[PATCH v4 1/2] dmaengine: at_hdmac: platform data move to use .id_table

[nicolas.ferre@atmel.com (Nicolas Ferre)]

On 10/24/2011 11:34 AM, Grant Likely :
> On Mon, Oct 17, 2011 at 02:56:40PM +0200, Nicolas Ferre wrote:
>> We remove the use of platform data from DMA controller driver.
>> We now use of .id_table to distinguish between compatible
>> types. The two implementations allow to determine the
>> number of channels and the capabilities of the controller.
>>
>> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>> Acked-by: Grant Likely <grant.likely@secretlab.ca>
>> ---
>>  drivers/dma/at_hdmac.c      |   48 ++++++++++++++++++++++++++++++++++---------
>>  drivers/dma/at_hdmac_regs.h |    8 +++++++
>>  2 files changed, 46 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
>> index fcfa0a8..d1869c5 100644
>> --- a/drivers/dma/at_hdmac.c
>> +++ b/drivers/dma/at_hdmac.c
>> @@ -1175,6 +1175,18 @@ static void atc_free_chan_resources(struct dma_chan *chan)
>>  
>>  /*--  Module Management  -----------------------------------------------*/
>>  
>> +static struct platform_device_id atdma_devtypes[] = {
>> +	{
>> +		.name = "at91sam9rl_dma",
>> +		.driver_data = ATDMA_DEVTYPE_SAM9RL,
>> +	}, {
>> +		.name = "at91sam9g45_dma",
>> +		.driver_data = ATDMA_DEVTYPE_SAM9G45,
>> +	}, {
>> +		/* sentinel */
>> +	}
>> +};
>> +
>>  /**
>>   * at_dma_off - disable DMA controller
>>   * @atdma: the Atmel HDAMC device
>> @@ -1193,18 +1205,32 @@ static void at_dma_off(struct at_dma *atdma)
>>  
>>  static int __init at_dma_probe(struct platform_device *pdev)
>>  {
>> -	struct at_dma_platform_data *pdata;
>>  	struct resource		*io;
>>  	struct at_dma		*atdma;
>>  	size_t			size;
>>  	int			irq;
>>  	int			err;
>>  	int			i;
>> +	u32                     nr_channels;
>> +	dma_cap_mask_t          cap_mask = {};
>> +	enum atdma_devtype	atdmatype;
>> +
>> +	dma_cap_set(DMA_MEMCPY, cap_mask);
>> +
>> +	/* get DMA parameters from controller type */
>> +	atdmatype = platform_get_device_id(pdev)->driver_data;
>>  
>> -	/* get DMA Controller parameters from platform */
>> -	pdata = pdev->dev.platform_data;
>> -	if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS)
>> +	switch (atdmatype) {
>> +	case ATDMA_DEVTYPE_SAM9RL:
>> +		nr_channels = 2;
>> +		break;
>> +	case ATDMA_DEVTYPE_SAM9G45:
>> +		nr_channels = 8;
>> +		dma_cap_set(DMA_SLAVE, cap_mask);
>> +		break;
>> +	default:
>>  		return -EINVAL;
> 
> Instead of this song and dance, why not make a configuration structure
> and embed that into the platform_device_id table?  Like this:
> 
> struct at_dma_platform_data at91sam9rl_config {
> 	.nr_channels = 2;
> 	.cap_mask = 0;
> };
> struct at_dma_platform_data at91samg45_config {
> 	.nr_channels = 8;
> 	.cap_mask = DMA_SLAVE;
> };
> static struct platform_device_id atdma_devtypes[] = {
> 	{
> 		.name = "at91sam9rl_dma",
> 		.driver_data = (unsigned long) at91sam9rl_config,
> 		/*
> 		 * Yes, I know, ugly cast; but one case will be needed
> 		 * regardless when the of_device_id table is added.
> 		 * It's due to the platform_device_id not using a
> 		 * void*
> 		 */
> 	}, {
> 		.name = "at91sam9g45_dma",
> 		.driver_data = (unsigned long) at91sam9g45_config,
> 	}, {
> 		/* sentinel */
> 	}
> };
> 
> And then the enum can be eliminated entirely.

That looks nice!

I send a patch that goes on top of this series to simplify things like
you indicate.

Thanks for your review.

>> +	}
>>  
>>  	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>  	if (!io)
>> @@ -1215,14 +1241,15 @@ static int __init at_dma_probe(struct platform_device *pdev)
>>  		return irq;
>>  
>>  	size = sizeof(struct at_dma);
>> -	size += pdata->nr_channels * sizeof(struct at_dma_chan);
>> +	size += nr_channels * sizeof(struct at_dma_chan);
>>  	atdma = kzalloc(size, GFP_KERNEL);
>>  	if (!atdma)
>>  		return -ENOMEM;
>>  
>> -	/* discover transaction capabilites from the platform data */
>> -	atdma->dma_common.cap_mask = pdata->cap_mask;
>> -	atdma->all_chan_mask = (1 << pdata->nr_channels) - 1;
>> +	/* discover transaction capabilities */
>> +	atdma->dma_common.cap_mask = cap_mask;
>> +	atdma->all_chan_mask = (1 << nr_channels) - 1;
>> +	atdma->devtype = atdmatype;
>>  
>>  	size = resource_size(io);
>>  	if (!request_mem_region(io->start, size, pdev->dev.driver->name)) {
>> @@ -1268,7 +1295,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
>>  
>>  	/* initialize channels related values */
>>  	INIT_LIST_HEAD(&atdma->dma_common.channels);
>> -	for (i = 0; i < pdata->nr_channels; i++) {
>> +	for (i = 0; i < nr_channels; i++) {
>>  		struct at_dma_chan	*atchan = &atdma->chan[i];
>>  
>>  		atchan->chan_common.device = &atdma->dma_common;
>> @@ -1313,7 +1340,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
>>  	dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n",
>>  	  dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
>>  	  dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)  ? "slave " : "",
>> -	  pdata->nr_channels);
>> +	  nr_channels);
>>  
>>  	dma_async_device_register(&atdma->dma_common);
>>  
>> @@ -1495,6 +1522,7 @@ static const struct dev_pm_ops at_dma_dev_pm_ops = {
>>  static struct platform_driver at_dma_driver = {
>>  	.remove		= __exit_p(at_dma_remove),
>>  	.shutdown	= at_dma_shutdown,
>> +	.id_table	= atdma_devtypes,
>>  	.driver = {
>>  		.name	= "at_hdmac",
>>  		.pm	= &at_dma_dev_pm_ops,
>> diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
>> index aa4c9ae..d7d6737 100644
>> --- a/drivers/dma/at_hdmac_regs.h
>> +++ b/drivers/dma/at_hdmac_regs.h
>> @@ -248,9 +248,16 @@ static inline struct at_dma_chan *to_at_dma_chan(struct dma_chan *dchan)
>>  
>>  /*--  Controller  ------------------------------------------------------*/
>>  
>> +enum atdma_devtype {
>> +	ATDMA_DEVTYPE_UNDEFINED = 0,
>> +	ATDMA_DEVTYPE_SAM9RL,	/* compatible with SAM9RL DMA controller */
>> +	ATDMA_DEVTYPE_SAM9G45,	/* compatible with SAM9G45 DMA controller */
>> +};
>> +
>>  /**
>>   * struct at_dma - internal representation of an Atmel HDMA Controller
>>   * @chan_common: common dmaengine dma_device object members
>> + * @atdma_devtype: identifier of DMA controller compatibility
>>   * @ch_regs: memory mapped register base
>>   * @clk: dma controller clock
>>   * @save_imr: interrupt mask register that is saved on suspend/resume cycle
>> @@ -260,6 +267,7 @@ static inline struct at_dma_chan *to_at_dma_chan(struct dma_chan *dchan)
>>   */
>>  struct at_dma {
>>  	struct dma_device	dma_common;
>> +	enum atdma_devtype	devtype;
>>  	void __iomem		*regs;
>>  	struct clk		*clk;
>>  	u32			save_imr;
>> -- 
>> 1.7.5.4
>>
> 
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-- 
Nicolas Ferre