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Message-ID: <4ECB7F89.6060408@atmel.com>
Date: Tue, 22 Nov 2011 11:55:05 +0100
From: Nicolas Ferre <nicolas.ferre@...el.com>
To: Grant Likely <grant.likely@...retlab.ca>
CC: vinod.koul@...el.com, devicetree-discuss@...ts.ozlabs.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 1/2] dmaengine: at_hdmac: platform data move to use
.id_table
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@...el.com>
>> Acked-by: Grant Likely <grant.likely@...retlab.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
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
--
Nicolas Ferre
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