[Qemu-devel] Question

[Qemu-devel] Question

[Mohammed Al-Saleh]

Hi all;

I know that cd_read_sector function (which is called from 
ide_atapi_cmd_reply_end) in ide.c will copy data from the CD-ROM to an 
intermediate buffer, but I could not find out when this buffer is written to 
the RAM. All of what I can see is after reading data, ide_transfer_start and 
de_set_irq are called, but then what? how data will go to the RAM? if data 
will be copied to the RAM implicitly through the interrupt, then where can I 
find the ultimate function that copies the data to the RAM.
Can any body answer my question? it will be very appreciated.

Thanks,

...Mohammed


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[Qemu-devel] CD-ROM Reading

[Mohammed Al-Saleh]

Hi all; 

I really need help from you.
I know that cd_read_sector function (which is called from 
ide_atapi_cmd_reply_end) in ide.c will copy data from the CD-ROM to an 
intermediate buffer, but I could not find out when this buffer is written to 
the RAM. All of what I can see is after reading data, ide_transfer_start and 
de_set_irq are called, but then what? how data will go to the RAM? if data 
will be copied to the RAM implicitly through the interrupt, then where can I 
find the ultimate function that copies the data to the RAM. 
Can any body answer my question? it will be very appreciated. 

Thanks, 

...Mohammed 


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Re: [Qemu-devel] CD-ROM Reading

[Samuel Thibault]

Mohammed Al-Saleh, le Thu 31 Jul 2008 15:46:13 -0600, a écrit :
> where can I find the ultimate function that copies the data to the    
> RAM.                                                                  

Are you looking for the call to cpu_physical_memory_write() in
dma_buf_rw?

Samuel

[Qemu-devel] CD-ROM Reading

[Mohammed Al-Saleh]

Hi all;


Two methods to read from the CD-ROM depending on the following condition in 
the hw/ide.c file:

if (s->atapi_dma) {
        ide_atapi_cmd_read_dma(s, lba, nb_sectors, sector_size);
} else {
        ide_atapi_cmd_read_pio(s, lba, nb_sectors, sector_size);
}

in the first case (ide_atapi_cmd_read_dma), it is obvious how data will be 
read from the CD-ROM into an io_buffer and then to the RAM. But in the 
second case(ide_atapi_cmd_read_pio), it is obvious how that data will be 
read from the CD-ROM into an io_buffer, but it is not obvious how or when 
the data will written to the RAM. I know that cd_read_sector function (which 
is called from ide_atapi_cmd_reply_end) in ide.c will copy data from the CD-
ROM to an intermediate buffer, but I could not find out when this buffer is 
written to the RAM. All of what I can see is after reading data, 
ide_transfer_start and ide_set_irq are called, but then what? how data will 
go to the RAM? if data will be copied to the RAM implicitly through the 
interrupt, then where can I find the ultimate function that copies the data 
to the RAM.

Can any body answer my question? it will be very appreciated.

Thanks,

...Mohammed

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