So! I am here again, LOL!
Whatever, the problem seems to reside at sdhci_bcm because on my Beagle Bone Black with sdhci_ti the performance is "normal". here on Raspberry Pi B it looks like 200 KB/s which is too low. The card as it is can do up to 7 MB/s writing (using a cardreader from laptop).
Code:
KDB: debugger backends: ddb
KDB: current backend: ddb
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FreeBSD 11.0-CURRENT #0 r283577: Wed May 27 01:17:31 UTC 2015
root@releng2.nyi.freebsd.org:/usr/obj/arm.armv6/usr/src/sys/RPI-B arm
FreeBSD clang version 3.6.1 (tags/RELEASE_361/final 237755) 20150525
VT: init without driver.
sema_sysinit
CPU: ARM1176JZ-S rev 7 (ARM11J core)
Supported features: ARM_ISA THUMB2 JAZELLE ARMv4 Security_Ext
WB enabled LABT branch prediction enabled
16KB/32B 4-way instruction cache
16KB/32B 4-way write-back-locking-C data cache
real memory = 503312384 (479 MB)
avail memory = 482803712 (460 MB)
random: entropy device infrastructure driver
random: selecting highest priority adaptor <Dummy>
random: SOFT: yarrow init()
random: selecting highest priority adaptor <Yarrow>
kbd0 at kbdmux0
ofwbus0: <Open Firmware Device Tree>
simplebus0: <Flattened device tree simple bus> mem 0x20000000-0x20ffffff on ofwbus0
cpulist0: <Open Firmware CPU Group> on ofwbus0
cpu0: <Open Firmware CPU> on cpulist0
bcm2835_cpufreq0: <CPU Frequency Control> on cpu0
intc0: <BCM2835 Interrupt Controller> mem 0xb200-0xb3ff on simplebus0
systimer0: <BCM2835 System Timer> mem 0x3000-0x3fff irq 8,9,10,11 on simplebus0
Event timer "BCM2835 Event Timer 3" frequency 1000000 Hz quality 1000
Timecounter "BCM2835 Timecounter" frequency 1000000 Hz quality 1000
bcmwd0: <BCM2708/2835 Watchdog> mem 0x10001c-0x100027 on simplebus0
gpio0: <BCM2708/2835 GPIO controller> mem 0x200000-0x2000af irq 57,59,58,60 on simplebus0
gpio0: read-only pins: 46-53.
gpio0: reserved pins: 48-53.
gpiobus0: <OFW GPIO bus> on gpio0
gpioled0: <GPIO led> at pin(s) 16 on gpiobus0
gpioc0: <GPIO controller> on gpio0
iichb0: <BCM2708/2835 BSC controller> mem 0x205000-0x20501f irq 61 on simplebus0
iicbus0: <OFW I2C bus> on iichb0
iic0: <I2C generic I/O> on iicbus0
iichb1: <BCM2708/2835 BSC controller> mem 0x804000-0x80401f irq 61 on simplebus0
iicbus1: <OFW I2C bus> on iichb1
iic1: <I2C generic I/O> on iicbus1
spi0: <BCM2708/2835 SPI controller> mem 0x204000-0x20401f irq 62 on simplebus0
spibus0: <OFW SPI bus> on spi0
bcm_dma0: <BCM2835 DMA Controller> mem 0x7000-0x7fff,0xe05000-0xe05fff irq 24,25,26,27,28,29,30,31,32,33,34,35,36 on simplebus0
mbox0: <BCM2835 VideoCore Mailbox> mem 0xb880-0xb8bf irq 1 on simplebus0
sdhci_bcm0: <Broadcom 2708 SDHCI controller> mem 0x300000-0x3000ff irq 70 on simplebus0
mmc0: <MMC/SD bus> on sdhci_bcm0
uart0: <PrimeCell UART (PL011)> mem 0x201000-0x201fff irq 65 on simplebus0
uart0: console (115200,n,8,1)
vchiq0: <BCM2835 VCHIQ> mem 0xb800-0xb84f irq 2 on simplebus0
vchiq0: [GIANT-LOCKED]
vchiq: local ver 6 (min 3), remote ver 6.
pcm0: <VCHQI audio> on vchiq0
bcm283x_dwcotg0: <DWC OTG 2.0 integrated USB controller (bcm283x)> mem 0x980000-0x99ffff irq 17 on simplebus0
usbus0 on bcm283x_dwcotg0
fb0: <BCM2835 VT framebuffer driver> on ofwbus0
fbd0 on fb0
VT: initialize with new VT driver "fb".
fb0: 656x416(656x416@0,0) 24bpp
fb0: fbswap: 0, pitch 1968, base 0x1e08c000, screen_size 818688
Timecounters tick every 10.000 msec
usbus0: 480Mbps High Speed USB v2.0
bcm2835_cpufreq0: ARM 700MHz, Core 250MHz, SDRAM 400MHz, Turbo OFF
ugen0.1: <DWCOTG> at usbus0
uhub0: <DWCOTG OTG Root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus0
sdhci_bcm0-slot0: Got data interrupt 0x00000002, but there is no active command.
sdhci_bcm0-slot0: ============== REGISTER DUMP ==============
sdhci_bcm0-slot0: Sys addr: 0x00000000 | Version: 0x00009902
sdhci_bcm0-slot0: Blk size: 0x00000040 | Blk cnt: 0x00000001
sdhci_bcm0-slot0: Argument: 0xe6240000 | Trn mode: 0x0000071b
sdhci_bcm0-slot0: Present: 0x01ff0000 | Host ctl: 0x00000001
sdhci_bcm0-slot0: Power: 0x0000000f | Blk gap: 0x00000000
sdhci_bcm0-slot0: Wake-up: 0x00000000 | Clock: 0x00003947
sdhci_bcm0-slot0: Timeout: 0x0000000e | Int stat: 0x00000000
sdhci_bcm0-slot0: Int enab: 0x01ff00fb | Sig enab: 0x01ff00fb
sdhci_bcm0-slot0: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci_bcm0-slot0: Caps: 0x00000000 | Max curr: 0x00000001
sdhci_bcm0-slot0: ===========================================
sdhci_bcm0-slot0: Got data interrupt 0x00000002, but there is no active command.
sdhci_bcm0-slot0: ============== REGISTER DUMP ==============
sdhci_bcm0-slot0: Sys addr: 0x00000000 | Version: 0x00009902
sdhci_bcm0-slot0: Blk size: 0x00000040 | Blk cnt: 0x00000001
sdhci_bcm0-slot0: Argument: 0xe6240000 | Trn mode: 0x0000071b
sdhci_bcm0-slot0: Present: 0x01ff0000 | Host ctl: 0x00000001
sdhci_bcm0-slot0: Power: 0x0000000f | Blk gap: 0x00000000
sdhci_bcm0-slot0: Wake-up: 0x00000000 | Clock: 0x00003947
sdhci_bcm0-slot0: Timeout: 0x0000000e | Int stat: 0x00000000
sdhci_bcm0-slot0: Int enab: 0x01ff00fb | Sig enab: 0x01ff00fb
sdhci_bcm0-slot0: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci_bcm0-slot0: Caps: 0x00000000 | Max curr: 0x00000001
sdhci_bcm0-slot0: ===========================================
sdhci_bcm0-slot0: Got data interrupt 0x00000002, but there is no active command.
sdhci_bcm0-slot0: ============== REGISTER DUMP ==============
sdhci_bcm0-slot0: Sys addr: 0x00000000 | Version: 0x00009902
sdhci_bcm0-slot0: Blk size: 0x00000040 | Blk cnt: 0x00000001
sdhci_bcm0-slot0: Argument: 0xe6240000 | Trn mode: 0x0000071b
sdhci_bcm0-slot0: Present: 0x01ff0000 | Host ctl: 0x00000001
sdhci_bcm0-slot0: Power: 0x0000000f | Blk gap: 0x00000000
sdhci_bcm0-slot0: Wake-up: 0x00000000 | Clock: 0x00003947
sdhci_bcm0-slot0: Timeout: 0x0000000e | Int stat: 0x00000000
sdhci_bcm0-slot0: Int enab: 0x01ff00fb | Sig enab: 0x01ff00fb
sdhci_bcm0-slot0: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci_bcm0-slot0: Caps: 0x00000000 | Max curr: 0x00000001
sdhci_bcm0-slot0: ===========================================
uhub0: 1 port with 1 removable, self powered
sdhci_bcm0-slot0: Got data interrupt 0x00000002, but there is no active command.
sdhci_bcm0-slot0: ============== REGISTER DUMP ==============
sdhci_bcm0-slot0: Sys addr: 0x00000000 | Version: 0x00009902
sdhci_bcm0-slot0: Blk size: 0x00000040 | Blk cnt: 0x00000001
sdhci_bcm0-slot0: Argument: 0xe6240000 | Trn mode: 0x0000071b
sdhci_bcm0-slot0: Present: 0x01ff0000 | Host ctl: 0x00000001
sdhci_bcm0-slot0: Power: 0x0000000f | Blk gap: 0x00000000
sdhci_bcm0-slot0: Wake-up: 0x00000000 | Clock: 0x00003947
sdhci_bcm0-slot0: Timeout: 0x0000000e | Int stat: 0x00000000
sdhci_bcm0-slot0: Int enab: 0x01ff00fb | Sig enab: 0x01ff00fb
sdhci_bcm0-slot0: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci_bcm0-slot0: Caps: 0x00000000 | Max curr: 0x00000001
sdhci_bcm0-slot0: ===========================================
mmc0: CMD7 failed, RESULT: 1
mmcsd0: 16GB <SDHC SD16G 8.0 SN 18DC8D0A MFG 04/2012 by 3 SD> at mmc0 25.0MHz/4bit/65535-block
random: unblocking device.
Root mount waiting for: usbus0
ugen0.2: <vendor 0x0424> at usbus0
uhub1: <vendor 0x0424 product 0x9512, class 9/0, rev 2.00/2.00, addr 2> on usbus0
uhub1: MTT enabled
uhub1: 3 ports with 2 removable, self powered
Root mount waiting for: usbus0
ugen0.3: <vendor 0x0424> at usbus0
smsc0: <vendor 0x0424 product 0xec00, rev 2.00/2.00, addr 3> on usbus0
Trying to mount root from ufs:/dev/ufs/rootfs [rw]...
smsc0: chip 0xec00, rev. 0002
miibus0: <MII bus> on smsc0
ukphy0: <Generic IEEE 802.3u media interface> PHY 1 on miibus0
ukphy0: none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
ue0: <USB Ethernet> on smsc0
ue0: Ethernet address: b8:27:eb:fc:5e:20
warning: no time-of-day clock registered, system time will not be set accurately
smsc0: chip 0xec00, rev. 0002
ue0: link state changed to DOWN
ue0: link state changed to UP
swap_pager: indefinite wait buffer: bufobj: 0, blkno: 1219, size: 4096
swap_pager: indefinite wait buffer: bufobj: 0, blkno: 1219, size: 4096