PowerQUICC Processors中的主题 Re: Enabling Data Cache in MPC5675K

Enabling Data Cache in MPC5675K

komodo — Wed, 12 Jun 2013 20:37:52 GMT

Hello All,

Would like to enable the data cache at startup assembly file. Can anyone guide me how to access the control registers and what are the steps I need to follow?

Thanks in advance for your time and help!

Re: Enabling Data Cache in MPC5675K

marius_grigoras — Thu, 13 Jun 2013 10:36:43 GMT

Hi,

Taking a look in the RM for e200 core [1] , this should be something like:

asm ("mfspr	3,1010");	/* enable d-cache */
asm ("ori		3, 3, 0x0001");
asm ("mtspr	1010,3");

asm ("mfspr	3,1013");	/* enable branch prediction in BUCSR */
asm ("ori		3, 3, 0x0001");
asm ("mtspr	1013,3");

	asm ("isync");
	asm ("msync");

Note that 1010 is an index for L1CSR0 core register and 1013 is an index for BUCSR core register.

Regards,

Marius

[1] http://www.freescale.com/files/32bit/doc/ref_manual/e200z760RM.pdf

Re: Enabling Data Cache in MPC5675K

komodo — Thu, 13 Jun 2013 13:37:10 GMT

Hi,

Thanks for the info!

In my task I have to specify a portion of SRAM for Data as DATA CACHE using MMU TLB table. I am not sure how MMU works with PPC. If any help to configure the memory as a data cacheable would be appreciated. Something like how to assign the RAM memory and command the controller that is use as Internal data cache.

Thanks.

Re: Enabling Data Cache in MPC5675K

marius_grigoras — Thu, 13 Jun 2013 13:51:51 GMT

Hi,

Please find below an example about how can configure cacheable a TLB entry:

// 1GB TLB entry 1: 0x00000000 - 0x3FFFFFFF; cacheable
asm ("lis		5, 0x1001");
asm ("ori		5, 5, 0x0000");
asm ("mtspr	624, 5");

asm ("lis		5, 0x8000");
asm ("ori		5, 5, 0x0A00");
asm ("mtspr	625, 5");

asm ("lis		5, 0x0000");
asm ("ori		5, 5, 0x0000	");
asm ("mtspr	626, 5");

asm ("lis		5, 0x0000");
asm ("ori		5, 5, 0x0015");
asm ("mtspr	627, 5");

asm ("tlbwe");

asm ("msync");

asm ("isync");

For SRAM initialization you can take a look in the processor Reference Manual.

Regards,

Marius

Re: Enabling Data Cache in MPC5675K

komodo — Thu, 13 Jun 2013 13:55:07 GMT

Thank you very much! This helps me.