On Monday 16 May 2011 12:21 AM, Wolfgang Denk wrote:
Dear Aneesh V,
In message1305202276-27784-4-git-send-email-aneesh@ti.com you wrote:
Add a framework for layered cache maintenance
- separate out SOC specific outer cache maintenance from maintenance of caches known to CPU
Add generic ARMv7 cache maintenance operations that affect all caches known to ARMv7 CPUs. For instance in Cortex-A8 these opertions will affect both L1 and L2 caches. In Cortex-A9 these will affect only L1 cache
D-cache operations supported:
- Invalidate entire D-cache
Needed before enabling the caches.
- Invalidate D-cache range
Needed if you are doing DMA.
- Flush(clean& invalidate) entire D-cache
Needed before Linux before disabling the caches.
- Flush D-cache range
Needed in case of DMA out.
How much of this is actually needed in the context of U-Boot?
Please see above. As far as I know OMAP doesn't do DMA in U-Boot.
...
- for (way = num_ways - 1; way>= 0 ; way--)
for (set = num_sets - 1; set>= 0; set--) {setway = (level<< 1) | (set<< log2_line_len) |(way<< way_shift);/* Invalidate data/unified cache line by set/way */asm volatile (" mcr p15, 0, %0, c7, c6, 2": : "r" (setway));}Braces needed for multiline for(). Please fix globally.
Ok.
...
- if (operation == ARMV7_DCACHE_INVAL_ALL)
v7_inval_dcache_level_setway(level, num_sets, num_ways,way_shift, log2_line_len);- else if (operation == ARMV7_DCACHE_CLEAN_INVAL_ALL)
v7_clean_inval_dcache_level_setway(level, num_sets, num_ways,way_shift, log2_line_len);Braces needed for multiline statements. Please fix globally.
- for (mva = start; mva< stop; mva = mva + line_len)
/* DCCIMVAC - Clean& Invalidate data cache by MVA to PoC */asm volatile ("mcr p15, 0, %0, c7, c14, 1" : : "r" (mva));And again etc. etc.
...
+void invalidate_dcache_all(void) +{ +}
+void flush_dcache_all(void) +{ +}
+void invalidate_dcache_range(unsigned long start, unsigned long stop) +{ +}
+void flush_dcache_range(unsigned long start, unsigned long stop) +{ +}
+void arm_init_before_mmu(void) +{ +}
+void flush_cache(unsigned long start, unsigned long size) +{ +}
Please do not add dead code. I consider it misleading to have functions which promise to perform something, and actually do nothing.
These are empty only in the else part of an #ifdef. When cache support is compiled out these need to be empty.
best regards, Aneesh