = SIFS + PLCP + get_duration(ACK_SIZE, 10);
erp.ack_timeout = PLCP + erp.difs + GET_DURATION(ACK_SIZE, 10);
erp.ack_consume_time = SIFS + PLCP + GET_DURATION(ACK_SIZE, 10);

if (bss_conf->use_short_preamble) {
erp.ack_timeout += SHORT_PREAMBLE;
Expand Down
4 changes: 2 additions & 2 deletions drivers/net/wireless/rt2x00/rt2x00queue.c
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Original file line number Diff line number Diff line change
Expand Up @@ -319,8 +319,8 @@ static void rt2x00queue_create_tx_descriptor(struct queue_entry *entry,
/*
* Convert length to microseconds.
*/
residual = get_duration_res(data_length, hwrate->bitrate);
duration = get_duration(data_length, hwrate->bitrate);
residual = GET_DURATION_RES(data_length, hwrate->bitrate);
duration = GET_DURATION(data_length, hwrate->bitrate);

if (residual != 0) {
duration++;
Expand Down

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