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Hi, If I'm not mistaken, when the C6415 connected to a host system as a PCI target device, the host or any other master device on the PCI bus can access to C6415's memory. By setting the DSPP register, theoretically (and practically??) the bus master can access to all visible range of the DSP's memory, including L2 (internal SRAM). This can be done by setting the DSPP to zero -> corresponding to L2. Normally, when booting C6415 through PCI, it is desired for the host to copy the dsp program into L2 and SDRAM. So, my question is, after the PCI boot process done, is there any way to prevent "unauthorized access" to L2 area (internal SRAM) by other PCI Bus Master devices on the PCI bus ? Is there any "memory protection scheme" for the C6415 ? I'm worried that any wrong acess to the L2 area might corrupt or even wipe out the code reside in L2!!! (okay...this shouldn't happens in normal circumtances).. Thanks.... -- BehCS |
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Memory Protection on C6415 ?
Started by ●December 10, 2003
Reply by ●December 10, 20032003-12-10
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Hi, I completely agree with your description, as we are also using the 6415 DSP in a PCI environment. Unfortunately, I don't see any possibility to block "external" PCI accesses. I suppose that you want to keep the possibility to use the PCI bus for some data transfer, so you cannot "disable" it completely (no idea if this is possible). You could perhaps have a look at the PCI configuration registers of the DSP. These are filled with default values, but it is possible to customize them at startup by storing custom values in an EEPROM. It is perhaps possible to disable some capabilities, but if yes, it will of course prevent you to download the code through PCI. (I have not investigated what is placed in these regs). Cheers J-F --- In , "behcsiang" <behcs@w...> wrote: > Hi, > > If I'm not mistaken, when the C6415 connected to > a host system as a PCI target device, the host or any > other master device on the PCI bus can access to C6415's > memory. > > By setting the DSPP register, theoretically (and practically??) > the bus master can access to all visible range of the > DSP's memory, including L2 (internal SRAM). This can be > done by setting the DSPP to zero -> corresponding to L2. > > Normally, when booting C6415 through PCI, it is > desired for the host to copy the dsp program into L2 > and SDRAM. > > So, my question is, after the PCI boot process done, > is there any way to prevent "unauthorized access" to L2 > area (internal SRAM) by other PCI Bus Master devices on > the PCI bus ? Is there any "memory protection scheme" > for the C6415 ? I'm worried that any wrong acess > to the L2 area might corrupt or even wipe out the code > reside in L2!!! (okay...this shouldn't happens in normal > circumtances).. > > Thanks.... > > -- > BehCS |
