Hi,
I think the implementation of setup_common_caches() in file
cpu_setup_6xx.S; not according to the spec as far as MPC74xx concerns.
Looking in the spec (MPC7450 RISC Microprocessor Family Reference
Manual, MPC7450UM Rev. 5 1/2005) section 3.4.1.5 L1 Instruction and Data
Cache Flash Invalidation it says:
"Note that HID0[ICFI] and HID0[DCFI] must not both be set with the same
mtspr instruction, due to the synchronization requirements described in
Section 2.4.2.4.1, "Context Synchronization."
But in the code those two do set together.
Also, the same section says:
"An isync must precede the setting of the HID0[ICFI] in order for the
setting to take effect."
But in the code, only 'sync' can be found.
/* Enable caches for 603's, 604, 750 & 7400 */
setup_common_caches:
mfspr r11,SPRN_HID0
andi. r0,r11,HID0_DCE
ori r11,r11,HID0_ICE|HID0_DCE
ori r8,r11,HID0_ICFI
bne 1f /* don't invalidate the D-cache
*/
ori r8,r8,HID0_DCI /* unless it wasn't enabled */
1: sync
mtspr SPRN_HID0,r8 /* enable and invalidate caches
*/
^^^^^^^^^^^^^^^^^^^ Here we set both ICFI and DCFI in the same
mtspr instruction. Also, no isync before setting ICFI.
sync
mtspr SPRN_HID0,r11 /* enable caches */
sync
isync
blr
Please advice.
Thanks.
