diff options
author | Drasko DRASKOVIC <drasko.draskovic@gmail.com> | 2011-07-07 17:59:13 +0200 |
---|---|---|
committer | Øyvind Harboe <oyvind.harboe@zylin.com> | 2011-08-09 23:17:28 +0200 |
commit | c18e02387b0628a9ecfc41a65af4802e8b95357e (patch) | |
tree | e5c0ebe5c2bf3ef8ce0ec7bf83b0a6d0b9f5c9a3 /src/target/mips32_pracc.c | |
parent | 1be7163408cc6420d85bf990a2dae46c559a12b1 (diff) |
mips32: Sync Caches to Make Instr Writes Effective
Pprogram that loads another program into memory is actually writing the
D- side cache.
The instructions it has loaded can't be executed until they reach the
I-cache.
After the instructions have been written, the loader should arrange to
write back any containing D-cache line and invalidate any locations
already in the I-cache.
For the MIPS Architecture Release2 cores, we can use synci command
that does this job.
For Release1 we must use "cache" instruction.
Diffstat (limited to 'src/target/mips32_pracc.c')
-rw-r--r-- | src/target/mips32_pracc.c | 239 |
1 files changed, 234 insertions, 5 deletions
diff --git a/src/target/mips32_pracc.c b/src/target/mips32_pracc.c index 1986e5ca..6b43479f 100644 --- a/src/target/mips32_pracc.c +++ b/src/target/mips32_pracc.c @@ -113,6 +113,11 @@ static int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info, static int mips32_pracc_write_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_t *buf); +static int mips32_pracc_sync_cache(struct mips_ejtag *ejtag_info, + uint32_t start_addr, uint32_t end_addr); +static int mips32_pracc_clean_invalidate_cache(struct mips_ejtag *ejtag_info, + uint32_t start_addr, uint32_t end_addr); + static int wait_for_pracc_rw(struct mips_ejtag *ejtag_info, uint32_t *ctrl) { uint32_t ejtag_ctrl; @@ -663,22 +668,246 @@ int mips32_cp0_write(struct mips_ejtag *ejtag_info, return retval; } +/** + * \b mips32_pracc_sync_cache + * + * Synchronize Caches to Make Instruction Writes Effective + * (ref. doc. MIPS32 Architecture For Programmers Volume II: The MIPS32 Instruction Set, + * Document Number: MD00086, Revision 2.00, June 9, 2003) + * + * When the instruction stream is written, the SYNCI instruction should be used + * in conjunction with other instructions to make the newly-written instructions effective. + * + * Explanation : + * A program that loads another program into memory is actually writing the D- side cache. + * The instructions it has loaded can't be executed until they reach the I-cache. + * + * After the instructions have been written, the loader should arrange + * to write back any containing D-cache line and invalidate any locations + * already in the I-cache. + * + * You can do that with cache instructions, but those instructions are only available in kernel mode, + * and a loader writing instructions for the use of its own process need not be privileged software. + * + * In the latest MIPS32/64 CPUs, MIPS provides the synci instruction, + * which does the whole job for a cache-line-sized chunk of the memory you just loaded: + * That is, it arranges a D-cache write-back and an I-cache invalidate. + * + * To employ synci at user level, you need to know the size of a cache line, + * and that can be obtained with a rdhwr SYNCI_Step + * from one of the standard “hardware registers”. + */ +static int mips32_pracc_sync_cache(struct mips_ejtag *ejtag_info, + uint32_t start_addr, uint32_t end_addr) +{ + static const uint32_t code[] = { + /* start: */ + MIPS32_MTC0(15,31,0), /* move $15 to COP0 DeSave */ + MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)), /* $15 = MIPS32_PRACC_STACK */ + MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)), + MIPS32_SW(8,0,15), /* sw $8,($15) */ + MIPS32_SW(9,0,15), /* sw $9,($15) */ + MIPS32_SW(10,0,15), /* sw $10,($15) */ + MIPS32_SW(11,0,15), /* sw $11,($15) */ + + MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)), /* $8 = MIPS32_PRACC_PARAM_IN */ + MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)), + MIPS32_LW(9,0,8), /* Load write start_addr to $9 */ + MIPS32_LW(10,4,8), /* Load write end_addr to $10 */ + + MIPS32_RDHWR(11, MIPS32_SYNCI_STEP), /* $11 = MIPS32_SYNCI_STEP */ + MIPS32_BEQ(11,0,6), /* beq $11, $0, end */ + MIPS32_NOP, + /* synci_loop : */ + MIPS32_SYNCI(0,9), /* synci 0($9) */ + MIPS32_SLTU(8,10,9), /* sltu $8, $10, $9 # $8 = $10 < $9 ? 1 : 0 */ + MIPS32_BNE(8,0,NEG16(3)), /* bne $8, $0, synci_loop */ + MIPS32_ADDU(9, 9, 11), /* $9 += MIPS32_SYNCI_STEP */ + MIPS32_SYNC, + /* end: */ + MIPS32_LW(11,0,15), /* lw $11,($15) */ + MIPS32_LW(10,0,15), /* lw $10,($15) */ + MIPS32_LW(9,0,15), /* lw $9,($15) */ + MIPS32_LW(8,0,15), /* lw $8,($15) */ + MIPS32_B(NEG16(24)), /* b start */ + MIPS32_MFC0(15,31,0), /* move COP0 DeSave to $15 */ + }; + + /* TODO remove array */ + uint32_t *param_in = malloc(2 * sizeof(uint32_t)); + int retval; + param_in[0] = start_addr; + param_in[1] = end_addr; + + retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 2, param_in, 0, NULL, 1); + + free(param_in); + + return retval; +} + +/** + * \b mips32_pracc_clean_invalidate_cache + * + * Writeback D$ and Invalidate I$ + * so that the instructions written can be visible to CPU + */ +static int mips32_pracc_clean_invalidate_cache(struct mips_ejtag *ejtag_info, + uint32_t start_addr, uint32_t end_addr) +{ + static const uint32_t code[] = { + /* start: */ + MIPS32_MTC0(15,31,0), /* move $15 to COP0 DeSave */ + MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)), /* $15 = MIPS32_PRACC_STACK */ + MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)), + MIPS32_SW(8,0,15), /* sw $8,($15) */ + MIPS32_SW(9,0,15), /* sw $9,($15) */ + MIPS32_SW(10,0,15), /* sw $10,($15) */ + MIPS32_SW(11,0,15), /* sw $11,($15) */ + + MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)), /* $8 = MIPS32_PRACC_PARAM_IN */ + MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)), + MIPS32_LW(9,0,8), /* Load write start_addr to $9 */ + MIPS32_LW(10,4,8), /* Load write end_addr to $10 */ + MIPS32_LW(11,8,8), /* Load write clsiz to $11 */ + + /* cache_loop: */ + MIPS32_SLTU(8,10,9), /* sltu $8, $10, $9 : $8 <- $10 < $9 ? */ + MIPS32_BGTZ(8,6), /* bgtz $8, end */ + MIPS32_NOP, + + MIPS32_CACHE(MIPS32_CACHE_D_HIT_WRITEBACK,0,9), /* cache Hit_Writeback_D, 0($9) */ + MIPS32_CACHE(MIPS32_CACHE_I_HIT_INVALIDATE,0,9), /* cache Hit_Invalidate_I, 0($9) */ + + MIPS32_ADDU(9,9,11), /* $9 += $11 */ + + MIPS32_B(NEG16(7)), /* b cache_loop */ + MIPS32_NOP, + /* end: */ + MIPS32_LW(11,0,15), /* lw $11,($15) */ + MIPS32_LW(10,0,15), /* lw $10,($15) */ + MIPS32_LW(9,0,15), /* lw $9,($15) */ + MIPS32_LW(8,0,15), /* lw $8,($15) */ + MIPS32_B(NEG16(25)), /* b start */ + MIPS32_MFC0(15,31,0), /* move COP0 DeSave to $15 */ + }; + + /** + * Find cache line size in bytes + */ + uint32_t conf; + uint32_t dl, clsiz; + + mips32_cp0_read(ejtag_info, &conf, 16, 1); + dl = (conf & MIPS32_CONFIG1_DL_MASK) >> MIPS32_CONFIG1_DL_SHIFT; + + /* dl encoding : dl=1 => 4 bytes, dl=2 => 8 bytes, etc... */ + clsiz = 0x2 << dl; + + /* TODO remove array */ + uint32_t *param_in = malloc(3 * sizeof(uint32_t)); + int retval; + param_in[0] = start_addr; + param_in[1] = end_addr; + param_in[2] = clsiz; + + retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 3, param_in, 0, NULL, 1); + + free(param_in); + + return retval; +} + + int mips32_pracc_write_mem(struct mips_ejtag *ejtag_info, uint32_t addr, int size, int count, void *buf) { + int retval; + switch (size) { case 1: - return mips32_pracc_write_mem8(ejtag_info, addr, count, (uint8_t*)buf); + retval = mips32_pracc_write_mem8(ejtag_info, addr, count, (uint8_t*)buf); + break; case 2: - return mips32_pracc_write_mem16(ejtag_info, addr, count,(uint16_t*)buf); + retval = mips32_pracc_write_mem16(ejtag_info, addr, count,(uint16_t*)buf); + break; case 4: if (count == 1) - return mips32_pracc_write_u32(ejtag_info, addr, (uint32_t*)buf); + { + retval = mips32_pracc_write_u32(ejtag_info, addr, (uint32_t*)buf); + } else - return mips32_pracc_write_mem32(ejtag_info, addr, count, (uint32_t*)buf); + { + retval = mips32_pracc_write_mem32(ejtag_info, addr, count, (uint32_t*)buf); + } + break; + default: + retval = ERROR_FAIL; } - return ERROR_OK; + /** + * If we are in the cachable regoion and cache is activated, + * we must clean D$ + invalidate I$ after we did the write, + * so that changes do not continue to live only in D$, but to be + * replicated in I$ also (maybe we wrote the istructions) + */ + uint32_t conf = 0; + int cached = 0; + + mips32_cp0_read(ejtag_info, &conf, 16, 0); + + switch (KSEGX(addr)) + { + case KUSEG: + cached = (conf & MIPS32_CONFIG0_KU_MASK) >> MIPS32_CONFIG0_KU_SHIFT; + break; + case KSEG0 : + cached = (conf & MIPS32_CONFIG0_K0_MASK) >> MIPS32_CONFIG0_K0_SHIFT; + break; + case KSEG1: + /* uncachable segment - nothing to do */ + break; + case KSEG2: + case KSEG3: + cached = (conf & MIPS32_CONFIG0_K23_MASK) >> MIPS32_CONFIG0_K23_SHIFT; + break; + default: + /* what ? */ + break; + } + + /** + * Check cachablitiy bits coherency algorithm - + * is the region cacheable or uncached. + * If cacheable we have to synchronize the cache + */ + if (cached == 0x3) + { + uint32_t start_addr, end_addr; + uint32_t rel; + + start_addr = addr; + end_addr = addr + count * size; + + /** select cache synchronisation mechanism based on Architecture Release */ + rel = (conf & MIPS32_CONFIG0_AR_MASK) >> MIPS32_CONFIG0_AR_SHIFT; + switch (rel) + { + case MIPS32_ARCH_REL1 : + /* MIPS32/64 Release 1 - we must use cache instruction */ + mips32_pracc_clean_invalidate_cache(ejtag_info, start_addr, end_addr); + break; + case MIPS32_ARCH_REL2 : + /* MIPS32/64 Release 2 - we can use synci instruction */ + mips32_pracc_sync_cache(ejtag_info, start_addr, end_addr); + break; + default : + /* what ? */ + break; + } + } + + return retval; } static int mips32_pracc_write_mem32(struct mips_ejtag *ejtag_info, uint32_t addr, int count, uint32_t *buf) |