Re: [PATCH] dmaengine: DW DMAC: split pdata to hardware properties and platform quirks

[Andy Shevchenko]

On Thu, 2016-09-15 at 16:14 +0300, Eugeniy Paltsev wrote:
> This patch is to address a proposal by Andy in this thread:
> http://www.spinics.net/lists/dmaengine/msg10754.html
> Split platform data to actual hardware properties, and platform
> quirks.
> Now we able to use quirks and hardware properties separately from
> different sources (pdata, device tree or autoconfig registers)
> 

My comments below.

Sorry for delayed answer.

> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> ---
> Âdrivers/dma/dw/core.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ| 31 +++++++++++++++-----------
> Âdrivers/dma/dw/platform.cÂÂÂÂÂÂÂÂÂÂÂÂ| 42 +++++++++++++++++++++----
> -----------
> Âinclude/linux/platform_data/dma-dw.h | 20 +++++++++++------
> Â3 files changed, 57 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
> index c2c0a61..9352735 100644
> --- a/drivers/dma/dw/core.c
> +++ b/drivers/dma/dw/core.c
> @@ -1451,10 +1451,25 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â
> Â	dw->regs = chip->regs;
> Â	chip->dw = dw;

+ empty line.

> +	/* Reassign the platform data pointer */
> +	pdata = dw->pdata;
> Â
> Â	pm_runtime_get_sync(chip->dev);
> Â
> -	if (!chip->pdata) {
> +	if ((!chip->pdata) ||
> +	ÂÂÂ(chip->pdata && test_bit(QUIRKS_ONLY_USED, &chip->pdata-

I don't think you need atomic test / set of those bits.

> >quirks))) {
> +
> +		/*
> +		Â* Fill quirks with the default values in case of
> pdata absence

/*
 * Multi-line comments should include full sentences
 * (punctuation matters).
 */

> +		Â*/
> +		if (!chip->pdata) {
> +			set_bit(QUIRKS_IS_PRIVATE, &pdata->quirks);
> +			set_bit(QUIRKS_IS_MEMCPY, &pdata->quirks);
> +			set_bit(QUIRKS_IS_NOLLP, &pdata->quirks);
> +		} else {
> +			pdata->quirks = chip->pdata->quirks;
> +		}
> +
> Â		dw_params = dma_readl(dw, DW_PARAMS);
> Â		dev_dbg(chip->dev, "DW_PARAMS: 0x%08x\n", dw_params);
> Â
> @@ -1464,9 +1479,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â			goto err_pdata;
> Â		}
> Â
> -		/* Reassign the platform data pointer */
> -		pdata = dw->pdata;
> -
> Â		/* Get hardware configuration parameters */
> Â		pdata->nr_channels = (dw_params >> DW_PARAMS_NR_CHAN
> & 7) + 1;
> Â		pdata->nr_masters = (dw_params >> DW_PARAMS_NR_MASTER
> & 3) + 1;
> @@ -1477,8 +1489,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â		pdata->block_size = dma_readl(dw, MAX_BLK_SIZE);
> Â
> Â		/* Fill platform data with the default values */
> -		pdata->is_private = true;
> -		pdata->is_memcpy = true;
> Â		pdata->chan_allocation_order =
> CHAN_ALLOCATION_ASCENDING;
> Â		pdata->chan_priority = CHAN_PRIORITY_ASCENDING;
> Â	} else if (chip->pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
> {
> @@ -1486,9 +1496,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â		goto err_pdata;
> Â	} else {
> Â		memcpy(dw->pdata, chip->pdata, sizeof(*dw->pdata));
> -
> -		/* Reassign the platform data pointer */
> -		pdata = dw->pdata;
> Â	}
> Â
> Â	dw->chan = devm_kcalloc(chip->dev, pdata->nr_channels,
> sizeof(*dw->chan),
> @@ -1569,7 +1576,7 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â				(dwc_params >> DWC_PARAMS_MBLK_EN &
> 0x1) == 0;
> Â		} else {
> Â			dwc->block_size = pdata->block_size;
> -			dwc->nollp = pdata->is_nollp;
> +			dwc->nollp = test_bit(QUIRKS_IS_NOLLP,
> &pdata->quirks);

Perhaps you need another patch which actually moves nollp to dwc->flags.

> Â		}
> Â	}
> Â
> @@ -1582,9 +1589,9 @@ int dw_dma_probe(struct dw_dma_chip *chip)
> Â
> Â	/* Set capabilities */
> Â	dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
> -	if (pdata->is_private)
> +	if (test_bit(QUIRKS_IS_PRIVATE, &pdata->quirks))
> Â		dma_cap_set(DMA_PRIVATE, dw->dma.cap_mask);
> -	if (pdata->is_memcpy)
> +	if (test_bit(QUIRKS_IS_MEMCPY, &pdata->quirks))
> Â		dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
> Â
> Â	dw->dma.dev = chip->dev;
> diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> index 5bda0eb..308b977 100644
> --- a/drivers/dma/dw/platform.c
> +++ b/drivers/dma/dw/platform.c
> @@ -12,6 +12,7 @@
> Â * published by the Free Software Foundation.
> Â */
> Â
> +#include <linux/bitops.h>
> Â#include <linux/module.h>
> Â#include <linux/device.h>
> Â#include <linux/clk.h>
> @@ -111,41 +112,48 @@ dw_dma_parse_dt(struct platform_device *pdev)
> Â		return NULL;
> Â	}
> Â
> -	if (of_property_read_u32(np, "dma-masters", &nr_masters))
> -		return NULL;
> -	if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS)
> -		return NULL;
> -
> -	if (of_property_read_u32(np, "dma-channels", &nr_channels))
> -		return NULL;
> -
> Â	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> Â	if (!pdata)
> Â		return NULL;
> Â
> +	set_bit(QUIRKS_ONLY_USED, &pdata->quirks);
> +
> +	if (of_property_read_bool(np, "is-private"))
> +		set_bit(QUIRKS_IS_PRIVATE, &pdata->quirks);
> +
> +	if (of_property_read_bool(np, "is-memcpy"))
> +		set_bit(QUIRKS_IS_MEMCPY, &pdata->quirks);
> +
> +	if (of_property_read_bool(np, "is-nollp"))
> +		set_bit(QUIRKS_IS_NOLLP, &pdata->quirks);

I would suggest to convert to unified device property API first.

> +
> +	if (of_property_read_u32(np, "dma-masters", &nr_masters))
> +		return pdata;
> +	if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS)
> +		return pdata;
> +
> Â	pdata->nr_masters = nr_masters;
> -	pdata->nr_channels = nr_channels;
> Â
> -	if (of_property_read_bool(np, "is_private"))
> -		pdata->is_private = true;
> +	if (of_property_read_u32(np, "dma-channels", &nr_channels))
> +		return pdata;
> Â
> -	if (!of_property_read_u32(np, "chan_allocation_order", &tmp))
> +	pdata->nr_channels = nr_channels;
> +
> +	if (!of_property_read_u32(np, "chan-allocation-order", &tmp))
> Â		pdata->chan_allocation_order = (unsigned char)tmp;
> Â
> -	if (!of_property_read_u32(np, "chan_priority", &tmp))
> +	if (!of_property_read_u32(np, "chan-priority", &tmp))
> Â		pdata->chan_priority = tmp;
> Â
> -	if (!of_property_read_u32(np, "block_size", &tmp))
> +	if (!of_property_read_u32(np, "block-size", &tmp))
> Â		pdata->block_size = tmp;
> Â
> Â	if (!of_property_read_u32_array(np, "data-width", arr,
> nr_masters)) {
> Â		for (tmp = 0; tmp < nr_masters; tmp++)
> Â			pdata->data_width[tmp] = arr[tmp];
> -	} else if (!of_property_read_u32_array(np, "data_width", arr,
> nr_masters)) {
> -		for (tmp = 0; tmp < nr_masters; tmp++)
> -			pdata->data_width[tmp] = BIT(arr[tmp] &
> 0x07);
> Â	}
> Â
> +	clear_bit(QUIRKS_ONLY_USED, &pdata->quirks);
> Â	return pdata;
> Â}
> Â#else
> diff --git a/include/linux/platform_data/dma-dw.h
> b/include/linux/platform_data/dma-dw.h
> index 5f0e11e..9cd8199 100644
> --- a/include/linux/platform_data/dma-dw.h
> +++ b/include/linux/platform_data/dma-dw.h
> @@ -37,10 +37,7 @@ struct dw_dma_slave {
> Â/**
> Â * struct dw_dma_platform_data - Controller configuration parameters
> Â * @nr_channels: Number of channels supported by hardware (max 8)
> - * @is_private: The device channels should be marked as private and
> not for
> - *	by the general purpose DMA channel allocator.
> - * @is_memcpy: The device channels do support memory-to-memory
> transfers.
> - * @is_nollp: The device channels does not support multi block
> transfers.
> + * @quirks: Bit field with platform quirks
> Â * @chan_allocation_order: Allocate channels starting from 0 or 7
> Â * @chan_priority: Set channel priority increasing from 0 to 7 or 7
> to 0.
> Â * @block_size: Maximum block size supported by the controller
> @@ -50,9 +47,18 @@ struct dw_dma_slave {
> Â */
> Âstruct dw_dma_platform_data {
> Â	unsigned int	nr_channels;
> -	bool		is_private;
> -	bool		is_memcpy;
> -	bool		is_nollp;
> +/* Only use quirks from platform data structure */
> +#define QUIRKS_ONLY_USED	0
> +/*
> + * The device channels should be marked as private and not for
> + * by the general purpose DMA channel allocator.
> + */
> +#define QUIRKS_IS_PRIVATE	1
> +/* The device channels do support memory-to-memory transfers. */
> +#define QUIRKS_IS_MEMCPY	2
> +/* The device channels do not support multi block transfers. */
> +#define QUIRKS_IS_NOLLP		3

You may move descriptions to above struct description field. It will be
consolidated and moreover visible in kernel-doc processed documents.

> +	unsigned long	quirks;
> Â#define CHAN_ALLOCATION_ASCENDING	0	/* zero to seven */
> Â#define CHAN_ALLOCATION_DESCENDING	1	/* seven to zero
> */
> Â	unsigned char	chan_allocation_order;

-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy