Re: [PATCH v2 3/8] spi: imx: add support for all SPI word width for DMA transfer

[Robin Gong <b38343@freescale.com>]

On Fri, Sep 25, 2015 at 07:57:10PM +0200, Anton Bondarenko wrote:
> DMA transfer for SPI was limited to up to 8 bits word size until now.
> Sync in SPI burst size and DMA bus width is necessary to correctly
> support other BPW supported by HW.
> 
> Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
> ---
>  drivers/spi/spi-imx.c | 121 ++++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 87 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 6c98eda..d9b730d 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -91,11 +91,15 @@ struct spi_imx_data {
>  
>  	struct completion xfer_done;
>  	void __iomem *base;
> +	unsigned long base_phys;
> +
>  	struct clk *clk_per;
>  	struct clk *clk_ipg;
>  	unsigned long spi_clk;
>  	unsigned int spi_bus_clk;
>  
> +	unsigned int bpw_w;
> +
It's better to change bytes_per_word for clear understanding,since bpw in spi means
bits_per_word...
>  	unsigned int count;
>  	void (*tx)(struct spi_imx_data *);
>  	void (*rx)(struct spi_imx_data *);
> @@ -201,9 +205,13 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
>  			 struct spi_transfer *transfer)
>  {
>  	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
> +	unsigned int bpw_w = transfer->bits_per_word;
>  
> -	if (spi_imx->dma_is_inited &&
> -	    (transfer->len > spi_imx->wml * sizeof(u32)))
> +	if (!bpw_w)
> +		bpw_w = spi->bits_per_word;
> +
> +	bpw_w = DIV_ROUND_UP(bpw_w, 8);
> +	if (spi_imx->dma_is_inited && (transfer->len > spi_imx->wml * bpw_w))
Please remove bpw_w here as I talked in the first patch.
>  		return true;
>  	return false;
>  }
> @@ -761,11 +769,62 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static int spi_imx_sdma_configure(struct spi_master *master)
> +{
> +	int ret;
> +	enum dma_slave_buswidth dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
> +	struct dma_slave_config slave_config = {};
> +	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
> +
> +	switch (spi_imx->bpw_w) {
> +	case 4:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +		break;
> +	case 2:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_2_BYTES;
> +		break;
> +	case 1:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
> +		break;
> +	default:
> +		pr_err("Not supported word size %d\n", spi_imx->bpw_w);
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	slave_config.direction = DMA_MEM_TO_DEV;
> +	slave_config.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
> +	slave_config.dst_addr_width = dsb_default;
> +	slave_config.dst_maxburst = spi_imx_get_fifosize(spi_imx)
> +					- spi_imx->wml;
> +	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
> +	if (ret) {
> +		pr_err("error in TX dma configuration.\n");
> +		goto err;
> +	}
> +
> +	memset(&slave_config, 0, sizeof(slave_config));
> +
> +	slave_config.direction = DMA_DEV_TO_MEM;
> +	slave_config.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;
> +	slave_config.src_addr_width = dsb_default;
> +	slave_config.src_maxburst = spi_imx_get_fifosize(spi_imx)
> +					- spi_imx->wml;
> +	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
> +	if (ret)
> +		pr_err("error in RX dma configuration.\n");
> +
> +err:
> +	return ret;
> +}
> +
>  static int spi_imx_setupxfer(struct spi_device *spi,
>  				 struct spi_transfer *t)
>  {
>  	struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
>  	struct spi_imx_config config;
> +	unsigned int bpw_w_new;
> +	int ret = 0;
>  
>  	config.bpw = t ? t->bits_per_word : spi->bits_per_word;
>  	config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
> @@ -789,9 +848,18 @@ static int spi_imx_setupxfer(struct spi_device *spi,
>  		spi_imx->tx = spi_imx_buf_tx_u32;
>  	}
>  
> -	spi_imx->devtype_data->config(spi_imx, &config);
> +	bpw_w_new = DIV_ROUND_UP(config.bpw, 8);
> +	if (spi_imx->dma_is_inited && spi_imx->bpw_w != bpw_w_new) {
> +		spi_imx->bpw_w = bpw_w_new;
> +		ret = spi_imx_sdma_configure(spi->master);
> +		if (ret != 0)
> +			pr_err("Can't configure SDMA, error %d\n", ret);
> +	}
>  
> -	return 0;
> +	if (!ret)
> +		ret = spi_imx->devtype_data->config(spi_imx, &config);
> +
> +	return ret;
>  }
>  
>  static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
> @@ -812,10 +880,8 @@ static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
>  }
>  
>  static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
> -			     struct spi_master *master,
> -			     const struct resource *res)
> +			     struct spi_master *master)
>  {
> -	struct dma_slave_config slave_config = {};
>  	int ret;
>  
>  	/* use pio mode for i.mx6dl chip TKT238285 */
> @@ -832,17 +898,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
>  		goto err;
>  	}
>  
> -	slave_config.direction = DMA_MEM_TO_DEV;
> -	slave_config.dst_addr = res->start + MXC_CSPITXDATA;
> -	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> -	slave_config.dst_maxburst = spi_imx_get_fifosize(spi_imx)
> -					- spi_imx->wml;
> -	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
> -	if (ret) {
> -		dev_err(dev, "error in TX dma configuration.\n");
> -		goto err;
> -	}
> -
>  	/* Prepare for RX : */
>  	master->dma_rx = dma_request_slave_channel(dev, "rx");
>  	if (!master->dma_rx) {
> @@ -851,23 +906,19 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
>  		goto err;
>  	}
>  
> -	slave_config.direction = DMA_DEV_TO_MEM;
> -	slave_config.src_addr = res->start + MXC_CSPIRXDATA;
> -	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> -	slave_config.src_maxburst = spi_imx_get_fifosize(spi_imx)
> -					- spi_imx->wml;
> -	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
> -	if (ret) {
> -		dev_err(dev, "error in RX dma configuration.\n");
> -		goto err;
> -	}
> -
>  	init_completion(&spi_imx->dma_rx_completion);
>  	init_completion(&spi_imx->dma_tx_completion);
>  	master->can_dma = spi_imx_can_dma;
>  	master->max_dma_len = MAX_SDMA_BD_BYTES;
>  	spi_imx->bitbang.master->flags = SPI_MASTER_MUST_RX |
>  					 SPI_MASTER_MUST_TX;
> +	spi_imx->bpw_w = 1;
> +	ret = spi_imx_sdma_configure(master);
> +	if (ret) {
> +		dev_info(dev, "cannot get setup DMA.\n");
> +		goto err;
> +	}
> +
>  	spi_imx->dma_is_inited = 1;
>  
>  	return 0;
> @@ -924,7 +975,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
>  	int ret;
>  	unsigned long timeout;
>  	unsigned long transfer_timeout;
> -	const int left = transfer->len % spi_imx->wml;
> +	const int left = transfer->len % (spi_imx->wml * spi_imx->bpw_w);
>  	struct spi_master *master = spi_imx->bitbang.master;
>  	struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg;
>  
> @@ -989,7 +1040,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
>  		dmaengine_terminate_all(master->dma_rx);
>  	} else {
>  		transfer_timeout = spi_imx_calculate_timeout(spi_imx,
> -							     spi_imx->wml * 2);
> +					spi_imx->bpw_w * spi_imx->wml * 2);
>  		timeout = wait_for_completion_timeout(
>  				&spi_imx->dma_rx_completion, transfer_timeout);
>  		if (!timeout) {
> @@ -1007,7 +1058,8 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
>  					    DMA_FROM_DEVICE);
>  
>  			spi_imx->rx_buf = pio_buffer;
> -			spi_imx->txfifo = left;
> +			spi_imx->txfifo = DIV_ROUND_UP(left, spi_imx->bpw_w);
> +
Looks not enough here, you have to set 'spi_imx->rx' per the right bpw.
>  			reinit_completion(&spi_imx->xfer_done);
>  
>  			spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TCEN);
> @@ -1207,6 +1259,7 @@ static int spi_imx_probe(struct platform_device *pdev)
>  		ret = PTR_ERR(spi_imx->base);
>  		goto out_master_put;
>  	}
> +	spi_imx->base_phys = res->start;
>  
>  	irq = platform_get_irq(pdev, 0);
>  	if (irq < 0) {
> @@ -1246,8 +1299,8 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	 * Only validated on i.mx6 now, can remove the constrain if validated on
>  	 * other chips.
>  	 */
> -	if (spi_imx->devtype_data == &imx51_ecspi_devtype_data
> -	    && spi_imx_sdma_init(&pdev->dev, spi_imx, master, res))
> +	if (spi_imx->devtype_data == &imx51_ecspi_devtype_data &&
> +	    spi_imx_sdma_init(&pdev->dev, spi_imx, master))
>  		dev_err(&pdev->dev, "dma setup error,use pio instead\n");
>  
>  	spi_imx->devtype_data->reset(spi_imx);
> -- 
> 2.5.2
>