Re: [ts-7000] Re: DMA with SSP on TS7400

["Breton M. Saunders" <>]

pakorn_0608 wrote:
> I search from the net that it have to include "<asm/glue.h>" and/or 
> "<asm-arm/caceflush>" for using "dmac_flush_range()".
>
> They have no on my linux include files of ts7400 provided on ftp.
>
> How do you use that, BMS? 
>   
Sorry - that was cut and paste from the tssdcard.c that I did for 
2.6.27+. It is most likely that we need to use a different function for 
your 2.4 series kernel.
Let me check some older source....

Ok - I'm pretty sure its flush_dcache_page. You will need to look 
through some other drivers (loop.c is the one I'm looking at now) to 
verify how the function is used.
It looks from a cursory glance that one must first grab the page to 
ensure it that it is in primary storge (e.g. not paged onto disk).

I'll have a little more time this evening, and will check again for you.

-Brett



> Is there anything that i have to do if i wanna use "dmac_flush_range"? 
>
> --- In  "pakorn_0608" <> wrote:
>   
>> Thank a lot for your advice, i learn a lot from you.
>>
>>
>> I'm using kernel 2.4.26 flatform, and, i also use GFP_DMA flag on my 
>> "kmalloc" command.
>>
>> Anyway,for my application, I'm using TS-7400 with ADS1278, adc 24bit/8CH.
>>
>> By now,I only using this chip only 1CH at 2k sampling.Protocol of ADS1278 is 
>> SPI, and There is some application which I have to use upto 8 channel but 
>> maybe in lower sampling.
>>
>> Not only this module that use transfer data via SPI, but it also have 
>> another module and application that transform data into some of standard 
>> file, moreover, it have web server for service some application for 
>> configuration and monitoring this data. There are moe a few but just a 
>> little job.
>>
>> In section of SPI,I use external interrupt to catch signal from ADS1278 and 
>> then send and recrieve data via SPI bus which depend on sampling rate, 
>> 2k/1CH/24bit by now, more in the future.
>>
>> It's sometime performance drop when i'm running full of them.
>> That why i try to use DMA for helping do some job of whole.
>>
>>
>> So, I'll try to use "dmac_flush_range" and tell the result soon.
>>
>>
>>
>> --- In  "Breton M. Saunders" <breton.saunders@> 
>> wrote:
>>     
>>> The symptoms you describe are likely caused by data not being flushed to 
>>> physical ram prior to invoking your dma transfer.
>>>
>>> Just checking back to the sdcard driver I did for the 7400. I did:
>>>
>>> dmac_flush_range(buf,buf+buflen); // where buf is a pointer to a virtual 
>>> address (e.g. not a bus address)
>>>
>>> prior to performing a dma transfer.
>>>
>>> Although not strictly necessary on this platform, you should probably 
>>> make sure you use the GFP_DMA flag when you allocate memory for your 
>>> buffers.
>>>
>>> Incidentally, you are running this on a >2.6.27 platform?
>>> Also, you aren't using the sdcard driver in dma mode right? There will 
>>> be some pretty serious problems if you are using TS's driver and just 
>>> banging commands directly into the M2M registers.
>>>
>>> I think at 6k bytes per second you might as well not bother with DMA. 
>>>  From memory, 6k transfers at half fifo size (4 bytes) per interrupt is 
>>> 1500 interrupts per second. Keeping the ISR time short, you'll hardly 
>>> notice a performance drop. The main issue, though, is what are the 
>>> peripherals you are addressing? If your peripheral is something like a 
>>> tmp127, then the amount of signaling needed will kill any advantage of a 
>>> dma driver. If you're transferring from a memory chip, then dma is 
>>> probably quite sensible.
>>>
>>> -bms
>>>
>>> pakorn_0608 wrote:
>>>       
>>>> Unfortunately for me,I test it more and check in deep.
>>>> Both of SSPTx and SSPRx are sometime update, not only one like i said 
>>>> before.
>>>>
>>>> For ts7400,I use virt_to_bus only for address that i got from "kmalloc", 
>>>> for SSPDR -address for SSPTX and SSPRx-, I doesn't use it.
>>>>
>>>> On the morning,I tried to use it with SSPDR. There is nothing comtout from 
>>>> SSP.
>>>> I thoght address of SSPDR is physical addresses by default for EP9302 on 
>>>> TS7400.
>>>>
>>>> I try to use bus_to_virt with the memory that use for keeping data from 
>>>> SSPRx. It's the same result.
>>>>
>>>> Anyway,Thanks so much, I learn a lot from you.
>>>>
>>>> Now i looking for mor information about flush cache cpu which another one 
>>>> tell me in another replying.
>>>>
>>>> I'm just read from a bit and it seem have a useful for me.
>>>> I'll try and update to you again if any progress.
>>>>
>>>>
>>>> --- In  Abid Rashid <abidrashid24@> wrote:
>>>>   
>>>>         
>>>>> Â 
>>>>> It is important to map virtual addresses to physical addresses whenever 
>>>>> you work with DMA. (Please note that virt_to_bus might restrict your 
>>>>> cross platform portability). 
>>>>> I am not sure which Addresses are you using for Rx. 
>>>>>
>>>>> Make sure you have mapped your DMA virtual addresses to Rx bus 
>>>>> addresses and vice versa.U might use bus_to_virt on DMA Rx addresses and 
>>>>> use this address to look at the data.
>>>>> If any thing else I cant help....
>>>>> Â 
>>>>> br,
>>>>> Abid
>>>>> --- On Mon, 3/15/10, pakorn_0608 <pakorn_0608@> wrote:
>>>>>
>>>>>
>>>>> From: pakorn_0608 <pakorn_0608@>
>>>>> Subject: [ts-7000] Re: DMA with SSP on TS7400
>>>>> To: 
>>>>> Date: Monday, March 15, 2010, 11:31 PM
>>>>>
>>>>>
>>>>> Â  
>>>>>
>>>>>
>>>>>
>>>>> Thanks a lot, Abid :-)
>>>>>
>>>>> The virt_to_bus it's work for me.
>>>>> bit by bit between SSPtx and SSP_CLK is come out correctly, but, i have 
>>>>> new problem now.
>>>>>
>>>>> Only SSPTx right , SSPRx is sometime right.
>>>>> I use printk" for show what i got from SSPRx by using DMA.
>>>>> On start up module,after enable DMA, the memory of SSPRx that i allocate 
>>>>> for DMA, It's sometime show my default value which i set it up on 
>>>>> initial, but, sometime it show correct value follow by what it get from 
>>>>> SSPRx.
>>>>>
>>>>> I'm finding the way to solve it.
>>>>> Could you have any suggestion to me?
>>>>>
>>>>> Pakorn
>>>>>
>>>>> --- In  .com, Abid Rashid <abidrashid24@ ...> wrote:
>>>>>     
>>>>>           
>>>>>>  
>>>>>> Kmalloc returned addresses need to be mapped to the bus addresses.
>>>>>> Use
>>>>>> bus_addr = virt_to_bus( virt_addr/ *returned from kmalloc*/);
>>>>>> address as the dma destination.
>>>>>> Hope it would help
>>>>>> br,
>>>>>> Abid
>>>>>>
>>>>>> --- On Mon, 3/15/10, pakorn_0608 <pakorn_0608@ ...> wrote:
>>>>>>
>>>>>>
>>>>>> From: pakorn_0608 <pakorn_0608@ ...>
>>>>>> Subject: [ts-7000] DMA with SSP on TS7400
>>>>>> To:  .com
>>>>>> Date: Monday, March 15, 2010, 3:21 AM
>>>>>>
>>>>>>
>>>>>>   
>>>>>>
>>>>>>
>>>>>>
>>>>>> Dear members,
>>>>>>
>>>>>> I'm use DMA on M2M mode with SSP, both of SSPTx and SSPRx for each 
>>>>>> channel.
>>>>>>
>>>>>> I have a bit problem with data that transmit and receive from SSP.
>>>>>>
>>>>>> I use "kmalloc" to get allocate memory address and i write some data 
>>>>>> into that address.
>>>>>> I can write and read correctly by using "printk".
>>>>>>
>>>>>> I'm also use it with SSPDR for transmit data from SPI by "outl" command, 
>>>>>> data come out from SSPTx with clock sync correctly.
>>>>>>
>>>>>> Anyway,It's wrong when i'm using with DMA register.
>>>>>>
>>>>>> For example, DMA M2M0 using with SSPtx, I set DMA register, source 
>>>>>> register with address from kmalloc "0xd120_10eo" , destination address 
>>>>>> SSPDR "0x808A_0008" and BCR by 3.
>>>>>>
>>>>>> There are data come out from SSPtx but it is not right value that it 
>>>>>> should be in memory address shown by "printk".
>>>>>>
>>>>>> Could someone have some suggest to me for using DMA with SSP for 7400 
>>>>>> board?
>>>>>>
>>>>>> ************ *******
>>>>>> example with some coding:
>>>>>> ************ *******
>>>>>>
>>>>>> /* I write it for kernel module*/
>>>>>> ...
>>>>>> char *buffer_dma[ MAX_EP93XX_ DMA_M2M_CHANNELS ];
>>>>>> .
>>>>>> .
>>>>>> .
>>>>>> buffer_dma[0] = kmalloc( size , GFP_KERNEL|GFP_ DMA); /* example size is 
>>>>>> 10*/
>>>>>>
>>>>>> for(i=0;i<10; i++)
>>>>>> {
>>>>>> buffer_dma[0] [i] = i*10;
>>>>>>
>>>>>> printk("Address of buffer_dma[0] [%d] = 0x%lx\n",i,( unsigned 
>>>>>> long)&buffer_ dma[0][i] );
>>>>>> printk("Value of buffer_dma[0] [%d] = %d\n",i,buffer_ dma[0][i] );
>>>>>> }
>>>>>>
>>>>>> /*
>>>>>> I print this value for show address and value
>>>>>> my address for buffer_dma[0] [0] is "0xd120_10eo" and value is 0
>>>>>> next, address for buffer_dma[0] [1] is "0xd120_10e1" and value is 10... 
>>>>>> and other value is shown correctly.
>>>>>>
>>>>>> I also use with SSP
>>>>>>
>>>>>> */
>>>>>>
>>>>>> for(i=0;i<10; i++)
>>>>>> {
>>>>>> outl(buffer_ dma[0][i] , SSPDR );
>>>>>> }
>>>>>>
>>>>>> /*
>>>>>> I'm set SSP 8 bit,
>>>>>> data come out from SSPTx is correctly , compare bit by bit with ssp_clock
>>>>>>
>>>>>> next i'm usongit with DMA M2M for SSPTx
>>>>>>
>>>>>> */
>>>>>>
>>>>>> outl(&buffer_ dma[0][0] , m2m_channel[ channel]. base + M2M_SAR_BASE0) ;
>>>>>> outl( SSPDR , m2m_channel[ channel]. base + M2M_DAR_BASE0) ;
>>>>>> outl(3 , m2m_channel[ channel]. base + M2M_BCR0);
>>>>>>
>>>>>> /*
>>>>>> After that i'm enable DMA 
>>>>>> my data that come out from SSPTx is wrong all,
>>>>>> even i change data in my buffer_dma[0] [i] on above 
>>>>>> data come out from SSPTx is still the same value.
>>>>>> It's not match with it should be in memory address
>>>>>> */
>>>>>>
>>>>>>       
>>>>>>             
>>>>
>>>>
>>>> ------------------------------------
>>>>
>>>> Yahoo! Groups Links
>>>>
>>>>
>>>>
>>>>         
>
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