[alsa-devel] [RFC PATCH 2/5] OMAP3: McBSP: Change the way how the FIFO is handled

[Nishanth Menon]

On 06/01/2010 09:59 AM, Peter Ujfalusi wrote:
> On Monday 31 May 2010 20:41:12 ext Nishanth Menon wrote:
>> On 05/31/2010 11:16 AM, Peter Ujfalusi wrote:
>>> Use the actual FIFO size in words as buffer_size on OMAP2.
>>> Change the threshold configuration to use 1 based numbering, when
>>> specifying the allowed threshold maximum or the McBSP threshold value.
>>> Set the default maximum threshold to (buffer_size - 0x10) intialy.
>>>
>>>>  From users of McBSP, now it is expected to use this method.
>>>
>>> Asking for threshold 1 means that the value written to threshold
>>> registers are going to be 0, which means 1 word threshold.
>>
>> just a 2cent minor comment: maybe omap_mcbsp_platform_data needs
>> structure documentation.. it might be difficult for folks to figure that
>> out from commit ID itself..
>
> I can add comments in the mach-omap2/mcbsp.c like this:
>

I had meant more of
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/kernel-doc-nano-HOWTO.txt;h=27a52b35d55bf1b6009551c97f400da5c14f59bc;hb=HEAD#l84

but i suspect that it is out of the scope of this patch at least.. and 
the comments below might be helpful at the least.
>>
>>> Signed-off-by: Peter Ujfalusi<peter.ujfalusi at nokia.com>
>>> ---
>>>
>>>    arch/arm/mach-omap2/mcbsp.c |   10 +++++-----
>>>    arch/arm/plat-omap/mcbsp.c  |   10 ++++++----
>>>    2 files changed, 11 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/mcbsp.c b/arch/arm/mach-omap2/mcbsp.c
>>> index 016fe60..9139958 100644
>>> --- a/arch/arm/mach-omap2/mcbsp.c
>>> +++ b/arch/arm/mach-omap2/mcbsp.c
>>> @@ -132,7 +132,7 @@ static struct omap_mcbsp_platform_data
>>> omap34xx_mcbsp_pdata[] = {
>>>
>>>    		.rx_irq		= INT_24XX_MCBSP1_IRQ_RX,
>>>    		.tx_irq		= INT_24XX_MCBSP1_IRQ_TX,
>>>    		.ops		=&omap2_mcbsp_ops,
>>>
>>> -		.buffer_size	= 0x6F,
>>> +		.buffer_size	= 0x80,
>
>   +		.buffer_size	= 0x80, /* The FIFO has 128 locations */
>
>>>
>>>    	},
>>>    	{
>>>    	
>>>    		.phys_base	= OMAP34XX_MCBSP2_BASE,
>>>
>>> @@ -142,7 +142,7 @@ static struct omap_mcbsp_platform_data
>>> omap34xx_mcbsp_pdata[] = {
>>>
>>>    		.rx_irq		= INT_24XX_MCBSP2_IRQ_RX,
>>>    		.tx_irq		= INT_24XX_MCBSP2_IRQ_TX,
>>>    		.ops		=&omap2_mcbsp_ops,
>>>
>>> -		.buffer_size	= 0x3FF,
>>> +		.buffer_size	= 0x500,
>
>   +		.buffer_size	= 0x500, /* The FIFO has 1024 + 256 locations */
>
>>>
>>>    	},
>>>    	{
>>>    	
>>>    		.phys_base	= OMAP34XX_MCBSP3_BASE,
>>>
>>> @@ -152,7 +152,7 @@ static struct omap_mcbsp_platform_data
>>> omap34xx_mcbsp_pdata[] = {
>>>
>>>    		.rx_irq		= INT_24XX_MCBSP3_IRQ_RX,
>>>    		.tx_irq		= INT_24XX_MCBSP3_IRQ_TX,
>>>    		.ops		=&omap2_mcbsp_ops,
>>>
>>> -		.buffer_size	= 0x6F,
>>> +		.buffer_size	= 0x80,
>
>   +		.buffer_size	= 0x80, /* The FIFO has 128 locations */
>
>>>
>>>    	},
>>>    	{
>>>    	
>>>    		.phys_base	= OMAP34XX_MCBSP4_BASE,
>>>
>>> @@ -161,7 +161,7 @@ static struct omap_mcbsp_platform_data
>>> omap34xx_mcbsp_pdata[] = {
>>>
>>>    		.rx_irq		= INT_24XX_MCBSP4_IRQ_RX,
>>>    		.tx_irq		= INT_24XX_MCBSP4_IRQ_TX,
>>>    		.ops		=&omap2_mcbsp_ops,
>>>
>>> -		.buffer_size	= 0x6F,
>>> +		.buffer_size	= 0x80,
>>>
>>>    	},
>>>    	{
>>>    	
>>>    		.phys_base	= OMAP34XX_MCBSP5_BASE,
>>>
>>> @@ -170,7 +170,7 @@ static struct omap_mcbsp_platform_data
>>> omap34xx_mcbsp_pdata[] = {
>>>
>>>    		.rx_irq		= INT_24XX_MCBSP5_IRQ_RX,
>>>    		.tx_irq		= INT_24XX_MCBSP5_IRQ_TX,
>>>    		.ops		=&omap2_mcbsp_ops,
>>>
>>> -		.buffer_size	= 0x6F,
>>> +		.buffer_size	= 0x80,
>>>
>>>    	},
>>>
>>>    };
>>>    #define OMAP34XX_MCBSP_PDATA_SZ		ARRAY_SIZE(omap34xx_mcbsp_pdata)
>>>
>>> diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
>>> index 51d8abf..6462968 100644
>>> --- a/arch/arm/plat-omap/mcbsp.c
>>> +++ b/arch/arm/plat-omap/mcbsp.c
>>> @@ -497,7 +497,8 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16
>>> threshold)
>>>
>>>    	}
>>>    	mcbsp = id_to_mcbsp_ptr(id);
>>>
>>> -	MCBSP_WRITE(mcbsp, THRSH2, threshold);
>>> +	if (threshold&&   threshold<= mcbsp->max_tx_thres)
>>> +		MCBSP_WRITE(mcbsp, THRSH2, threshold - 1);
>>>
>>>    }
>>>    EXPORT_SYMBOL(omap_mcbsp_set_tx_threshold);
>>>
>>> @@ -519,7 +520,8 @@ void omap_mcbsp_set_rx_threshold(unsigned int id, u16
>>> threshold)
>>>
>>>    	}
>>>    	mcbsp = id_to_mcbsp_ptr(id);
>>>
>>> -	MCBSP_WRITE(mcbsp, THRSH1, threshold);
>>> +	if (threshold&&   threshold<= mcbsp->max_rx_thres)
>>> +		MCBSP_WRITE(mcbsp, THRSH1, threshold - 1);
>>>
>>>    }
>>>    EXPORT_SYMBOL(omap_mcbsp_set_rx_threshold);
>>>
>>> @@ -1696,8 +1698,8 @@ static inline void __devinit
>>> omap34xx_device_init(struct omap_mcbsp *mcbsp)
>>>
>>>    {
>>>
>>>    	mcbsp->dma_op_mode = MCBSP_DMA_MODE_ELEMENT;
>>>    	if (cpu_is_omap34xx()) {
>>>
>>> -		mcbsp->max_tx_thres = max_thres(mcbsp);
>>> -		mcbsp->max_rx_thres = max_thres(mcbsp);
>>> +		mcbsp->max_tx_thres = max_thres(mcbsp) - 0x10;
>>> +		mcbsp->max_rx_thres = max_thres(mcbsp) - 0x10;
>>>
>>>    		/*
>>>    		
>>>    		 * REVISIT: Set dmap_op_mode to THRESHOLD as default
>>>    		 * for mcbsp2 instances.
>
> Is this sufficient?
>

Regards,
Nishanth Menon