imx233 evk via SPI ENC28J60 very slow

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imx233 evk via SPI ENC28J60 very slow

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tonimartín
Contributor I

Hello.

I am working with imx233 EVK and the ENC28J60 ethernet chip which is connected via SPI.

After doing tests with iperf, I get a maximum of 2Mbps transmission.

10Mbps:
[ID] Interval Transfer Bandwidth Jitter Lost / Total Datagrams
[3] 0.0-30.2 sec 7.68 MBytes 2.13 Mbits / sec 12.578 ms 25128/30604 (82%)
[4] Local 10.5.0.61 port 12345 connected with 10.200.100.10 port 55178

2Mbps:
[ID] Interval Transfer Bandwidth Jitter Lost / Total Datagrams
[3] 0.0-30.0 sec 7.12 MBytes 1.99 Mbits / sec 1.668 ms 24/5104 (0.47%)

1Mpbs:
[ID] Interval Transfer Bandwidth Jitter Lost / Total Datagrams
[4] 0.0-30.0 sec 3.58 MBytes 1.00 Mbits / sec 0.600 ms 0/2553 (0%)

The test is with UDP packets.

I have seen the SPI bus runs at 6 MHz, should not be able to transmit to 6Mbps?. The chip is the only ethernet device linked to SPI. Is it possible to see actual speed that is being transmitted by SPI?

Thank you.

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lategoodbye
Senior Contributor I

Hi Toni,

assume you run Linux on the imx233.

I have seen the SPI bus runs at 6 MHz, should not be able to transmit to 6Mbps?

No, running this Ethernet interface leads to a lot of additional SPI protocol overhead plus the UDP protocol overhead.

If you need more speed you could try this:

  • increase SPI clock speed
  • check for Kernel parameter ENC28J60_WRITEVERIFY and try to disable it
  • switch to Micrel KS8852

BR Stefan

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tonimartín
Contributor I

Hello Stefan.

Thank for your answer

assume you run Linux on the imx233.

Yes, linux 2.6.31

  • increase SPI clock speed

If increase SPI clock speed above 6Mhz, imx233 stops working.


  • check for Kernel parameter ENC28J60_WRITEVERIFY and try to disable it

Is disable: # CONFIG_ENC28J60_WRITEVERIFY is not set

switch to Micrel KS8852

Change de ethernet card is de last option, if is not possible increase transmission rate.

Any other option?


In this post describe the same problem:


http://www.microchip.com/forums/m634249.aspx


Said it may violate the setup and activation times of CS (see http://ww1.microchip.com/downloads/en/DeviceDoc/39662e.pdf 16-6). Someone has changed the spi driver to resolve this problem.


I change mxs_spi.c to add delay:


static inline void mxs_spi_enable(struct mxs_spi *ss)

{

ndelay(50);

    __raw_writel(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0_SET);

    __raw_writel(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0_CLR);

}

static inline void mxs_spi_disable(struct mxs_spi *ss)

{

ndelay(50);

    __raw_writel(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0_CLR);

    __raw_writel(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0_SET);

}

But not work Smiley Sad

Thanks.

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