openwrt/upstream - upstream openwrt

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author	Hal Martin <hal.martin@gmail.com>	2019-09-07 16:28:18 +0000
committer	Hauke Mehrtens <hauke@hauke-m.de>	2019-09-21 01:12:35 +0200
commit	3819c1638a9d300840d0f869628891f9696be112 (patch)
tree	8d3af91a9ef965d6a49c3a1190fb79244efe3ee1 /package/kernel/gpio-button-hotplug/src
parent	f4da28c301890115e5c6b632aa6550fbc59f8e24 (diff)
download	upstream-3819c1638a9d300840d0f869628891f9696be112.tar.gz upstream-3819c1638a9d300840d0f869628891f9696be112.tar.bz2 upstream-3819c1638a9d300840d0f869628891f9696be112.zip

sunxi: Add support for Banana Pi M2 Ultra

CPU: Allwinner R40 Quad-Core Cortex-A7 @ 1.2GHz GPU: Mali 400 MP2 Memory: 2GB DDR3 onboard (shared with GPU) Onboard: Storage microSD card slot Onboard: Storage 8GB eMMC Onboard: Network 10/100/1000M Ethernet RJ45 Onboard: Network WiFi 802.11b/g/n 1x1 (AMPAK AP6212; brcmfmac) Onboard header: SPI, I2C, GPIO, UART USB: Two USB 2.0 Host, One USB 2.0 OTG Known issues: - WiFi doesn't work - eMMC not supported Signed-off-by: Hal Martin <hal.martin@gmail.com>

Diffstat (limited to 'package/kernel/gpio-button-hotplug/src')

0 files changed, 0 insertions, 0 deletions

From 03333931c17d9c62ba4063d4e4fec1578c0729a7 Mon Sep 17 00:00:00 2001 From: Eric Dumazet <eric.dumazet@gmail.com> Date: Sat, 12 May 2012 21:23:23 +0000 Subject: [PATCH] codel: use u16 field instead of 31bits for rec_inv_sqrt commit 6ff272c9ad65eda219cd975b9da2dbc31cc812ee upstream. David pointed out gcc might generate poor code with 31bit fields. Using u16 is more than enough and permits a better code output. Also make the code intent more readable using constants, fixed point arithmetic not being trivial for everybody. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- include/net/codel.h | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) --- a/include/net/codel.h +++ b/include/net/codel.h @@ -133,13 +133,17 @@ struct codel_params { struct codel_vars { u32 count; u32 lastcount; - bool dropping:1; - u32 rec_inv_sqrt:31; + bool dropping; + u16 rec_inv_sqrt; codel_time_t first_above_time; codel_time_t drop_next; codel_time_t ldelay; }; +#define REC_INV_SQRT_BITS (8 * sizeof(u16)) /* or sizeof_in_bits(rec_inv_sqrt) */ +/* needed shift to get a Q0.32 number from rec_inv_sqrt */ +#define REC_INV_SQRT_SHIFT (32 - REC_INV_SQRT_BITS) + /** * struct codel_stats - contains codel shared variables and stats * @maxpacket: largest packet we've seen so far @@ -173,17 +177,18 @@ static void codel_stats_init(struct code * http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2) * - * Here, invsqrt is a fixed point number (< 1.0), 31bit mantissa) + * Here, invsqrt is a fixed point number (< 1.0), 32bit mantissa, aka Q0.32 */ static void codel_Newton_step(struct codel_vars *vars) { - u32 invsqrt = vars->rec_inv_sqrt; - u32 invsqrt2 = ((u64)invsqrt * invsqrt) >> 31; - u64 val = (3LL << 31) - ((u64)vars->count * invsqrt2); + u32 invsqrt = ((u32)vars->rec_inv_sqrt) << REC_INV_SQRT_SHIFT; + u32 invsqrt2 = ((u64)invsqrt * invsqrt) >> 32; + u64 val = (3LL << 32) - ((u64)vars->count * invsqrt2); - val = (val * invsqrt) >> 32; + val >>= 2; /* avoid overflow in following multiply */ + val = (val * invsqrt) >> (32 - 2 + 1); - vars->rec_inv_sqrt = val; + vars->rec_inv_sqrt = val >> REC_INV_SQRT_SHIFT; } /* @@ -195,7 +200,7 @@ static codel_time_t codel_control_law(co codel_time_t interval, u32 rec_inv_sqrt) { - return t + reciprocal_divide(interval, rec_inv_sqrt << 1); + return t + reciprocal_divide(interval, rec_inv_sqrt << REC_INV_SQRT_SHIFT); } @@ -326,7 +331,7 @@ static struct sk_buff *codel_dequeue(str codel_Newton_step(vars); } else { vars->count = 1; - vars->rec_inv_sqrt = 0x7fffffff; + vars->rec_inv_sqrt = ~0U >> REC_INV_SQRT_SHIFT; } vars->lastcount = vars->count; vars->drop_next = codel_control_law(now, params->interval,


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