iMX6 SSI in TDM master mode and SDMA
Markus Pargmann
mpa at pengutronix.de
Tue Oct 27 08:20:53 PDT 2015
Hi,
On Tuesday 27 October 2015 15:45:11 Roberto Fichera wrote:
> Hi There,
>
> I'm having an SDMA freeze when putting the SSI in TDM master mode while
> developing a DAHDI kernel driver. Kernel is the official freescale v3.14.28.
Please use the mainline kernel. fsl-ssi has really good mainline support. I
don't think anyone can help you with such an old kernel.
Regards,
Markus
>
> The DTS is setting the pinmux as:
>
> /*
> * set IOMUX SD3_DATA0-3 to PCM SLIC signal
> */
> pinctrl_audmux_1: audmuxgrp-3 {
> fsl,pins = <
> MX6SX_PAD_SD3_DATA1__AUDMUX_AUD6_TXC 0x130B1 /* PCLK */
> MX6SX_PAD_SD3_DATA2__AUDMUX_AUD6_TXFS 0x130B1 /* FSYNC */
> MX6SX_PAD_SD3_DATA0__AUDMUX_AUD6_RXD 0x130B1 /* DTX */
> MX6SX_PAD_SD3_DATA3__AUDMUX_AUD6_TXD 0x130B1 /* DRX */
> >;
> };
>
> SSI1 is the default in imx6sx.dtsi but enabled in my custom DTS, the DMA use
> the mode 1 IMX_DMATYPE_SSI_SP
>
> ssi1: ssi at 02028000 {
> compatible = "fsl,imx6sx-ssi", "fsl,imx21-ssi";
> reg = <0x02028000 0x4000>;
> interrupts = <GIC_SPI 46 IRQ_TYPE_LEVEL_HIGH>;
> clocks = <&clks IMX6SX_CLK_SSI1_IPG>,
> <&clks IMX6SX_CLK_SSI1>;
> clock-names = "ipg", "baud";
> dmas = <&sdma 37 1 0>, <&sdma 38 1 0>;
> dma-names = "rx", "tx";
> status = "disabled";
> };
>
> The SSI1 is connected in PCM mode to a SiLabs SLIC Si32178 and from
> hardware point of view all PCLK and FSYNC are correct (2048KHz having 8 slots @ 32bit width).
> The SLIC is reporting stable both PCLK and FSYNC while running for a day.
>
> Both RX and TX FIFOs are setup to trigger DMA transfer once
> their related watermarks reach 8 slots of 8bits each.
>
> So far so good I've setup a DMA transfer for both TX and RX FIFOs, in the _probe() function
>
> tdm_real_slots are the number of masked slots, currently 2 and the both TX and RX watermarks
> are set to tdm_real_slots * 4 = 8 bytes
>
> ssi_private->tx_chan = dma_request_slave_channel_reason(&pdev->dev, "tx");
> if (IS_ERR(ssi_private->tx_chan))
> {
> dev_err(&pdev->dev, "could not get TX DMA\n");
> ssi_private->tx_chan = NULL;
> }
> else
> {
> slave_config.direction = DMA_MEM_TO_DEV;
> slave_config.dst_addr = ssi_private->ssi_phys + offsetof(struct ccsr_ssi, stx0);
> slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> slave_config.dst_maxburst = ssi_private->tdm_real_slots * 4;
> ret = dmaengine_slave_config(ssi_private->tx_chan, &slave_config);
> if (ret) {
> dev_err(&pdev->dev, "error in TX DMA configuration.\n");
> }
> }
>
> ssi_private->rx_chan = dma_request_slave_channel_reason(&pdev->dev, "rx");
> if (IS_ERR(ssi_private->rx_chan))
> {
> printk("could not get RX DMA\n");
> ssi_private->rx_chan = NULL;
> }
> else
> {
> slave_config.direction = DMA_DEV_TO_MEM;
> slave_config.src_addr = ssi_private->ssi_phys + offsetof(struct ccsr_ssi, srx0);
> slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> slave_config.src_maxburst = ssi_private->tdm_real_slots * 4;
> ret = dmaengine_slave_config(ssi_private->rx_chan, &slave_config);
> if (ret) {
> dev_err(&pdev->dev, "error in RX DMA configuration.\n");
> }
> }
>
> Both TX and RX dma descriptors are initialized like this:
>
> if ( ssi_private->use_dma )
> {
> struct dma_async_tx_descriptor *desc;
>
> ssi_private->rx_callback = callback;
> ssi_private->rx_userparam = userparam;
> ssi_private->rx_buffer_len = buffer_len;
> ssi_private->rx_buffer_count = buffer_len;
> ssi_private->rx_buf = dma_alloc_coherent(NULL, buffer_len,
> &ssi_private->rx_dmaaddr, GFP_KERNEL);
> if (!ssi_private->rx_buf) {
> printk("cannot alloc RX DMA buffer.\n");
> return -ENOMEM;
> }
>
> desc = dmaengine_prep_dma_cyclic(ssi_private->rx_chan, ssi_private->rx_dmaaddr,
> buffer_len, ssi_private->tdm_real_slots*4,
> DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
> if (!desc) {
> printk("Prepare for the RX slave dma failed!\n");
> return -EINVAL;
> }
>
> desc->callback = dma_rx_callback;
> desc->callback_param = ssi_private;
>
> printk("RX: prepare for the DMA.\n");
> dmaengine_submit(desc);
> dma_async_issue_pending(ssi_private->rx_chan);
> }
>
> if ( ssi_private->use_dma )
> {
> struct dma_async_tx_descriptor *desc;
>
> ssi_private->tx_callback = callback;
> ssi_private->tx_userparam = userparam;
> ssi_private->tx_buffer_len = buffer_len;
> ssi_private->tx_buffer_count = buffer_len;
> ssi_private->tx_buf = dma_alloc_coherent(NULL, buffer_len,
> &ssi_private->tx_dmaaddr, GFP_KERNEL);
> if (!ssi_private->tx_buf) {
> printk("cannot alloc TX DMA buffer.\n");
> return -ENOMEM;
> }
>
> desc = dmaengine_prep_dma_cyclic(ssi_private->tx_chan, ssi_private->tx_dmaaddr,
> buffer_len, ssi_private->tdm_real_slots*4,
> DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
> if (!desc) {
> printk("Prepare for the TX slave dma failed!\n");
> return -EINVAL;
> }
>
> desc->callback = dma_tx_callback;
> desc->callback_param = ssi_private;
>
> printk("TX: prepare for the DMA.\n");
> dmaengine_submit(desc);
> dma_async_issue_pending(ssi_private->tx_chan);
> }
>
> Once I'll enable the SSI clock to enable the TDM, I'm getting only 2000 or so interrupts and then everything freeze.
> Below some log related to the imx-sdma reporting correctly all wml, shp_addr and 2 entry having 8 bytes each
>
> dmaengine: private_candidate: wrong capabilities
> dmaengine: __dma_request_channel: success (dma1chan0)
> imx-sdma 20ec000.sdma: load_address = 960
> imx-sdma 20ec000.sdma: wml = 0x00000008
> imx-sdma 20ec000.sdma: shp_addr = 0x02028000
> imx-sdma 20ec000.sdma: per_addr = 0x00000000
> imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
> imx-sdma 20ec000.sdma: event_mask1 = 0x00000040
> dmaengine: private_candidate: wrong capabilities
> dmaengine: private_candidate: dma1chan0 busy
> dmaengine: __dma_request_channel: success (dma1chan1)
> imx-sdma 20ec000.sdma: load_address = 891
> imx-sdma 20ec000.sdma: wml = 0x00000008
> imx-sdma 20ec000.sdma: shp_addr = 0x02028008
> imx-sdma 20ec000.sdma: per_addr = 0x00000000
> imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
> imx-sdma 20ec000.sdma: event_mask1 = 0x00000020
> si3217x_ssi_probe: SSI base is 0xa0b10000 clock rate is 2048000Hz, TDM Frame rate 8000Hz, channels 8 having 8 bits word
> length
> si3217x_audmux_probe: AUDMUX base is 0xa0b18000
> si3217x_probe: SPI setup mode 3, 8 bits/w, 10000000 Hz max
> imx-sdma 20ec000.sdma: sdma_prep_dma_cyclic channel: 2
> imx-sdma 20ec000.sdma: load_address = 891
> imx-sdma 20ec000.sdma: wml = 0x00000008
> imx-sdma 20ec000.sdma: shp_addr = 0x02028008
> imx-sdma 20ec000.sdma: per_addr = 0x00000000
> imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
> imx-sdma 20ec000.sdma: event_mask1 = 0x00000020
> imx-sdma 20ec000.sdma: entry 0: count: 8 dma: 0x9c4a0000 intr
> imx-sdma 20ec000.sdma: entry 1: count: 8 dma: 0x9c4a0008 wrap intr
> RX: prepare for the DMA.
> imx-sdma 20ec000.sdma: sdma_prep_dma_cyclic channel: 1
> imx-sdma 20ec000.sdma: load_address = 960
> imx-sdma 20ec000.sdma: wml = 0x00000008
> imx-sdma 20ec000.sdma: shp_addr = 0x02028000
> imx-sdma 20ec000.sdma: per_addr = 0x00000000
> imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
> imx-sdma 20ec000.sdma: event_mask1 = 0x00000040
> imx-sdma 20ec000.sdma: entry 0: count: 8 dma: 0x9c495000 intr
> imx-sdma 20ec000.sdma: entry 1: count: 8 dma: 0x9c495008 wrap intr
> TX: prepare for the DMA.
> si3217x_ssi_setup: tdm_slots_enabled=0x00000003, 0xfffffffc
> si3217x_ssi_setup: SSI_STMSK=0x000000fc,SSI_SRMSK=0x000000fc
> si3217x_ssi_set_clock: BIT_CLK=53248000
>
> Finally the SSI1 registers are set like this:
>
> ssi_scr=0x000000bf
> ssi_sier=0x01d005f5
> ssi_stcr=0x000002e8
> ssi_srcr=0x00000288
> ssi_stccr=0x0000670b
> ssi_srccr=0x0000670b
> ssi_sfcsr=0x0088f088
> ssi_stmsk=0xfffffffc
> ssi_srmsk=0xfffffffc
>
> and the statistics related to DMA freeze as
>
> RX DMA frame count=1001
> RX DMA addr=0x9c659000
> RX DMA buffer len=16
> TX DMA frame count=1003
> TX DMA addr=0x9c658000
> TX DMA buffer len=16
>
> Does anyone can suggest how to make the DMA working?
>
> Thanks in advance,
> Roberto Fichera.
>
>
>
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>
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