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As per Freescale chip errata, disable buffered writes.

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This commit is contained in:
Eric Norum
2009-06-02 21:13:44 +00:00
parent 222f86844e
commit 14eefeabaa
2 changed files with 19 additions and 3 deletions
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4
c/src/lib/libbsp/m68k/uC5282/ChangeLog
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@@ -1,3 +1,7 @@
2009-06-02 Eric Norum <norume@aps.anl.gov>
* startup/bspstart.c: Turn off buffered writes.
2009-04-28 Chris Johns <chrisj@rtems.org>
* start/start.S: Update for boot_card command line change.

18
c/src/lib/libbsp/m68k/uC5282/startup/bspstart.c
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@@ -59,6 +59,20 @@ extern char RamBase[];
* should be followed immediately by a NOP instruction. This avoids the cache
* corruption problem.
* DATECODES AFFECTED: All
*
*
* Buffered writes must be disabled as described in "MCF5282 Chip Errata",
* MCF5282DE, Rev. 6, 5/2009:
* SECF124: Buffered Write May Be Executed Twice
* Errata type: Silicon
* Affected component: Cache
* Description: If buffered writes are enabled using the CACR or ACR
* registers, the imprecise write transaction generated
* by a buffered write may be executed twice.
* Workaround: Do not enable buffered writes in the CACR or ACR registers:
* CACR[8] = DBWE (default buffered write enable) must be 0
* ACRn[5] = BUFW (buffered write enable) must be 0
* Fix plan: Currently, there are no plans to fix this.
*/
#define m68k_set_cacr_nop(_cacr) asm volatile ("movec %0,%%cacr\n\tnop" : : "d" (_cacr))
#define m68k_set_cacr(_cacr) asm volatile ("movec %0,%%cacr" : : "d" (_cacr))
@@ -69,7 +83,7 @@ extern char RamBase[];
* Read/write copy of cache registers
* Split instruction/data or instruction-only
* Allow CPUSHL to invalidate a cache line
* Enable buffered writes
* Disable buffered writes
* No burst transfers on non-cacheable accesses
* Default cache mode is *disabled* (cache only ACRx areas)
*/
@@ -77,7 +91,6 @@ uint32_t mcf5282_cacr_mode = MCF5XXX_CACR_CENB |
#ifndef RTEMS_MCF5282_BSP_ENABLE_DATA_CACHE
MCF5XXX_CACR_DISD |
#endif
MCF5XXX_CACR_DBWE |
MCF5XXX_CACR_DCM;
uint32_t mcf5282_acr0_mode = 0;
uint32_t mcf5282_acr1_mode = 0;
@@ -243,7 +256,6 @@ void bsp_start( void )
mcf5282_acr0_mode = MCF5XXX_ACR_AB((uint32_t)RamBase) |
MCF5XXX_ACR_AM((uint32_t)RamSize-1) |
MCF5XXX_ACR_EN |
MCF5XXX_ACR_BWE |
MCF5XXX_ACR_SM_IGNORE;
m68k_set_acr0(mcf5282_acr0_mode);