imx28 SPI Slave DMA

tomi — Fri, 21 Feb 2014 20:36:59 GMT

Hi,

after a long time working with SPI Slave experiments and many help from Freescale and DENX people i got a spi slave running with DMA but if i got an commuication error between SPI host and Slave the DMA transfer times out and i can not reset the spi or dma channel can anyone help me about this.

I have tried reset dma , reset spi block.. but nothing helps

code snipped from mxs_spi.c:

ss->pdesc->cmd.cmd.bits.bytes = len;

ss->pdesc->cmd.cmd.bits.pio_words = 1;

ss->pdesc->cmd.cmd.bits.wait4end = 1;

ss->pdesc->cmd.cmd.bits.dec_sem = 1;

ss->pdesc->cmd.cmd.bits.irq = 1;

//ss->pdesc->cmd.cmd.bits.chain = 1; // hello TF

ss->pdesc->cmd.cmd.bits.command = write ? DMA_READ : DMA_WRITE;

ss->pdesc->cmd.address = spi_buf_dma;

ss->pdesc->cmd.pio_words[0] = c0;

mxs_dma_desc_append(ss->dma, ss->pdesc);

mxs_dma_reset(ss->dma);

mxs_dma_ack_irq(ss->dma);

mxs_dma_enable_irq(ss->dma, 1);

init_completion(&ss->done);

mxs_dma_enable(ss->dma);

//wait_for_completion(&ss->done);

retw = wait_for_completion_timeout(&ss->done,500); // hello TF 5s

printk(" retw = %x\n",retw);

// fixme after a timeout we have to reset kernel dont know why

if(retw != 0){ // hello TF we have got a value

count = 10000;

while ((__raw_readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN)

&& count--)

continue;

if (count <= 0) {

printk(KERN_ERR "%c: timeout on line %s:%d\n",

write ? 'W' : 'C', __func__, __LINE__);

status = -ETIMEDOUT;

}

if (!dma_buf)

dma_unmap_single(ss->master_dev, spi_buf_dma, len, dir);

printk("Status on ok = %x\n",__raw_readl(ss->regs + HW_SSP_STATUS));

}else{

printk(KERN_ERR "%c: tom timeout on line %s:%d\n",

write ? 'W' : 'C', __func__, __LINE__);

status = -ETIMEDOUT;

tryed out some of this but without any success

printk("Status = %x\n",__raw_readl(ss->regs + HW_SSP_STATUS));

mxs_dma_disable(ss->dma);

mxs_dma_reset(ss->dma);

//mxs_dma_ack_irq(ss->dma);

//mxs_dma_enable_irq(ss->dma, 1);

//mxs_reset_block((void __iomem *)ss->regs + HW_SSP_CTRL0, 0);

printk("Status = %x\n",__raw_readl(ss->regs + HW_SSP_STATUS));

__raw_writel(BM_SSP_CTRL1_DMA_ENABLE, ss->regs + HW_SSP_CTRL1_CLR);

printk("Status = %x\n",__raw_readl(ss->regs + HW_SSP_STATUS));

the SSP_Status Register returns 0xE0200020 maybe anyone can interpret it dont know how bit 21 can be resetet (DMASENSE) i think this is the problem

during a normal operation without a timeout SSP Status returns 0xE0040020

thanks for help

Thomas

Re: imx28 SPI Slave DMA

YixingKong — Fri, 04 Apr 2014 07:09:53 GMT

Thomas

We are sorry for getting back to you so late. Are you still stuck with the issue? If you have somehow to resolved the issue, can we close the discussion? If you still need help, please feel free to reply with an update to this discussion.

Thanks,

Yixing

Re: imx28 SPI Slave DMA

YixingKong — Thu, 10 Apr 2014 06:54:13 GMT

Thomas

Had your issue got resolved? If yes, we are going to close the discussion in 3 days. If you still need help, please feel free to reply with an update to this discussion.

Thanks,

Yixing

Re: imx28 SPI Slave DMA

YixingKong — Mon, 14 Apr 2014 06:36:20 GMT

Thomas

This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this discussion, or create another discussion.

Thanks,

Yixing

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