From f16593034a30bcbef8f63c37d0f2b9e1a0902c2d Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 20 Oct 2015 16:33:53 -0700 Subject: [PATCH] usb: dwc2: host: Fix ahbcfg for rk3066 The comment for ahbcfg for rk3066 parameters (also used for rk3288) claimed that ahbcfg was INCR16, but it wasn't. Since the bits weren't shifted properly, the 0x7 ended up being masked and we ended up programming 0x3 for the HBstLen. Let's set it to INCR16 properly. As per Wu Liang Feng at Rockchip this may increase transmission efficiency. I did blackbox tests with writing 0s to a USB-based SD reader (forcefully capping CPU Freq to try to measure efficiency): cd /sys/devices/system/cpu/cpu0/cpufreq echo userspace > scaling_governor echo 126000 > scaling_setspeed for i in $(seq 10); do dd if=/dev/zero of=/dev/sdb bs=1M count=750 done With the above tests I found that speeds went from ~15MB/s to ~18MB/s. Note that most other tests I did (including reading from the same USB reader) didn't show any difference in performance. Tested-by: Heiko Stuebner Acked-by: John Youn Reviewed-by: Liangfeng Wu Signed-off-by: Douglas Anderson Signed-off-by: Felipe Balbi --- drivers/usb/dwc2/platform.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c index 5859b0fa19ee..e61d773cf65e 100644 --- a/drivers/usb/dwc2/platform.c +++ b/drivers/usb/dwc2/platform.c @@ -108,7 +108,8 @@ static const struct dwc2_core_params params_rk3066 = { .host_ls_low_power_phy_clk = -1, .ts_dline = -1, .reload_ctl = -1, - .ahbcfg = 0x7, /* INCR16 */ + .ahbcfg = GAHBCFG_HBSTLEN_INCR16 << + GAHBCFG_HBSTLEN_SHIFT, .uframe_sched = -1, .external_id_pin_ctl = -1, .hibernation = -1, -- 2.20.1