Skip to content

Commit

Permalink
rt2x00: Reduce calls to bbp_read()
Browse files Browse the repository at this point in the history 
The link_tuner() function will always call bbp_read()
at the start of the function. Because this is an
indirect register access has some costs attached
to it (especially for USB hardware).

We already store the value read from the register
into the vgc_level value inside the link structure.
Instead of reading from the register we can read that
field directly and base the tuner on that value.

This reduces the time the registers are locked with
the csr_mutex and speeds up the link_tuner processing.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
  • Loading branch information
Ivo van Doorn authored and John W. Linville committed Jan 29, 2009
1 parent 84e3196 commit eb20b4e
Show file tree
Hide file tree
Showing 5 changed files with 92 additions and 95 deletions.
27 changes: 14 additions & 13 deletions drivers/net/wireless/rt2x00/rt2400pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -600,35 +600,36 @@ static void rt2400pci_link_stats(struct rt2x00_dev *rt2x00dev,
qual->false_cca = bbp;
}

static inline void rt2400pci_set_vgc(struct rt2x00_dev *rt2x00dev, u8 vgc_level)
{
rt2400pci_bbp_write(rt2x00dev, 13, vgc_level);
rt2x00dev->link.vgc_level = vgc_level;
rt2x00dev->link.vgc_level_reg = vgc_level;
}

static void rt2400pci_reset_tuner(struct rt2x00_dev *rt2x00dev)
{
rt2400pci_bbp_write(rt2x00dev, 13, 0x08);
rt2x00dev->link.vgc_level = 0x08;
rt2400pci_set_vgc(rt2x00dev, 0x08);
}

static void rt2400pci_link_tuner(struct rt2x00_dev *rt2x00dev)
{
u8 reg;
struct link *link = &rt2x00dev->link;

/*
* The link tuner should not run longer then 60 seconds,
* and should run once every 2 seconds.
*/
if (rt2x00dev->link.count > 60 || !(rt2x00dev->link.count & 1))
if (link->count > 60 || !(link->count & 1))
return;

/*
* Base r13 link tuning on the false cca count.
*/
rt2400pci_bbp_read(rt2x00dev, 13, &reg);

if (rt2x00dev->link.qual.false_cca > 512 && reg < 0x20) {
rt2400pci_bbp_write(rt2x00dev, 13, ++reg);
rt2x00dev->link.vgc_level = reg;
} else if (rt2x00dev->link.qual.false_cca < 100 && reg > 0x08) {
rt2400pci_bbp_write(rt2x00dev, 13, --reg);
rt2x00dev->link.vgc_level = reg;
}
if ((link->qual.false_cca > 512) && (link->vgc_level < 0x20))
rt2400pci_set_vgc(rt2x00dev, ++link->vgc_level);
else if ((link->qual.false_cca < 100) && (link->vgc_level > 0x08))
rt2400pci_set_vgc(rt2x00dev, --link->vgc_level);
}

/*
Expand Down
50 changes: 25 additions & 25 deletions drivers/net/wireless/rt2x00/rt2500pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -639,29 +639,33 @@ static void rt2500pci_link_stats(struct rt2x00_dev *rt2x00dev,
qual->false_cca = rt2x00_get_field32(reg, CNT3_FALSE_CCA);
}

static inline void rt2500pci_set_vgc(struct rt2x00_dev *rt2x00dev, u8 vgc_level)
{
if (rt2x00dev->link.vgc_level_reg != vgc_level) {
rt2500pci_bbp_write(rt2x00dev, 17, vgc_level);
rt2x00dev->link.vgc_level_reg = vgc_level;
}
}

static void rt2500pci_reset_tuner(struct rt2x00_dev *rt2x00dev)
{
rt2500pci_bbp_write(rt2x00dev, 17, 0x48);
rt2x00dev->link.vgc_level = 0x48;
rt2500pci_set_vgc(rt2x00dev, 0x48);
}

static void rt2500pci_link_tuner(struct rt2x00_dev *rt2x00dev)
{
int rssi = rt2x00_get_link_rssi(&rt2x00dev->link);
u8 r17;
struct link *link = &rt2x00dev->link;
int rssi = rt2x00_get_link_rssi(link);

/*
* To prevent collisions with MAC ASIC on chipsets
* up to version C the link tuning should halt after 20
* seconds while being associated.
*/
if (rt2x00_rev(&rt2x00dev->chip) < RT2560_VERSION_D &&
rt2x00dev->intf_associated &&
rt2x00dev->link.count > 20)
rt2x00dev->intf_associated && link->count > 20)
return;

rt2500pci_bbp_read(rt2x00dev, 17, &r17);

/*
* Chipset versions C and lower should directly continue
* to the dynamic CCA tuning. Chipset version D and higher
Expand All @@ -677,38 +681,34 @@ static void rt2500pci_link_tuner(struct rt2x00_dev *rt2x00dev)
* then corrupt the R17 tuning. To remidy this the tuning should
* be stopped (While making sure the R17 value will not exceed limits)
*/
if (rssi < -80 && rt2x00dev->link.count > 20) {
if (r17 >= 0x41) {
r17 = rt2x00dev->link.vgc_level;
rt2500pci_bbp_write(rt2x00dev, 17, r17);
}
if (rssi < -80 && link->count > 20) {
if (link->vgc_level_reg >= 0x41)
rt2500pci_set_vgc(rt2x00dev, link->vgc_level);
return;
}

/*
* Special big-R17 for short distance
*/
if (rssi >= -58) {
if (r17 != 0x50)
rt2500pci_bbp_write(rt2x00dev, 17, 0x50);
rt2500pci_set_vgc(rt2x00dev, 0x50);
return;
}

/*
* Special mid-R17 for middle distance
*/
if (rssi >= -74) {
if (r17 != 0x41)
rt2500pci_bbp_write(rt2x00dev, 17, 0x41);
rt2500pci_set_vgc(rt2x00dev, 0x41);
return;
}

/*
* Leave short or middle distance condition, restore r17
* to the dynamic tuning range.
*/
if (r17 >= 0x41) {
rt2500pci_bbp_write(rt2x00dev, 17, rt2x00dev->link.vgc_level);
if (link->vgc_level_reg >= 0x41) {
rt2500pci_set_vgc(rt2x00dev, link->vgc_level);
return;
}

Expand All @@ -718,12 +718,12 @@ static void rt2500pci_link_tuner(struct rt2x00_dev *rt2x00dev)
* R17 is inside the dynamic tuning range,
* start tuning the link based on the false cca counter.
*/
if (rt2x00dev->link.qual.false_cca > 512 && r17 < 0x40) {
rt2500pci_bbp_write(rt2x00dev, 17, ++r17);
rt2x00dev->link.vgc_level = r17;
} else if (rt2x00dev->link.qual.false_cca < 100 && r17 > 0x32) {
rt2500pci_bbp_write(rt2x00dev, 17, --r17);
rt2x00dev->link.vgc_level = r17;
if (link->qual.false_cca > 512 && link->vgc_level_reg < 0x40) {
rt2500pci_set_vgc(rt2x00dev, ++link->vgc_level_reg);
link->vgc_level = link->vgc_level_reg;
} else if (link->qual.false_cca < 100 && link->vgc_level_reg > 0x32) {
rt2500pci_set_vgc(rt2x00dev, --link->vgc_level_reg);
link->vgc_level = link->vgc_level_reg;
}
}

Expand Down
9 changes: 7 additions & 2 deletions drivers/net/wireless/rt2x00/rt2x00.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -286,9 +286,14 @@ struct link {
struct link_ant ant;

/*
* Active VGC level
* Active VGC level (for false cca tuning)
*/
int vgc_level;
u8 vgc_level;

/*
* VGC level as configured in register
*/
u8 vgc_level_reg;

/*
* Work structure for scheduling periodic link tuning.
Expand Down
49 changes: 22 additions & 27 deletions drivers/net/wireless/rt2x00/rt61pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1046,21 +1046,27 @@ static void rt61pci_link_stats(struct rt2x00_dev *rt2x00dev,
qual->false_cca = rt2x00_get_field32(reg, STA_CSR1_FALSE_CCA_ERROR);
}

static inline void rt61pci_set_vgc(struct rt2x00_dev *rt2x00dev, u8 vgc_level)
{
if (rt2x00dev->link.vgc_level != vgc_level) {
rt61pci_bbp_write(rt2x00dev, 17, vgc_level);
rt2x00dev->link.vgc_level = vgc_level;
rt2x00dev->link.vgc_level_reg = vgc_level;
}
}

static void rt61pci_reset_tuner(struct rt2x00_dev *rt2x00dev)
{
rt61pci_bbp_write(rt2x00dev, 17, 0x20);
rt2x00dev->link.vgc_level = 0x20;
rt61pci_set_vgc(rt2x00dev, 0x20);
}

static void rt61pci_link_tuner(struct rt2x00_dev *rt2x00dev)
{
int rssi = rt2x00_get_link_rssi(&rt2x00dev->link);
u8 r17;
struct link *link = &rt2x00dev->link;
int rssi = rt2x00_get_link_rssi(link);
u8 up_bound;
u8 low_bound;

rt61pci_bbp_read(rt2x00dev, 17, &r17);

/*
* Determine r17 bounds.
*/
Expand Down Expand Up @@ -1091,37 +1097,31 @@ static void rt61pci_link_tuner(struct rt2x00_dev *rt2x00dev)
* Special big-R17 for very short distance
*/
if (rssi >= -35) {
if (r17 != 0x60)
rt61pci_bbp_write(rt2x00dev, 17, 0x60);
rt61pci_set_vgc(rt2x00dev, 0x60);
return;
}

/*
* Special big-R17 for short distance
*/
if (rssi >= -58) {
if (r17 != up_bound)
rt61pci_bbp_write(rt2x00dev, 17, up_bound);
rt61pci_set_vgc(rt2x00dev, up_bound);
return;
}

/*
* Special big-R17 for middle-short distance
*/
if (rssi >= -66) {
low_bound += 0x10;
if (r17 != low_bound)
rt61pci_bbp_write(rt2x00dev, 17, low_bound);
rt61pci_set_vgc(rt2x00dev, low_bound + 0x10);
return;
}

/*
* Special mid-R17 for middle distance
*/
if (rssi >= -74) {
low_bound += 0x08;
if (r17 != low_bound)
rt61pci_bbp_write(rt2x00dev, 17, low_bound);
rt61pci_set_vgc(rt2x00dev, low_bound + 0x08);
return;
}

Expand All @@ -1133,8 +1133,8 @@ static void rt61pci_link_tuner(struct rt2x00_dev *rt2x00dev)
if (low_bound > up_bound)
up_bound = low_bound;

if (r17 > up_bound) {
rt61pci_bbp_write(rt2x00dev, 17, up_bound);
if (link->vgc_level > up_bound) {
rt61pci_set_vgc(rt2x00dev, up_bound);
return;
}

Expand All @@ -1144,15 +1144,10 @@ static void rt61pci_link_tuner(struct rt2x00_dev *rt2x00dev)
* r17 does not yet exceed upper limit, continue and base
* the r17 tuning on the false CCA count.
*/
if (rt2x00dev->link.qual.false_cca > 512 && r17 < up_bound) {
if (++r17 > up_bound)
r17 = up_bound;
rt61pci_bbp_write(rt2x00dev, 17, r17);
} else if (rt2x00dev->link.qual.false_cca < 100 && r17 > low_bound) {
if (--r17 < low_bound)
r17 = low_bound;
rt61pci_bbp_write(rt2x00dev, 17, r17);
}
if ((link->qual.false_cca > 512) && (link->vgc_level < up_bound))
rt61pci_set_vgc(rt2x00dev, ++link->vgc_level);
else if ((link->qual.false_cca < 100) && (link->vgc_level > low_bound))
rt61pci_set_vgc(rt2x00dev, --link->vgc_level);
}

/*
Expand Down
52 changes: 24 additions & 28 deletions drivers/net/wireless/rt2x00/rt73usb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -924,21 +924,27 @@ static void rt73usb_link_stats(struct rt2x00_dev *rt2x00dev,
qual->false_cca = rt2x00_get_field32(reg, STA_CSR1_FALSE_CCA_ERROR);
}

static inline void rt73usb_set_vgc(struct rt2x00_dev *rt2x00dev, u8 vgc_level)
{
if (rt2x00dev->link.vgc_level != vgc_level) {
rt73usb_bbp_write(rt2x00dev, 17, vgc_level);
rt2x00dev->link.vgc_level = vgc_level;
rt2x00dev->link.vgc_level_reg = vgc_level;
}
}

static void rt73usb_reset_tuner(struct rt2x00_dev *rt2x00dev)
{
rt73usb_bbp_write(rt2x00dev, 17, 0x20);
rt2x00dev->link.vgc_level = 0x20;
rt73usb_set_vgc(rt2x00dev, 0x20);
}

static void rt73usb_link_tuner(struct rt2x00_dev *rt2x00dev)
{
int rssi = rt2x00_get_link_rssi(&rt2x00dev->link);
u8 r17;
struct link *link = &rt2x00dev->link;
int rssi = rt2x00_get_link_rssi(link);
u8 up_bound;
u8 low_bound;

rt73usb_bbp_read(rt2x00dev, 17, &r17);

/*
* Determine r17 bounds.
*/
Expand Down Expand Up @@ -979,36 +985,31 @@ static void rt73usb_link_tuner(struct rt2x00_dev *rt2x00dev)
* Special big-R17 for very short distance
*/
if (rssi > -35) {
if (r17 != 0x60)
rt73usb_bbp_write(rt2x00dev, 17, 0x60);
rt73usb_set_vgc(rt2x00dev, 0x60);
return;
}

/*
* Special big-R17 for short distance
*/
if (rssi >= -58) {
if (r17 != up_bound)
rt73usb_bbp_write(rt2x00dev, 17, up_bound);
rt73usb_set_vgc(rt2x00dev, up_bound);
return;
}

/*
* Special big-R17 for middle-short distance
*/
if (rssi >= -66) {
low_bound += 0x10;
if (r17 != low_bound)
rt73usb_bbp_write(rt2x00dev, 17, low_bound);
rt73usb_set_vgc(rt2x00dev, low_bound + 0x10);
return;
}

/*
* Special mid-R17 for middle distance
*/
if (rssi >= -74) {
if (r17 != (low_bound + 0x10))
rt73usb_bbp_write(rt2x00dev, 17, low_bound + 0x08);
rt73usb_set_vgc(rt2x00dev, low_bound + 0x08);
return;
}

Expand All @@ -1020,8 +1021,8 @@ static void rt73usb_link_tuner(struct rt2x00_dev *rt2x00dev)
if (low_bound > up_bound)
up_bound = low_bound;

if (r17 > up_bound) {
rt73usb_bbp_write(rt2x00dev, 17, up_bound);
if (link->vgc_level > up_bound) {
rt73usb_set_vgc(rt2x00dev, up_bound);
return;
}

Expand All @@ -1031,17 +1032,12 @@ static void rt73usb_link_tuner(struct rt2x00_dev *rt2x00dev)
* r17 does not yet exceed upper limit, continue and base
* the r17 tuning on the false CCA count.
*/
if (rt2x00dev->link.qual.false_cca > 512 && r17 < up_bound) {
r17 += 4;
if (r17 > up_bound)
r17 = up_bound;
rt73usb_bbp_write(rt2x00dev, 17, r17);
} else if (rt2x00dev->link.qual.false_cca < 100 && r17 > low_bound) {
r17 -= 4;
if (r17 < low_bound)
r17 = low_bound;
rt73usb_bbp_write(rt2x00dev, 17, r17);
}
if ((link->qual.false_cca > 512) && (link->vgc_level < up_bound))
rt73usb_set_vgc(rt2x00dev,
min_t(u8, link->vgc_level + 4, up_bound));
else if ((link->qual.false_cca < 100) && (link->vgc_level > low_bound))
rt73usb_set_vgc(rt2x00dev,
max_t(u8, link->vgc_level - 4, low_bound));
}

/*
Expand Down

0 comments on commit eb20b4e

Please sign in to comment.