[PATCH v2] bitops: Provide generic sign_extend32 function

From: Andreas Herrmann
Date: Mon Aug 30 2010 - 14:34:15 EST

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From: Andreas Herrmann <andreas.herrmann3@xxxxxxx>

This patch moves code out from wireless drivers where two different
functions are defined in three code locations for the same purpose and
provides a common function to sign extend a 32-bit value.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@xxxxxxx>
---
drivers/net/wireless/ath/ath5k/phy.c | 8 +-------
drivers/net/wireless/ath/ath9k/ar5008_phy.c | 12 ++++++------
drivers/net/wireless/ath/ath9k/ar9002_phy.c | 8 ++++----
drivers/net/wireless/ath/ath9k/ar9003_phy.c | 12 ++++++------
drivers/net/wireless/ath/ath9k/hw.h | 6 ------
drivers/net/wireless/iwlwifi/iwl-4965.c | 20 ++------------------
include/linux/bitops.h | 11 +++++++++++
7 files changed, 30 insertions(+), 47 deletions(-)

Differences to first version.
(1) Rename to sign_extend32 - it handles only 32-bit values
(2) Adapt function calls in ath*k code - the common function uses bit
position (0..31) instead of number of bits (1..32)

Andreas

diff --git a/drivers/net/wireless/ath/ath5k/phy.c b/drivers/net/wireless/ath/ath5k/phy.c
index 6284c38..c9295b4 100644
--- a/drivers/net/wireless/ath/ath5k/phy.c
+++ b/drivers/net/wireless/ath/ath5k/phy.c
@@ -1101,18 +1101,12 @@ int ath5k_hw_channel(struct ath5k_hw *ah, struct ieee80211_channel *channel)
PHY calibration
\*****************/

-static int sign_extend(int val, const int nbits)
-{
- int order = BIT(nbits-1);
- return (val ^ order) - order;
-}
-
static s32 ath5k_hw_read_measured_noise_floor(struct ath5k_hw *ah)
{
s32 val;

val = ath5k_hw_reg_read(ah, AR5K_PHY_NF);
- return sign_extend(AR5K_REG_MS(val, AR5K_PHY_NF_MINCCA_PWR), 9);
+ return sign_extend32(AR5K_REG_MS(val, AR5K_PHY_NF_MINCCA_PWR), 8);
}

void ath5k_hw_init_nfcal_hist(struct ath5k_hw *ah)
diff --git a/drivers/net/wireless/ath/ath9k/ar5008_phy.c b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
index 3d2c867..0a7d136 100644
--- a/drivers/net/wireless/ath/ath9k/ar5008_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
@@ -1498,25 +1498,25 @@ static void ar5008_hw_do_getnf(struct ath_hw *ah,
int16_t nf;

nf = MS(REG_READ(ah, AR_PHY_CCA), AR_PHY_MINCCA_PWR);
- nfarray[0] = sign_extend(nf, 9);
+ nfarray[0] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CH1_CCA), AR_PHY_CH1_MINCCA_PWR);
- nfarray[1] = sign_extend(nf, 9);
+ nfarray[1] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CH2_CCA), AR_PHY_CH2_MINCCA_PWR);
- nfarray[2] = sign_extend(nf, 9);
+ nfarray[2] = sign_extend32(nf, 8);

if (!IS_CHAN_HT40(ah->curchan))
return;

nf = MS(REG_READ(ah, AR_PHY_EXT_CCA), AR_PHY_EXT_MINCCA_PWR);
- nfarray[3] = sign_extend(nf, 9);
+ nfarray[3] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CH1_EXT_CCA), AR_PHY_CH1_EXT_MINCCA_PWR);
- nfarray[4] = sign_extend(nf, 9);
+ nfarray[4] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CH2_EXT_CCA), AR_PHY_CH2_EXT_MINCCA_PWR);
- nfarray[5] = sign_extend(nf, 9);
+ nfarray[5] = sign_extend32(nf, 8);
}

/*
diff --git a/drivers/net/wireless/ath/ath9k/ar9002_phy.c b/drivers/net/wireless/ath/ath9k/ar9002_phy.c
index adbf031..4b99c33 100644
--- a/drivers/net/wireless/ath/ath9k/ar9002_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9002_phy.c
@@ -474,21 +474,21 @@ static void ar9002_hw_do_getnf(struct ath_hw *ah,
int16_t nf;

nf = MS(REG_READ(ah, AR_PHY_CCA), AR9280_PHY_MINCCA_PWR);
- nfarray[0] = sign_extend(nf, 9);
+ nfarray[0] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_EXT_CCA), AR9280_PHY_EXT_MINCCA_PWR);
if (IS_CHAN_HT40(ah->curchan))
- nfarray[3] = sign_extend(nf, 9);
+ nfarray[3] = sign_extend32(nf, 8);

if (AR_SREV_9285(ah) || AR_SREV_9271(ah))
return;

nf = MS(REG_READ(ah, AR_PHY_CH1_CCA), AR9280_PHY_CH1_MINCCA_PWR);
- nfarray[1] = sign_extend(nf, 9);
+ nfarray[1] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CH1_EXT_CCA), AR9280_PHY_CH1_EXT_MINCCA_PWR);
if (IS_CHAN_HT40(ah->curchan))
- nfarray[4] = sign_extend(nf, 9);
+ nfarray[4] = sign_extend32(nf, 8);
}

static void ar9002_hw_set_nf_limits(struct ath_hw *ah)
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_phy.c b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
index a491854..e52634e 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
@@ -1025,25 +1025,25 @@ static void ar9003_hw_do_getnf(struct ath_hw *ah,
int16_t nf;

nf = MS(REG_READ(ah, AR_PHY_CCA_0), AR_PHY_MINCCA_PWR);
- nfarray[0] = sign_extend(nf, 9);
+ nfarray[0] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CCA_1), AR_PHY_CH1_MINCCA_PWR);
- nfarray[1] = sign_extend(nf, 9);
+ nfarray[1] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_CCA_2), AR_PHY_CH2_MINCCA_PWR);
- nfarray[2] = sign_extend(nf, 9);
+ nfarray[2] = sign_extend32(nf, 8);

if (!IS_CHAN_HT40(ah->curchan))
return;

nf = MS(REG_READ(ah, AR_PHY_EXT_CCA), AR_PHY_EXT_MINCCA_PWR);
- nfarray[3] = sign_extend(nf, 9);
+ nfarray[3] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_EXT_CCA_1), AR_PHY_CH1_EXT_MINCCA_PWR);
- nfarray[4] = sign_extend(nf, 9);
+ nfarray[4] = sign_extend32(nf, 8);

nf = MS(REG_READ(ah, AR_PHY_EXT_CCA_2), AR_PHY_CH2_EXT_MINCCA_PWR);
- nfarray[5] = sign_extend(nf, 9);
+ nfarray[5] = sign_extend32(nf, 8);
}

static void ar9003_hw_set_nf_limits(struct ath_hw *ah)
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 399f7c1..5dad02f 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -858,12 +858,6 @@ static inline struct ath_hw_ops *ath9k_hw_ops(struct ath_hw *ah)
return &ah->ops;
}

-static inline int sign_extend(int val, const int nbits)
-{
- int order = BIT(nbits-1);
- return (val ^ order) - order;
-}
-
/* Initialization, Detach, Reset */
const char *ath9k_hw_probe(u16 vendorid, u16 devid);
void ath9k_hw_deinit(struct ath_hw *ah);
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965.c b/drivers/net/wireless/iwlwifi/iwl-4965.c
index d92b729..92ded39 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965.c
+++ b/drivers/net/wireless/iwlwifi/iwl-4965.c
@@ -1551,22 +1551,6 @@ static void iwl4965_txq_update_byte_cnt_tbl(struct iwl_priv *priv,
}

/**
- * sign_extend - Sign extend a value using specified bit as sign-bit
- *
- * Example: sign_extend(9, 3) would return -7 as bit3 of 1001b is 1
- * and bit0..2 is 001b which when sign extended to 1111111111111001b is -7.
- *
- * @param oper value to sign extend
- * @param index 0 based bit index (0<=index<32) to sign bit
- */
-static s32 sign_extend(u32 oper, int index)
-{
- u8 shift = 31 - index;
-
- return (s32)(oper << shift) >> shift;
-}
-
-/**
* iwl4965_hw_get_temperature - return the calibrated temperature (in Kelvin)
* @statistics: Provides the temperature reading from the uCode
*
@@ -1603,9 +1587,9 @@ static int iwl4965_hw_get_temperature(struct iwl_priv *priv)
* "initialize" ALIVE response.
*/
if (!test_bit(STATUS_TEMPERATURE, &priv->status))
- vt = sign_extend(R4, 23);
+ vt = sign_extend32(R4, 23);
else
- vt = sign_extend(le32_to_cpu(priv->_agn.statistics.
+ vt = sign_extend32(le32_to_cpu(priv->_agn.statistics.
general.common.temperature), 23);

IWL_DEBUG_TEMP(priv, "Calib values R[1-3]: %d %d %d R4: %d\n", R1, R2, R3, vt);
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index fc68053..a68246e 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -109,6 +109,17 @@ static inline __u8 ror8(__u8 word, unsigned int shift)
return (word >> shift) | (word << (8 - shift));
}

+/**
+ * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
+ * @value: value to sign extend
+ * @index: 0 based bit index (0<=index<32) to sign bit
+ */
+static inline __s32 sign_extend32(__u32 value, int index)
+{
+ __u8 shift = 31 - index;
+ return (__s32)(value << shift) >> shift;
+}
+
static inline unsigned fls_long(unsigned long l)
{
if (sizeof(l) == 4)
--
1.6.4.4

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Next message: Valerie Aurora: "Re: [PATCH 0/5] hybrid union filesystem prototype"
Previous message: Andres Salomon: "Re: [PATCH 9/9] x86: OLPC: add OLPC device-tree support"
In reply to: Bob Copeland: "Re: [PATCH] bitops: Provide generic sign_extend function (moving itout from wireless code)"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]